Preparation of Anion Conducting Pore Filling Membranes for Direct Hydrazine Fuel Cells

Abstract

Hydrazine fuel cells in an alkaline medium are a promising energy conversion technology due to the extraordinary properties of hydrazine as a hydrogen carrier. Alkaline electrolyte fuel cells allow the use of less expensive metals such as cobalt and nickel as an electrode catalyst. The devices consist of a pair of electrochemical reactions at electrodes and anion movement through electrolytes to complete full electrochemical cells. Anions move from cathode to anode or vice versa for electron exchanges. Pathway for ions is normally in an aqueous phase. Regardless, the introduction of any aqueous phase in energy conversion devices causes many problems during fabrication, operation, maintenance, and so on. Thus, much efforts have been devoted to develop quasi-solid electrolytes such as gel polymer, ion exchangeable polymers, impregnation of ions in porous matrix and so on. An approach to minimize areal resistance of film-type polymeric electrolytes is to make membrane thickness as thin as possible. In this study, pore filling membranes have been studied as a new type of electrolytes. Pore filling membranes are made by impregnating monomers into thin porous substrates, followed by heat or UV cured polymerization. Pore filling membranes with the thickness of 20-50 μm were prepared using porous substrates with hydrophilized surface. A technique to make the surface of pore filling membranes hydrophilic were developed so as to adsorb liquid hydrated hydrazine fuel in KOH supporting electrolyte. Characterization in terms of ion conductivity, ion exchange capacity, water uptake, dimensional stability, mechanical strength was carried out and discussed. Acknowledgment This research was supported by the Technology Development Program to Solve Climate Changes of the National Research Foundation (NRF) funded by the Ministry of Science, ICT ＆ Future Planning(NRF-2018M1A2A2063866).