A novel in situ diffusion strategy to fabricate high performance cathodes for low temperature proton-conducting solid oxide fuel cells†
Abstract
Developing new low-cost high-performance cobalt-free cathode materials for low temperature proton-conducting solid oxide fuel cells (H-SOFCs) has been an imperative topic. In response to this challenge, we herein develop a novel in situ Pr diffusion strategy based on a Sm0.2Ce0.8O2−δ–Pr(Pr0.5Ba1.5)Cu3O7−δ (SDC–PBCu, 3 : 7 wt%) compound, to achieve a perovskite-related proton-blocking composite cathode (PBCC) Ce1−xPrxO2−δ–Ba2CeCu3O7.4–Sm2Ba1.33Ce0.67Cu3O9–CuO (PDC–BCC–SBCC–CuO) for BaZr0.1Ce0.7Y0.2O3−δ-based H-SOFCs. The single cell achieves a remarkable performance with a maximum power density (MPD) of 1000 and 566 mW cm−2, corresponding to the interfacial polarization resistance (RP) of 0.037 and 0.188 Ω cm2 at 700 and 600 °C, respectively. The XRD results demonstrate that the PBCu phase disappears after the calcination of the mixed SDC–PBCu composite powder at 900 °C, with the formation of four new phases including fluorite structured PDC, orthorhombic layered material BCC, tetragonal perovskite-related SBCC and a small quantity of metallic oxide CuO, being favorable for a superior cathode performance. The ascendant electrochemical performance including the very high MPD and the lower RP obtained here indicate that the quaternary cobalt-free PBCC PDC–BCC–SBCC–CuO is a preferable alternative for high-performance low-temperature H-SOFCs.