A dual-function chromium-trapping current collector enabling poisoning-free and durable high-temperature fuel cells

Abstract

High-temperature degradation remains a critical barrier to solid oxide fuel cell (SOFC) commercialization, with Cr vapor–induced electrode poisoning representing one of the most persistent challenges. Here, we present a Co–Ni spinel oxide as a dual-function current collector that actively scavenges Cr vapor while maintaining efficient electrical coupling between the cell and interconnects. Upon Cr exposure, the spinel incorporates Cr via preferential substitution at octahedral Co sites, assisted by Ni acting as a redox-flexible mediator, thereby enabling effective Cr interception without compromising electrical conductivity. Foam- and porous-layer-type Cr-trapping current collectors were developed for practical implementation in realistic SOFC systems. Under severe Cr exposure, reference cells exhibited a 17.6% performance loss over 200 h, whereas cells incorporating the Cr-trapping collector showed complete suppression of degradation, demonstrating robust and sustained electrode protection. This strategy provides a simple, scalable, and effective route to enhancing SOFC durability and extending system lifetime.