| Membrane electrode assembly (MEA) is one of the key components of a PEMFC. The catalyst layer of the MEA is generally composed of three phases, namely a catalyst electronic conductive phase, a polyelectrolyte ionic conductive phase, and a void pores phase. These three phases are usually distributed randomly. The disordered microstructure of the catalyst layer results in the lower utilization of catalyst and the higher charge- and mass-transfer resistance. Therefore, improving the performance of PEM fuel cells by optimizing the microstructure of the MEA has been very important. In this study, electric field assisted fabrication of membrane electrode assemblies (MEAs) for fuel cells is proposed, with the aim of improving the electronic and ionic connections in the catalyst layers and increasing the efficiency of catalyst utilization.We studied the effect of an electric field on the orientation of the polarizable particles dispersed in the simulated system of the catalyst ink.Anodic and cathodic electrodes have been prepared by the perpendicular application of an electric field to the catalyst ink spread on the surface of a gas diffusion layer (GDL) while the ink is drying. The thus prepared electrodes were hot-pressed onto a Nafion membrane to form the MEAs. The performance of the electric field-treated MEAs (E-MEA) thus prepared was compared with that of common MEAs (C-MEA) without electric field treatment in a single-cell DMFC. The E-MEAs, as well as single electrodes, were also characterized by EIS, CV, and SEM methods in order to determine the changes in the E-MEAs resulting from electric field treatment. Direct methanol fuel cells (DMFCs) with the E-MEAs showed a substantial improvement in performance as compared with C-MEAs. Under the same operating conditions, the maximum power density of a DMFC was increased from 42.3 to 60.0 mW·cm-2 when a C-MEA was replaced by an E-MEA treated with a 5000 V·cm-1 and 0.1 Hz ac electric field. Based on cyclic voltammetry (CV) data, it has been shown that Pt utilization in the cathode reaches a maximum of 62% for the E-MEA, as opposed to 37% for the C-MEA.In recent years, direct carbonaceous compound polymer electrolyte membrane fuel cells have been developed rapidly. However, the comparability of the research results of different researchers is poor because of the different experimental conditions, and the research of the performance of the high-temperture carbonaceous compound polymer electrolyte membrane fuel cells is lacking. In this paper, we investigated the performance of the high-temperture polymer electrolyte membrane fuel cells with the MEAs prepared by Nafion?115 membrane, using ethanol, formic acid, dimethy and ethylene glycol as fuels under the higher operating pressures of the anode and the cathode, and compared with the performance of the direct methanol fuel cell operating under the same conditions. The experimental results showed that the direct methanol fuel cell presented a higher peak power density, whereas the direct dimethy fuel cell showed a higher open-circuit voltage.In addition, we prepared the MEAs with the modified sulfonated poly (aryl ether ketone) proton exchange membranes fabricated by us, and investigated the performance of the liquid-feed and vapor-feed direct methanol fuel cells and the carbonaceous compound polymer electrolyte membrane fuel cells using formic acid, ethylene glycol, isopropanol and dimethy as fuels. Single cell performance experiment indicated that the 30wt% PES/SPEEK (DS=68.3%) membrane is a competitive substitute as a proton exchange membrane for the direct carbonaceous compound polymer electrolyte membrane fuel cells.
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