Newer polymer electrolytes and electrocatalysts for direct alcohol fuel cells

Abstract

Direct Alcohol Fuel Cells (DAFCs) are gaining tremendous interest as energy source for portable application, since liquid fuel without the external reforming system could avoid storage and safety issues. Among DAFCs, Direct Methanol Fuel Cells (DMFCs) and Direct Ethanol Fuel Cells (DEFCs) gain importance due to easy availability and higher specific energies of the fuels, methanol and ethanol, used in them. However, progress in commercialisation of DMFCs and DEFCs is retarded due to (i) the slow kinetics and incomplete oxidation of methanol and ethanol at the anode, (ii) the slow kinetics of oxygen reduction reaction (ORR) along with the competing alcohol oxidation reaction at the cathode. Hence, a lot of advancement has been taking place in the development of (i) cost-effective membrane electrolytes with reduced alcohol permeability without much loss in ionic conductivity, (ii) high-performing alcohol oxidation catalysts and (iii) alcohol tolerant ORR catalysts. In the present chapter, the recent advances in Nafion and SPEEK-based blend and composite membranes with potential inorganic additives with reduced alcohol permeability are highlighted for their application in DAFCs. In addition, the recent development of electrocatalysts exhibiting Strong Metal Support Interaction (SMSI) in achieving higher rate of alcohol oxidation and, alcohol-tolerant ORR is highlighted.