Membrane‐Supported Nonvolatile Acidic Electrolytes Allow Higher Temperature Operation of Proton‐Exchange Membrane Fuel Cells

Abstract

The feasibility of using nonvolatile molten and solid acidic electrolyte impregnated ion‐exchange membranes in higher temperature proton‐exchange membrane fuel cells (PEMFCs) to alleviate their water dependence is investigated. Higher temperature PEMFC operation reduces CO poisoning as well as passivation of the Pt electrocatalyst by other condensable species. Further, higher temperature operation could eventually allow direct use of low‐temperature reformable fuels such as methanol in the PEMFC. The methodology proposed here involves supporting an appropriate acidic solid, melt, or solution of low volatility within the pores of Nafion® so as to enhance its protonic conductivity at higher temperatures and lower humidity levels. Preliminary experimental results reported here for a PEM fuel cell operating at temperatures of 110 to 120°C based on Nafion supported solutions of heteropolyacid indicate the feasibility of the technique.