Electrolyte Membrane Fuel Cell Research Articles

Effect of Contamination in the Carbon Catalyst Support on Chemical Degradation of Polymer Electrolyte Membranes in Fuel Cells

Chemical degradation of polymer electrolyte membranes (PEMs) is an important issue related to the durability of polymer electrolyte fuel cells (PEFCs). Although various studies have been conducted on the chemical degradation of PEMs, the relationship between cathode catalyst materials and chemical degradation of the PEM has not yet been fully understood. Here, we conduct accelerated chemical degradation tests of the PEM and investigate the effect of using cathode electrocatalysts with different carbon support materials. This aims to clarify the effect of the choice of carbon support on the chemical degradation of PEMs. It is confirmed that contaminants in the carbon support material can have a significant impact on chemical degradation of the PEM.

Green Nanocomposite Electrodes/Electrolytes for Microbial Fuel Cells—Cutting-Edge Technology

Fuel cell efficiency can be improved by using progressive electrodes and electrolytes. Green nanomaterials and green technologies have been explored for the manufacturing of high-performance electrode and electrolyte materials for fuel cells. Platinum-based electrodes have been replaced with green materials and nanocomposites using green fabrication approaches to attain environmentally friendly fuel cells. In this regard, ecological and sustainable electrode- and electrolyte-based membrane electrode assemblies have also been designed. Moreover, green nanocomposites have been applied to form the fuel cell electrolyte membranes. Among fuel cells, microbial fuel cells have gained research attention for the incorporation of green and sustainable materials. Hence, this review essentially focuses on the potential of green nanocomposites as fuel cell electrode and electrolyte materials and application of green synthesis techniques to attain these materials. The design of and interactions with nanocomposites have led to synergistic effects on the morphology, impedance, resistance, power density, current density, electrochemical features, proton conductivity, and overall efficiency. Moreover, we deliberate the future significance and challenges of the application of green nanocomposites in electrodes and electrolytes to attain efficient fuel cells.

Enhancing water uptake and hydroxide ion conductivity of alkali fuel cell electrolyte membrane by layered double hydroxide

Novel hydroxide ion-conductive composite membranes were fabricated through incorporating coprecipitation-synthesized magnesium (Mg)–aluminum (Al)-type layered double hydroxides (LDHs) into a potassium hydroxide (KOH)-doped polybenzimidazole (PBI) membrane to improve the hydroxide ion conductivity for the application to alkali fuel cells. The addition of LDH was essential for improving the water affinity of the PBI–KOH membranes. Although the KOH uptake of the LDH-incorporated PBI membranes decreased with increasing amounts of LDHs in the water uptake test, thermal analysis showed that the water content in the membrane increased with increasing amounts of added LDHs. LDH-incorporated PBI membranes showed the high hydroxide ion conductivity and the reduced dependent of the humidity because of the high amount of adsorbed water and high ionic conductivity of LDHs. The alkaline fuel cell performance evaluation test showed that the prepared PBI–KOH membrane with 30 wt% LDH had the highest power output, exhibiting a maximum power density of 210 mW cm−1 at 80 °C, which is more than double that of the cell device without LDH. Improved performance due to the high-water adsorption and hydroxide ion conductivity was achieved by incorporating LDHs into the KOH-doped PBI membranes.

Fluoropolymers and Their Nanohybrids As Energy Materials: Application to Fuel Cells and Energy Harvesting.

The current review article provides deep insight into the fluoropolymers and their applications in energy technology, especially in the field of energy harvesting and the development of fuel cell electrolyte polymeric membranes. Fluoropolymers have gained wide attention in the field of energy applications due to their versatile properties. The incorporation of nanofillers within the fluoropolymer to develop the nanohybrid results in an enhancement in the properties, like thermal, mechanical, gas permeation, different fuel cross-over phenomena through the membrane, hydrophilic/hydrophobic nature, ion transport, and piezo-electric properties for fabricating energy devices. The properties of nanohybrid materials/membranes are influenced by several factors, such as type of filler, their size, amount of filler, level of dispersion, surface acidity, shape, and formation of networking within the polymer matrix. Fluoropolymer-based nanohybrids have replaced several commercial materials due to their chemical inertness, better efficacy, and durability. The addition of certain electroactive fillers in the polymer matrix enhances the polar phase, which enhances the applicability of the hybrid for fuel cell and energy-harvesting applications. Poly(vinylidene fluoride) is one of the remarkable fluoropolymers in the field of energy applications such as fuel cell and piezoelectric energy harvesting. In the present review, a detailed discussion of the different kinds of nanofillers and their role in energy harvesting and fuel cell electrolyte membranes is projected.

Modifications on Promoting the Proton Conductivity of Polybenzimidazole-Based Polymer Electrolyte Membranes in Fuel Cells.

Hydrogen-air proton exchange membrane fuel cells (PEMFCs) and direct methanol fuel cells (DMFCs) are excellent fuel cells with high limits of energy density. However, the low carbon monoxide (CO) tolerance of the Pt electrode catalyst in hydrogen-air PEMFCs and methanol permanent in DMFCs greatly hindered their extensive use. Applying polybenzimidazole (PBI) membranes can avoid these problems. The high thermal stability allows PBI membranes to work at elevated temperatures when the CO tolerance can be significantly improved; the excellent methanol resistance also makes it suitable for DMFCs. However, the poor proton conductivity of pristine PBI makes it hard to be directly applied in fuel cells. In the past decades, researchers have made great efforts to promote the proton conductivity of PBI membranes, and various effective modification methods have been proposed. To provide engineers and researchers with a basis to further promote the properties of fuel cells with PBI membranes, this paper reviews critical researches on the modification of PBI membranes in both hydrogen-air PEMFCs and DMFCs aiming at promoting the proton conductivity. The modification methods have been classified and the obtained properties have been included. A guide for designing modifications on PBI membranes for high-performance fuel cells is provided.

(Invited) Redesigning of the Electrode/Membrane Interface Using Patterned Polymer Electrolyte Membrane for Fuel Cells

For the realization of commercially viable polymer electrolyte membrane fuel cells (PEMFCs), it is essential that the development of PEMFCs capable to exhibit high performance over long-term operation with minimal use of precious metal-based catalysts. To achieve this, substantial efforts have been devoted to the development of highly active catalysts for oxygen reduction reaction (ORR). Thanks to recent advances in nanotechnology, novel Pt-based catalysts exhibiting high ORR mass activity that exceed the U.S. Department of Energy (DOE) activity target standard (0.44 A mgPt -1 at 0.9 VIR-free) have been reported. However, it is uncertain whether these advanced catalysts can be used as a substitute in practical applications because the practical applicability of the PEMFCs is eventually determined by the performance at much higher current density (HCD, > 1.5 A cmgeo -2), unlike the kinetic activity test condition (several mA cmgeo -2). Therefore, from more practical point of view, improvement of the HCD performance of PEMFC plays a key role in realizing commercially viable PEMFC. The HCD performance is highly affected by the ion conduction and mass transport of the reactant gases and water through the membrane electrode assembly (MEA). Particularly, it has been recently found that the mass transport limitations become more severe as the catalyst loading decreases, because of the reduced active sites available for the electrochemical reaction due to decreased active material loading. Therefore, it is critical to alleviate transport-related problems that lead to the cell potential drop at HCD to realize the high-performance PEMFC with minimal use of precious metal catalysts.Since the charge and mass transport are greatly influenced by not only the characteristics of the key components like catalysts, membranes, and gas diffusion layers, but also the structure of the MEAs. Particularly, the interface between the electrode and the electrolyte membrane has a considerable impact on the electrochemical characteristics of the PEMFC. As a result, there is a growing research activity to engineer this interface to enhance the practical performance of the PEMFCs. One promising approach to redesign the electrode/membrane interface is the introduction of 3-D patterned membrane surface. In recent years, our group has employed various structural patterns to the polymer electrolyte membrane, from simple line and prism structures to micro-nano multiscale architectures. We have applied them to various polymer electrolyte membrane-based fuel cell systems, like PEMFC, DMFC, and AEMFC. Regardless of the applied structure and the system, it is demonstrated that properly redesigned electrode/membrane interface using the patterned membrane significantly improves not only the HCD performance related to the mass transport through the MEAs, but also contact between the two layers, which can contribute to enhance the durability of the PEMFCs. In addition, the guided cracking technique introduced by combining the patterned membrane and simple mechanical stretching can improve the performance and durability of various type of fuel cells.

Penetration of Hydrogen into Polymer Electrolyte Membrane for Fuel Cells by Quantum and Molecular Dynamics Simulations.

The advent of the Hydrogen Society created great interest around hydrogen-based energy a decade ago, with several types of vehicles based on hydrogen fuel cells already being produced in the automotive sector. For highly efficient fuel cell systems, the control of hydrogen inside a polymer-based electrolyte membrane is crucial. In this study, we investigated the molecular behavior of hydrogen inside a polymer-based proton-exchange membrane, using quantum and molecular dynamics simulations. In particular, this study focused on the structural difference of the pendent-like side chain polymer, resulting in the penetration ratio of hydrogen into the membrane deriving from the penetration depth of the membrane’s thickness while keeping the simulation time constant. The results reveal that the penetration ratio of the polymer with a shorter side chain was higher than that with the longer side chain. This was justified via two perspectives; electrostatic and van der Waals molecular interactions, and the structural difference of the polymers resulting in the free volume and different behavior of the side chain. In conclusion, we found that a longer side chain is more trembling and acts as an obstruction, dominating the penetration of hydrogen inside the polymer membrane.

Radiation-Grafted Polymer Electrolyte Membranes for Fuel Cells

Fuel cells are one of the most efficient energy conversion systems to produce electricity. A solid ion-conducting polymer membrane is employed as both separator and electrolyte for polymer electrolyte membrane fuel cells and anion-exchange membrane fuel cells. Radiation-induced graft polymerization is a versatile method for the fabrication of low-cost alternatives to commercial polymer membranes. In this method, typically a base polymer is exposed to ionizing radiation which generates active radical sites within the polymer substrate. Then a suitable vinyl monomer is polimerized on these active sites to form a graft copolymer. Finally, a subsequent chemical treatment is performed to introduce hydrophilic groups to hydrophobic polymer backbone so that an ion conducting membrane is formed. There are various studies about the influence of radiation grafting parameters on membrane properties. Moreover, the favorable fuel cell relevant and polarization properties of such radiation-grafted membranes were reported. Thus, radiation-grafted polymer membranes are one of the significant low-cost alternatives for fuel cells. This review focuses on the preparation, characterization of fuel cell relevant properties and fuel cell performance of radiation-grafted membranes.

Fuel cell electrolyte membranes based on copolymers of protic ionic liquid [HSO3-BVIm][TfO] with MMA and hPFSVE

Polymeric ionic liquids (PILs) have recently been attracting great attention as new types of electrolytes for polymer exchange membrane fuel cells (PEMFCs), clean energy devices, due to their outstanding properties. In this work, the copolymerization of the ionic liquid (IL) 1-(4-sulphobutyl)-3-vinylimidazolium trifluoromethanesulphonate, [HSO3-BVIm][TfO], with methyl methacrylate (MMA) and perfluoro-3,6-dioxa-4-methyl-7-octene sulfonyl fluoride in its hydrolyzed form (hPFSVE), respectively, was performed for the preparation of structurally new IL copolymer membranes with enhanced conductive properties in comparison with the pristine PIL form. Membranes were synthesized through a facile photopolymerization method under UV radiation. The effect of temperature under wet and dry conditions on the ionic conductivities of the resulting membranes was analyzed. The performances of the new membranes were also assessed in a proton exchange fuel cell for power generation. Both poly([HSO3-BVIm][TfO]-co-MMA) and poly([HSO3-BVIm][TfO]-co-hPFSVE) electrolyte membranes offered high conductivity even in dry conditions (in the order 10−3 - 10−2 S cm−1). At low MMA and hPFSVE amounts (10 mol%), the ionic conductivity and power performances of the resulting membranes were enhanced in comparison with the membrane only constituted of the polymerizable IL showing the promising prospects of these ionic liquid-based copolymers as proton exchange membranes, with power outputs up to 45 mW cm−2.

(Invited) Multiscale Molecular Modeling for Polymer Electrolyte Membrane for Fuel Cell

Multi-scale “molecular” modeling approach has been developed and applied to polymer electrolyte membrane. The goal of this work is to investigate the possible morphology, structure, dynamics, and mechanical properties of perfluorosulfonic acid (PFSA) membrane with realistic polymer chain lengths (>100 monomer units) by molecular dynamics (MD) simulations. First, we have carried out a series of all-atom (AA) MD simulations of PFSA polymer with a short chain length (10 monomer units) to yield reference structural data for building a coarse-grained (CG) molecular model. Although many phenomenological modeling based on dissipative particle dynamics has been proposed previously, a chemically accurate CG model should be beneficial to investigate the morphology in realistic membranes and to provide a concrete molecular design. Thus, we attempted to construct a predictive CG model for the structure and morphology of PFSA membranes that is compatible with the SDK CG water model. [1] As a first trial, we extended the parameter set in the SDK CG force field to examine a hydrated PFSA membrane based on thermodynamic and structural data from experiments and AA-MD simulations. However, a noticeable degradation of the morphology was detected, which motivated us to improve the structural properties by a combination with the iterative Boltzmann inversion (IBI) approach. The hybrid SDK/IBI model was determined to reasonably reproduce both the thermodynamic and structural properties of the PFSA membrane for all examined water contents. [2] In addition, the obtained CG model demonstrated good transferability. Then, we used the CG-MD to simulate realistic long-chained (including more than 120 monomer units) PFSA membranes. We obtained successfully a well converged structure for this long-chained membrane system. We also developed a reverse-mapping method and successfully used it to produce a well-equilibrated structure at all-atom resolution. We further investigated the mechanical properties of this realistic PSFA membranes at AA resolution. The uniaxial tension tests were conducted to understand the mechanical behavior of hydrated PEM membranes, especially the failure mechanism of the membranes. It was observed that the results (Poisson's ratio, free volume) of the uniaxial deformation were sensitive to the hydration level. This computational methodology will provide more chemically realistic predictions of the PEM membrane properties and give an insight into how to develop the large-scale atomistic PEM model in a multi-scale framework. We will further discuss the effect of equivalent weight (EW) and side chain length on morphology and dynamics of PFSA membranes.[3,4][1] Shinoda et al., Mol. Simul. 33, 27 (2007).[2] Kuo et al., J. Chem. Phys. 147, 094904 (2017).[3] Kuo et al., J. Phys. Chem. C 120, 25832 (2016).[4] Kuo et al., Polymer, 146, 53 (2018).

Patterning Polymer Electrolyte Membrane for Fuel Cell and Electrolysis Applications

Patterning polymer electrolyte membrane offers the prospect of enhancing the thermodynamic efficiency for a wide range of electrochemical systems that utilize membrane electrode assemblies (MEAs). In this work, several different polymer electrolyte membrane chemistries (both proton exchange and hydroxide exchange membranes) were patterned via conventional soft lithography using poly(dimethyl siloxane) (PDMS) molds. The patterned membranes displayed excellent fidelity after dropcasting on the PDMS mold and various structures and feature sizes were generated using the versatile soft lithography approach. This report concludes with preliminary results of patterned membranes for proton exchange and hydroxide exchange membrane fuel cells and proton exchange water electrolysis. These preliminary results convey that mass transfer resistances are more prominent in patterned membranes over non-patterned membranes.

(Invited) Polymer Electrolyte Membranes for Fuel Cells: An Overview of Where We Have Been

In this contribution, a review of the efforts to improve membranes for fuel cells will be presented. Several themes will be interwoven: What we have measured over the years, the insight provided and what is missing in most studies of membranes.A historical perspective on the time-sequential major membrane issues, including some resolution and some circumvention of these issues. Types of membranes used and their relative merits as applicable to specific requirements.Our state of understanding of membrane processes.The roles of experimental and computational studies of membranes. This talk is dedicated to Russ Kunz who always engaged in discussions as a gentleman with appropriate skepticism and obvious enthusiasm. Acknowledgements We gratefully acknowledge the long support of this work by the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy FCTO, DARPA and by the Office of Naval Research. We also thank 3M, DuPont and Dow for providing membranes.

Patterning Polymer Electrolyte Membranes for Fuel Cell and Electrolysis Applications

Electrochemical processes have experienced a renaissance in recent years for the synthesis of commodity chemicals because their potential to integrate with electrified renewable energy sources and prospect to produce chemicals with a lower energy footprint under milder operating conditions. The heart of many electrochemical processes for electrolysis and energy storage and conversion, is the membrane electrode assembly (MEA) that intersects ions, electrons, and the products/reactants-percolating electrolyte. Optimizing the electrode-electrolyte interface in MEAs is vital for maximizing the thermodynamic efficiency of electrochemical processes. For example, the interface must foster facile mass transfer and charge-transfer to cater reaction kinetics. Patterning polymer electrolyte membranes’ (PEMs) surfaces is an attractive methodology capable of enlarging the electrode-electrolyte interfacial area, where reactants, catalysts, and PEMs coexist in MEAs. To date, there have been only a handful of micropatterned PEM demonstrations using 3D printing(1), plasma etching(2), mechanical abrasion(3), thermal imprint lithography(4, 5), multiplex lithography(6), photolithography(7), hot embossing(8), pulsed laser micromachining(9), or their combinations. It is more important to note that there exist even fewer demonstrations for their use in electrochemical technologies that provide electrical energy (e.g, fuel cells) and no demonstrations for electrolysis applications. This presentation reports our work on patterning PEM surfaces through photolithography and block copolymer lithography. Conventional photolithography methods enable micropatterning with feature sizes limited to above ~ 1 mm, whereas block copolymer lithography(10-12) allows nanopatterned features from sub-10nm to 100 nm over large areas without the need to directly write features (i.e., it is a low cost and scalable patterning technique). In this work, technical demonstrations of micro- and nano-patterned PEMs are given for alkaline anion-exchange membrane fuel cells, carbon dioxide electrolysis, and water electrolysis. Single-cell current-voltage relationships in addition to impedance spectra of the patterned PEMs used in MEAs for the aforementioned applications are provided. Connections between patterned feature sizes and MEA performance with individual resistance components will be discussed. Figure 1 below depicts a micropatterned PEM and self-assembled, nanostructured block copolymer templates.

Quantitative Evaluation of Chemical Degradation of Polymer Electrolyte Membrane for Fuel Cells and the Method of Lifetime Prediction

A fuel cell vehicle (FCV) is a vehicle that utilizes fuel cells as its power source. Development of fuel cells for FCV is always aimed at a more compactsize by means of higher power density and longer driving range through enhanced energy efficiency. Fuel cells also require endurance reliability comparable to internal combustion engines, and cost reductions will be required to encourage widespread consumer use. The power generating part of a fuel cell is called the membrane electrode assembly (MEA), which consists of a polymer electrolyte membrane (PEM) and electrodes with a catalyst. The performance of the fuel cell is mainly determined by the activity of the catalyst on each electrode and by the proton conductivity of the PEM. Because the performance, energy efficiency, durability, and cost of fuel cells are all related and involve trade-offs, optimization of the PEM design cannot be readily achieved. A particular issue that has faced optimization of the PEM design is the amount of time it takes to estimate PEM durability. The only method available has been to test it over a long period of time, and this is why FCV has had such an extended development period. In order to optimize the PEM design in less time, a new method capable of estimating durability without durability testing must be developed. To this aim, we first made it possible to quantitatively evaluate the rate of chemical degradation of PEM to estimate durability and predict its lifetime. Next, we developed a mathematical formula for the rate of chemical degradation of the PEM to predict its service life. Two possible reaction mechanisms have been proposed as the chemical degradation of the perfluorosulfonic acid (PFSA) membrane. One is the scission of the main chains of the polymer and the other is an unzipping reaction in which the end groups of the main chains progressively degrade. In order to quantitatively estimate the rate of chemical degradation of the PFSA membrane, we numerically modelized these two reaction mechanisms. When a scission of the main chain occurs, the location of the split becomes two new end groups, which suggests that the number of points of origin for an unzipping reaction increases exponentially. The fluoride release behavior was calculated based on this model. As a result, we confirmed that the experimental fluoride release data can be explained by these two reaction mechanisms of chemical degradation. In order to describe the fluoride release quantity F as a function of duration time t, exponential function Eq. (1) was formulated to closely match the experimental results. F(t) = a [exp(b･t) - 1] (1) One of the factors that influence the chemical degradation rate of the PEM is contamination by metal ions. Adding a radical quencher is a well-known method to assure durability of the PEM by mitigating chemical degradation. In order to estimate the acceleration of PEM degradation caused by metal ion contamination or the mitigation effects offered by a radical quencher, durability testing was carried out using different levels of metal ion contamination or radical quencher additives. The results of these tests show that fluoride release behavior can be represented by Eq. (1) by fixing coefficient b and varying only coefficient a. Coefficient ais therefore defined as the accelerating factor of chemical degradation. The accelerating factor can be obtained by making Eq. (1) fit the experimental fluoride release data, and it can be used as an indicator of the severity of chemical degradation. Introducing the concept of accelerating factor to represent the fluoride release rate made it possible to deal quantitatively with the effect of factors that accelerate or mitigate chemical degradation. Moreover, the size of acceleration or mitigation effect caused by multiple factors can be indicated with a single variable. We confirmed changes in accelerating factor during FCV operation with bench testing, which demonstrated the driving modes of an actual vehicle using a fuel cell stack with the same specifications as stacks installed in actual vehicles. The fluoride release rate was calculated from the accelerating factor envisioning actual FCV operation. Fluoride release behavior can be converted into membrane thickness loss. In this way, decrease in membrane thickness during FCV operation and the lifetime of the PEM can be predicted using calculations.

Examination of the grid‐connected polymer electrolyte membrane fuel cell's electrical behaviour and control

Fuel cells (FCs) are considered as one of the most promising sources of electrical energy that can meet environmental constraints. One of the important steps to ensure clean energy is seamless power transfer from the FC to the grid. In this study, the behaviour of the FC under AC load and grid connection of FC system is simulated. Required interface for FCs' grid connection is performed with PSCAD software. For this purpose, polymer electrolyte membrane (PEM) FC model is developed in PSCAD software. Power converter units are designed to supply DC and AC loads. Control structures are developed for DC–DC converter and DC–AC inverter models in PSCAD. Power conditioning units are separately controlled by proportional–integral controller. The electrical behaviour and control of FCs are investigated and simulated using PSCAD software. Then a developed PEM FC system model is tested for AC load conditions. The PEM FC system is connected to grid and the behaviours of grid connected FC system are examined.

SIPN Systems Used as Membranes for Fuel Cell

Membranes must show chemical, electrochemical and dimensional stability and proton conductivity for application as a Polymer Electrolyte Membrane in Fuel Cells. The Semi-interpenetrating polymer network membranes (SIPN) obtained in this work were synthesized from polyethyleneimine and diglycidyl ether of bisphenol A with curing agent 4,4' diaminodiphenyl-sulphone. The membranes were studied while immersed in H3PO4 and after sulfonation. The samples were characterized by FTIR, TGA, DSC and electrochemical Impedance Spectroscopy (EIS). The SIPN membranes show high thermal stability above 270oC, which is sufficient for their application in PEMFC for intermediate temperature operation. The membrane doped with 20% H3PO4 shows higher conductivity value, 0,08 S.cm-1, than the sulfonated samples,10-2 Scm-1.

Current Status and Future Outlook of Fuel Cell Vehicle Development in Toyota

Fuel Cell Vehicle (FCV) offers one of solutions to the issues in energy and climate change. It is well known that FCV is zero-emission and hydrogen can be made from a variety of energy resources. FCV has such environmental friendly features but the recent FCV also has useful features in cruising range of more than 500km, startability under subzero condition and about 3 minutes refueling time. Furthermore, it shows attractive drivability in excellent response under lower vehicle speed cruising; another feature is that it can be used as emergency power supply, that roughly estimated to supply a household for one week by FCV, and a shelter for several hundred people for about five days by Fuel Cell Bus (FC bus) with fully fueled condition. It is considered that FC system is applicable to from small vehicle to large bus since it has longer cruising range and shorter refueling time compared to EV which is more popular than FCV now. However, both FCV and EV need years before these vehicles will be widespread because of higher cost and lack of infrastructures. For the moment, HV or Plug-in HV are considered to be major vehicle in next generation because of advantages in cost reduction and infrastructure development. FCV will increase gradually in the market according to progress of its development. Toyota started the development of FCV in 1992. After several model changes and market experiences with limited market introduction in 2002, the model “FCHV-adv” in 2008 shows excellent performances in drivability under subzero condition, cruising range and durability. These performances are reaching the levels of gasoline vehicle. Toyota announced to start selling commercial FCV “MIRAI” in December 2014 in Japan. The system uses Toyota-developed components including the Toyota FC Stack, FC boost converter, and high-pressure hydrogen tanks. Toyota FC Stack The new Toyota FC Stack achieves a maximum output of 114 kW. Electricity generation efficiency has been enhanced through the use of 3D fine mesh flow channels, which ensure uniform generation of electricity on cell surfaces, providing compact size and a high level of performance, and a power output density of 3.1 kW/L. The amount of water on fuel cell electrolyte membranes has a substantial influence on electricity generation efficiency. Control of the amount of water is carried out using an internal circulation system for circulating the water created when generating electricity, meaning the Toyota FC Stack is a system that, unlike systems used in all other previous Toyota fuel cell vehicles, does not require the use of a humidifier. FC Boost Converter A new compact, high-efficiency, high-capacity converter has been developed to boost power generated in the Toyota FC Stack to 650 volts. Increasing the voltage has made it possible to reduce the size of the electric motor and the number of Toyota FC Stack fuel cells, leading to a smaller, higher-performance Toyota Fuel Cell System, thereby reducing system costs. High-pressure Hydrogen Tanks Tanks with a three-layer structure made of carbon fiber-reinforced plastic and other materials are used to store hydrogen at a very high pressure of 70 MPa (70 megapascals, or approximately 700 bars). Compared to the high pressure hydrogen tanks used in the Toyota FCHV-adv model, tank storage has been increased by approximately 20 percent while both weight and size have been reduced to achieve a world-leading 5.7 wt%.

Nanofluid as Cooling Medium in Polymer Electrolyte Membrane (PEM) Fuel Cell: A Study on Potentials and Possibilities

Keywords:Thermal management; PEM fuel cell;NanofluidAbstract. Tremendous need for an optimum conversion efficiency of a Polymer Exchange Membrane Fuel Cell (PEMFC) operation has triggered varieties of advancements namely on the thermal management engineering scope. Excellent heat dissipation is correlated to higher performance of a fuel cell thus increasing its conversion efficiency. This study reveals the potential advancement in thermal engineering of a fuel cell stack related to nanofluid technology. Nanofluids are seen as a potential evolution of nanotechnology hybridisation with fuel cell serving as a cooling medium. The thermophysical characteristics have been reviewed and challenges with regards to fuel cell application is discussed. Nanofluid has been successfully tested on many thermal management systems isolated from thermoelectrical environments such as fuel cell. The main challenge is formulating a nanofluid coolant with high thermal conductivity but with strict limit on electrical conductivity of less than 5 μS/cm. Lack of electrical conductivity data for various nanofluids in open literature is another challenge in nanofluid application in fuel cell.

Development of Aromatic Polymer Electrolyte Membrane for Fuel Cell

Development of Aromatic Polymer Electrolyte Membrane for Fuel Cell

Electrolyte Membranes for Fuel Cells: Synthesis, Characterization and Degradation Analysis

Electrolyte Membranes for Fuel Cells: Synthesis, Characterization and Degradation Analysis