Method for preparing phosphate-doped polybenzimidazole membrane electrode for fuel cell

Abstract

The invention discloses a method for preparing a phosphate-doped polybenzimidazole membrane electrode for a fuel cell. On the one hand, 4,4'-oxybis(benzoic acid) and 3,3',4,4'-biphenyltetramine serve as monomers to prepare poly[2,2'-(p-oxy- diphenylene)-5-5'-bisbenzimidazole], the poly[2,2'-(p-oxy-diphenylene)-5-5'-bisbenzimidazole] is cast to form a membrane, and the membrane is doped with phosphate to prepare an electrolyte membrane with good mechanical strength; on the other hand, in the process of preparing a phosphate-doped gas diffusion electrode, poly-[2,2'-(m-phenylene)-5,5'-bisbenzimidazole] is prepared into the gas diffusion electrode in the presence of a platinum / carbon catalyst, the gas diffusion electrode is doped with phosphate, the components are uniformly distributed, strong-volatility acid is not used in the process, and a process of mixing solid materials does not exist. The membrane electrode prepared by the method can be used for hydrogen-oxygen fuel cell power generation under the conditions that the temperature is higher than 100 DEG C and the humidification is not carried out. The open-circuit voltage is 0.845V, and the maximum power density is 191mW / cm<2> (560mA / cm<2>, 0.34V) under the conditions that the temperature of the fuel cell is 150DEG C and the humidification is not carried out. The preparation method has the advantages of controllable conditions in the technological process and good repeatability of the process.

Description

technical field The invention relates to a method for preparing a membrane electrode for a fuel cell, in particular to a method for preparing a phosphoric acid-doped polybenzimidazole membrane electrode for a fuel cell. Background technique The polymer electrolyte membrane fuel cell system is clean, efficient, low operating temperature and fast start-up, and has attracted much attention in the research and development of chemical technology in the new century. A traditional polymer electrolyte membrane fuel cell uses a cation exchange membrane as the electrolyte membrane, hydrogen as a fuel is directly supplied to the anode, and oxygen or air as an oxidant is supplied to the cathode. In the anode chamber, hydrogen dissociates under the action of the anode catalyst in the membrane electrode to generate protons and electrons, and the protons migrate to the cathode in the cation exchange membrane. The electrons pass through the external circuit and load, and combine with the o...

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Problems solved by technology

In this patent, methanesulfonic acid and tetrafluoroacetic acid are used for dissolving polybenzimidazole compounds. These two acids are highly volatile and will corrode the active components of the catalyst during stirring and mixing with the catalyst; the patent disclosed In the preparation method, the solid material and the binder are mixed, and the two are not easy to mix evenly, which will reduce the power generation performance of the fuel cell

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