High-performance corrosion-resistant fluorine-doped tin oxide as an alternative to carbon support in electrodes for PEM fuel cells

Abstract

The advent of new technologies and growing demand for fuel cell innovation has led to the development of novel non-carbon material strategies with inherent electrical conductance and corrosion resistance. Problems are often observed with carbon-based support materials, due to their limited electrochemical stability. The emphasis is therefore on fabricating high-performance, stable non-carbon alternatives that exhibit advantageous electrochemical properties compared to conventional carbon black, and are thus regarded as ideal electrocatalyst support materials. In this work, we investigated the influence of dopants, and the morphology of conductive, porous doped tin-based oxides, on corrosion resistance and electrical conductivity for fuel cell electrode applications. Among the various doping elements, fluorine anion doping into tin oxide plays a key role in the formation of such structures as a complexing agent for improving electrical conductivity and suppressing electrochemical dissolution processes. When used in polymer electrolyte membrane fuel cells with platinum electrocatalyst loading, fluorine tin oxide nanotubes exhibit not only cell performance comparable to that of state-of-the-art commercial Pt/C, but also excellent cycling stability. The superior electrochemical performance and stability of this novel non-carbon support material is due to its unique features, i.e., excellent electrical conductivity, electrochemical corrosion resistance, and electronic and compressive strain effects due to strong metal-support interactions.