Study On The Self-humidifying Proton Exchange Membrane Applied In High Temperature And Hydrophilic Materials In Catalyst Layer

The self-humidifying membrane electrode assembly(MEA) is a new type of MEA that humidifying the electrode by reusing the produced water of the cell reaction. This kind of MEA is mainly through the humidifying modification of membrane electrode materials or the structure optimization to the membrane electrode, making the membrane electrode keep good water retention or the produced water in the cathode diffusing to the electrolyte membrane and the anode side at the low humidity condition. Application of the self-humidifying membrane electrode assembly to the proton exchange membrane fuel cell can not only greatly improve the output performance of air-cooling fuel cell and high temperature proton exchange membrane fuel cell, but also can simplify the structure of fuel cell system and reduce the high cost of fuel cells. It has great significance with the future of fuel cell as a new type of energy equipment used in the industry and human life, and the commercialization of fuel cell.In this paper, the research mainly includes two aspects: the research of self-humidifying membrane materials and the research of self-humidifying catalytic layer hydrophilic materials. Firstly, we studied the physical and electrochemical performance advantages of short-side-chain(SSC) perfluorosulfonic acid(PFSA) to apply in high temperature self-humidifying membrane, then, we prepared an Aquivion/PTFE composite membrane by adding PTFE as the matrix to solve the physical stability problem of the SSC PFSA membrane caused by large swelling stress after absorbing water. Finally, we prepared a SSC PFSA self-humidifying composite membrane with excellent physical and electrochemical properties. In addition, in this paper we also studied the preparation of Nafion/Silica hydrophilic nanoparticles via electrostatic self-assembly function to replace traditional Nafion resin material to hydrophilic modification of catalytic layer, improving the water retention ability of catalytic layer under the condition of low humidity. Through some relevant test and analysis, the main conclusions draw as following:(1) The prepared Aquivion/PTFE SSC PFSA composite membrane has excellent electrochemical performance under the condition of low humidity, and the physical stability performance of SSC PFSA membrane is greatly improved due to the addition of PTFE matrix membrane, it is very superior self-humidifying proton exchange membrane materials;(2) The prepared Nafion/Silica hydrophilic nanoparticles to replace traditional Nafion hydrophilic resin material used in catalytic layer, it showed better fuel cell performance under the condition of low humidity, is a very good self-humidifying modification materials in catalytic layer. While, its performance is related to the content of silica in nanoparticles, the best content of silica is 6 wt%.