Shijie You, Xiaobo Gong, Wei Wang et al.

Advanced Energy Materials • 2015

Microbial fuel cell (MFC) can generate electricity from organic substances based on anodic electrochemically active microorganisms and cathodic oxygen reduction reaction (ORR), thus exhibiting promising potential for harvesting electric energy from organic wastewater. The ORR performance is crucial to both power production efficiency and overall cost of MFC. A new type of metal‐organic‐framework‐derived electrocatalysts containing cobalt and nitrogen‐doped carbon (CoNC) is developed, which is effective to enhance activity, selectivity, and stability toward four‐electron ORR in pH‐neutral electrolyte. When glucose is used as the substrate, the maximum power density of 1665 mW m −2 is achieved for the optimized CoNC pyrolyzed at 900 °C, which is 39.8% higher than that of 1191 mW m −2 for commercial Pt/C catalyst in the single‐chamber MFC. The improved performance of CoNC catalyst can be attributed to large surface area, microporous nature, and the involvement of nitrogen‐coordinated cobalt species. These properties enable the efficient ORR by increasing the active sites and enhancing mass transfer of oxygen and protons at “water‐flooding” three‐phase boundary where ORR occurs. This work provides a proof‐of‐concept demonstration of a noble‐metal‐free high‐efficiency and cost‐effective ORR electrocatalyst for effective recovery of electricity from biomass materials and organic wastewater in MFC.

David Tucker, Comas Haynes, Patrick Geoghegan

ASME 2015 13th International Conference on Fuel Cell Science, Engineering and Technology • 2015

Solid oxide fuel cell (SOFC)/ gas turbine (GT) hybrid systems possess the capacity for unprecedented performances, such as electric efficiencies nearly twice that of conventional heat engines at variable scale power ratings inclusive of distributed generation. Additionally, these hybrids can have excellent operational flexibility with turndowns possibly as great as 85%. There are, however, developmental needs such as turbomachinery characterization and re-design. A leading example is that of greater propensity to have occurrences of stall-surge given the significantly different operating environment in contrast to conventional heat engines. Additionally, dynamic variation in power generation has to be done with significant a priori insight to avoid thermomechanical threats to cell stack and turbomachinery. State-of-the-art approaches involving hardware-in-the-loop simulation and, ultimately, additive manufacturing are being pursued to enable such characterization and re-design considerations given variable and dynamic operability requirements. Compressor performance in hybrid systems has been characterized at the United States National Energy Technology Laboratory (NETL), inclusive of a capability of feed forward hardware-in-the-loop simulation of hybrid systems under dynamic conditions and a capability of replacing turbine and compressor components at a relatively low cost. This paper highlights some of the simulation results, and the net result is an approach that addresses hybrid system developmental needs for accommodating generation transients.

Emiliano Pipitone, Stefano Beccari, Giuseppe Genchi

Journal of Engineering for Gas Turbines and Power • 2017

Internal combustion engine development focuses mainly on two aspects: fuel economy improvement and pollutant emissions reduction. As a consequence, light duty spark ignition (SI) engines have become smaller, supercharged, and equipped with direct injection and advanced valve train control systems. The use of alternative fuels, such as natural gas (NG) and liquefied petroleum gas (LPG), thanks to their lower cost and environmental impact, widely spread in the automotive market, above all in bifuel vehicles, whose spark ignited engines may run either with gasoline or with gaseous fuel. The authors in previous works experimentally tested the strong engine efficiency increment and pollutant emissions reduction attainable by the simultaneous combustion of gasoline and gaseous fuel (NG or LPG). The increased knock resistance, obtained by the addition of gaseous fuel to gasoline, allowed the engine to run with stoichiometric mixture and best spark timing even at full load. In the present work, the authors extended the research by testing the combustion of gasoline–NG mixtures, in different proportions, in supercharged conditions, with several boost pressure levels, in order to evaluate the benefits in terms of engine performance, efficiency, and pollutant emissions with respect to pure gasoline and pure NG operation. The results indicate that a fuel mixture with a NG mass percentage of 40% allows to maximize engine performance by adopting the highest boost pressure (1.6 bar), while the best efficiency would be obtained with moderate boosting (1.2 bar) and NG content between 40% and 60% in mass.

Elif Durna Pişkin, Nevim Genç

Journal of Chemical Technology & Biotechnology • 2023

Abstract BACKGROUND The high organic load and low biodegradability of the effluent from baker's yeast production limit its use as a substrate in microbial fuel cell (MFC) systems. In this study, baker's yeast production wastewater was used as a substrate in the anode chamber to assess the impact of various pretreatment methods [dilution, microwave (MW), acidic‐thermal, basic‐thermal and ultrasound (US)] on electricity generation and waste treatment. Additionally, azo dye was used as an electron acceptor at the cathode. Power density and coulomb efficiency were evaluated for electricity generation, and chemical oxygen demand (COD) removal and azo dye removal parameters were evaluated for treatability. RESULTS The maximum power densities obtained were 83.53, 46.54, 19.41, 67.40, 41 and 33 mW m −2 for MW, acidic thermal, alkaline‐thermal and US pretreatments, diluted raw and raw wastewater, respectively. To determine the most suitable pretreatment method, PROMETHEE was performed using the criteria of maximum power density, COD removal, azo dye removal, coulombic efficiency and pretreatment cost. The most suitable method was found to be MW pretreatment. The order of the alternatives was found to be MW > US > acidic/thermal > diluted raw > raw > alkaline/thermal. With the MW pretreatment, 81.34% azo dye removal, 5 g L −1 COD removal, 0.27% coulombic efficiency and €0.284 L −1 pretreatment cost were obtained. CONCLUSION The most suitable pretreatment method to be applied to wastewater for the treatment of baker's yeast production wastewater and high energy production was determined as MW using the PROMETHEE approach. © 2023 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI).

Aslan Kosakian, Fei Wei, Jeremy (Jie) Zhou et al.

ECS Meeting Abstracts • 2023

Water management is crucial for achieving high-performance proton-exchange-membrane fuel cells (PEMFCs), as it helps keep the electrolyte hydrated while avoiding performance degradation and cell shutdown due to liquid-water accumulation. According to ex-situ measurements [1-3], accumulation of liquid water in gas-diffusion layers (GDLs) of PEMFCs is a transient process that can be accompanied with oscillations in capillary pressure and saturation. To understand how liquid-water accumulation and drainage impact PEMFC performance hysteresis and stability, a transient cell-level model that accounts for electrode structure and composition and is computationally efficient is needed. A number of volume-averaged models that describe the electrode structure through pore-size distribution have been developed in the past [4-7], but they are steady-state and thus cannot predict dynamic PEMFC performance. Existing transient models have also not been used to analyze cyclic liquid-water accumulation [8-10]. In this work, a transient two-phase 2D PEMFC model is developed in the open-source fuel-cell modeling software OpenFCST [11] and applied to analyze PEMFC performance hysteresis and stability during liquid-water accumulation and drainage cycles. The model accounts for the electrode structure through a mixed-wettability pore-size-distribution framework and incorporates a novel dynamic boundary condition to describe the experimentally observed cyclic liquid-water accumulation. Results of the numerical simulations are compared to transient current-density and resistance data at two polarization scan rates and during voltage steps measured with an in-house single-channel cell at multiple operating conditions. This work demonstrates how high breakthrough pressure and rapid liquid-water removal from GDLs may cause highly unstable fuel-cell operation with strong hysteresis and oscillations in the polarization curve (such as those in the figure below) that closely resemble experimental reports [12]. Numerical simulations also reveal the existence of a scan rate that maximizes polarization hysteresis due to a match between the time scale of GDL flooding and of a complete voltage sweep. Fast-scan polarization sweeps are shown most suitable for detecting catalyst-layer flooding that depends on its wettability and occurs within single seconds in contrast to GDL flooding that takes hundreds of seconds. Overall, this work brings more attention to the transient analysis of fuel-cell performance under wet conditions. Figure: Polarization-curve oscillations caused by cyclic liquid-water removal from the cathode GDL. Similar fluctuations have been experimentally observed in [12]. Transient graphs show the dynamics of current density and cathode GDL saturation. Operating conditions are 60 °C, 90% RH, 1.5 atm; scan rate is 0.5 mV/s. References J. T. Gostick et al., J. Electrochem. Soc. 157.4 (2010) C. Quesnel et al., J. Phys. Chem. C 119.40 (2015) D. Ziegler, B.Sc. thesis, Hochschule Mannheim / University of Alberta (2020) A. Z. Weber et al., J. Electrochem. Soc. 151.10 (2004) M. Eikerling, J. Electrochem. Soc. 153.3 (2006) V. Mulone and K. Karan, Int. J. Hydrog. Energy 38.1 (2013) Zhou et al., J. Electrochem. Soc. 164.6 (2017) R. J. Balliet and J. Newman, J. Electrochem. Soc. 158.8 (2011) I. V. Zenyuk et al., J. Electrochem. Soc. 163.7 (2016) A. Goshtasbi et al., J. Electrochem. Soc. 166.7 (2019) M. Secanell et al. ECS Transactions 64.3 (2014) C. Ziegler and D. Gerteisen, J. Power Sources 188.1 (2009) Figure 1

Scott A Mauger, K.C. Neyerlin, Ami C. Yang-Neyerlin et al.

ECS Meeting Abstracts • 2017

Roll-to-roll (R2R) coating is the most economical and highest throughput method for producing fuel cell electrodes. R2R coating encompasses many different methodologies to create uniform films on a moving web substrate (Figure 1a). One of the methodologies, gravure coating, uses rollers patterned with grooves or wells that fill with liquid, which is then transferred from the gravure roller to the substrate when the come into contact, creating a film (Figure 1b). Here, we present our work that utilized gravure coating to create highly uniform proton exchange membrane fuel cell electrodes on diffusion media. In addition to X-ray fluorescence, we utilized an in-line reactive impinging flow technique, developed by NREL, to characterize electrode uniformity. 1 Additionally, we explored the materials-process-performance relationships associated with R2R coating of PEMFC electrodes. Lab-scale fabrication of electrodes sequentially builds up the thickness of the electrode through spraying multiple layers of a dilute dispersion to create a homogenous electrode. In contrast, with gravure coating a concentrated dispersion is coated, forming a thick, wet film that dries to form the electrode. Using several electrochemical diagnostic techniques 2,3 and electron microscopy, we explored the foundational relationships between ink formulation, coating physics, drying conditions, and substrate to understand how parameters such as ionomer-to-carbon ratio, solvent blend, and diffusion media porosity influenced electrode morphology, concentration gradients of materials, and critical MEA performance parameters such as surface area, activity, and oxygen transport (Figure 1c). Figure 1 (a) NREL’s roll-to-roll coating station, (b) illustration of the gravure coating processes, and (c) polarization curves and electrochemical impedance spectra comparing spray-coated and roll-to-roll coated electrodes. Acknowledgements: This work was supported by the U.S. Department of Energy under Contract No. DE-AC36-08GO28308 with the National Renewable Energy Laboratory. Funding provided by U.S. Department of Energy Office of Energy Efficiency and Renewable Energy Fuel Cell Technology Office, program manager Nancy Garland. S.A.M. would also like to thank Guido Bender and Brian Green for assistance with reactive impinging flow measurments. 1. Zenyuk, I. V., Englund, N., Bender, G., Weber, A. Z. & Ulsh, M. Reactive impinging-flow technique for polymer-electrolyte-fuel-cell electrode-defect detection. J. Power Sources 332, 372–382 (2016). 2. Thompson, E. L. & Baker, D. Proton Conduction on Ionomer-Free Pt Surfaces. ECS Trans. 41, 709–720 (2011). 3. Neyerlin, K. C. et al. New Insights from Electrochemical Diagnostics Pertaining to the High Current Density Performance of Pt-Based Catalysts. 230th ECS Meeting Abstracts (2016). Figure 1

Karan Singh, Abhimanyu Sharma, Jaspreet Singh et al.

Resource Recovery from Industrial Wastewater through Microbial Electrochemical Technologies • 2024

Utilizing different catholytes in microbial fuel cells (MFCs) has demonstrated considerable potential in the remediation of industrial effluents. The choice of a catholyte is crucial in enhancing the performance and efficiency of MFCs, which in turn has a significant influence on the overall wastewater treatment process. Several catholytes, such as oxygen, ferricyanide, and other redox mediators, have been discovered and utilized to enhance electron transfer kinetics and optimize power production in MFCs. The selection of an appropriate catalyst is determined by factors such as the distinctive composition of wastewater, the desired level of treatment effectiveness, and the economic viability. The highest mean power output was attained by combining ferricyanide with a multilayer structure, such as a hexacyanoferrate cathode. Utilizing several catholytes in MFCs is an innovative and encouraging approach for treating industrial wastewater. The potential of MFCs to provide sustainable and efficient solutions for industrial wastewater treatment is increasing as catalyst selection, system design, and operating procedures continue to progress. Fuel cells are anticipated to operate within the mesophilic temperature range, which is optimal for wastewater purification.

Sarmistha Baruah, Akshai Kumar, Nageswara Rao Peela

ECS Meeting Abstracts • 2024

Sustainable energy generation has recently gained popularity due to the rising energy demand and environmental concerns caused by conventional non-renewable energy sources. In the context of portable electronics, and microsystems all would require fully integrated, dependable power generation. In this regard, paper-based microfluidic fuel cells (PMFC), have drawn significant attention. By utilizing the inherent properties of paper substrate and microfluidic reactant streams, this fuel cell device takes away the requirement of any membranes or external pumps that are necessary for conventional FCs. In co-laminar flow, where PMFCs work, a unique diffusive mixing area serves as a pseudo-membrane by preventing the convective mixing of two reactants. The reactants flow by capillary action with the aid of an absorbent pad. While the ions transport across the channel through the mixing zone. This not only makes the pumping of fluids into paper-based systems simpler, but also provides numerous other benefits such as cost-effectiveness, simplicity in manufacturing, ease of disposal, and portability over traditional FCs. In this work, we synthesized a Ni-Co catalyst encapsulated within zeolite 4A (also known as LTA) via a hydrothermal synthesis route. The resulting catalyst exhibited better catalytic activity of 12.1 mA cm -2 at 1.12 V vs Ag/AgCl and retained remarkable stability (~77%) even after 1000 cycles CV test in 0.1 M KOH + 1 M methanol. By utilizing this catalyst as anode and Pt/AC (5 wt%) as cathode, we demonstrate a Y-shaped membraneless PMFC using Whatman filter paper grade 41 as paper substrate. It has been shown that the device can deliver power densities in the range of 2 - 10 mW cm -2 (Fuel: methanol, Oxidant: KMnO 4 ), and can retain power output for at least 30 min. Additionally, the power of the cell can easily be raised by connecting two or more cells in series, making these PMFCs suitable for micro/nano power generation systems. Keywords: Fuel cell, Microfluidic, Paper substrate, Co-laminar flow, Zeolite 4A.

Edson Baltazar Estrada-Arriaga, Yvonne Guillen-Alonso, Cornelio Morales-Morales et al.

Water Science and Technology • 2017

Two different air-cathode stacked microbial fuel cell (MFC) configurations were evaluated under continuous flow during the treatment of municipal wastewater and electricity production at a hydraulic retention time (HRT) of 3, 1, and 0.5 d. Stacked MFC 1 was formed by 20 individual air-cathode MFC units. The second stacked MFC (stacked MFC 2) consisted of 40 air-cathode MFC units placed in a shared reactor. The maximum voltages produced at closed circuit (1,000 Ω) were 170 mV for stacked MFC 1 and 94 mV for stacked MFC 2. Different power densities in each MFC unit were obtained due to a potential drop phenomenon and to a change in chemical oxygen demand (COD) concentrations inside reactors. The maximum power densities from individual MFC units were up to 1,107 mW/m2 for stacked MFC 1 and up to 472 mW/m2 for stacked MFC 2. The maximum power densities in stacked MFC 1 and MFC 2 connected in series were 79 mW/m2 and 4 mW/m2, respectively. Electricity generation and COD removal efficiencies were reduced when the HRT was decreased. High removal efficiencies of 84% of COD, 47% of total nitrogen, and 30% of total phosphorus were obtained during municipal wastewater treatment.

Mahdi Azimi Gandomani, Hassan Ghassemi, Guanghua He

Polish Maritime Research • 2024

Abstract This research emphasizes the importance of optimal design for tidal turbines under various ducts and blade sections to enhance efficiency. A Reynolds-Averaged Navier-Stokes (RANS) solver with turbulence model is used to investigate the performance of horizontal-axis tidal current turbines (HATCT) under different ducts and blade sections. Analyses were conducted using various meshes and, in several stages, to ensure the accuracy of the results. Six types of different blades sections and winglets are selected and the numerical results of thrust, torque and power coefficients are compared. demonstrating the accepTable accuracy of this analytical method. It is indicated that the effect of the winglet caused to increase the power coefficient. The numerical results were compared and validated with experimental data and found in good agreement. Finally, the effect of the different duct shapes with turbine type 1 at TSR = 5 is obtained with significant results of the power coefficient.

K Lee, A Yamawaki

Journal of Physics: Conference Series • 2023

Abstract We are developing a game programming software library so that high-level synthesis, HLS, can automatically generate high-performance and low-power hardware modules. A mobile terminal with a user-available reconfigurable device like Field programmable gate array, FPGA, we have proposed will efficiently perform game application built in HLS-oriented game library instead of power-hungry software execution. The dynamic hardware reconfiguration on a single FPGA can execute many kinds of game applications. Our previous research has developed software description methods for two-background scrolling in HLS-oriented game programming library by using two methods. They are (1) Full-parallel equips plural physical ports loading background images individually making HLS hardware execute the entire process parallelly increasing the amount of hardware: (2) Semi-parallel shares the single port loading background images serially, suppressing the hardware growth while achieving moderate performance by overlapping operation phases. We investigate two methods about execution time and power efficiency on the parallax scrolling with 2 to 4 backgrounds. The execution times of full-parallel hardware at 100MHz clock frequency are constantly about 9.65 [ms] while those of semi-parallel are 28, 38 and 47 [ms]. The PC at 3.2 GHz shows 78, 98 and 105 [ms] respectively as well. The power efficiencies about the full-parallel estimated considering hardware enlargement are 167, 208 and 112 times compared to the software execution in the PC, while those of semi-parallel are 94, 88 and 75 times. This fact indicates that the full-parallel is better strategy for parallax background scrolling in this case although more hardware resource are invested.

Kantipudi V. V. S. R. Chowdary, Kundan Kumar, Byamakesh Nayak et al.

Vehicles • 2023

Electric vehicles are becoming more popular as an alternative to conventional gasoline-powered vehicles. In order to strengthen charging infrastructure, dynamic wireless charging (DWC) is a promising technology through which the vehicle battery can be continuously charged while the vehicle is in motion. The main challenge of the DWC system is to investigate the capability for power transfer with the variation in operating parameters in consideration of enhanced efficiency. This study proposes an innovative approach to improve the performance of dynamic wireless charging systems by investigating the magnetic coupler via finite element analysis, exploring power pulsation and mutual inductances with variations in longitudinal, lateral, and air gap distances as variable factors. In addition to this, efficiency analysis is also explored with respect to the mutual inductance and various compensation schemes. The simulation studies are carried out using computer-assisted software, i.e., COMSOL Multiphysics 5.5 and MATLAB version 2022b. Finally, a comparative analysis of power transferred, mutual inductance, and efficiency is presented by the compensation schemes.

David A. Cullen, Brian Sneed, Karren L. More

ECS Meeting Abstracts • 2016

The performance of polymer electrolyte membrane fuel cells (PEMFCs) is primarily controlled by the materials within membrane electrode assemblies (MEAs), which consist of an anode and cathode separated by a proton-conducting membrane. Developing highly stable MEAs is one key to wide-spread commercialization of this clean energy technology. The electrodes consist of a complex hierarchal structure, which must be capable of simultaneously transporting hydrogen, protons, electrons, oxygen, and water to and way from the critical electrocatalytic active sites. In conventional PEMFCs, Pt serves as the active catalyst, and is sometimes alloyed with a transition metal such as Co or Ni to enhance activity or lower cost.[1] In non-platinum group metal (non-PGM) electrodes, the catalytically active site takes the form of Fe or Co metal-nitrogen-carbon (M-N-C) complexes.[2] In either case, understanding the evolution of these catalysts, and the complex support structures in which they reside, in relation to observed performance losses is essential for furthering fuel cell development. Scanning transmission electron microscopy (STEM) is an ideal analytical characterization tool for performing both pre- and post-mortem nano to mesoscale compositional and structural characterization of the individual material components in MEAs. STEM has been used to quantify key changes responsible for performance gains and losses during fuel cell conditioning and cycling.[3,4] These structural changes can vary widely in both extent and scale, from carbon-corrosion-related electrode thinning at the micron scale to dealloying-induced reordering on the surfaces of advanced Pt-alloy catalysts at the atomic scale. This presentation will focus on three topics spanning multiple length scales in the MEA. Beginning at the atomic scale, strain effects and skeleton structures arising from in situ Ni dealloying in Pt-alloy nanostructured thin films (NSTF) will be presented. The surface structure and composition is critical to electrocatalytic activity, and, as shown by the aberration-corrected Z-contrast STEM image in Fig. 1a, these structures can be resolved with atomic resolution. Changes in surface structure/strain will be studied as a function of fuel cell cycling and electrochemical activity. At the nanoscale, carbon support effects on Pt anchoring and agglomeration will be presented, highlighting the critical role that catalyst-support interactions and corrosion-resistant supports play in MEA durability (Fig. 1b). Finally, at the mesoscale, changes in electrode structure with aging in non-PGM MEAs will be presented, highlighting the key role that hierarchal pore structures (spanning the micro to macro) play in fuel cell performance. Complementary imaging and compositional mapping by energy dispersive X-ray spectroscopy, as shown in Fig. 1c, provide unique insight into how both changes in mechanical and chemical structure impact durability. References V. R. Stamenkovic et al., Nat. Mater. 6 (2007) 241. G. Wu, K. L. More, C. M. Johnston, P. Zeleany, S cience 332 (2011) 443. D. A. Cullen et al., J. Mater. Chem. A , 3 (2015) 1660. B. Han et al., Energy Environ. Sci. , 8, 258 (2015). Acknowledgements Research sponsored by the Fuel Cell Technologies Office, Office of Energy Efficiency and Renewable Energy, U.S. Department of Energy (DOE) and ORNL’s Center for Nanophase Materials Sciences (CNMS), which is a DOE Office of Science User Facility. Figure 1

Jaecheul Yu, Youghyun Park, Taeho Lee

Journal of Industrial Microbiology and Biotechnology • 2015

Abstract A closed-circuit microbial fuel cell (C-MFC) was operated to investigate the electron flux under fed-batch mode, and the results were compared to those of open-circuit MFC (O-MFC) and a fermentation reactor (F-reactor). The current was the largest electron sink (52.7 % of influent SCOD) in C-MFC, whereas biomass and methane gas were the most significant electron sinks in O-MFC and F-reactor. Interestingly, some of the unknown sink may have accumulated in the electrode of O-MFC. Principal component analysis based on gradient gel electrophoresis profiles showed that the microbial communities were significantly affected by the growth conditions and the presence of electrode, regardless of the circuit connection. Therefore, the electrode and circuit mode might help to control the amount of biomass and enhance the MFC performance.

A. I. ElSherbini, A. M. Al-Qattan

ASME 2008 6th International Conference on Fuel Cell Science, Engineering and Technology • 2007

Air conditioning (A/C) systems are the major consumers of power in hot climates. In a country like Kuwait, A/C accounts for 85% of power supplied to homes during peak hours and 55% of annual energy consumption by the residential sector. A fuel-cell-based cogeneration system is proposed to improve the efficiency of generating and utilizing power for cooling in residential buildings. Distributed electric power is generated by a solid oxide fuel cell (SOFC). The electricity is used to operate high-efficiency water-cooled chillers in a district-cooling setup, which replaces packaged A/C units typically used for homes. The exhaust fuel and heat from the SOFC operate a gas turbine and an absorption chiller. A thermal energy storage tank is used for storing chilled water to reduce the total capacity of the system and, hence, capital investment. The integrated fuel-cell air-conditioning (FCAC) system improves the cooling-to-fuel efficiency, expressed as coefficient of performance, by 375%. The peak power requirement is reduced by 65% and the total fuel energy is reduced by 58%. An example system of 2 MW delivers 3750 RT (13.2 MW) of cooling to a district. Over a 9-month period, it saves 94 TJ of fuel energy and feeds 5.21 GWh of electricity to the grid as a surplus.

Carlo Santoro, Rohan Gokhale, Barbara Mecheri et al.

ChemSusChem • 2017

Abstract Iron(II) phthalocyanine (FePc) deposited onto two different carbonaceous supports was synthesized through an unconventional pyrolysis‐free method. The obtained materials were studied in the oxygen reduction reaction (ORR) in neutral media through incorporation in an air‐breathing cathode structure and tested in an operating microbial fuel cell (MFC) configuration. Rotating ring disk electrode (RRDE) analysis revealed high performances of the Fe‐based catalysts compared with that of activated carbon (AC). The FePc supported on Black‐Pearl carbon black [Fe‐BP(N)] exhibits the highest performance in terms of its more positive onset potential, positive shift of the half‐wave potential, and higher limiting current as well as the highest power density in the operating MFC of (243±7) μW cm −2 , which was 33 % higher than that of FePc supported on nitrogen‐doped carbon nanotubes (Fe‐CNT(N); 182±5 μW cm −2 ). The power density generated by Fe‐BP(N) was 92 % higher than that of the MFC utilizing AC; therefore, the utilization of platinum group metal‐free catalysts can boost the performances of MFCs significantly.

I Munfarida, M Munir, W Nilandita

IOP Conference Series: Earth and Environmental Science • 2023

Abstract The increasing of population growth is positively correlated with the energy demand which leads to fossil fuel depletion. New renewable energy is one of the solutions to address the future energy crisis. Microbial fuel cell (MFC) is one of the renewable energy sources since this device is able to convert chemical energy into electrical energy by using microorganisms. Many researchers have studied MFCs from wastewater as a medium for producing electricity through MFC systems. MFC performance depends on microbe metabolism, membrane, and electrodes. This study compared bioelectricity generation on a Batch System of Microbial Fuel Cell from residential wastewater using two types of anode electrodes (zinc plate and graphite rod). The consortium of indigenous wastewater bacteria has been used for MFC. An artificial membrane was made in the laboratory derived from the chitosan-jelly combination. Chitosan was extracted from crustacean shells. The research was conducted in the laboratory by directly measuring the voltage on the MFC system for three (3) days. This research reveals that the MFCs with zinc plate anode electrodes generated higher voltage throughout the days evaluated, with peaks of 970 mV. Meanwhile, MFC with graphite rod anode resulted in 880 mV maximum. This research finding of MFCs with zinc plate as electrode materials could be the key to sustainable bioelectricity generation from wastewater.

Camilo Enrique La Rotta-Hernández, Kyriale Vascocelos-Morant, Paulo Henrique da Silva et al.

ECS Meeting Abstracts • 2014

Recent researches have promoted the progressive application and substitution of expensive metallic and abiotic catalysts used in the cathodic reduction of oxygen by oxidasic enzymes as well as the use of better electron transportation systems to improve the current deficiencies and to diminish the implementation costs of the bioelectrodes for biofuel cells (BFC). Nevertheless, most of these biocatalysts still have serious problems, regarding use and stabilization. In contrast, the use of electronic mediators remains restricted due to their price and toxicity. As an attractive and promising alternative we studied the in-situ production of oxidasic enzymes as well the use of novel fungal biomolecules applied as electron shuttles. As such, we initiated the screening with 12 Brazilian indigenous fungal strains. At the end, three fungi were identified as sources of oxidasic enzymes (mono or polyphenol oxidases): Aspergillus sp . (SIS-18), Penicillium sp. (SIS-21), and Rhyzopus microsporus var. microsporus (SIS-31), and four strains as sources of pigments with high redox capacity: Aspergillus sp . (red), Penicillium sp. (green), Talaromyces sp. (orange) and Penicillium sp. (yellow). The production of these fungal biomolecules was controlled by the used of different carbon substrates including glucose and glycerol. The In-situ production was studied by chronoamperometric analysis in fungal air-cathodes and compared with the profiles obtained for Laccase from T. versicolor in terms of coulumbic efficiencies and maxima current densities. The BFC system was composed by an anodic compartment with a graphite electrode submerged in 20 mmol L -1 Potassium Ferrocyanide and a fungal cathodic compartment with Pt-Black carbon or free Pt graphite electrodes submerged in the culture medium. A saline bridge of saturated KCl was used as cation exchange system. Fungal BCF were studied in parallel with submerged cultures during 7 days at 28 o C, in terms of substrate consumption, enzyme production and biomass production. Novel fungal pigments were obtained in separate experiments from submerged cultures after 15 days. Crude extracts were characterized by chromatography and spectrometry. Cyclovoltammetric analyses were compared with well-known mediators as triphenylmethane dyes and tiazinic dyes, and also in the presence of bioelectrodes composed by glucose oxidase (GOx) or laccase (LAC). The electrochemical analyses were performed in a 25 mL cell using graphite as working electrode, Pt as auxiliary electrode and Ag|AgCl in saturated KCl as reference in 10 mmol L -1 potassium phosphate buffer pH 5.0 or in 10 mmol L -1 KCl. Although the highest oxidasic activity was found for the strain SIS-21 (4600 UI.mL -1 ), the strain SIS-31 showed the highest current density value of 125.27 mA.cm -2 . In terms of coulumbic efficiencies, using glucose as substrate, the obtained values were of 23.8%, 46.5% e 56.5%, for SIS-18, SIS-21 and SIS-31, respectively. Cyclovoltammograms of the enzymatic extracts in the presence of 10 mmol mL -1 or in 100 mmol L -1 of potassium phosphate buffer pH 5.0, showed similar profiles for SIS-18 and SIS-31 with two oxidation peaks and one reduction peak, whereas for SIS-21 two oxidation peaks and two reduction peaks were observed. This observation could indicate the presence of monoxidases in the case of SIS-18 and 31; and a polyphenoloxidase for SIS-21. On the other hand, Preliminary analyses by cyclicvoltammetry of the pigments showed in general similar profiles, being observed two oxidation peaks and three reduction peaks. Also increases on current densities for GOx in the presence of 1 mmol mL -1 glucose and for LAC in the presence of 1 mmol mL -1 pyrogallol were observedwhen the pigments were evaluated along with these enzymes. Currently, we are studying the mechanisms for electron transportation of these pigments based on the structure-activity analyses and the concomitant in-situ used of pigment producer strains with the ones with proven oxidasic activity.

Qian Fu, Naoya Fukushima, Haruo Maeda et al.

Bioscience, Biotechnology, and Biochemistry • 2015

Abstract We examined whether a hyperthermophilic microbial fuel cell (MFC) would be technically feasible. Two-chamber MFC reactors were inoculated with subsurface microorganisms indigenous to formation water from a petroleum reservoir and were started up at operating temperature 80 °C. The MFC generated a maximum current of 1.3 mA 45 h after the inoculation. Performance of the MFC improved with an increase in the operating temperature; the best performance was achieved at 95 °C with the maximum power density of 165 mWm−2, which was approximately fourfold higher than that at 75 °C. Thus, to our knowledge, our study is the first to demonstrate generation of electricity in a hyperthermophilic MFC (operating temperature as high as 95 °C). Scanning electron microscopy showed that filamentous microbial cells were attached on the anode surface. The anodic microbial consortium showed limited phylogenetic diversity and primarily consisted of hyperthermophilic bacteria closely related to Caldanaerobacter subterraneus and Thermodesulfobacterium commune.

Badillo-Cardoso Jonathan, Minsoo Kim, Jung Rae Kim

Journal of Electrochemical Science and Technology • 2023

<p>Microbial fuel cells (MFCs) are a bioelectrochemical system where electrochemically active bacteria convert organic waste into electricity. Poly(vinyl alcohol) (PVA) and chitosan (CS) are polymers that have been studied as potential alternative ion exchange membranes to Nafion for many electrochemical systems. This study examined the optimal mixing ratio of PVA and chitosan CS in a PVA:CS composite membrane for MFC applications. PVA:CS composite membranes with 1:1, 2:1, and 3:1 ratios were synthesized and tested. The water uptake and ion exchange capacity, Fourier transform infrared spectra, and scanning electron microscopy images were analyzed to determine the physicochemical properties of PVA:CS membranes. The prepared membranes were applied to the ion exchange membrane of the MFC system, and their effects on the electrochemical performance were evaluated. These results showed that the composite membrane with a 3:1 (PVA:CS) ratio showed comparable performance to the commercialized Nafion membrane and produced more electricity than the other synthesized membranes. The PVA:CS membrane implemented MFCs produced a maximum power density of 0.026 mW cm<sup>−2</sup> from organic waste with stable performance. Therefore, it can be applied to a cost-effective MFC system.</p>

Subhajit Roy

International Journal of Energy Optimization and Engineering • 2016

As it is known Microgrid is a miniature grid consist of one or more numbers of same or by different conventional or non-conventional generation sources. Here one can consider Microturbine (MT) as the main source of generation and it may or may not be connected with the main grid. The author discussed modeling of different types of Micro turbine during implementation of mathematical modeling of split-shaft type with the help of MATLAB® Simulink®. From developed models can be describe behavior of a MicroGrid (MG) under islanded mode as MT and SOFC as the sources. SOFC can change its electrical output power (30%) high or low, but take more time to response than MT (2-3 times more). It is demonstrated that Microturbines and fuel-cells are capable of providing a load-following service in the distributed generation system. Results prove the effectiveness of the two developed models in the studying and analysis of the transient dynamic response of MG.

Wei Xu, Zheng Fan, Xingxing Wu et al.

ECS Meeting Abstracts • 2015

Hexavalent chromium (CrO 4 2- , Cr 2 O 7 2- , CrO 3 , CrF 6 , etc.) is seriously hazardous substance inducing various point mutations in DNA and oxidative changes in proteins due to its strong oxidational properties [1] . Notably, Cr(VI) is strongly oxidative which can oxidize most organics such as urine in wastewater. Thus, it is possible to develop a fuel cell by using hexavalent chromium and urine as fuels according to the following reaction mechanism: Anode reaction: CO(NH 2 ) 2 +6OH - →N 2 +CO 2 +5H 2 O+6e E 0 = -0.746 V vs. SHE Cathode reaction: Cr 2 O 7 2- +14H + +6e→2Cr 3+ +7H 2 O E 0 = +1.33 V vs. SHE Overall reaction: CO(NH 2 ) 2 +Cr 2 O 7 2- +8H + →N 2 +CO 2 +2Cr 3+ +6H 2 O E 0 = +2.076 V This work shows a strategy of reducing Cr(VI) by human urine with self-generation electricity via a urine/Cr(VI) fuel cell (UCrFC), in which urine functions as fuel and Cr(VI) severs as electrons acceptor. Urine is electro-oxidized on carbon supported nano-Ni catalyst at anode and Cr(VI) is electro-reduced at catalyst-free cathode in acid medium [2,3] . An ion selective separator, consisting of an anion exchange membrane (AEM) and a cation exchange membrane (CEM), AEM||KCl aq ||CEM separator , is introduced to improve the cell performance by hindering the crossover of dichromate and ammonium. A maximum power density of 3400 mW m -2 (159 times to microbial fuel cells [4] ) was achieved with an OCV of 1.3 V (twice of that in microbial fuel cells [4] ) in AEM||KCl aq ||CEM-UCrFC, when using 50 mg L -1 Cr(VI) in 0.25 M H 2 SO 4 as catholyte and neat urine as anolyte. The apparent first-order kinetic constants of Cr(VI) reduction were -0.224, -0.145 and -0.118 h -1 , respectively, when initial concentration of Cr(VI) were 13, 22 and 50 mg L -1 . Total organic carbon and total nitrogen removal from urine were observed in 71 h in the anode chamber, with removal efficiency of 79.2% and 78.4%, respectively. At the same time, ~93% of Cr(VI) was removed in the cathode chamber. A high cathodic coulombic efficiency of more than 98% was achieved. One liter of fresh urine could reduce about 28 g of Cr(VI) via UCrFC. This fuel cell provides an alternative technology for using waste (human urine) to treat another waste (hexavalent chromium), and is potentially applicable to other waste/waste system. References : 1. A. D. Dayan, A. J. Paine, Hum. Exp. Toxicol. 2001 , 20, 439-451. 2. W. Xu, H. Zhang, G. Li & Z. Wu, Scientific Reports , 2014 , 4: 5863. 3. B. Yu, H. Zhang, W. Xu, G. Li & Z. Wu, Scientific Reports , 2014 , 4: 5860.. 4. L. P. Huang, X. L. Chai, S. A. Cheng, G. H. Chen, Chem. Eng. J. 2011 , 166, 652-661.

Ryosuke Ichikawa, Ryo Sakakibara, Suguru Uemura et al.

ECS Meeting Abstracts • 2023

Polymer electrolyte fuel cells (PEFCs) are widely used for automobiles and other applications due to their excellent start-ability and load followability. For further popularization in the future, it is expected to be applied to commercial vehicles such as large trucks and buses. However, insufficient cooling of the PEFC becomes a major issue, for example when heavy-duty vehicle needs to operate on uphill roads at high-loads and high- temperatures. This is because conventional electrolyte membranes use water as a proton-conducting carrier, so PEFC’s operation temperature must be controlled below 100°C. In this study, we focus on high-temperature PEFC (HT-PEFC), which is expected to improve cooling performance by high-temperature operation (over 100°C). HT-PEFC can operate under non-humidified high-temperature environment by doping phosphoric acid as a proton-conducting carrier in the electrolyte membrane. Then, we evaluate the usefulness of the HT-PEFC by performance analysis using a FC system simulator. We use FC-DynaMo (1),(2) , which is researched and developed by NEDO's industry-academia-government collaboration project, as the FC system simulator. FC-DynaMo is based on the FC stack system of Toyota motor corporation's 2nd generation MIRAI. As shown in Figure 1, in addition to the FC stack, hydrogen system, air system, and cooling system are also modeled, making it possible to simulate unsteady operation. The target vehicle for the simulation is a heavy-duty truck (Class8), and the results of a survey conducted by Zhang et al. (3) on the various uses of in the United States were used as a reference. From the results including output power, vehicle speed, and road gradient, we extracted and used the driving data of long-haul with continuous uphill and downhill roads, which is considered to be the high-load and high-temperature operation. For the membrane electrode assembly (MEA) of HT-PEFC, we used APM STD (PBI-MEA) manufactured by Advent technologies, which uses a polybenzimidazole membrane. We give the characteristic that the exchange current density increases exponentially as the temperature rises, referring to the study of Korsgaard et al. (4) . In addition, proton conductivity is given as 10S/m published by Advent technologies. Figure 2(a) shows the calculated IV characteristic of MIRAI-MEA. And Figure 2(b) shows the that of PBI-MEA. As the temperature rises, the effect of reducing the activation overpotential by increasing the exchange current density can be confirmed. These results are in good agreement with the study which investigated the operation characteristics of PBI-MEA by Chen et al. (5) and Waller et al. (6). However, compared to the IV characteristic of MIRAI-MEA shown in Figure 2(a), the overpotential is too large, the maximum output is less than half, and the heat generation is nearly double. This is because it is nearly twice as large as the MIRAI-MEA’s activation overpotential, which causes a decrease in output power and an increase in heat generation. With this current PBI-MEA performance, it is difficult to evaluate the system compared with MIRAI-MEA. Therefore, in this study, we hypothetically set up a high-temperature MEA assuming future development (Virtual HT-MEA). Virtual HT-MEA is given MIRAI-MEA’s low activation overpotential and the characteristics of PBI-MEA that don’t dry-out at high-temperature. Figure 2(c) shows the Virtual HT-MEA’s IV characteristics. Here, at high current density, the performance at 120°C and 180°C is lower than that at 70°C because the concentration overpotential increases due to the decrease in the oxygen molar concentration at high-temperature. Figure 3 shows the results of Class8 driving simulation with each MEA adapted to the FC stack. In the MIRAI-MEA shown in Figure 3(a), a combination of 4-FC stack systems and 5-cooling systems is optimal. With this combination, the FC cell temperature can be controlled below 95°C. Figure 3(b) shows the analysis results of the FC stack using PBI-MEA. As shown in Figure 2(b), the PBI-MEA has a large overpotential, so a combination of 10-FC stack systems and 5-cooling systems is required to meet the request power. The current PBI-MEA’s performance cannot show the merits of non-humidified high-temperature operation. Figure 3(c) shows the analysis results of the FC stack using the Virtual HT-MEA. Stable operation is possible with 4-FC stack systems and 2-cooling systems. This means that 3-cooling systems can be reduced compared to the MIRAI-MEA’s system. This is because the cooling performance is improved due to the larger temperature difference between the outside air and the FC stacks. Reference (1)S.Hasegawa, et al., ECS Transactions ,104, (2021) (2)S.Hasegawa, et al., ECS Transactions ,109, (2022) (3)C.Zhang, et al., Transportation Research, Part D95, (2021) (4)A.R.Korsgaad, et al., Journal of Power Sources ,162, (2006) (5)C.-Y.Chen, et al., Journal of Power Sources ,195, (2010) (6)M.G.Waller, et al., International Journal of Hydrogen Energy ,41, (2016) Figure 1

Cui‐e Zhao, Jiansheng Wu, Yuanzhao Ding et al.

ChemElectroChem • 2015

Abstract Efficiently transporting extracellular electrons from microbial biofilms to the electrodes is challenging and critical in achieving high‐performance microbial fuel cells (MFCs). In this work, we develop a simple and effective method to fabricate hybrid electroactive biofilms by inserting bacteria into graphene–carbon‐nanotube (G–CNT) networks (namely, G–CNT‐biofilm) as an anode for MFCs. This novel architecture greatly enhances direct extracellular electron transfer between Shewanella oneidensis and the electrode, due to strong adhesion of the hybrid conducting biofilm onto the anode surface, as well as the large surface area of graphene and the high conductivity of CNTs. A current density of 120 μA cm −2 and a maximum power density of 97.9 μW cm −2 are obtained in the MFC with the hybrid biofilm anode, which is significantly higher than those of a naturally growing biofilm anode (20 μA cm −2 and 6.5 μW cm −2 ).

Markus Kordel, Dominik Radler

ECS Meeting Abstracts • 2024

Hydrogen fuel cells and hydrogen internal combustion engines face challenges in competing with battery electric systems in mobile applications due to their lower overall system efficiency. Evaluating the impact of various technologies on the system level is crucial for assessing their economic and ecological potential. Thermodynamic constraints, such as Carnot efficiency, inherently limit the efficiency of these systems. To address this, efforts to enhance the efficiency of fuel cells and internal combustion engines must explore untapped potentials, such as utilizing pressure energy between pressurized tanks and fuel cell systems, which is about 15 % of the higher heating value of the hydrogen stored in the 700 bar tanks. One promising approach involves employing an open metal hydride refrigeration system, utilizing pressure energy through alternating exothermic hydrogen absorption and endothermic desorption in metal hydride reactors. This system provides quasi-continuous cooling power for climatizing train cabins, drivers’ cabs, and refrigerated trailers (see Fig. 1). A lab-scale prototype, currently at TRL 4, demonstrates this quasi-continuous cooling power with steady-state hydrogen mass flows and an electrochemical efficiency of 81 %.With this prototype, efficiency improvements were achieved through optimized valve switching times (Weckerle et al. 2020). However, further optimization is warranted, particularly through simulation-based techniques leveraging realistic driving patterns of heavy-duty vehicles. Here we present the validation of a metal hydride simulation model with control strategy enhancements, evaluated under heavy-duty applications such as hydrogen regional trains and refrigeration trucks. Our simulation model, validated by repeated experiment analyses within a 95% confidence interval, facilitates optimization of heat transfer fluid and hydrogen flow, resulting in longer desorption cycles and higher efficiency of 86 – 91 % with the lab-scale prototype as a reference. The reactors are modeled as plate heat exchangers with a heat source in Matlab Simulink, utilizing a first-order reaction approach based on isothermal pressure-temperature characterization of the material. Optimization of desorption cycles, incorporating variations in heat transfer fluid flow, absorption and desorption cycle durations, and hydrogen mass flow through bypass valves, is performed via scripted methods. Extended desorption cycles significantly reduce switching cycles (see Fig. 2), with the main performance impact attributed to the heating or cooling requirements of the reactor's lump heat mass during transitions. The integration of this improved control strategy with existing vehicle models enables a more realistic assessment of system performance compared to current practices. Even modest improvements, such as a 5 % points efficiency enhancement, can lead to significant energy savings, exemplified by a reduction of 370 kWh/a in the annual energy consumption of a hydrogen regional train (Kordel et al. 2024). This study emphasizes the importance of application efficiency and energy consumption as key indicators for enhancing the competitiveness of mobile hydrogen applications. The presentation will delve into the validation process, optimization workflow and application-specific results and show the impact on the efficiency of hydrogen trains and refrigerated trailers. With this research, we aim to bridge the gap between technological advances and real-world applications in hydrogen science. Literature: Kordel, Markus; Heeland, Matthew Maikel; Knetsch, Kevin (2024): IRSA 2023 Proceedings: Waste Energy AC Technologies in H2-Multiple Units. In: Nils Nießen und Christian Schindler (Hg.): IRSA 2023 : Tagungsband/proceedings: Aachen, Germany 22-23 November 2023, S. 561–581. Online verfügbar unter https://elib.dlr.de/202183/. Weckerle, C.; Nasri, M.; Hegner, R.; Bürger, I.; Linder, M. (2020): A metal hydride air-conditioning system for fuel cell vehicles – Functional demonstration. In: Applied Energy 259, S. 114187. DOI: 10.1016/j.apenergy.2019.114187. Acknowledgement: The author would like to acknowledge the ESCALATE project (Grant Agreement No: 101096598), which the European Union funds under the Horizon Research and Innovation Programs. Figure 1

Wei Liu, Wei Mu, Yulin Deng

Angewandte Chemie • 2014

Abstract Herein, we report high‐performance fuel cells that are catalyzed solely by polyoxometalate (POM) solution without any solid metal or metal oxide. The novel design of the liquid‐catalyst fuel cells (LCFC) changes the traditional gas–solid‐surface heterogeneous reactions to liquid‐catalysis reactions. With this design, raw biomasses, such as cellulose, starch, and even grass or wood powders can be directly converted into electricity. The power densities of the fuel cell with switchgrass (dry powder) and bush allamanda (freshly collected) are 44 mW cm −2 and 51 mW cm −2 respectively. For the cellulose‐based biomass fuel cell, the power density is almost 3000 times higher than that of cellulose‐based microbial fuel cells. Unlike noble‐metal catalysts, POMs are tolerant to most organic and inorganic contaminants. Therefore, almost any raw biomass can be used directly to produce electricity without prior purification.

Ashok D. Vidhate, Shruti Suman

Journal of Physics: Conference Series • 2021

Abstract In VLSI technology the circuit has small size. The efficient size gained due to decreasing chip design to nano-scale. But as chip size becomes very less the factor which adversely affects the design is maintaining constant current in CMOS integrated circuit. Current mirror replicates input current at the output. There is need to design current mirror circuit such that it works efficiently with low power requirement. In this work the survey of different CM circuits analysed and studies. Each CM has its advantages, limitations and research gap which is noted and applicable for further development.

Shantanu Shukla, Kailyn Domican, Marc Secanell

ECS Meeting Abstracts • 2014

Performance of a polymer electrolyte membrane (PEM) fuel cells depends upon several electrode parameters such as platinum loading, micro-structure and ionomer content. These parameters can be varied by changing the catalyst ink formulation and electrode fabrication technique [1]. In this work, inkjet printing is investigated as an electrode fabrication technology. Our results show that with this technique, it is possible to have an electrode thickness of less than 2 µm with an evenly distributed micro-structure and a platinum loading of around 25 µg/cm2 [2]. The platinum mass activity of these electrodes is seen to be up to 8 times higher that a conventionally fabricated electrode at high current densities, mainly due to the reduction in macro-scale transport losses due to the reduced thickness (Figure 1). Electrode current density at low overpotentials was improved with increasing Pt loading by increasing the number of deposited layers. However, this resulted in an increased electrode thickness which increased the mass-transport losses thereby reducing the platinum mass activity at high current densities. It was hypothesized that patterning of electrodes would help reducing mass-transport losses at the macro-scale by having through-plane pathways for the reactant gases and water. It has also been shown that patterning of the electrodes influences the electrochemical active area of the cell [3]. This work studies the fabrication process of patterned electrodes and their performance when compared to a normal electrode. First, the resolution of our inkjet printer technology was studied. Various patterns were tested using two printer cartridges having drop volumes of 1 pL and 10 pL corresponding to a nozzle diameter of 9 µm and 21 µm respectively. It is shown that distinguishable patterns as small as 200 µm x 200 µm could be fabricated. The maximum resolution is shown to be a function of the nozzle diameter, substrate used, number of active nozzles during the fabrication process, droplet spacing, and number of printed layers. Figure 2 shows sample spacing resolutions between the patterns fabricated. Smaller nozzle size helps in increasing the pattern resolution. Minimum distinguishable spacing between the patterns was found to be 100 µm when using the 1 pL cartridge and 500 µm with the 10 pL cartridge. Figure 3 shows a performance comparison at 70% RH and a cell temperature of 80 C between two catalyst coated membranes with a 5 cm2 cathode layer obtained using: a) a patterned electrode, and b) a conventional electrode (15 layers). The estimated cathodic Pt loading for both the CCMs is approximately 0.175 mg/cm2. It can be seen that patterning significantly improves the cell performance at high current densities due to reduction in the mass-transport losses as there is lower resistance to the flow of gases through the electrode. This effect will be more prominent once the performance plots are obtained when using cathodic reactant gas with lower oxygen concentration. The effects of cell performance on the type of patterns and the substrate used for ink deposition is underway. References [1] S. Shukla, S. Bhattacharjee and M. Secanell. ECS Transactions, 58(1):1409–1428, 2013. [2] S. Shukla, K. Taufertshoefer, S. Bhattacharjee, K. Karan, D. Malevich, E. Halliop and M. Secanell. Proceedings of the 10th ASME Fuel Cell Science, Engineering and Technology Conference, San Diego, California, US, July 23-26, 2012 [3] D. Malevich, M. Saha, E. Halliop, B. Peppley, Jon G. Pharoah and K. Karan. ECS Transactions, 50(2): 423–427, 2013

Piotr Bujlo, Grzegorz Pasciak, Jacek Chmielowiec et al.

Journal of Energy • 2012

This paper presents the results of development of a hybrid fuel cell supercapacitor power system for vehicular applications that was developed and investigated at the Energy Sources Research Section of the Wroclaw Division of Electrotechnical Institute (IEL/OW). The hybrid power source consists of a polymer exchange membrane fuel cell (PEMFC) stack and an energy-type supercapacitor that supports the system in time of peak power demands. The developed system was installed in the HY-IEL electric scooter. The vehicle was equipped with auxiliary components (e.g., air compressor, hydrogen tank, and electromagnetic valves) needed for proper operation of the fuel cell stack, as well as electronic control circuits and a data storage unit that enabled on-line recording of system and vehicle operation parameters. Attention is focused on the system energy flow monitoring. The experimental part includes field test results of a vehicle powered with the fuel cell-supercapacitor system. Values of currents and voltages recorded for the system, as well as the vehicle’s velocity and hydrogen consumption rate, are presented versus time of the experiment. Operation of the hybrid power system is discussed and analysed based on the results of measurements obtained.

Shin Hasegawa, Jinhua Chen, Hiroshi Koshikawa et al.

ECS Meeting Abstracts • 2014

Introduction A pre-irradiation grafting method is a fascinating technique for direct introduction of a new functional polymer phase as a grafting chain into polymer films serving as a substrate which allows those films to retain their characteristics such as thermal stability, mechanical strength, and electronic properties. The radiation technique has been widely applied to the preparation of high performance fuel cell polymer electrolyte membranes (PEMs) for vehicles and domestic co-generation systems [1]. The PEMs of aromatic hydrocarbon polymers, so-called “super engineering plastics” including poly (ether ether ketone) (PEEK), have useful characteristics such as high mechanical strength, gas barrier property, and radiation resistance. However, PEEK films also have high chemical resistance; thus, it is difficult to introduce grafting monomers into the films. Recently, we succeeded in radiation-induced grafting of Ethyl 4-styrenesulfonate (E4S) into a PEEK film with grafting degrees around 100% [2]. We report herein the synthesis, characterization, and electrolyte properties of graft-type PEEK PEM with thin PEEK films less than 50 mm thickness. Fuel cell performance of graft-type PEEK PEM was estimated at 80 °C under 30 and 100% RH conditions. Experiments Graft-type PEEK PEM was synthesized by pre-irradiation grafting of E4S into PEEK films (Scheme 1) [3]. The PEEK films were immersed in a 10 wt% DVB solution of 1,4-dioxane at 50°C for 24h. The PEEK-g-DVB films were pre-irradiated with a 60 Co γ-ray source (JAEA Takasaki, Gunma, Japan) at room temperature in argon atmosphere to a absorbed dose of 160 kGy. Then, the samples were immersed in 15 ml of the E4S solution of 1,4-dioxane (1/1 v/v) at 80 °C. The obtained PEEK-g-DVB-g-E4S film was hydrolyzed in 95 °C hot water for 24h (PEEK-g-DVB-g-PSSA PEM). The ion exchange capacity (IEC (mmol/g)), proton conductivity (S/cm) in-plane direction at room temperature, and water uptake (WU) was measured according to the previous report [2]. Proton conductivity was estimated at 80 °C in 30%RH; mechanical strength was measured at 80 °C in 100% RH, which is severe conditions for the fuel cell operation, was measured as previously reported [4]. The membrane/electrodes assembly (MEA) (Pt loading 0.5 mg/cm 2 ) prepared by hot-press set into a 5 cm 2 . The fuel cell test was carried out at 80°C in a RH range of 30-100%. Results and Discussion According to the previously reported methods, we could prepare the PEEK-based PEM with grafting degrees of 88-107% and ion exchange capacity (IEC) of 2.3 – 2.5 mmol/g using the original PEEK substrates with film thickness of 6, 12, 16, 25, and 50 mm (Table 1). The variation of film thickness does not affect the conductivity and water uptake of the PEM. This is one of the thinnest PEM possessing sufficient conductivity as well as high mechanical strength (60 MPa of tensile strength at break). Then, we compare the fuel cell performance of the single fuel cell devices consisting of the PEEK-based PEM with various thicknesses in the operation condition at 80 ºC and 100%RH. As expected from the similar ion conductivity around 0.045 S/cm, the thinner PEM showed higher cell voltages at the current density in the range from 0.2 to 1.0 A/cm 2 . Especially, compared with a Nafion212 film (thickness: 50 μm), higher cell voltages (namely, power densities (W/cm 2 )) can be achieved in the PEM with film thickness less than 12 mm (Figure 1). The above results imply the advantages of mechanically tough PEEK as an original polymer substrate to be able to decrease the film thickness, resulting in higher power density owing to the less cell resistance. 19 μm PEEK PEM has good proton conductivity (0.0068 S/cm) at 80°C and 30%RH. The elastic modulus of the grafted film showed twice higher than that of Nafion 212 film at 80 degree and 100%RH. Acknowledgments For support of this work, the authors acknowledge the financial support from a Grant-in-Aid for Scientific Research (KAKENHI, No. 24550263) from the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan. References [1] T. Yamaki, M. Asano, Y. Maekawa, Y. Morita, T. Suwa, J. H. Chen, N. Tsubokawa, K. Kobayashi, H. Kubota and M. Yoshida, Radiation Physics and Chemistry 2003 , 67 , 403-407. [2] S. Hasegawa, K. Sato, T. Narita, Y. Suzuki, S. Takahashi, N. Morishita and Y. Maekawa, Journal of Membrane Science 2009 , 345 , 74-80. [3] J. Chen, M. Asano, Y. Maekawa and M. Yoshida, Journal of Membrane Science 2008 , 319 , 1-4. [4] T. D.Tap, S. Sawada, S. Hasegawa, Y. Katsumura, and Y. Maekawa, Journal of Membrane Science 2013 , 447 , 19-25.

Ruediger Schweiss, Magnus Herb, Raj Earla et al.

ECS Meeting Abstracts • 2023

Gas diffusions layers (GDLs) constitute vital subcomponents of proton exchange membrane fuel cells (PEMFCs) since they participate in all relevant transport processes (gases, vapor, liquid water, electricity and heat).Meanwhile, state-of-the-art GDLs are produced on commercial scale using high volume reel-to-reel (R2R) processes. In almost any case, GDLs are designed as dual-layer structures with a macro-porous carbon fiber-based substrate (backing) and a micro-porous layer (MPL) consisting of carbon particulates bonded with polytetrafluoroethylene (PTFE) binder. A body of scientific work has verified that different aspects of the MPL microstructure and the MPL/macroporous substrate interface play a substantial role in the water management of PEMFCs [1-6]. A systematic study was performed based on a singular backing using different MPL types and penetration levels.A simple method to estimate the micro-porous layer penetration in gas diffusion layers based on data obtained from force-deflection behavior of backings and MPL-coated GDLs is proposed. Comparison with SEM and previously published tomographic studies shows that a good estimate for the extent of MPL intrusion into the backing is obtained. MPL loading and penetration is shown to affect different ex-situ GDL properties (in-plane gas permeability, electrical and thermal conductivity) as well as the GDL single cell performance characteristics with respect to humification and high current density operation. Keywords: Gas diffusion layers, Microporous Layer, PEMFC fuel cells Weber, and J. Newman, “Effects of microporous layers in polymer electrolyte fuel cells”, J. Electrochem. Soc. 152, A677-A688 (2005). Lee, R. Yip, P. Antonacci, N. Ge, T. Kotaka, Y. Tabuchi, and A. Bazylak, Synchrotron investigation of microporous layer thickness on liquid water distribution in a PEM fuel cell, J. Electrochem. Soc. 162, F669-F676 (2015). Zhou, S. Shukla, A. Putz, and M. Secanell, “Analysis of the role of the microporous layer in improving polymer electrolyte fuel cell performance”, Electrochim. Acta. 268, 366-382 (2018). Cho, J. Park, H. Oh, K. Min, E. Lee, and J.Y. Jyoung, “Analysis of the transient response and durability characteristics of a proton exchange membrane fuel cell with different micro-porous layer penetration thicknesses”, Appl. Energy 111, 300-309 (2013). T. Gostick, M. A. Ioannidis, M. W. Fowler, and M. D. Pritzker, “On the role of the microporous layer in PEMFC operation.”, Electrochem. Comm. 11, 576-579 (2009). P. Ramasamy, E. C. Kumbur, M. M. Mench, W. Liu, D. Moore, and M. Murthy, “Investigation of macro- and micro-porous layer interaction in polymer electrolyte fuel cells”, Int. J. Hydrogen Energy 33, 3351-3367 (2008).

Jinxing Ma, Zhiwei Wang, Xinwei Li et al.

Environmental Progress & Sustainable Energy • 2013

An aerated‐cathode microbial fuel cell ( MFC ) was used in this study for bioelectricity generation using the recovered organic matters ( ROMs ) from real municipal wastewater. Although no preacclimation or inoculation was used before the cell startup, the voltage began to increase as the operation of MFC was started. The working voltage registered the maximum value of 256.3 mV after 120–130 h operation. Proton accumulation and pH deviation in the anode chamber resulted in the deterioration of cell performance during the experiment. Electrochemical impedance spectroscopy analysis showed that the polarization resistance was the dominant component of internal resistance compared to the ohm resistance. It was also found that total suspended solids ( TSS ) and volatile suspended solids ( VSS ) reduction rate could reach 56.9% and 62.1% in the working MFC, respectively, comparedwith 31.7% of TSS reduction and 31.9% of VSS reduction in the control test. It indicated that bioelectricity generation could enhance the ROMs degradation. F ourier transform infrared spectrometry spectra demonstrated that the aliphatic compounds and protein‐like substances related to Amide II could be preferentially hydrolyzed and biodegraded in the working MFC . The hydrolysis of the particulate organic matters was the rate limiting step for bioelectricity generation. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 290–297, 2014

Yuting Zhang, Kai Cheng, Hong Mei et al.

Water • 2024

To enhance the removal of COD (Chemical Oxygen Demand) by microalgae, this study constructed a novel microalgae–microalgae microbial fuel cell system (AA-MFC). It investigated the coupling relationship between the COD treatment efficiency at the anode and the production of high-value microalgal products at the cathode, as well as explored the effects of different initial inoculum densities and light–dark cycles. The experiment first measured the operational performance of the newly constructed AA-MFC in open-circuit and closed-circuit modes, demonstrating that this novel AA-MFC could start up rapidly within 32 h and operate stably. The results showed that the AA-MFC enhanced the removal of COD and the growth of microalgae biomass at the anode while maintaining stable power generation. When the initial inoculation density of the anode was 1.2 × 108 cell/cm2 and the light–dark cycle time was 18:6 h, the AA-MFC had the most obvious promoting effect on the COD removal of the anode. Compared with normal culture conditions, the COD removal rate increased by 26.0% to 96.1%. These results indicate that the AA-MFC can not only effectively remove pollutants, but also promote the accumulation of high-value microalgae biomass.

A. A. Kulikovsky

Journal of Fuel Cell Science and Technology • 2008

We report the analytical solution to a problem of voltage and current distribution in a two-cell stack with the small amplitude resistive spot in one of the cells. Voltage disturbance in the defective cell increases almost linearly with the characteristic spot radius. The general expression for voltage loss due to a spot in an N-cell stack is obtained; it is stack current density times peak spot resistivity times square of the characteristic spot radius. Based on the solutions derived, a method for spot detection in a stack is discussed.

Paulina Sawicka-Chudy, Elżbieta Rybak-Wilusz, Marian Cholewa

Journal of Renewable and Sustainable Energy • 2016

Here, we evaluated the efficiency of a solar domestic hot water system in a dormitory in Rzeszow. Radiance exposure was analyzed based on information obtained from an online database (the meteorological station in Rzeszow-Jasionka). The mean seasonal and annual solar irradiation of a flat surface and surfaces inclined at 30°, 45°, and 60° from the horizontal plane in Rzeszow were determined. The mean monthly irradiation was compared with that in selected European cities based on the Photovoltaic Geographical Information System meteorological database. The thermal solar panel area and final consumption of solar energy in Poland from 2005 to 2014 are also presented. The characteristics of the analyzed building, distribution of the inhabitants, and consumption of hot water from 2009 to 2014 are described. The heat demand was determined by hot water consumption per day per person based on hot water consumption metering and heat metering. The solar energy conversion efficiency was determined after the solar thermal collectors were installed in the building. The relation of the heat demand calculated based on the thermal energy utilized to heat water per person and heat metering for heating water was also analyzed. We also present a method of calculating the annual (stratified by month) ratio of solar energy utilization. Energy savings for the building were calculated. Improvements that could further increase the solar energy efficiency and shorten the investment payback period are proposed.

Simone Lombardi, Laura Tribioli, Giovanni Di Ilio et al.

SAE International Journal of Advances and Current Practices in Mobility • 2022

<div class="section abstract"><div class="htmlview paragraph">The port-logistic sector has a crucial role in goods transport, as the 85-90% of international trade is achieved by means of maritime routes. The latest reports from the International Maritime Organization show that the port-logistic related activities are an important source of air pollution, both for the use of large auxiliary power systems on ships, which operate during port stays, as well as for the employment of fossil fueled road vehicles for on-site operations. As a matter of fact, the most important maritime facilities are located nearby urban areas and therefore reduction of the environmental impact in ports becomes of primary importance. Thus, in the pursuit of a greener in-port mobility, a progressive replacement of fossil fuels with cleaner alternatives must be promoted.</div><div class="htmlview paragraph">This paper presents the analysis of the performance of a hydrogenfueled plug-in fuel cell/battery hybrid vehicle for cargo-handling in roll-on and roll-off port operations. The powertrain of the proposed vehicle has been designed by the authors in a previous work, based on experimental data acquired during in-port operations for the fossil fuel powered counterpart. An optimized energy management strategy, based on the application of the Pontryagin’s Minimum Principle, is used to assess the maximum energy and hydrogen savings that can be attained with such a powertrain. Results are obtained over different mission profiles, in terms of driving and duty cycles, in order to represent typical port operations and ensure the accomplishment of the defined target missions. Outputs from this study set the basis for the design of an optimization-based real time energy management strategy, to maximize the potential of such vehicles in the view of the replacement of the conventional vehicles for in-port operations.</div></div>

Richard O'Neil Stroman, Gregory S. Jackson

ECS Meeting Abstracts • 2014

Hydrogen peroxide – direct borohydride fuel cells (H 2 O 2 -DBFCs) have high theoretical energy density and cell voltage [1-3], yet these desirable characteristics have not been demonstrated in a practical system. Parasitic chemical reactions competing with the desired electrochemical reactions are partly to blame [4]. Efforts to improve H 2 O 2 -DBFC performance have been hindered by its complexity; the reactions have many intermediate steps and pathways that are difficult to resolve experimentally [5, 6]. Furthermore, the relative rates of electrode reactions are influenced by transport in the reactant flow channels, where advection, diffusion, and migration occur [7]. A numerical model can make the complexity manageable and offer new insights by revealing relationships that are difficult to measure. To this end, a H 2 O 2 -DBFC model has been developed and calibrated to experiments with a single-cell H 2 O 2 -DBFC. The calibrated model was used to investigate the relationships between transport in the flow channels, parasitic side reactions, and DBFC performance. In the H 2 O 2 -DBFC shown in Fig. 1, a Nafion 117 membrane separates parallel flow channels. The channel walls are graphite electrodes coated with electro-deposited catalysts. Fuel (1-50 mM NaBH 4 / 2 M NaOH) is oxidized at the Au anode and oxidizer (10-40 mM H 2 O 2 / 1 M H 2 SO 4 ) is reduced at the Pd:Ir cathode, while Na + and H 2 O cross the membrane. The steady-state finite-difference model includes diffusion, migration, and advection in the flow channels, transport across the membrane, multiple charge transfer reactions at each electrode to yield mixed potentials, and chemical parasitic reactions at each electrode. It is formulated in MATLAB and solved by a modified Newton solver in SUNDIALS. Model features were chosen to reflect experimental observations. For example, experiments showed that low cathode potential caused by oxidizer-lean stoichiometry can lead to H + reduction at the cathode, therefore this reaction was included in the model. The model was calibrated to experiments by fitting predicted polarization curves to measured curves. Electrode reaction rates were modeled with global expressions that summarized many intermediate steps, and the fitted parameters were the rate constants in those global expressions. Predicted vs. measured polarization curve comparisons showed good agreement (R 2 ≥ 0.920) over the fuel cell operating space. The predicted and measured limiting current densities agreed, indicating transport was modeled accurately. Results from the calibrated model show compact concentration boundary layers in both channels, which limit reactant utilization and current density. Transport limits are most pronounced at the cathode because BH 4 - has higher diffusivity than H 2 O 2 , BH 4 - transport is aided by migration, and BH 4 - can provide up to 8e - while H 2 O 2 only consumes up to 2e - . Decreasing inlet concentrations, flow rates, and cell voltage result in lower losses to parasitic side reactions as these changes decrease reactant concentrations near the electrodes, which favors charge transfer reactions. Peak conversion efficiency coincides with peak power density because thermodynamic efficiency and parasitic reaction rates both decrease (relative to charge transfer reaction rates) with increasing current density. This work shows that advection, migration and diffusion must be included in H 2 O 2 -DBFC models, and that global reactions are sufficient to capture the essential features of complex H 2 O 2 -DBFC reactions. References [1] I. Merino-Jimenez, C.P. de Leon, A.A. Shah, F.C. Walsh, J Power Sources, 219 (2012) 339-357. [2] C.P. de Leon, F.C. Walsh, A. Rose, J.B. Lakeman, D.J. Browning, R.W. Reeve, J Power Sources, 164 (2007) 441-448. [3] N.A. Choudhury, R.K. Raman, S. Sampath, A.K. Shukla, J Power Sources, 143 (2005) 1-8. [4] K.S. Freitas, B.M. Concha, E.A. Ticianelli, M. Chatenet, Catal Today, 170 (2011) 110-119. [5] G. Rostamikia, A.J. Mendoza, M.A. Hickner, M.J. Janik, J Power Sources, 196 (2011) 9228-9237. [6] G. Rostamikia, M.J. Janik, J Electrochem Soc, 156 (2009) B86-B92. [7] R.O. Stroman, G.S. Jackson, J Power Sources, 247 (2014) 756-769. Fig 1. Schematic of the H 2 O 2 -DBFC.

B. Kirubadurai, R. Jaganraj, M. Vinothkumar et al.

International Review of Applied Sciences and Engineering • 2025

Abstract Fuel cells are a pivotal technology in the changes towards sustainable and clean energy methods due to their high energy performance and environmentally aligning functioning. This investigation carried out an overall computational analysis to investigate the influences of these crucial factors on the efficiency of a single fuel cell. This research work measures the influence of parameters on key performance variables like polarization curves, electric potential and current density output. The results show that higher inlet pressures and mass flow rates significantly enhance reactant transport, thereby decreasing concentration losses and improving polarized current outcomes. GDL porosity and electrode exchange coefficients are found to play a significant role in enhancing reactant distribution and electrochemical reaction kinetics leading to good utilization of fuel and higher cell performance. Conversely, higher inlet temperatures negatively impact efficiency due to rises in thermal stresses and reduced reactant concentrations at critical reaction zone. Furthermore, the research identifies optimal ranges for these parameters, offering actionable insights for improving fuel cell design and operation. These results contribute to the broader efforts in advancing fuel cell technologies paving the way for their effective deployment in clean energy applications. This study underscores the importance of integrating computational analysis into the optimization of high-performance and durable fuel cells for the energy demands of the future.

Ping He, Colin Fraser, Rajesh Bashyam et al.

ECS Meeting Abstracts • 2014

Introduction For many fuel cell system applications hydrogen has to be generated from locally available fuels due to the difficulty to store and transport hydrogen gas. Methanol is one of the high hydrogen content liquid fuels that is readily available in many geographic areas and provides a suitable FC fuel. A fuel processing system, including a reformation stage is usually used to convert the methanol to hydrogen gas to feed to the anode channels of the PEMFC stack. The fuel processor is required to meet specific technical and market demands, such as cost, fuel efficiency and purity levels (e.g., CO, methanol concentration) in its output fuel stream. Meeting those constraints requires a number of reformer and fuel cell stack design trade-offs. For this reason, every reformate based fuel cell system is the result of a series of compromises [1]. In order to understand reformer requirements, a study was conducted on the impacts of a small amount of methanol present in the reformate stream. The goal of this communication is to discuss the impacts of methanol in the reformer output stream on the fuel cell anode performance and durability. Experimental An artificial gas mixture of 71%H 2 , 20% CO 2 , 8% N 2 , and 1% methanol vapor was used to mimic the reformer output fuel stream. All the fuel cell tests were conducted on a Ballard standard research testing cell with an active MEA geometry area of 45cm 2 . The anode was made with a CO tolerant electrode with 0.1 mg/cm 2 PtRu/C catalyst, and the cathode contains 0.4 mg/cm 2 Pt/C. The cell operation temperature was 75 o C, under 5 psig and 100% RH for both MEA sides. The gas flow rates were set to a very high level in order to keep the reactants concentrations approximately uniform across the MEA active area. In order to understand the methanol impact, a dynamic hydrogen electrode (DHE) was mounted onto some of the MEAs to examine the anode and the cathode potentials [2]. Methanol impact on MEA CO tolerance and the anode stability in an accelerating stress testing (AST) were investigated. This AST is used to accelerate the anode degradation in start-up/shutdown processes [3]. Results and Discussions Figure 1 gives the MEA performances with and without the presence of 1% methanol vapor. The polarization behaviors of anode and cathode measured against the DHE are also given in the same plot. As we can see the introduction of 1 % methanol significantly decreased the MEA performance, and this performance loss is dominantly due to cathode performance loss, although the methanol was introduced in the anode side. In-situ cathode cyclic voltammograms were conducted and confirmed that a significant amount of methanol crossed over to the cathode side. The oxidation of the crossover methanol in the oxygen rich cathode occupied the oxygen reduction (ORR) sites and resulted in the decreased ORR activity. In addition, the methanol oxidation current also reduced the ORR current output efficiency. A small stream of air is commonly introduced into the anode under reformed fuel operation in order to oxidize any carbon monoxide present, referred to as “air bleed”. An anode air bleed sensitivity test was used to evaluate the anode catalyst layer CO tolerance. We found that in spite of the lower performance in the presence of methanol, methanol did not significantly impact the air bleed sensitivity. It has been found [3,4] that one of the MEA performance loss failure modes is Ru crossover to the cathode side in reformate tolerant anode designs, due to the use of Ru/C catalyst to improve CO tolerance. The impact of methanol on Ru stability in fuel cell start up /shutdown processes was also studied in this research. More detailed discussion will be presented. References [1] D. G. Loffler, K. Taylor, D. Mason; J. Power Sources; 117 84-91 (2003) [2] V. M. Lauritzen, P. He, A. P. Young, S. Knights, V. Colbow, and P. Beattie; J. New Mat for Electrochem. Sys. 143, (2007). [3] P. He, T. T. H. Cheng, R. Bashyam, A. P. Young and S. Knights; ECS Transactions, 33 (1) 1273-1279 (2010) [4] R. Bashyam, P. He, S. Wessel and S. Knights; ECS Transactions, 41 (1) 837-844 (2011)

Namgee Jung, Mansu Kim, KwangSup Eom et al.

ECS Meeting Abstracts • 2014

Polymer electrolyte membrane fuel cell (PEMFC) stack in a fuel cell vehicle can be exposed to the flooding conditions induced by direct flow of condensed water into the electrodes through the cooled gas lines during winter. Therefore, the anode flooding was intentionally and repeatedly caused by introduction of the condensed water through the anode gas line during long-term operation, which resulted in considerable performance degradation of PEMFC. After the long-term durability test, the anode thickness was decreased, and the ratio of Pt to carbon in the anode was increased. In addition, the simulated and repeated fuel starvation situation in half-cell made the carbon surface of Pt/C catalyst severely oxidized due to induced high potential (> 1.5 V RHE ). The cyclic voltammogram (CV) of the anode in the single cell after the long-term test under the anode flooding condition indicated similar feature of oxidized carbon surface like the CV in the half-cell. Therefore, it was concluded that the repeated fuel starvation by the anode flooding generated the severe carbon corrosion in the anode since the electrode potential locally rose up higher than 1.0 V RHE .