Y.‐N. Wu, S.‐J. Liao, H.‐N. Su et al.

Fuel Cells • 2010

Abstract Carbon nanotubes (CNTs) were shortened from 5 to 15 μm to ca. 200 nm using ball milling with ethanol as the milling aid agent, and a platinum catalyst with these shortened carbon nanotubes (SCNTs) as the support was prepared by a high‐pressure colloidal method. It was found that this catalyst with SCNTs showed much higher activity than a platinum catalyst with normal CNTs as support; for methanol anodic oxidation, the activity of the Pt/SCNTs was 50% higher than that of the Pt/CNTs, and the Pt/SCNTs also showed higher activity for the cathodic reduction of oxygen. The Pt/SCNTs were characterised by X‐ray diffraction scanning and transmission electron microscropy. It is suggested that the significant performance enhancement when SCNTs are used as support might result from the generation of new surfaces and defects, the opening of closed nanotubes in the process of milling, higher platinum dispersion on the shortened nanotubes and the interaction of platinum nanoparticles with the SCNTs.

Yongjin Zou, John Pisciotta, R. Blake Billmyre et al.

Biotechnology and Bioengineering • 2009

Abstract The current study introduces an aerobic single‐chamber photosynthetic microbial fuel cell (PMFC). Evaluation of PMFC performance using naturally growing fresh‐water photosynthetic biofilm revealed a weak positive light response, that is, an increase in cell voltage upon illumination. When the PMFC anodes were coated with electrically conductive polymers, the rate of voltage increased and the amplitude of the light response improved significantly. The rapid immediate positive response to light was consistent with a mechanism postulating that the photosynthetic electron‐transfer chain is the source of the electrons harvested on the anode surface. This mechanism is fundamentally different from the one exploited in previously designed anaerobic microbial fuel cells (MFCs), sediment MFCs, or anaerobic PMFCs, where the electrons are derived from the respiratory electron‐transfer chain. The power densities produced in PMFCs were substantially lower than those that are currently reported for conventional MFC (0.95 mW/m 2 for polyaniline‐coated and 1.3 mW/m 2 for polypyrrole‐coated anodes). However, the PMFC did not depend on an organic substrate as an energy source and was powered only by light energy. Its operation was CO 2 ‐neutral and did not require buffers or exogenous electron transfer shuttles. Biotechnol. Bioeng. 2009; 104: 939–946. © 2009 Wiley Periodicals, Inc.

Giulia Massaglia, Adriano Sacco, Alain Favetto et al.

Energies • 2021

In the present work, sedimentary microbial fuel cells (s-MFC) have been proposed as effective tools to power remote sensors in different aquatic environments, thanks to their ability to produce renewable and sustainable energy continuously and autonomously. The present work proposes the optimization of cylindrical sedimentary microbial fuel cells (s-MFC) as a compact and cost-effective system suitable to be integrated as a payload in an Autonomous Underwater Vehicle (AUV). To this purpose, a new AUV payload, named MFC-payload, is designed to host the cylindrical s-MFC and a data acquisition system to collect and store information on the voltage produced by the cell. Its overall performance was evaluated during two field measurement campaigns carried out in the Mediterranean Sea. This investigation demonstrates the power production by s-MFC during operation of the AUV in seawater and analyzes the actual influence of environmental conditions on the output power. This study demonstrates that energy production by s-MFCs integrated in AUV systems is decoupled by the navigation of the autonomous vehicle itself, showing the effectiveness of the application of MFC-based technology as a power payload for environmental analysis. All these latter results demonstrate and confirm the ability of the devices to continuously produce electricity during different AUV operation modes (i.e., depth and speed), while changing environmental conditions (i.e., pressure, temperature and oxygen content) demonstrate that cylindrical s-MFC devices are robust system that can be successfully used in underwater applications.

Ayodeji Oladiran Awodugba, Gbadebo Taofeek Yusuf

Preprints.org • 2017

The focus of this research is to improve the performance of dye-sensitized solar cells (DSSC) through the adoption of high-quality FTO thin films and incorporation of graphene with DSSC photoanode to enhance its electrical transport. In this research, nanostructured FTO films were first grown with homemade Streaming Process for Electroless and Electrochemical Deposition technology (SPEED) using Tin (II) chloride dihydrate and ammonium fluoride and other chemical formulations. The FTO structural property was measured by X-ray diffraction (XRD); the films’ optical property was determined with transmittance spectra to curve over the wavelength range of 200-1000 nm measured with a spectrophotometer while scanning electron microscope (SEM) was used to determine the morphological properties of the samples. The electrical transport was evaluated by Hall Effect measurements at room temperature with a four-point probe. The FTO samples with the best structural, optical and electrical properties were employed as electrodes and counter electrodes of DSSC along with titanium dioxide. Thus, effect of graphene on the efficiency of DSSC was investigated. It was shown that a graphene-based DSSC showed an efficiency of 7.98% which is slightly higher than that of DSSC prototype without graphene (6.02%). The higher efficiency obtained with graphene can be credited to the ultrahigh surface area and thermal conductivity of graphene which tend to enhance the charge mobility and photovoltaic performance of DSSC. More research is however required to determine the exact amount of graphene that could achieve optimal DSSC performance. Further studies will also offer an adequate clarification for starting point of the better incorporation of graphene in DSSCs.

Wilgince Apollon, Iryna Rusyn, Noris Evelin Paucar et al.

Resources • 2025

Microbial fuel cells (MFCs) are environmentally friendly energy converters that use electrochemically active bacteria (EAB) as catalysts to break down organic matter while producing bioelectricity. Traditionally, MFC research has relied on simple organic substrates, such as acetate, glucose, sucrose, butyrate, and glutamate, the production of which involves energy-intensive, CO2-dependent processes and chemically aggressive methods. In contrast, nonconventional waste streams offer a more sustainable alternative as feedstocks, aligning with zero-waste and regenerative agricultural principles. This review highlights the potential of nonconventional organic wastes, such as fruit and vegetable wastes, raw human and livestock urine, and farm manure, as globally available and low-cost substrates for MFCs, particularly in household and farming applications at small-scale waste levels. Furthermore, complex waste sources, including hydrocarbon-contaminated effluents and lignin-rich industrial wood waste, which present unique challenges and opportunities for their integration into MFC systems, were examined in depth. The findings of this review reveal that MFCs utilizing nonconventional substrates can achieve power outputs comparable to traditional substrates (e.g., 8314 mW m−2–25,195 mW m−2 for crude sugarcane effluent and raw distillery effluent, respectively) and even superior to them, reaching up to 88,990 mW m−2 in MFCs utilizing vegetable waste. Additionally, MFCs utilizing hydrocarbon-containing petroleum sediment achieved one of the highest reported maximum power densities of 50,570 mW m−2. By integrating diverse organic waste streams, MFCs can contribute to carbon-neutral energy generation and sustainable waste management practices.

L.V. Potapenko, L.M. Skachok, N.I. Horbachenko

Agriciltural microbiology • 2018

Objective. Carry out economic and energy evaluation of fertilizing systems of agricultural crops, including for the use of microbial preparations.
 Methods. Field, laboratory, statistical-economic, calculation-comparative.
 Results. On the basis of studies in a long-term field experiment on sod-podzolic soils, economic and energy estimation of crop cultivation in the crop rotation line: lupine - winter rye – potato - oats-was carried out depending on fertilizing systems and pre-seed bacterization of seeds. The prospect of improved organomineral fertilizing system “animal manure + NPK + green manure” has been shown. This fertilizing system provides growth of the conditionally pure profit of crop rotation by UAH 6,922/ha. Using fertilizing system “animal manure + NPK + green manure” for cultures of crop rotation provides an opportunity to increase the conditionally pure profit 2.2 times in comparison with the mineral fertilizing system. With the addition of green manuring to mineral fertilizing system, the conditionally net profit increased from UAH 3,066 to UAH 4,598/ha, or by 50 %. Due to the use of microbial preparations for inoculation of seeds, the profit increases by UAH 1,641/ha, and the return on costs is provided for UAH 1 at the level of UAH 5.09 to 8.10. For energy efficiency, the alternative organic-mineral fertilizing system (animal manure + NPK + green manure) exceeded the traditional one (animal manure + NPK) by 43 % without the use of microbial preparations and by 61 % using biopreparations, and mineral – 2.6 times. The obtained results demonstrate significant prospects for the biological factors of fertilization of crops for their cultivation in short crop rotation.
 Conclusion. The application of organo-mineral fertilizing system (animal manure + NPK + green manure) in combination with microbial preparations in the cultivation of crops in short crop rotation provides high economic and energy efficiency.

N. Zhao, Y. Chu, Z. Xie et al.

Fuel Cells • 2020

Abstract Proton exchange membrane fuel cells (PEMFCs) continue to face cost and durability challenges which need to be addressed before their large scale commercialization. The PEM is an essential component of the fuel cell stack and its durability is thus a critical factor for the overall fuel cell reliability. Significant membrane degradation leads to the development of internal transfer leaks and cell short circuiting irreversibly affecting the fuel cell's functionality. In this study, perfluorosulfonic acid (PFSA) membranes were investigated for the effects of operating temperature and relative humidity on membrane durability using an open circuit voltage (OCV) accelerated stress test. The response surface methodology (RSM) was used to evaluate and optimize the effects of the operating temperature and humidity. As a result, the optimum fuel cell operational region was mapped and suggested as an alternative approach to maintain membrane durability without modifying membrane materials. The mapping could provide valuable guidelines for PEMFC designers and system engineers to optimize the operating conditions during idling to achieve a targeted membrane lifetime.

Zainab Syed, Kumar Sonu, Monika Sogani

Biofuels, Bioproducts and Biorefining • 2021

Abstract The increased use of estrogens in modern livestock farming has caused them to enter the environment and they have become a serious human health concern. Studies have suggested that animal waste treatment using bio‐electrochemical systems may reduce their environmental impact. Bio‐electrochemical systems hold great potential as green bioenergy conversion systems utilizing different bio‐wastes as the feedstock. The present work involves the development of a laboratory‐scale microbial fuel cell (MFC) for energy generation from two different cattle manures (cow dung and buffalo dung) as bio‐waste after ultrasonication pretreatment for a period ranging from 4 to 8 min. The maximum power density in both the cattle manures is reported with 5.5 min of ultrasonication pretreatment at 40 kHz, 120 W, at 25 °C. Two similar setups of a single‐chambered membrane‐less MFC were fed with pretreated cow dung (PCD) and pretreated buffalo dung (PBD) as substrates in the anodic chamber, and the effects of various parameters such as temperature and time were investigated. The maximum chemical oxygen demand and biochemical oxygen demand removal were 80% and 87% respectively, with PBD. The coulombic efficiency of PBD‐MFC was slightly higher (0.53%) than that of PCD‐MFC (0.48%). The maximum voltage (0.65 V) and power density (12.75 mW m −2 ) were also recorded with PBD‐MFC. Energy recovery was also studied by electrically stacking five individual units of these MFCs into series and parallel arrangements. The parallel and series PBD‐MFC stacks yielded 22 and 12 times higher power output respectively than the individual unit. © 2021 Society of Chemical Industry and John Wiley & Sons, Ltd

Nan Jiang, Li Huang, Teng Cai et al.

Research Square • 2020

Abstract In this study, thin-film composite with embedded polyester screen (TFC-ES), cellulose triacetate with a cast nonwoven (CTA-NW) and cellulose triacetate with embedded polyester screen (CTA-ES) were examined as the intermediate membranes in osmotic microbial fuel cells (OsMFCs). The reactors were fed with actual landfill leachate and the performance was studied in two operation modes: active layer facing draw solution (AL-DS) and active layer facing feed solution (AL-FS). The OsMFC with CTA-ES exhibited the best energy generation (maximum power density: 0.44 W m -2 ) and pollutant removal efficiency (ammonia nitrogen: 70.12 ± 0.28%, total nitrogen: 74.04 ± 0.33%) in the AL-FS mode, which could be ascribed to the lowest internal resistance (236.75 ohm) and highest microbial richness. Pseudomonas was the highest proportion of microbial in OsMFCs. The results of this study has demonstrated the potential of OsMFCs for landfill leachate treatment.

Williamson Gustave, Zhao-feng Yuan, Raju Sekar et al.

Preprints.org • 2018

Soil microbial fuel cells (sMFC) are a novel technique that use organic matters in soils as an alternative energy source. External resistance (ER) is a key factor influencing sMFC performance and, furthermore, alters the soil’s biological and chemical reactions. However, little information is available on how the microbial community and soil component changes in sMFC with different ER. Therefore, the effects of anodes of sMFC at different ER (2000 Ω, 1000 Ω, 200 Ω, 80 Ω and 50 Ω) were examined by measuring organic matter (OM) removal efficiency, trace elements in porewater and bacterial community structure in contaminated paddy soil. The results indicated that ER has significant effects on sMFC power production, OM removal efficiency and bacterial beta diversity. Moreover ER influences iron, arsenic and nickel concentration as well in soil porewater. In particular, greater current densities were observed at lower ER (2.4mA, 50Ω) compared to a higher ER (0.3mA, 2000Ω). The removal efficiency of OM increased with decreasing ER whereas it decreased with soil distance away from the anode. Furthermore, principal coordinate analysis (PCoA) revealed that ER may shape the bacterial communities that develop in the anode vicinity but have minimal effect on that of the bulk soil. The current study illustrates that lower ER can be used to selectively enhance the relative abundance of electrogenic bacteria and lead to high OM removal.

, Andrew C. Chien, et al.

Journal of Energy and Power Technology • 2021

The metallic copper, alkaline earth metal oxide, boron, and perovskite were incorporated on the surface of a Ni-cermet anode, and the performance of the modified Solid Oxide Fuel Cell (SOFC) anode was evaluated. The cell performance was analyzed by voltage-current characteristics (V-I curve) and H2-CH4 step reactions (P-t curve) in a potentiostatic mode. Besides, we also determined if a metallic phase or high electronic conductivity of the anode is important for a cell to perform well when H2 is used as a fuel, whereas both conductivity and anti-coking capability are critical while using CH4 as a fuel. The results showed that the anodes containing magnesium oxide (MgO), lanthanum strontium titanate (La0.4Sr0.4TiO3−γ), and boron were relatively resistant to the degradation in the CH4 environment when compared with others. The underlying mechanism varied mainly with electronic and structural promotion by the dopants as well as their material compatibility with the Ni-cermet substrate. These findings were evidenced and supported by surface analysis as well as in-situ infrared and mass spectroscopic studies too.

Young Je Park, Won young Choi, Hyunguk Choi et al.

ECS Meeting Abstracts • 2024

In the global energy market, several major unions and industries release the roadmap that utilize the hydrogen as the energy carrier, to achieve the fully electrification of transportation for carbon neutrality. Polymer electrolyte fuel cells (PEFCs) are suitable for heavy-duty vehicles (HDVs) due to advantages such as fast refueling (< 5 min), long driving range (> 300 miles), and higher efficiencies (>60%) [1] . HDVs often encounter tougher conditions than light-duty vehicles (LDVs), including longer distances, extended operating hours, and challenging terrain. The ORR electrode running under such environments suffers from severe liquid water flooding of pores. Addressing this issue requires controlling the water management, crucial for mitigating voltage losses at high current density (HCD) [2] . The cathode GDL acts as a central hub of the bidirectional flow during the operation, achieving an optimal balance between electrode and channel. The overlapping of liquid and gas pathways can lead to a significant increase in mass transport resistance (MTR). Engineering the liquid/gas highways to avoid the overlapping, many researchers have spent much effort on breakthrough strategy for the flooding problem following parameters: pore size distribution, surface roughness, and surface wettability [3-4] . Within the cell, water molecules generated by the ORR condense in various places. Adjusting the microstructure serves as an effective method for managing the pathway of condensed liquid water [5] . Especially, condensed water at the CL-MPL interface along the in-plane is challenging to discharge through microporous due to capillary pressure. To dramatically improve the performance, it is essential to clearly understand the correlation between three-dimensional microstructure of the MPL, CL-GDL interface, and the mass transport resistance at HCD. In this study, we proposed a straightforward strategy that significantly reduces MTR by simple structural change from non-penetrative crack to penetrative crack via carving the designed MPL crack. Firstly, advanced transparent XRM device enables X-CT analysis under conditions that mirror the actual PEFC operating environment. The voids at the CL-MPL interface are considered to serve as potential drop sources related with MTR, where the vapor generated by the ORR is likely to condense. Secondly, to discharge the condensed liquid at the interfaces under low-temperature and/or high-current density conditions, we have explored microstructural benefits of penetrative cracks. All parameters known to be associated with liquid water transport are fully-controlled except for crack microstructure (crack-free, non-penetrative crack, and penetrative crack). Finally, the stability test at HCD indicated a notable enhancement of liquid discharge and gas injection in GDLs with the penetrated cracks. Our results suggest that penetrative crack with concise fabrication method can provide stable water management capability for improving the performance at HCD of PEFC. [1] Cullen, David A., et al. "New roads and challenges for fuel cells in heavy-duty transportation." Nature energy 6.5 (2021): 462-474. [2] Cai, Fengyang, Shanshan Cai, and Zhengkai Tu. "Proton exchange membrane fuel cell (PEMFC) operation in high current density (HCD): Problem, progress and perspective." Energy Conversion and Management 307 (2024): 118348. [3] Lin, Pengzhu, et al. "Quadrilateral-Patterned Perforated Gas Diffusion Layers Boost the Performance of Fuel Cells." ACS Energy Letters 9 (2024): 1710-1716. [4] Csoklich, Christoph, Thomas J. Schmidt, and Felix N. Büchi. "High performance gas diffusion layers with added deterministic structures." Energy & Environmental Science 15.3 (2022): 1293-1306. [5] Wen, Qinglin, et al. "Janus gas diffusion layer for enhanced water management in proton exchange membrane fuel cells (PEMFCs)." ACS Energy Letters 7.11 (2022): 3900-3909.

Noor Ul Hassan, Mrinmay Mandal, Garrett Huang et al.

Advanced Energy Materials • 2020

Abstract The primary function of the ionomers that are incorporated into fuel cell electrode catalyst layers is to provide pathways for ion transport between the catalyst active sites and the electrolyte. This is influenced by many variables, including the ion‐exchange capacity, water uptake, and molecular weight. In anion exchange membrane fuel cells (AEMFCs), controlling ionomer water uptake is particularly important and tailoring this property in each electrode is an important consideration when looking to maximize cell performance. In this study, three poly(norbornene) tetrablock copolymer ionomers with a range of physical properties are synthesized and incorporated into AEMFC anode and cathode electrodes. Systematic electrode engineering with these ionomers allows the peak power density to be increased by 100% (1.6 W cm ‐2 → 3.2 W cm ‐2 ) and the current density at 0.2 V to be increased by 59% (5.9 A cm ‐2 → 9.4 A cm ‐2 ). Moreover, the top‐performing electrode configuration is tested in an operating AEMFC at the US Department of Energy defined current density of 600 mA cm ‐2 for 2000 h, showing a record‐low voltage decay rate of 15.36 µV h ‐1 – only 3.65% –a over 2000 h. This work sets a new bar for AEMFCs, reporting the best combination of performance and durability of any AEMFC to date.

Yujing Jiang, Pingping Li, Yuanyuan Wang et al.

Journal of Materials Chemistry A • 2019

Trifunctional modification of individual bacterial cells results in fast start-up and high stability and output of microbial fuel cells.

Sharon B. Velasquez‐Orta, Tom P. Curtis, Bruce E. Logan

Biotechnology and Bioengineering • 2009

Abstract Bioelectricity production from a phytoplankton, Chlorella vulgaris , and a macrophyte, Ulva lactuca was examined in single chamber microbial fuel cells (MFCs). MFCs were fed with the two algae (as powders), obtaining differences in energy recovery, degradation efficiency, and power densities. C. vulgaris produced more energy generation per substrate mass (2.5 kWh/kg), but U. lactuca was degraded more completely over a batch cycle (73 ± 1% COD). Maximum power densities obtained using either single cycle or multiple cycle methods were 0.98 W/m 2 (277 W/m 3 ) using C. vulgaris , and 0.76 W/m 2 (215 W/m 3 ) using U. lactuca . Polarization curves obtained using a common method of linear sweep voltammetry (LSV) overestimated maximum power densities at a scan rate of 1 mV/s. At 0.1 mV/s, however, the LSV polarization data was in better agreement with single‐ and multiple‐cycle polarization curves. The fingerprints of microbial communities developed in reactors had only 11% similarity to inocula and clustered according to the type of bioprocess used. These results demonstrate that algae can in principle, be used as a renewable source of electricity production in MFCs. Biotechnol. Bioeng. 2009;103: 1068–1076. © 2009 Wiley Periodicals, Inc.

Aquiles Perez, Amir Abtahi, Ali Zilouchian

ASME 2008 Power Conference • 2007

Pulse-width modulation of hydrogen delivery is proposed to accomplish better performance of PEM fuel cells. By evaluating power consumption patterns and time delays associated with hydrogen and air consumption, optimal functional feedback controllers are developed. By matching the ON and OFF times for the hydrogen and oxygen supply valves, in conjunction with a system fuzzy controller (1), the power output is matched to specific load requirements. The fluid transient behavior is also monitored, to develop functional relationships between the power curve, and the fluid conditions, in order to optimize the system performance. These functions are then used to update and improve the performance of the controller.

Xinpei LIU, Yang LI, Yangguo ZHAO et al.

Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University • 2022

In the long-term electricity generation and driving sensor work process of marine sediment microbial fuel cells(MSMFCs), its cathode in the seawater may be embedded into the marine sediment, which will affect the electrochemical performance and lead to MSMFCs failure. The article simulated the embedding ratio of cathodes in sediment in the laboratory: 1/3, 1/2, 2/3, in order to investigate the changes of the electrochemical performance of the cathode and the electricity generation performance of MSMFCs. The results show that: the open circuit potential dropped and the required longer steady time with the higher embedding ratio of the cathode. Its capacitance decreased gradually, and the minimum capacitance was 32 F/cm 2 (2/3 group), which was 0.72 times of the Blank. The kinetic activity decreased firstly and then increased, and its maximum activity was 1.61 times of the Blank (2/3 group); The maximum power density of the MSMFCs was 140.83 mW/m 2 (1/3 group), which was 1.21 times of the Blank. With the increase of embedding ratio of the cathode in the marine sediment, its electrochemical performance and electricity generation performance of MSMFCs both fluctuates, but the normal operation of MSMFCs can still be ensured.

Eva Novillo, Mónica Pardo, Alberto García-Luis

Journal of Fuel Cell Science and Technology • 2010

Reduced greenhouse gas emissions via improved energy efficiency represent the ultimate challenge for the energy economy of the future. In this context, fuel cells for power generation aboard aircrafts have a promising potential to effectively contribute to the greening of air transportation. They can simplify today’s aircraft comprising electric, pneumatic, and hydraulic systems toward a more electric airplane. Although they are not considered in the short term as an alternative propulsion system for commercial aviation, many efforts are being devoted to their use as auxiliary power units and even aiming to build a distributed power network that might alleviate duties of the engine driven generators. In addition they allow new functions such as zero emission during taxiing on ground and/or increase safety by replacing the emergency ram-air turbine (RAT) by a fuel cell based emergency power generator. The present paper focuses on the effort that Compañía Española de Sistemas Aeronáuticos (CESA) is putting into the development of an aeronautical fuel cell system based on a high-temperature PEMFC covering all aspects from fundamental research in materials and processes to final integration concepts as a function of different architectures. A great deal of time and effort has been invested to overcome the challenges of PEM fuel cell operation at high temperatures. Among the advantages of these systems are the enhancement of electrochemical kinetics, the simplification of water management and cooling, the recovery of wasted heat, and the possibility of utilizing reformed hydrogen thanks to higher tolerance to impurities. However, new problems arise with the high-temperature concept that must be addressed such as structural and chemical degradation of materials at elevated temperatures. One of the aeronautical applications, where a fuel cell has an important role to play in the short term is the emergency power unit. Weight and mechanical complexity of traditional ram-air turbines could be drastically reduced by the introduction of a hydrogen fueled system. In addition, the output of the fuel cell is aircraft’s speed independent. This means additional power supply in case of emergency allowing a safer landing of the aircraft. However, a RAT replacement must overcome the specific difficulties concerning the very short start-up times allowed and the heating/cooling strategies to quickly raise the temperature to elevated levels and accurately maintaining the optimum operating range once in service.

Rajesh Ahluwalia, Xiaohua Wang, Jui-Kun Peng et al.

ECS Meeting Abstracts • 2019

Previous studies have shown that meeting the 30 $/kW e cost and 8,000-h durability targets for automotive fuel cell systems (FCS) requires high-activity oxygen reduction reaction (ORR) cathode catalysts that are stable under cyclic potentials at low Pt loadings (<0.1 mg-Pt/cm 2 ). We have evaluated the performance and durability of a state-of-the-art (SOA) fuel cell stack and system under automotive relevant conditions using data obtained for a membrane electrode assembly (MEA) operated under differential cell conditions. The MEA has de-alloyed Pt 3 Co catalyst supported on a high surface area carbon (HSAC) in cathode, Pt catalyst supported on Vulcan carbon in anode, thin 12-μm reinforced PFSA membrane, and 200-μm thick diffusion media with microporous layers. The Pt loadings are 0.1 mg/cm 2 in the cathode catalyst and 0.025 mg/cm 2 in the anode catalyst. We formulated a model for ORR kinetics on d-PtCo/C catalyst by using the measured polarization data at low current densities together with the ionic conductivity of the cathode catalyst layer derived from the Galvanostatic impedance data obtained in H 2 /N 2 , and a transient solid solution model for oxide coverage as a function of potential, relative humidity and temperature. The kinetic model indicates that d-PtCo/C catalyst has 650 A/g Pt mass activity, which is double the mass activity of annealed Pt catalyst that has nearly the same particle size, and easily exceeds the target of 440 A/g Pt . In accelerated stress tests (AST) with 0.6-0.95 V square wave potentials in cyclic voltammetry, there are negligible changes in kinetic parameters denoting the reaction order for O 2 partial pressure, activation energy and relative humidity (RH) dependence. As indicated in Fig. 1, the specific activity (µA/cm Pt 2 ) degraded by ~33% in AST during which time the electrochemically active surface area (ECSA) decreases by 7.5% and nearly stayed constant with further decrease in ECSA. We concluded that the mass activity, which is a product of specific activity and ECSA, degrades in AST initially because of decrease in specific activity due to cobalt dissolution and subsequently because of decrease in ECSA due to coarsening of catalyst particles. We determined the oxygen transport resistance of the d-PtCo/C electrode (R cf ) by (a) using the measured polarization data at high current densities; (b) estimating mass transfer overpotentials (η m ) from the ORR kinetic model; (c) determining the limiting current densities (i L ) at which η m equals 400 mV; (d) estimating the oxygen transport resistance (η m ) from i L ; and (e) extracting the pressure-dependent and pressure-independent (R cf ) parts of R m . We concluded that after 30,000 AST cycles, the pressure-dependent part of R m representing O 2 transport resistance in gas channel and gas diffusion layer (GDL) showed small changes; however R cf has increased by >50% at 40% RH exposure and >125% at 100% RH exposure. Lower roughness (S Pt , cm Pt 2 /cm 2 ) because of catalyst coarsening accounts for 8% of the increase in R cf at 40% exposure and for 45% increase at 100% exposure. Also, 48-60% of the increase in R cf may be associated with the reduction in O 2 permeability through the ionomer film on the catalyst particles supported on HSAC. We developed an integral cell model using the differential cell data to evaluate the performance and cost of an automotive FCS with the d-PtCo/C catalyst relative to the targets of 65% peak efficiency, 8.0 kW e /g stack Pt utilization, 1000 mW/cm 2 stack power density and 40 $/kW cost, all subject to 1.45 kW/K (Q/ΔT) heat rejection constraint. The analysis indicates that the SOA catalyst can achieve 9.5 ± 0.5 kW e /g stack Pt utilization and 1180 ± 55 mW/cm 2 gross stack power density at 656 mV cell voltage, 2.5 atm stack inlet pressure, 95 o C stack coolant outlet temperature, and 1.5 cathode stoichiometry. The projected system cost is 46.0 ± 0.7 $/kW e at high manufacturing volume (500,000 units/year). At lower manufacturing volumes, the estimated costs are 51 $/kW e at 100,000 units/year and 88 $/kW e at 10,000 units/year. We projected FCS performance degradation in terms of ECSA loss by conducting simulations at constant air flow rate (variable cathode stoichiometry) and heat rejection (Q). The simulations indicate that meeting the target of 10% derating in FCS power over lifetime requires controlling the stack operating conditions to limit the ECSA loss to 35%. At end of life, we estimate that mass activity has degraded by ~50%, specific activity by 25%, and the cell voltage at rated power by 30 mV. Increase in kinetic overpotential due to Co dissolution and coarsening of catalyst particles accounts for the majority of the projected cell voltage loss at rated power. Figure 1

Huai-Suen Shiau, Adam Z Weber

ECS Meeting Abstracts • 2016

Among the existing fuel-cell types, alkaline-exchange-membrane fuel cells (AEMFC) have intriguing features as compared to proton-exchange-membrane fuel cells (PEMFC). Their major advantage is the possibility of using non-noble catalysts due to faster oxygen-reduction reaction (ORR) kinetics in alkaline than in acidic media. However, water management is a more serious concern in AEMFCs because OH- conductivity is more highly dependent on water content and the ORR consumes water. Compared to PEMFCs, the lower performance of AEMFCs is mostly caused by extremely nonuniform distribution of water in the ionomer phase between the anode and cathode as well as the increased overpotential for the hydrogen oxidation reaction. In this presentation, we will discuss the performance-limiting mechanisms specific to different operating conditions (e.g. varying inlet relative humidity (RH)) based on a cell-level mathematical model. For example, anode flooding can be a critical issue at 100% RH, whereas at lower RH high ionic transport resistance in the cathode dominates due to dehydrated ionomer phase at high current, where the impact of water-consuming ORR kinetic polarization is also critical. Low AEMFC performance at high current is not simply due to mass transport issues with vapor/membrane water, but a consequence of poor water distribution leading to sluggish OH- conduction and ORR kinetics. A sensitivity analysis of design parameters including the humidifying condition and membrane property is performed to identify the most significant factors controlling performance. Overall, water management and ionic/mass transport characteristics of an AEMFC assembly are discussed in detailed. The developed model will be used to examine and elucidate performance bottlenecks and enable strategies to overcome them, significantly increasing the possibility of AEMFC commercialization. Acknowledgements This work was funded by the Fuel Cell Technologies Office, Office of Energy Efficiency and Renewable Energy, of the U. S. Department of Energy under contract number DE-AC02-05CH11231, program manager David Peterson.

Bhavana Parackal, Hamidreza Khakdaman, Yves Bourgault et al.

International Journal of Electrochemistry • 2018

An improved mathematical model was used to extend polarization curves for direct propane fuel cells (DPFCs) to larger current densities than could be obtained with any of the previous models. DPFC performance was then evaluated using eleven different variables. The variables related to transport phenomena had little effect on DPFC polarization curves. The variables that had the greatest influence on DPFC polarization curves were all related to reaction rate phenomena. Reaction rate phenomena were dominant over the entire DPFC polarization curve up to 100 mA/cm 2 , which is a value that approaches the limiting current densities of DPFCs. Previously it was known that DPFCs are much different than hydrogen proton exchange membrane fuel cells (PEMFCs). This is the first work to show the reason for that difference. Reaction rate phenomena are dominant in DPFCs up to the limiting current density. In contrast the dominant phenomenon in hydrogen PEMFCs changes from reaction rate phenomena to proton migration through the electrolyte and to gas diffusion at the cathode as the current density increases up to the limiting current density.

Benjamin Britton, Scot Jones, Nathan Chen et al.

ECS Meeting Abstracts • 2023

Until recently it was thought that hydrocarbon-based (i.e. non-fluorinated) proton-exchange membranes faced intractable issues in achieving the high performances, chemical stability, and mechanical integrity for effective integration into fuel cells. However, Pemion ® PF1-HLF8-15-X, a composite membrane incorporating a new class of polyarylene sulfonic acids, has been commercialized to meet and exceed precedents set for decades by perfluorosulfonic acids (PFSAs) membranes. These attributes include: The first demonstrable success in all three categories of US Department of Energy accelerated stress tests (open circuit, humidity cycling, combined oxidative-mechanical cycling) without additives, using mass-market components and processes. This suggests greater system lifetimes are achievable and readily incorporated by fuel cell OEMs. Consistent high performances that exceed heavy duty targets (e.g. peak power densities >1.4 W/cm² with a 15 µm membrane) exhibiting comparable area resistances to state-of-the-art PFSA-based materials but across a broader operational temperature range, including a higher temperature operating window of 95 °C without area resistance gain and 110 °C without degradation, This enables long-targeted benefits, chief among which are heat exchanger size reductions and an end to over-specification for heavy duty transportation and aviation applications. Significantly reduced gas crossover in all conditions This enables greater fuel efficiency and the potential for increased component lifetimes or operational pressures. A green and “future proof” chemistry In light of EU-REACH and EPA threat of regulation and the fact that PFSAs emit fluorinated acid derivative PFAS of concern during operation, hydrocarbon materials are the only way to ensure a robust supply chain into the future, with additional benefits of simplifying recycling at end-of-life. These combined benefits represent the near-term potential to realize a step-function alteration in the economic viability of fuel cell systems for both transportation and stationary applications.

Ji Eon Chae, Youngseung Na, Jieun Choi et al.

ECS Meeting Abstracts • 2018

Fuel cells are high-efficiency, environment-friendly power generation systems which produce electricity and thermal energy through electrochemical reactions between hydrogen and oxygen. Unlike conventional generators, it produces electricity directly without the energy conversion process through combustion of fuel. It is attracting attention as a next generation energy source that has a low energy loss, high power generation efficiency, and can be used as a distributed power source. Up to date, a various types of fuel cells were developed and studied. However, the high cost of fuel cell systems which are composed of the precious metal catalyst, the perfluorosulfonic acid membrane such as Nafion, and humidifier etc. was the problem. Especially, in regard to the humidification system, the hydration of membrane is significant for proton and hydroxyl ion conduction on the fuel cell operations. Therefore, the PEMFCs need a considerable size of humidifier which supplies moisture to the PEMFC. Due to the humidifier, the total fuel cell system becomes big and heavy. Because of the reason, it is difficult to load PEMFC in the system which requires the limit of weight and volume such as unmanned aerial vehicles. In this work, a new type of polymer electrolyte fuel cell, which is composed of anion exchange membrane (AEM) and cation exchange membrane (CEM) at a one to one ratio (named half- half cell) as shown in Figure 1, is proposed for non-humidified system. As it occurs the electrochemical reactions in the anode (AEM) on hydrogen oxidation reaction (HOR) and in the cathode (CEM) on oxygen reduction reaction (ORR), water was generated on the dry condition and affected for the fuel cell operation. As shown in Figure 2 (a), the half- half cell was carried out for a long term test at 0.6 V constant voltage mode for 60 days and analyzed by current-voltage polarization, electrochemical impedance spectroscopy. And the each performance of AEM and CEM was investigated with specially produced and divided separator and measured. In current aspect, we ascertained that the overall cell performance comes from CEM part and the AEM part is just for pertaining to generate water in Figure 2 (b). For investigating the flow of generated water through the separator channel to the naked eye, the acrylic transparent single cell was used. Also, we compared the effect of the generated water on consumption alternately between CEM and AEM (orthogonal) and on passing through each membrane completely (parallel) by describing the calculated relative humidity in the cell. Finally, the MEAs were piled up in order of bipolar plates, and MEAs to 5 unit and put in one direction on the flow channel. The stack was tested with alternating nitrogen and fuel (hydrogen and oxygen) to observe how well the fully dried MEA could perform. The electrochemical reactions can be reoccurred and it was operated rapidly in a few minutes because of the already activated MEAs. We carried out the long-term durability of the stack through a repetitive cycle in the non-humidified condition for 210 h. The details will be discussed in presentation. Figure 1

Timo Rüde, Yulin Lu, Leon Anschütz et al.

Energy Technology • 2023

The benzyltoluene‐based liquid organic hydrogen carrier (LOHC) system enables the safe transport and loss‐free storage of hydrogen. At least 26% of the lower heating value of the released hydrogen, however, has to be invested in form of heat to release the stored hydrogen. The low operation temperatures of catalytic distillation (CD) can facilitate waste heat integration to reduce external heat demand. Herein, the continuous hydrogen release from perhydro benzyltoluene via CD is demonstrated. It is revealed in the experimental results that this mode of operation leads to a high hydrogen release rate and very efficient noble metal catalyst usage at exceptionally mild conditions. The hydrogen‐based productivity of platinum of 0.35 g H2 g Pt −1 min −1 (0.7 kW LHV_H2 g Pt −1 ) at a dehydrogenation temperature of only 267 °C is found to be nearly four times higher than for the conventional continuous liquid‐phase dehydrogenation at the same temperature. Furthermore, simulation results of the CD process are described. The feasibility of a fully heat‐integrated process for electricity generation from the released hydrogen via CD using waste heat from the fuel cell for the CD reboiler is demonstrated. The technical potential of coupling the H12–BT dehydrogenation by CD with high‐temperature fuel cell operation is highlighted by the simulation.

Vaibhav Vibhu, Izaak C. Vinke, Fotios Zaravelis et al.

Energies • 2022

Ni-gadolinia-doped ceria (GDC) based electrode materials have drawn significant attention as an alternative fuel electrode for solid oxide cells (SOCs) owing to mixed ionic conductivity of GDC and high electronic and catalytic activity of Ni. Moreover, the catalytic activity and electrochemical performance of the Ni-GDC electrode can be further improved by dispersing small quantities of other metal additives, such as gold or molybdenum. Therefore, herein, we considered gold and molybdenum modified Ni-GDC electrodes and focused on the upscaling; hence, we prepared 5 × 5 cm2 electrolyte-supported single cells. Their electrochemical performance was investigated at different temperatures and fuel gas compositions. The long-term steam electrolysis test, up to 1700 h, was performed at 900 °C with −0.3 A·cm−2 current load. Lastly, post-test analyses of measured cells were carried out to investigate their degradation mechanisms. Sr-segregation and cobalt oxide formation towards the oxygen electrode side, and Ni-particle coarsening and depletion away from the electrolyte towards the fuel electrode side, were observed, and can be considered as a main reason for the degradation. Thus, modification of Ni/GDC with Au and Mo seems to significantly improve the electro-catalytic activity of the electrode; however, it does not significantly mitigate the Ni-migration phenomenon after prolonged operation.

Chan Kim, Yong Jung Kim, Yoong Am Kim et al.

Journal of Applied Physics • 2004

The potential of cup-stacked-type carbon nanotubes (CSCNTs) as a catalyst support for the direct methanol fuel cells has been investigated by the electrochemical oxidation of methanol at various temperatures. The CSCNT-supported platinum–ruthenium (Pt–Ru) bimetallic catalyst exhibited twice as high a power density as the Pt–Ru catalyst supported on Vulcan XC-72 carbon, which is widely used as a catalyst support for the DMFC electrodes. The microscopic analysis of the CSCNT-supported Pt–Ru catalysts revealed that the bimetallic electrocatalysts were well dispersed on the CSCNT supports, and the particle size of the electrocatalysts was ca.5nm . The results of this work indicate that the performance of the carbon support materials is largely influenced by their electrical properties, morphology and crystallographic structures.

Dena Kartouzian, Arezou Mohseninia, Henning Markötter et al.

ECS Meeting Abstracts • 2019

The influence of porosity modifications of either microporous layer (MPL) or the catalyst layer of a low temperature Polymer Electrolyte Membrane Fuel Cell (PEMFC) on the performance of the cell has been investigated in many studies. However, we have been focusing in our study on the interactive impact of this morphological modification of both cathode MPL and catalyst layer in the water distribution and transport inside the cell and consequently also on the performance of the cell. In this study, three types of cathode MPLs with different porosity distributions and three type of membrane electrode assemblies (MEA) with different porosity of the catalyst layer are manufactured. Five one-cell fuel cells are investigated using combinations of those in-house made layers. To modify the porosity of the cathode MPL polymer particle in two sizes of 30 µm and 1.5 µm from company Chemisnow ® are introduced into the carbon slurry, which are then evaporated out of the MPL during the sintering process. For the catalyst layers, 0.5 µm Polystyrene particles are mixed in the electrode slurry with variable weight fractions and then washed out of the dried MEA. A more detailed description of the production procedure of these layers will be demonstrated in the presentation. Performance of fuel cells using these five combination of cathode MPL and electrode are measured using a Fuel Cell with 25 cm² active area and 3 serpentine channel flow fields. Neutron Radiography is used to investigate the water distribution dynamics and water content of the fuel cell. For this purpose, a specially designed single cell with 8 cm² active area and 3 serpentine channel flow fields is used. The measurements are obtained at two different humidity values on both cathode and anode inlet gases of RH=70% and RH=120% and different current densities. With an exposure time of 10 s, images with 12.4 µm pixel size are achieved. The quantitative analysis of the water thickness in the cathode GDL and cathode electrode of 5 cells at RH=120% for an increasing current density is shown at an exemplary radiogram for water distribution inside the cell with our reference cathode MPL and electrode (without porosity modification). Also the Current (I Cell ) and Voltage (V Cell ) evolution of the same cell is shown in figure 1. All cells have reached a water content plateau even before reaching the highest current density of 1A/cm². The cell with a porous catalyst layer and a double layer cathode MPL shows the highest water content on the cathode side of the cell, whereas the cell with a highly porous catalyst layer and a porous MPL shows the lowest water content of all cells, comparable to the water thickness observed for the cell without modified layers. Further results of both water content and performance dependent on porosity changes will be provided in the presentation. Figure 1

Hoai-An Trinh, Van-Du Phan, Hoai-Vu-Anh Truong et al.

Electronics • 2022

Developing an energy management strategy (EMS) is an important requirement to satisfy the load power demand for a proton-exchange membrane fuel cell (PEMFC) hybrid system under different working conditions. For this objective, this paper proposes an EMS to control the power distribution between the PEMFC, battery (BAT), and supercapacitor (SC) and regulate the DC bus voltage for matching the load power demand. In this strategy, fuzzy logic rules (FLRs) and low-pass filters (LPFs) are utilized to determine the reference currents for energy sources based on their dynamic response. In addition, current and voltage control loops are designed to provide the appropriate gains for compensators that can maintain a stable voltage on the DC bus. Finally, simulations are conducted in the MATLAB/Simulink environment to validate and compare the effectiveness of the proposed strategy with others. The simulation results present that the proposed EMS achieves the highest distributed power accuracy with an error of (−2.1→2.6) W, while reducing the DC bus voltage ripple by 1% under various load working conditions in comparison to the other approaches.

Jayanthi Velayudhan, Sangeetha Subramanian

Emerging Materials Research • 2025

Microbial fuel cells (MFCs) offer a promising dual-function solution for sustainable energy generation and wastewater treatment. However, improving their power output remains a significant challenge due to conventional conductive binders’ high cost and limited conductivity. This study introduces a novel approach by developing a binder-free selenium nanoparticle (SeNP)–decorated cathode and integrating a bioanode to enhance MFC performance. The cathode was prepared by simple dip-coating method. SeNPs were synthesized using ascorbic acid and the extracellular extract of lysinibacillus xylanilyticus, providing a cost-effective and eco-friendly cathode modification. Concurrently, Shewanella putrefaciens was immobilized on the anode to enrich electroactive biofilms and facilitate extracellular electron transfer. The MFC designed with a binder-free SeNP-decorated cathode (B-Se-G) and bioanode achieved a record-high power density of 7000 µW/m 2 , significantly superior to C-Se-G (4761 µW/m 2 ) and the bare graphite electrode. This improvement was attributed to enhanced electrochemical catalytic activity, higher extracellular electron transfer efficiency, increased chemical oxygen demand removal, and improved coulombic efficiency. Integrating an exoelectrogen-enriched bioanode and a binder-free selenium-decorated cathode represents a breakthrough in MFC technology, offering a scalable, cost-effective, and sustainable solution for simultaneous wastewater treatment and bioelectricity generation. These findings provide new insights into optimizing MFC architecture for enhanced performance and practical implementation.

Alexandros Dokouzis, Dimitra Zoi, George Leftheriotis

Materials • 2020

In the present work, we propose a new architecture for partly covered photoelectrochromic devices with a modified anode layout, so that the TiO2 film is deposited first on the substrate, covering a small part of its surface, followed by the WO3 film that covers the remaining device area. As a result, the TiO2 film can be subjected to the proper thermal and chemical treatment without affecting the electrochromic performance of the WO3 film. The proposed design led to photoelectrochromic (PEC) devices with a power conversion efficiency (PCE) four times higher than that of typical partly covered devices, with a measured maximum of 4.9%. This, in turn, enabled a reduction in the total area covered by the photovoltaic unit of the devices by four times (to 5% from 20%), thus reducing its visual obstruction, without affecting the depth, uniformity and speed of coloration. A detailed study of the parameters affecting the performance of the new devices revealed that, with the cover ratio decreasing, PCE was increasing. The photocoloration efficiency also exhibited the same trend for cover ratio values below 15%. Storage of the devices in short circuit conditions was found to accelerate optical reversibility without affecting their photovoltaic and optical performance.

Mengkun Tian, Wesley Tennyson, Alexander Blair Papandrew et al.

ECS Meeting Abstracts • 2017

Solid acid fuel cells (SAFC) working at intermediate temperature (250°C) have many advantages compared to the lower temperature proton exchange membrane fuel cell (PEMFC), such as increased catalyst activity and are more resistant to CO poisoning. 1, 2 The state-of-the-art cathode is comprised of porous protonic conductor coated by Pt. 3, 4 There are two major roles of Pt in the cathode: (1) the oxygen reduction reaction (ORR) catalyst and (2) the electron conductor. To maintain a highly electron conductive network, a high fraction of Pt has to be loaded in ‘conventional’ SAFC electrodes. However, to generate wider application, the cost of the cathode must be reduced significantly. The function of Pt as electron conductor can be replaced by the catalyst support to achieve this reduction in loading. The catalyst support must have high electron conductivity, corrosion-resistance and high surface area. The carbon nanostructures are the common catalyst supports used in the fuel cells. In our previous studies, we demonstrated that multi-wall carbon nanotubes are much more stable during fuel cell testing compared to the single wall carbon structures. 5 Indeed, pure single layer or few-layer carbon supports are well known to be particularly vulnerable to corrosion in the present of water. However, previous research showed that substitutional boron can lower the electron density of the reactive carbon, leading to a reduction in the rate of O 2 chemisorption. 6 Meanwhile, very small amounts of boron (~1%) have been demonstrated to enhance the conductivity of the single carbon structure. 7 In our recent studies, we synthesize the pure single wall carbon, carbon structures in hydrogen gas and with boron loading. Surprisingly, the boron loading induces the growth of few-layer graphenes (FLGs), which exhibit much better corrosion resistance than the single wall carbon and carbon synthesized in hydrogen gas which consists of multi-wall and single-wall carbon structure. In this research, we focus on the structural investigation of those FLGs. Characterization of the FLGs are performed by high resolution transmission electron microscopy (HRTEM) imaging, monochromated electron energy-loss spectroscopy (EELS), nano-beam electron diffraction (NBED), aberration corrected scanning transmission electron microscopy (STEM) imaging, X-ray photoelectron spectroscopy (XPS), nuclear magnetic resonance (NMR), Raman spectroscopy and X-ray diffraction (XRD). Representative STEM images in a low and high magnification are shown in Figure 1 (a)-(b). A significantly structure deviation compared to pure graphene/graphite is evident due to 1-3% boron loading. Those results indicate the few-layer graphene does not stack in a normal graphitic way in the c direction. The EELS, XPS and NMR show complicated electronic states of the boron in the carbon, implying boron does not have to be in the substitutional site. For example, Figure 1(c) show a representative EELS spectrum taken from a FLG. The featureless boron K-edge looks like to be taken from amorphous boron instead of substitutional boron. This result is also supported by the NBED and XRD, showing a non-flat features of the FLGs. Finally, we used the density functional theory (DFT) to explain the excellent oxygen resistance of FLG with this unique structure. Acknowledgments This work is supported by ARPA-E via cooperative agreement DE-AR0000499. The synthesis science is supported by BES-MSED. We thank JIAM and CNMS for microscopy use. Reference 1. K. Ishiyama, F. Kosaka, I. Shimada, Y. Oshima and J. Otomo, Journal of Power Sources, 2013, 225, 141-149. 2. A. B. Papandrew, R. W. Atkinson Iii, R. R. Unocic and T. A. Zawodzinski, Journal of Materials Chemistry A, 2015, 3, 3984-3987. 3. A. B. Papandrew, C. R. I. Chisholm, R. A. Elgammal, M. M. Özer and S. K. Zecevic, Chemistry of Materials, 2011, 23, 1659-1667. 4. A. B. Papandrew, C. R. I. Chisholm, S. K. Zecevic, G. M. Veith and T. A. Zawodzinski, Journal of The Electrochemical Society, 2013, 160, F175-F182. 5. A. B. Papandrew, R. A. Elgammal, M. Tian, W. D. Tennyson, C. M. Rouleau, A. A. Puretzky, G. M. Veith, D. B. Geohegan and T. A. Zawodzinski, Journal of Power Sources, 2017, 337, 145-151. 6. B. Yuan, W. Xing, Y. Hu, X. Mu, J. Wang, Q. Tai, G. Li, L. Liu, K. M. Liew and Y. Hu, Carbon, 2016, 101, 152-158. 7. M. Harada, T. Inagaki, S. Bandow and S. Iijima, Carbon, 2008, 46, 766-772. Figure 1

Hwijin Seo, Anna Joicy, Myoung Eun Lee et al.

Energies • 2023

Ultrasound and combined alkaline–ultrasound pretreatment (AUP) strategies were examined for primary sewage sludge (SS) disintegration and were utilized to evaluate the degree of solubilization (DS). Further, the pretreated primary SS was operated in microbial electrolysis cells (MECs) to maximize methane production and thereby improve the reactor performance. The highest DS of 67.2% of primary SS was recorded with the AUP. MEC reactors operated with the AUP showed the highest methane production (240 ± 6.4 mL g VSin−1). VS (61.1%) and COD (72.2%) removal in the MEC ALK-US showed the best organic matter removal efficiency. In the modified Gompertz analysis, the substrate with the highest degree of solubilization (AUP) had the shortest lag phase (0.2 ± 0.1 d). This implies that forced hydrolysis via pretreatment could enhance biodegradability, thereby making it easy for microorganisms to consume and leading to improved MEC performances. Microbial analysis implicitly demonstrated that pretreatment expedited the growth of hydrolytic bacteria (Bacteroidetes and Firmicutes), and a syntrophic interaction with electroactive microorganisms (Smithella) and hydrogenotrophic methanogens (Methanoculleus) was enriched in the MECs with AUP sludge. This suggests that the AUP strategy could be useful to enhance anaerobic digestion performance and provide a new perspective on treating primary SS in an economical way.

Alexander Schenk, Stefan Gamper, Christoph Grimmer et al.

ECS Meeting Abstracts • 2016

High-temperature polymer electrolyte fuel cells (HT-PEFCs) are a suitable technology for decentralized small scale electricity and heat production. HT-PEFCs do not require hydrogen infrastructure and are characterized by a simpler and therefore less expensive system compared to available fuel cell systems. In combination with a reformer unit, HT-PEFC systems offer an efficiency gain over conventional combustion of hydrocarbons, such as natural gas. In near future, HT-PEFCs will be even more effective and efficient when renewable biofuels and hydrogen are widespread available. We present an efficient HT-PEFC based combined heat and power (µ-CHP) system for the provision of electrical energy and hot water in single family households (see Table 1). Due to the optimized design and layout of the fuel cell based µ-CHP system and the respective manufacturing processes of the catalysts and the membrane electrode assemblies (MEA), the demand for cost effective and greenhouse gas efficient energy at customer level is addressed. Major efforts were devoted to the establishment of scalable catalyst deposition methods, which enable a loss-free utilization of precious metals. By using appropriate multimetallic catalyst systems at anode and cathode, the precious metal loading was reduced by approx. 20% in comparison to commercially available electrodes without compromising performance (see Figure 1) [1]. Furthermore, by introducing post-preparation treatments, the stability of the catalysts was enhanced over commercial Pt/C. The activity and stability of the catalyst systems were evaluated ex situ by means of cyclic voltammetry and accelerated stress tests using a rotating disk electrode (RDE) setup. Furthermore, the catalyst systems were characterized in situ by means of polarization curves, continuous operation, accelerated stress tests and electrochemical impedance spectroscopy measurements at single cell, stack and at system level (see Figure 1). Acknowledgment Financial support was provided by The Climate and Energy Fund of the Austrian Federal Government and The Austrian Research Promotion Agency (FFG) through the program Energieforschung (e!Mission). [1] A. Schenk, C. Grimmer, M. Perchthaler, S. Weinberger, B. Pichler, C. Heinzl, C. Scheu, F.-A. Mautner, B. Bitschnau, V. Hacker, Platinum–cobalt catalysts for the oxygen reduction reaction in high temperature proton exchange membrane fuel cells – Long term behavior under ex-situ and in-situ conditions, J. Power Sources. 266 (2014) 313–322. Figure 1

Nancy Hammad, Amr El-Nemr, Ibrahim G. Shaaban

Applied Sciences • 2024

Alkali-activated slag (AAS) materials are one of the most promising sustainable construction composites. These novel materials are highly characterized by their improved mechanical and durability properties. Nevertheless, the high shrinkage rate hinders their full-scale applications. The low Ca/Si ratio, complex hydration process, and fine pore microstructure are the main causes of the reported shrinkage behavior. This study introduces Bacillus subtilis culture for healing the cracking behavior. The enzymatic action leads to precipitating calcium carbonate crystals that fill AAS cracks and pores. Incorporating calcium oxide has been recommended in multiple studies. The main purpose of adding calcium oxide is to enhance the engineering properties of AAS and provide more calcium ions for the biochemical reactions induced by the added bacteria. However, inconsistent findings about the influence of calcium oxide have been reported. This research provides further insights into the effect of calcium oxide (CaO) on the performance of microbial self-healing efficiency in AAS composite. The results highlight that incorporating calcium oxide as 7% of the binder partial replacement has an impact on the engineering properties of bio-AAS materials. The study recommends correlating the percentage of free calcium ions within the AAS mixture with the microbial activity.

Abul K. Azad, Abdalla M. Abdalla, Ahmed Afif et al.

Research Square • 2021

Abstract Protonic ceramic fuel cells (PCFCs) have become the most efficient, clean and cost-effective electrochemical energy conversion devices in recent years. While significant progress has been made in developing proton conducting electrolyte materials, mechanical strength and durability still need to be improved for efficient applications. We report that adding 5 mol% Zn to the Y-doped barium cerate-zirconate perovskite electrolyte material can significantly improve the sintering properties, mechanical strength, durability and performance. Using same proton conducting material in anodes, electrolytes and cathodes to make a strong structural backbone shows clear advantages in mechanical strength over other arrangements with different materials. Rietveld analysis of the X-ray and neutron diffraction data of BaCe 0.7 Zr 0.1 Y 0.15 Zn 0.05 O 3-δ (BCZYZn05) revealed a pure orthorhombic structure belonging to the Pbnm space group. Structural and electrochemical analyses indicate highly dense and high proton conductivity at intermediate temperature (400-700 °C). The anode-supported single cell, NiO-BCZYZn05 | BCZYZn05 | BSCF-BCZYZn05, demonstrates a peak power density of 872 mW cm -2 at 700 °C which is one of the highest power density in an all-protonic solid oxide fuel cell. This observation represents an important step towards commercially viable SOFC technology.

Yi-Tang Chang, Chu-Wen Yang, Yu-Jie Chang et al.

BioMed Research International • 2013

Synthetic sewage containing high concentrations of pharmaceuticals and personal care products (PPCPs, mg/L level) was treated using an anoxic/aerobic (A/O) reactor coupled with a microbial fuel cell (MFC) at hydraulic retention time (HRT) of 8 h. A novel design of solid plain graphite plates (SPGRPs) was used for the high surface area biodegradation of the PPCP-containing sewage and for the generation of electricity. The average COD Cr and total nitrogen removal efficiencies achieved were 97.20% and 83.75%, respectively. High removal efficiencies of pharmaceuticals, including acetaminophen, ibuprofen, and sulfamethoxazole, were also obtained and ranged from 98.21% to 99.89%. A maximum power density of 532.61 mW/cm 2 and a maximum coulombic efficiency of 25.20% were measured for the SPGRP MFC at the anode. Distinct differences in the bacterial community were presented at various locations including the mixed liquor suspended solids and biofilms. The bacterial groups involved in PPCP biodegradation were identified as Dechloromonas spp., Sphingomonas sp., and Pseudomonas aeruginosa . This design, which couples an A/O reactor with a novel design of SPGRP MFC, allows the simultaneous removal of PPCPs and successful electricity production.

Jeffrey Book, Joel Golden, Ian Martens et al.

ECS Meeting Abstracts • 2018

Described here are the latest results from field tests of the Benthic Microbial Fuel Cell (BMFC). The BMFC sits on the sediment/water (benthic) interface of marine environments where it utilizes organic matter naturally residing in marine sediments as its fuel and oxygen in overlying water as its oxidant to generate electrical power. Both fuel and oxidant are used as found in the environment. The BMFC is expected to generate power indefinitely due to constant replenishment of organic matter and oxygen by naturally occurring mass transport (i.e., diffusion, advection, and tidal pumping); durability of its electrode catalysts consisting of self-forming biofilms comprised of microorganisms naturally inhabiting the benthic interface; and lack of moving, degrading, or depleting components. The BMFC is being developed to persistently power battery-powered oceanographic sensors presently limited in operational lifetime by battery depletion. During the past 10 years, we have successfully deployed small scale (< 0.1 Watt continuous output) BMFCs in coastal waters world wide ranging in depth from < 1 m to > 1000 m over for up to 2 years before being retrieved without any depletion in power output; and have powered a riverine metrological buoy with a radio transceiver link, a hydrophone with a radio transceiver link, and a surveillance camera with a cellular link. The highest power density we have thus far achieved is 0.39 Watt continuous power per square meter footprint area of sediment surface occupied by an early prototype that required extensive in-water manipulation by divers to deploy. This BMFC had a 29-liter volume, a 0.09-square meter footprint area (area of sediment surface occupied), and sustained 0.036 Watt continuously. Subsequently, by scaling up this BMFC we achieved the highest sustained power by a BMFC of 0.47 Watt continuous power (370 liter, 1.2 square meter footprint area, 0.39 Watt continuous power per square meter footprint area). Based on the 3.1 square meter footprint area of the oceanographic moorings we presently use to house battery-powered sensors, our long-term goal of a BMFC-equipped mooring capable of sustaining > 1 Watt is thought achievable. This amount of power, the equivalent of 440 alkaline D cells per year of operation based on optimal battery performance, is more than sufficient to operate complicated oceanographic instruments (e.g., an acoustic Doppler current profiler), including processing and transmitting data at least once a day either by acoustic telemetry or by radio to satellites. Practical considerations that limit the size of oceanographic battery packs (weight, cost, and size) compounded by poor battery performance at low temperatures encountered at the bottom of most marine environments limit the duration of most battery-powered sensors to 1 year. In contrast, the putative unlimited duration of BMFCs make them appealing for long-duration applications if BMFCs can be reliably deployed without in-water manipulation. Our current efforts to be reported on here center on iterative design and evaluation of full scale (targeting > 1 Watt continuous power) by BMFCS that do not require in-water manipulation by divers and/or remotely operated vehicles to deploy (i.e., drop and go). The challenge for deployment is the requirement that the anode be in contact with anoxic sediment and isolated from over lying oxic water. Our most recent design, to be described here, sustained 0.03 W continuous power when configured with a 1-m diameter bottom mount sensor mooring and was deployed without in-water manipulation. The power is intended to increase dramatically for each design-evaluation cycle and is projected to reach > 1 Watt continuous power as the mass-transport accessible surface area of the anode is increased. At this time 2 BMFC-equipped moorings are undergoing field testing. In addition to describing the results of these field tests, results of earlier deployments will be presented in which the dependency of BMFC power output vs sediment properties and environmental conditions was evaluated.

Gábor Márk Tardy, Bálint Lóránt, Miklós Gyalai-Korpos et al.

Biotechnology Letters • 2020

Abstract Objectives Single-chamber air cathode microbial fuel cells (MFCs) were applied as biosensors for biochemical oxygen demand (BOD) measurement of real wastewaters with considerable suspended and/or slowly biodegradable organic content. Results The measurement method consists of batch sample injection, continuous measurement of cell voltage and calculation of total charge (Q) gained during the biodegradation of organic content. Diverse samples were analyzed: acetate and peptone samples containing only soluble readily biodegradable substrates; corn starch and milk samples with suspended and colloidal organics; real domestic and brewery wastewaters. Linear regression fitted to the Q vs. BOD 5 measurement points of the real wastewaters provided high (> 0.985) R 2 values. Time requirement of the measurement varied from 1 to 4 days, depending on the composition of the sample. Conclusions Relative error of BOD measured in the MFCs comparing with BOD 5 was less than 10%, thus the method might be a good basis for the development of on-site automatic BOD sensors for real wastewater samples.

Jinrong Lu, Linde Ren, Cheng Li et al.

New Journal of Chemistry • 2022

Herein, the output power density produced by Zn/Co-S-3DHFLM as the cathode catalyst of an MFC was higher than that of Co-3DHFLM.

F. Khaled, B. Allard, O. Ondel et al.

Energy Harvesting and Systems • 2015

Cover letter An autonomous flyback converter was designed for energy harvesting from Microbial Fuel Cells (MFCs). The circuit was optimized to minimize the losses and maximize the efficiency. A Maximum Power Point Tracking (MPPT) algorithm was implanted in the converter to extract the maximum power available from MFC. Discontinuous conduction mode operation of the flyback allows controlling the MPP operation by impedance matching. The flyback can start-up at low voltage, around 300 mV. The output open circuit voltage is about 20 V and the voltage at MPP is 6.4 V with a maximum efficiency of 71.2%. Abstract : Microbial fuel cells (MFCs) use bacteria as the catalysts to oxidize organic matter and generate electricity. This energy can be used to supply low power electronic systems. A power management unit between the MFCs and the load is required to adapt the voltage and control the operation. The low voltage and low power characteristics of MFCs prohibit the use of standard converter topologies since the threshold voltage of standard CMOS transistors in CMOS technology is higher than the output voltage of MFCs. A low-voltage start-up sub-circuit is required to charge a primary capacitor to supply the driver. A specific sub-circuit is also required to control the operation of MFCs for Maximum Power Point Tracking (MPPT) issues. An optimized Discontinuous Conduction Mode (DCM) autonomous flyback converter for energy harvesting is presented for ambient sources, like MFCs. The converter is designed, fabricated, and tested. An MPPT algorithm is integrated in the system to control the operation and to extract the maximum available power from the MFC. The converter is able of start and step-up MFC output voltage to a value higher than 3 V under load. The peak efficiency of the converter is 71.2%.