Alkaline Fuel Cells Research Articles

Welcome Remarks - I01E: Polymer Electrolyte Fuel Cells & Electrolyzers 20 (PEFC&E 20) - Materials for Alkaline Fuel Cells and Direct-Fuel Fuel Cells

Welcome to I01E: Polymer Electrolyte Fuel Cells & Electrolyzers 20 (PEFC&E 20) - Materials for Alkaline Fuel Cells and Direct-Fuel Fuel Cells! Take a moment to listen to welcome remarks from the lead organizer, William Mustain.

Structure–Property Relationship in Poly(Terphenylene)-Based Anion Exchange Membranes; The Impact of Backbone Structure for the Free Volume Control in Alkaline Fuel Cell Application

The commercial application of anion exchange membrane fuel cells (AEMFCs) has been impeded by the lack of high ion conductivity and mechanical/chemical stability of the currently used anion exchange membranes (AEMs). A new class of aromatic polymers, which contain conducting head groups directly onto the polymer backbone were developed to attain long-term stability along with high conductivity. Inspired from this, a series of poly(terphenylene)-based anion exchange membranes devoid of benzylic sites or aryl-ether bonds, that are vulnerable to attack by hydroxide ion, were synthesized and were investigated for their physicochemical properties for alkaline fuel cell applications. The polymer backbones having N,N-dimethylpiperidinium conducting head group were synthesized using acid-catalyzed Friedel-Crafts polycondensation reaction between N-methyl-4-piperidone and meta/para-terphenyl monomers. Along with meta-terphenyl homopolymer, another three sets of copolymers were synthesized by introducing the kink structured meta-terphenyl in different ratios with para-terphenyl to control the free volume. The copolymer membrane, m-p-CoP-50, prepared from meta/para terphenyl monomers with a 1:1 molar ratio displayed a well-balanced water uptake, dimensional stability and the highest conductivity. The experimental procedures and the results will be discussed in detail.

Optimization of the Catalytic Layer for Alkaline Fuel Cells Based on Fumatech Membranes and Ionomer

Polymer electrolyte fuel cells with alkaline anion exchange membranes (AAEMs) have gained increasing attention because of the faster reaction kinetics associated with the alkaline environment compared to acidic media. While the development of anion exchange polymer membranes is increasing, the catalytic layer structure and composition of electrodes is of paramount importance to maximize fuel cell performance. In this work, we examine the preparation procedures for electrodes by catalyst-coated substrate to be used with a well-known commercial AAEM, Fumasep® FAA-3, and a commercial ionomer of the same nature (Fumion), both from Fumatech GmbH. The anion exchange procedure, the ionomer concentration in the catalytic layer and also the effect of membrane thickness, are investigated as they are very relevant parameters conditioning the cell behavior. The best power density was achieved upon ion exchange of the ionomer by submerging the electrodes in KCl (isopropyl alcohol/water solution) for at least one hour, two exchange steps, followed by treatment in KOH for 30 min. The optimum ionomer (Fumion) concentration was found to be close to 50 wt%, with a relatively narrow interval of functioning ionomer percentages. These results provide a practical guide for electrode preparation in AAEM-based fuel cell research.

A Composite Anion Conducting Membrane Based on Quaternized Cellulose and Poly(Phenylene Oxide) for Alkaline Fuel Cell Applications.

In this study, composite anion exchange membranes (AEMs) were synthesized by cross-linking poly(phenylene oxide) (PPO) with cellulose functionalized by 1,4-diazabicyclo[2.2.2]-octane (DABCO) or di-guanidine (DG). The structural and morphological characteristics of the synthesized AEMs were characterized by FTIR, 1H-NMR, SEM, TEM, and AFM, while their performance was evaluated in terms of ionic conductivity, water uptake, ion exchange capacity, and tensile strength with respect to the loading of the quaternized cellulose in the quaternized PPO (qPPO) matrix. The composite AEMs exhibited considerably enhanced mechanical and alkaline stability as well as good anion conductivity. The composite AEM with 7 wt% of cellulose functionalized with DG in the qPPO matrix (qPPO/DG-Cel7) exhibited a maximum hydroxide conductivity of 0.164 S cm−1. Furthermore, a urea/O2 fuel cell prepared using this composite membrane showed a maximum power density of 12.3 mW cm−2. The results indicated that the cellulose-based composite membranes showed a satisfactory performance in alkaline fuel cell applications.

Optimisation Study of Co Deposition on Chars from MAP of Waste Tyres as Green Electrodes in ORR for Alkaline Fuel Cells

Oxygen Reduction Reaction (ORR) catalysts, from waste automobile tyres obtained from Microwave assisted pyrolysis (MAP), were enriched with Co and Cu using the simple treatments sonochemical and electrochemical deposition. Catalytic activity was evaluated through onset potential and number of exchanged electrons measurements. Electrochemical data demonstrate an improvement in catalytic activity of the electrochemical modified char with Co. Char electrodes enriched with Co show a maximum positive shift of 40 mV with respect to raw char electrodes with a number of exchanged electrons per O2 molecule close to 4 (as for Pt) for the best sample. This corresponds to a reduction of the production of unwanted oxygen peroxide from 23% for raw char to 1%. Sample structure evolution before and after electrochemical deposition and electro-catalysis was investigated by scanning transmission electron microscopy and XPS. Such electrochemical treatments open new possibilities of refining waste chars and finding an economic alternative to noble metals-based catalysts for alkaline fuel cells.

Solid‐State Alkaline Fuel Cell Performance of Pentablock Terpolymer with Methylpyrrolidinium Cations as Anion Exchange Membrane and Ionomer

AbstractIn this study, pentablock terpolymers with methylpyrrolidinium cations were characterized and investigated as anion exchange membranes and ionomers for solid‐state alkaline fuel cells. The pentablock terpolymer (with methylpyrrolidinium cations) membranes exhibited higher fuel cell power density and durability than commercial FuMA‐Tech (with quaternary ammonium cations) membranes at 30 °C, 100% relative humidity (RH). Optimization of the catalyst ink composition (i.e., solids and solvent ratio) and fuel cell performance of membrane electrode assemblies (MEAs) with pentablock terpolymers as both the membrane and ionomer were also investigated. Optimization of the fuel cell operating conditions corroborates with the in situ electrochemical impedance spectroscopy results. The pentablock terpolymer MEA exhibited a maximum power density of 83.3 mW cm−2 and voltage decay rate of 0.7 mV h−1 after 100 h of operation under 40 °C, 100% RH. These results show promise for pentablock terptolymers with methylpyrrolidinium cations as a commercially attractive low‐cost alternative anion exchange membrane and ionomer for solid‐state alkaline fuel cells.

Numerical Study of Solar Hydrogen Production System for Rural Areas Employing TRNSYS

In this study, solar heating water system and hydrogen production were modeled and simulated by using System Simulation Software TRNSYS. What’s more the system was optimized by TRNSYS/GenOpt. The electricity grid was the auxiliary electrical energy for the system. Hot water was generated by solar collector and then transported to a hold-up vessel with supplementary heat source. Photovoltaic (PV) panels generated electricity which was used to product hydrogen by electrolyzing water. Alkaline Fuel Cell used the hydrogen to generate electrical energy for the supplementary heating source of hold-up vessel. The systems for north-China rural areas in Hebei Province were designed and the hourly system operating characteristic using the optimum volume of vessel was investigated. According to the experimental hot water load of one farmhouse, the hourly and annual electrolytic hydrogen volume, the hourly electrical energy generated by photovoltaic panels, the energy conversion characteristic of the system, the hourly pressure in the storage tank of hydrogen were studied by TRNSYS. According to the simulation results, the most covering rate of solar energy varied from 20% appearing in January to 80% appearing in August.

Piperidinium-Based Anion-Exchange Membranes with an Aliphatic Main Chain for Alkaline Fuel Cells

A series of cross-linked piperidinium-based anion exchange membranes (AEMs) with an aliphatic main-chain was prepared by UV-initiated polymerization of 1-methyl-1-(4-vinylbenzyl)piperidinium chlori...

Methods of Hydroxide-Ion Form Anion Exchange Membrane Characterization

Alkaline fuel cells (AFCs) are of high interest because they utilize lower cost catalyst and separator materials relative to polymer electrolyte membrane fuel cells. AFCs require anion exchange membranes (AEMs) that have high alkaline durability and high hydroxide ion conductivity. Herein, numerous AEMs from top research groups in the field are evaluated and compared as hydroxide conducting solid state electrolytes. While the hydroxide-anion form of AEMs is the most relevant anion form for alkaline fuel cell and electrolysis applications, it remains difficult to evaluate hydroxide form membranes as they quickly convert to carbonate- and bicarbonate-anion forms upon exposure to air. NREL has developed protocols to allow for high throughput, parallel characterization of AEM materials in hydroxide-anion form. This work assesses six optimized membranes with varied backbone chemical structures: perfluoro (PF), poly(aryl ether sulfone) (PAES), polyethylene (PE), polyfluorene (PFN), polystyrene (PS), polyphenylene (PPN). Methods are established for evaluating true hydroxide-ion properties of these AEMs at varying temperature and relative humidity, including conductivity, durability, and water uptake. Standardized comparisons of the top performing hydroxide conducting AEMs of different backbone types provides valuable insight into optimal chemistries for achieving high conductivity and durability.

Fabrication of Mg-Al Layered Double Hydroxide Thin Membrane for All-Solid-State Alkaline Fuel Cell Using Glass Paper as a Support

Layered double hydroxides (LDHs) are promising solid electrolytes for all solid-state alkaline fuel cells (AFCs) because of inorganic clay-like materials. However, LDHs were usually obtained as powder, and the formation of thin membranes as a separator of a fuel cell is rather difficult. In this study, a glass paper, non-woven fabric of fine glass fibers with more than 90% porosity, was used as a support for Mg-Al LDH powder, and self-standing, thin membranes for all solid-state AFCs were fabricated. Crystals of Mg-Al LDH were deposited in the inside of the glass paper by repeated immersion in Mg-Al LDH-dispersed solution and drying. Thickness of the obtained Mg-Al LDH thin membrane was about 150 µm, and LDH layer showed c-axis orientation because of the plate-like structure. The H2-O2 fuel cell using the Mg-Al LDH thin membrane as an electrolyte showed open circuit voltage of more than 0.9 V, indicating that the Mg-Al LDH thin membrane is dense and has high gas barrier property. The H2-O2 fuel cell using the Mg-Al LDH thin membrane showed higher power density compared with that using pelletized Mg-Al LDH powder as the electrolyte. The glass paper is proved to be very effective support for making thin Mg-Al LDH electrolyte membrane.

Multifunctional Electrocatalysts: Ru–M (M = Co, Ni, Fe) for Alkaline Fuel Cells and Electrolyzers

Moving from proton exchange membrane fuel cells to anion exchange membrane fuel cells (AEMFCs) enables the use of non-Pt-group (NPG) metals as cathodes for the oxygen reduction reaction, since the ...

The MOF/GO‐based derivatives with Co@CoO core‐shell structure supported on the N‐doped graphene as electrocatalyst for oxygen reduction reaction

AbstractThe development of nonprecious catalyst for oxygen reduction reaction (ORR) is important for the commercialization of the alkaline fuel cells (AFCs). Herein, we prepared a kind of Co‐based nanoparticles (NPs) with a core‐shell (Co@CoO) structure supported on the N‐doped graphene (Co@CoO/NG) as an efficient ORR catalyst via simply pyrolyzing the ZIF‐67 anchored on the synthesized graphene oxide (GO). The catalytic activity for ORR of the obtained Co@CoO/NG is comparable with the state‐of‐art Pt/C catalyst in terms of the onset and half‐wave potential in the alkaline solution. In addition, the Co@CoO/NG exhibited an excellent ORR durability and antimethanol activity compared to the commercial Pt/C. This research would provide a simple strategy to prepare the high‐performance nonprecious metal‐based catalysts for AFCs.

Combinatorial Studies of Palladium-Based Oxygen Reduction Electrocatalysts for Alkaline Fuel Cells.

Hydrogen fuel cells have emerged as promising, potentially renewable energy-based, energy conversion technologies for powering electric vehicles. However, the sluggish oxygen reduction reaction (ORR) at the cathode has remained a longstanding challenge and requires the design of nonplatinum electrocatalysts with high activity and, ideally, low cost. Here, we present a combinatorial study of Pd-Cu thin-film electrodes with well-defined composition and structures, prepared by magnetron sputtering, as a fast method for assessing the ORR activity of binary alloys. This represents a facile catalyst screening method, using replaceable glassy carbon disk electrodes, which enables the rapid and reliable evaluation of ORR activity using standard rotating disk electrode (RDE) measurements. Among nine Pd-Cu alloys, Pd50Cu50 was identified as the most promising composition for the ORR and employed as a target for nanoparticle synthesis. The PdCu nanoparticles, supported on carbon, achieved a mass-specific and surface-specific activity, 3 and 2.5 times, respectively, as high asPd/Cin 1 M KOH. PdCu/C further exhibited an impressive durability with only 3 and 13 mV negative shifts in the half-wave potential after 20000 and 100000 potential cycles, respectively. The combinatorial approach guiding the nanoparticle synthesis, described herein, provides an optimized high-throughput screening method for other binary or ternary alloys as fuel cell electrocatalysts.

KOH-doped Porous Polybenzimidazole Membranes for Solid Alkaline Fuel Cells

In this study the preparation and properties of potassium hydroxide-doped meta-polybenzimidazole membranes with 20–30 μm thickness are reported as anion conducting polymer electrolyte for application in fuel cells. Dibutyl phthalate as porogen forms an asymmetrically porous structure of membranes along thickness direction. One side of the membranes has a dense skin layer surface with 1.5–15 μm and the other side of the membranes has a porous one. It demonstrated that ion conductivity of the potassium hydroxide-doped porous membrane with the porogen content of 47 wt.% (0.090 S cm−1), is 1.4 times higher than the potassium hydroxide-doped dense membrane (0.065 S cm−1). This is because the porous membrane allows 1.4 times higher potassium hydroxide uptake than dense membranes. Tensile strength and elongation studies confirm that doping by simply immersing membranes in potassium hydroxide solutions was sufficient to fill in the inner pores. The membrane-electrode assembly using the asymmetrically porous membrane with 1.4 times higher ionic conductivity than the dense non-doped polybenzimidazole (mPBI) membrane showed 1.25 times higher peak power density.

Anion Exchange Membrane Based on Interpenetrating Polymer Network with Ultrahigh Ion Conductivity and Excellent Stability for Alkaline Fuel Cell.

A high-performance anion exchange membrane (AEM) is critical for the development of alkaline fuel cell. In this work, AEMs with an interpenetrating polymer network (IPN) are synthesized. An electron microscope clearly reveals a highly efficient “ion channel” network, which is constructed with a small amount of cation exchange groups. This specially designed ion channel leads to extraordinary hydroxide conductivity (e.g., 257.8 mS cm−1 at 80 °C) of IPN AEMs at moderate ion exchange capacity (IEC = 1.75 mmol g−1), as well as excellent long-term alkaline stability at harsh condition which showed that 81% of original conductivity can be retained after a long time for 1248 hours. Moreover, a remarkable peak power density of 1.20 W cm−2 (0.1 MPa backpressure) with nonprecious metal (FeNx-CNTs) as oxygen reduction reaction (ORR) catalyst in a fuel cell test was achieved. This work offers a general strategy to prepare high-performance AEMs based on IPN structure design.

Preface

2019 5th International Conference on Advances in Environment Research (ICAER 2019) which was successfully held in Singapore during 13-15 August, 2019. ICAER 2019 was organized by Hong Kong Chemical, Biological & Environmental Engineering Society (HKCBEES), Environment and Agriculture Society (EAS).ICAER 2019 is one of the leading international conferences for presenting novel and fundamental advances in the fields of Advances in Environment Research. It also serves to foster communication among researchers and practitioners working in a wide variety of scientific areas with a common interest in improving Advances in Environment Research related techniques. Prof. Ngai Weng Chan from Universiti Sains Malaysia, Malaysia has been invited to do the welcome address; Prof. Kuo-Lun Tung from National Taiwan University, Taiwan has given his keynote speech”Highly Zeolite-Loaded Polyvinyl Alcohol Composite Membranes for Alkaline Fuel-Cell Electrolytes”; Assoc. Prof. Dr. Shanti Faridah binti Salleh from Universiti Malaysia Sarawak (UNIMAS), Sarawak, Malaysia has shared her keynote speech “Rural Electrification for Sustainable Development: Key Issues and Challenges”; Prof. Ngai Weng Chan from School of Humanities, Universiti Sains Malaysia, Malaysia has also presented his keynote speech”Holistic Urban Water Management Integrating Rainfall Harvesting, Water Conservation and Sustainable Drainage Systems in Universiti Sains Malaysia”.Many researchers, engineers, academicians as well as industrial professionals from all over the world have presented their research results and development activities. There were two sessions for presentations: Environmental Management and Engineering, Renewable Energy and Electric Energy. It is a golden opportunity for the students, researchers and engineers to interact with the experts and specialists to get their advice or consultation on technical matters, sales and marketing strategies.

Polysulfone Copolymer as Polymer Electrolyte for Alkaline Fuel Cell and Li-Ion Battery Applications

Polysulfone Copolymer as Polymer Electrolyte for Alkaline Fuel Cell and Li-Ion Battery Applications

An Improved Hydroxide Conversion Process of Anionic Exchange Membranes for Alka-line Fuel Cells

An Improved Hydroxide Conversion Process of Anionic Exchange Membranes for Alka-line Fuel Cells

The Effect of Cross-linking Technique on Membrane Performance for Direct Methanol Alkaline Fuel Cell Application

In this study, anion exchange membranes (AEM) based on poly(vinyl alcohol) (PVA) were prepared by two different cross-linking techniques and the effects of application sequence of thermal and chemical cross-linking technique on properties of AEM were investigated. Poly(ethylene glycol) diglycidly ether (PEGDGE) was used as a chemical cross-linking agent instead of the commonly used glutaraldehyde (GA). Evaluation of the fuel cell-related properties of the prepared membranes showed that the technique of cross-linking and the application sequence of techniques affected the properties of membranes. Promisingly, it was found that the membranes prepared by firstly chemical cross-linking and then thermal cross-linking at 150˚C (PPP150) exhibited high ionic conductivity (47 mS/cm), membrane selectivity values (89 x104 S.s/cm3) and sufficient mechanical strength. These encouraging results indicate that AEMs-based on PVA cross-linked by chemical technique with PEGDGE and then thermal technique may be considered as a promising membrane for Direct Methanol Alkaline Fuel Cell (DMFC) applications.

Highly Anion Conductive Polymers: How Do Hexafluoroisopropylidene Groups Affect Membrane Properties and Alkaline Fuel Cell Performance?

Novel anion conductive aromatic copolymers containing hexafluoroisopropylidene groups as the hydrophobic component and fluorenyl groups substituted with pendant hexyltrimethylammonium groups as the...