Papers by Keyword: Membrane Electrode Assembly (MEA)

Abstract: In this work, a quaternized polysulfone/PTFE/H₃PO₄ composite membrane was prepared and used to a high temperature sustainable proton exchange membrane (HTPEM). This HTPEM was prepared based on a porous PTFE membrane, which can sustainable for 200 °C. Pt/C nano-suspension was prepared and deposited layer-by-layer on the gas diffusion layer (GDL) using electrohydrodynamic atomization (EHDA) deposition technique for the formation of cathode and anode catalyst layers (CLs). The CLs presented well packed and porous features. This EHDA deposited cathode and anode CLs, GDL and HTPEM were assembled to a membrane electrode assembly (MEA) and high temperature methanol fuel cell (HTMFC). The results showed that low concentration and high flow rate of methanol aqueous solution led to the loss of phosphoric acid on HTPEM, which resulted in the decline of the HTPEM. When the concentration and the flow rate of the methanol aqueous solution was increased and reduced, respectively, the cell can work properly at a temperature of 170 °C.

Abstract: . In order to obtain suitable titanium mesh MEA (membrane electrode assembly) for direct methanol fuel cell (DMFC) molding temperature conditions, titanium mesh was used as electrode substrate material, Nafion 117 membrane was used as proton exchange membrane, PtRu/XC-72R and Pt/XC-72R were used as anode catalyst and cathode catalyst respectively, anode and cathode of titanium mesh MEA were prepared by drop-coating method. When the MEAs were molded by hot-pressing under 5 MPa for 180 s with different temperatures of 115°C, 135°C and 155°C, respectively, the maximum power density of Ti mesh-based MEAs increases firstly, after the first peak, it gradually decreases along with the increase of molding pressure conditions, and the maximum power density appears at the molding temperature of 135°C, so conclude that molding temperature of 135°C is more appropriate for making the titanium mesh MEA.

Abstract: In order to reduce the costs, improve the performances and promote the industry process, basing on calculus and finite element thinking, conceptual design of special-shaped membrane electrode assembly (S-MEA) was proposed, including six shapes. S-MEA size was determined by calculating, admeasuring and devising elaborately, whose basic parameter was gained from experiment datum. S-MEA was made up of titanium mesh anode layer, anode catalyst layer, Nafion membrane layer, cathode catalyst layer, gas diffusion layer and titanium mesh cathode layer in turn, which was different from MEA of the fluid field bipolar plates in the macro-structure but had the same micro-mechanism. Three-dimensional model was devised through Pro/E, planar diagrammatic drawing was created by the software also, and detail drawing was designed further with CAD. The process of preparing S-MEA was researched basing on the design. Then three typical S-MEA prototypes were made by bend-hot-pressing with home-made molds and precision hydraulic machine, including open triangular cross-section MEA, circular cross-section MEA and square cross-section MEA.

Abstract: Anode for direct methanol fuel cell (DMFC) was fabricated on Nafion 117 membrane by electrophoretic deposition (EPD) method. An ethanol suspension containing Pt-Ru/C and Nafion ionomer was utilized, in which Pt-Ru/C and Nafion ionomer formed composite particles. The prepared electrode was tightly attached to the membrane without mechanical pressing and heat treatment. The electrode composition, i.e., the ratio between Pt-Ru/C and ionomer in the electrode, was controllable by Nafion content in the suspension, and strongly influenced on the DMFC performance. Accordingly, the anode with ionomer fraction of 26% exhibited the highest performance, which was more than twice as high as the performance attained in a standard electrode fabrication (hot press method).

Abstract: An experimental and numerical study of polymer electrolyte membrane fuel cell (PEMFC) is presented and compared with the experimental data to investigate the effects of pressure gradient, flow rate, humidification and supplied oxidant type for the practical application. The membrane and electrolyte assembly (MEA) materials are implemented by double-tied catalyst layers. A single-phase two-dimensional steady-state model is is implemented for the numerical analysis. Testing condition is fixed at 60sccm and 70°C in anode and cathode, respectively. It is found that the performance of PEMFC depend highly on the conditions as gas pressure, temperature, thickness, supplied oxidant type (Oxygen/Air) as well as humidification. The results show that the humidification effect enhances the performance more than 20% and the pure oxygen gas as fuel improves current density more than 25% compared to ambient air suppliance as oxidant.

Abstract: An experimental study is carried out to investigate the performance and the practical application of polymer electrolyte membrane fuel cell(PEMFC) with the double-tied catalyst layers in a Membrane Electrolyte Assembly (MEA). Characteristics of PEMFC depend highly on the conditions such as gas pressure, temperature, thickness, supplied oxidant type (Oxygen/Air) as well as humidification. They are controlled under the same condition for the comparison of the simulation. Testing condition is fixed at 60sccm and 70°C in anode and cathode, respectively. The humidification about 15% the performance is improved no humidification rather. The current density is increased around 20% significantly when pure oxygen gas is provided as an oxidant. It is found that measured values of unit cell voltage and current are influenced strongly by the type and amount of oxidant, which give more enhanced values in case of oxygen compared to the ambient air as oxidant.