Membrane development for direct alkaline methanol fuel cells

Fuel cell is an electrochemical power device that convert the chemical energy of a fuel directly into electrical energy. Direct Methanol Fuel Cell (DMFC)'s power density is lower than the other type of fuel cell's power densities due to relatively slow methanol oxidation reaction taking place at anode side and methanol crossover from anode side to cathode side. For this reason, the approach taken in many studies was to develop an alkali media of the DMFC. Also oxygen reduction can perform lower costs in alkaline environment with using non-platinium catalysts. Despite all these advantages, the development of an anionic polymer electrolyte membrane suitable for DAMFC are not yet at the desired level. In this M Sc. thesis, an cross-linked anionic polymer electrolite membrane based on Polyviniylalcohol (PVA) dopped Potassium Hydroxide (KOH) was developed and their cell performance was evaluated. Glutaraldehit (GA) and Polietilenglikoldiglisidileter (PEGDGE) were used as a crosslinking agent and optimum type and amount of crosslinking agent were determined. It's aimed that reduce the methanol crossover with nanosized fillers (TiO2 and SiO2). Prepared membrane's performance curves were obtained and the maximum power densities were determined. In addition to membranes performance in DAMFC, their water uptake capacity, and methanol permeability were determined. Keywords: GA, DMFC, DAMFC, PEGDGE, PVA, Polymer Electrolite Membrane.