The Priority and Challenge of High-Power Performance of Low-Platinum Proton-Exchange Membrane Fuel Cells

TLDR

Reducing PEMFC cathode Pt loadings from 0.4–0.8 mg Pt cm⁻² to ~0.1 mg Pt cm⁻² has introduced a resistance term near the catalyst surface that limits high‑current performance, yet past progress suggests that concerted materials and electrode design can overcome this hurdle. The study aims to address high‑current density losses by designing catalysts with high, stable Pt dispersion and ionomers that do not constrain oxygen reduction reaction rates. The approach involves developing such catalysts and ionomers that interact with Pt without limiting oxygen reduction reaction rates. At ~0.1 mg Pt cm⁻² cathode loading, performance drops sharply above 1 A cm⁻², preventing stack cost reduction.

Abstract

Substantial progress has been made in reducing proton-exchange membrane fuel cell (PEMFC) cathode platinum loadings from 0.4–0.8 mgPt/cm2 to about 0.1 mgPt/cm2. However, at this level of cathode Pt loading, large performance loss is observed at high-current density (>1 A/cm2), preventing a reduction in the overall stack cost. This next developmental step is being limited by the presence of a resistance term exhibited at these lower Pt loadings and apparently due to a phenomenon at or near the catalyst surface. This issue can be addressed through the design of catalysts with high and stable Pt dispersion as well as through development and implementation of ionomers designed to interact with Pt in a way that does not constrain oxygen reduction reaction rates. Extrapolating from progress made in past decades, we are optimistic that the concerted efforts of materials and electrode designers can resolve this issue, thus enabling a large step toward fuel cell vehicles that are affordable for the mass market.