Kenan Dalkilic, Aysenur Ugurlu

• 2024

This study investigates the biogas production from cattle manure in a combined microbial electrolysis cell and anaerobic digestion system (MEC+AD). The MEC+AD reactors were operated on semi continuous mode under different voltage applications and different organic loading rates varying from 7 g VS/L.d to 30 g VS/L.d. The study was carried out in two parts. In the first part, combined MEC+AD system and conventional anaerobic digestion were compared in terms of biogas production and organic removal performances at hydraulic retention times of 5, 4, and 3 days to see the effects of voltage application. In the second part, MEC+AD reactors were operated under different voltage applications (0.3, 0.6, and 1.0 V) and organic loading rates at constant hydraulic retention time of 2 days. In terms of biogas production and organic removal rate, MEC+AD reactors were superior to anaerobic control reactor owing to the voltage application. The biogas production of MEC+AD reactors increased from 1.75 to 5.13 L/L/d (71.6-77.8 % CH4) with the increase in organic loading rate. On the other hand, the highest methane yield (0.217 L/g VS) was observed at the lowest organic loading rate of 6.72 g VS/L/d at 5 days hydraulic retention time. The effect of different voltages was not significant in the reactors due to the similar biogas productions and organic removal rates. MEC+AD reactors still operated efficiently even at the highest organic loading rate of 30 g VS/L/d without any instability problem.

Joel Kuhn, Olivera Kesler

Fuel Cells • 2023

Abstract Metal‐supported solid oxide cells with Yttria‐stabilized zirconia (YSZ) electrolytes fabricated by atmospheric plasma spraying are routinely found to have open‐circuit voltages (OCVs) below the Nernst potential due to gas crossover and combustion resulting from electrolyte defects. To improve splat bonding and reduce coating defects, YSZ electrolytes were fabricated here at >800°C substrate temperatures and torch‐substrate relative velocities of 4 and 12 m/s by atmospheric suspension plasma spraying. Electrolyte microstructures appeared dense, with porosities estimated to be approximately 2.2–3.5 vol%. Minimal segmentation cracking was observed on samples fabricated at 12 m/s. The full cells that were electrochemically tested had permeabilities in the range of 4–6 × 10 −19 m 2 , and the maximum recorded OCV was ∼26 mV below the Nernst potential for 750°C. Potential performance gains from YSZ deposition at substrate temperatures >800°C may have been masked by poor substrate‐fuel electrode contact. Using electrochemical impedance spectroscopy, it was found that the ohmic and polarization resistances decreased and increased, respectively, over time. The calculated distribution of relaxation times of the tested cells, together with observations from the literature, were employed to identify possible cell degradation mechanisms observed during short‐term durability testing.

Rajesh Kumar Prasad

International Journal of Biomass and Renewables • 2023

Lignocellulosic biomass plays a pivotal role in sustainable energy production, with a focus on indirect biomass fuel cells (IDBFC) and direct biomass fuel cells (DBFC). IDBFCs require the initial conversion of biomass into simpler forms like sugars, biogas, syngas, or biocharfor subsequent electricity generation. In contrast, DBFCs offer a more direct approach, generating electricity from biomass without intermediate steps. Lignocellulosic biomass, composed of cellulose, lignin, and hemicellulose, has diverse applications, from bioethanolto direct electricity generation. However, the complex composition of lignocellulosic compounds, including carbon, hydrogen, oxygen, phosphorus, nitrogen, and sulfur, poses challenges for efficient enzymatic hydrolysis, a crucial factor in achieving high power density inMicrobial Fuel Cells (MFCs). MFCs use microorganisms to convert substrates into electricity, influenced by factors like substrate degradation rate, circuit resistance, electron transfer rates, proton mass transfer, electrode materials, and operational conditions. The selection of proper electrode materials is vital for optimising MFC performance. At the heart of MFC performance are electricigens, microorganisms facilitating electron transfer from biomass to the anode through direct or indirect mechanisms. Direct electron transfer (DET), relying on physical contact between microorganism membranes and the anode, is preferred for its efficiency and eco-friendliness. The paper also explores the importance of nutrient supplements (macro and micro) in enhancing bio-methane production and process stability in agro-industrial biogas mono-digestion plants. Nutrient balance significantly affects microbial generation time, degradation rates, and gas production in anaerobic digestion processes. In conclusion, understanding the intricate interplay between lignocellulosic biomass energy fuel cells, electricigens, and their performance factors is crucial for advancing sustainable energy production. MFCs show promise in utilising sludge and various waste biomasses, positioning them as practical, reliable, and versatile power sources in the evolving landscape of renewable energy technologies.
 Keywords: Lignocellulosic waste, bioenergy, microbial fuel cells (MFCs), electricigens

Asmaa Selim, Gábor Pál Szijjártó, András Tompos

Polymers • 2022

Perfluorosulfonic acid (PFSA) polymers such as Nafion are the most frequently used Proton Exchange Membrane (PEM) in PEM fuel cells. Nafion XL is one of the most recently developed membranes designed to enhance performance by employing a mechanically reinforced layer in the architecture and a chemical stabilizer. The influence of the water and acid pre-treatment process on the physicochemical properties of Nafion XL membrane and Membrane Electrode Assembly (MEA) was investigated. The obtained results indicate that the pre-treated membranes have higher water uptake and dimensional swelling ratios, i.e., higher hydrophilicity, while the untreated membrane demonstrated a higher ionic exchange capacity. Furthermore, the conductivity of the acid pre-treated Nafion XL membrane was ~ 9.7% higher compared to the untreated membrane. Additionally, the maximum power densities obtained at 80 °C using acid pre-treatment were ~ 0.8 and 0.93 W/cm2 for re-cast Nafion and Nafion XL, respectively. However, the maximum generated powers for untreated membranes at the same condition were 0.36 and 0.66 W/cm2 for re-cast Nafion and Nafion XL, respectively. The overall results indicated that the PEM’s pre-treatment process is essential to enhance performance.

Jing Jin, Charles Amanze, Richmond Anaman et al.

Minerals • 2022

Microbial community changes in response to acid stress in microbial fuel cells (MFCs) were studied. Acid mine drainage (AMD) wastewater is usually difficult to treat because of the high concentration of sulfate and heavy metals. MFCs, which have multiple functions based on the principle of synergistically treating organic and heavy metal wastewater while generating electrical energy, represent a promising direction for the development of new heavy metal wastewater treatment technologies. Maintaining a neutral or slightly alkaline wastewater pH in MFCs facilitates the growth of electricity-producing microorganisms in the anode chamber. Studies on the response of anode electroactive biofilms to acidic pH stress and its correlation with changes in AMD treatment capacity have not been reported. Results showed that the anolyte pH of 4.0 and 5.0 affected the electron output capacity of the electrogenic microbial community in the MFCs. In contrast, MFCs working at an anolyte pH of 6.0 exhibited a high efficiency of chemical energy conversion to electrical energy. The microbial abundance and microbial diversity of the electroactive biofilm were significantly affected by the H+ concentration in the medium when the ambient acidity was continuously reduced. The classic exoelectrogen Geobacter decreased gradually with the increase of H+ concentration in the medium. In addition, Cu2+ was recovered from the simulated AMD in the MFCs cathodic chambers at low anode pH, but the removal rate of Cu2+ decreased as the pH of the anode environment decreased. At 48 h, 86.2% of Cu2+ was removed from the MFCs cathode solution at pH 5.0, while the removal rate of Cu2+ from the MFCs cathode solution at pH 4.0 was 84.2%. Trace amounts of Cu2O and Cu3(OH)2[CO3]2 were present on the cathode, which reduced the amount of Cu2+ that precipitated on the cathode carbon cloth. Conversely, the concentration of Cu2+ in the catholyte of MFCs with electroactive biofilm at pH 6.0 decreased rapidly, and by 36 h, no detectable Cu2+ was present in the cathodic solution. This study will provide researchers with valuable information regarding the optimal pH for resource recovery with MFCs.

K.-F. Chiu, M. Y. Hsieh

Journal of Fuel Cell Science and Technology • 2006

Carbon electrodes are one of the key materials in polymer electrolyte fuel cells (PEFC), or proton exchange membrane fuel cells (PEMFC). The electrodes should allow water or water vapor, which is produced by the redox reactions, to flow out of the cells efficiently. In the meantime, the catalysis reactions are not interfered. In this study, the carbon electrodes for PEMFC have been modified in terms of the hydrophobic and hydrophilic properties by plasma irradiation. The process utilized inductively coupled plasma (ICP) driven by applying radio frequency (rf) power on an induction coil. A pure Ar, O2, and Ar∕O2 gas mixture were used as the plasma gas. Only one side of the sample has been treated. The material properties of the plasma treated and untreated carbon electrodes were investigated by Raman spectroscopy, Fourier transformed infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). FTIR results show the plasma treatments effectively modified the functional groups on the carbon surface, and therefore the hydrophilic and hydrophobic properties of the surface. SEM and Raman spectra data suggested that the ion bombardment during plasma treatments alters the surface morphology and carbon bonding structures of the samples, which also result in a hydrophilic surface. The treated carbon electrodes were used as cathodes and have been packed with commercial carbon anodes and catalyst coated membrane to form 5cm×5cm fuel cells. The current-voltage polarization curves of these fuel cells were measured and compared. The test results show the feasibility of improving the cell performance by plasma treated electrodes. The feasibility of altering the hydrophobic and hydrophilic properties by plasma treatment has been demonstrated. The capillary effect due to the unbalanced hydrophilicity between the treated and untreated electrode surfaces may be responsible for the improved cell performance.

Saad Ahmed, Yangben Cai, Muhammad Ali et al.

Journal of Applied Polymer Science • 2018

ABSTRACT In this study, we incorporated commercially available p ‐toluene sulfonic acid coated boehmite nanofillers (commercially known as OS 1 ) into the chitosan (CS) matrix to fabricate CS–OS 1 nanocomposite membranes with a high proton conductivity for fuel‐cell applications. These nanocomposite membranes were characterized by Fourier transform infrared spectroscopy, energy‐dispersive X‐ray spectroscopy, X‐ray diffraction analysis, scanning electron microscopy, and thermogravimetric analysis. Their mechanical properties, water uptake, ion‐exchange capacity, and proton conductivity were also determined. The results show that the incorporation of OS 1 to CS chains can inhibit the mobility of CS chains and, hence, enhance the thermal stability and mechanical properties of CS–OS 1 nanocomposite membranes. The composite membrane with 5 wt % OS 1 showed a proton conductivity of 0.032 S/cm; this was almost equal to that of commercially available Nafion 117. We concluded that CS–OS 1 nanocomposite membranes have potential for fuel‐cell applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 46904.

Shien Tang, Xinglei Zhuang, Wanqi Zhao et al.

Journal of Chemical Technology & Biotechnology • 2024

Abstract BACKGROUND Biogenic metal nanoparticle‐modified electrodes have a promising prospect for improving the efficiency of microbial fuel cells (MFCs) for hexavalent chromium (Cr(VI))‐containing wastewater treatment. In this study, a graphene (GO) electrode was modified with chemical gold nanoparticles (ChemAu) and biogenic gold nanoparticles (BioAu), respectively, and the two modified electrodes were then used as MFC biocathode electrodes to treat Cr(VI)‐containing wastewater. RESULTS The results demonstrated that the BioAu/GO biocathode‐based MFC obtained the highest power density (95.78 ± 1.11 mW m −2 ) and Cr(VI) removal rate (2.17 ± 0.51 mg L −1 h), which were 13.19 and 1.03 times higher than those of the graphite paper biocathode‐based MFC, respectively. The Cr(VI) removal efficiency of the BioAu/GO biocathode‐based MFC under close‐circuit condition reached 87.61 ± 0.19%, which was 3.74 times higher than that recorded under open‐circuit conditions, indicating the critical role of the bioelectrochemical reduction reaction mediated by the BioAu/GO biocathode on Cr(VI) removal. CONCLUSION The BioAu/GO electrode first confirmed its superior performance to the ChemAu/GO electrode in Cr(VI)‐reducing MFCs due to its excellent material properties. This study provides a technical reference for the exploration of efficient bioelectrode materials based on biogenic metal nanoparticles for MFCs to treat recalcitrant pollutant‐containing wastewater. © 2024 Society of Chemical Industry (SCI).

Aniket Raut, Haoyan Fang, Yu-Chung Lin et al.

Energy Advances • 2022

This work underscores the relationship between the mechanical properties of anion exchange membranes and pH, which together can have a profound effect on the power output of the fuel cells.

Jinwon Lee, Changwook Seol, Joondong Kim et al.

Energy Technology • 2021

With increasing demand for high‐efficiency and clean energy sources, the polymer electrolyte membrane fuel cell (PEMFC) has received attention in a wide range of fields including transportation and back‐up power. For securing the economic viability of PEMFC, the U.S. Department of Energy (DOE) provides the target of the total Pt catalyst loading as 0.125 mg Pt cm −2 on both cathode and anode, which is much less than that currently used (>0.25 mg Pt cm −2 for cathode). An optimized ratio of catalyst loading between the anode and cathode with a fixed Pt catalyst loading according to the DOE target is figured out by conducting diverse electrochemical measurements with varying the catalyst loading ratio in single‐cells. Among the experimental set, the membrane electrode assembly (MEA) with 70% catalyst loading on the cathode side shows the highest performance with the maximum power density of 643 mW cm −2 , while the MEA with 90% catalyst loading on the cathode side exhibits inferior performance. Experimental results are validated by suggesting the theoretical model, which was established based on considering both the electrochemical kinetics of hydrogen oxidation and oxygen reduction reaction.

N. Videau, G. Fontes, D. Flumian et al.

Fuel Cells • 2016

Abstract This paper proposes a DC–DC converter dedicated to high efficiency and high voltage conversion ratio, which is well suited for fuel cell applications. At high voltage conversion ratio the proposed converter, named here mirror boost converter, has a better ratio of active/freewheeling times which, compared with conventional structures, reduces the penalty on efficiency induced by the high conversion ratio. This converter also uses eight interleaved coupled‐inductors, which reduces the current and voltage ripple and makes possible to use of smaller passive components. Coupling all phases with an inter‐cell transformer (ICT) also improves the power density, volume and losses of the magnetic component compared to separate inductors. A comparison with a classical double boost converter is realized using the same material. The proposed converter reaches a peak efficiency of 96.5% at 17 kW and 95.3% at 42 kW for a voltage conversion ratio around 10. The mirror boost converter has about half the losses of the double boost converter at same fuel cell power and delivers 69% more power at the maximum measured current phase.

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.