A novel in situ diffusion strategy to fabricate high performance cathodes for low temperature proton-conducting solid oxide fuel cells

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-delta-Pr(Pr0.5Ba1.5)Cu3O7-delta (SDC-PBCu, 3 : 7 wt%) compound, to achieve a perovskite-related proton-blocking composite cathode (PBCC) Ce(1-x)PrxO(2-delta)-Ba2CeCu3O7.(4)-Sm2Ba1.33Ce0.67Cu3O9-CuO (PDC-BCC-SBCC-CuO) for BaZr0.1Ce0.7Y0.2O3-delta-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 Omega cm(2) at 700 and 600 degrees C, respectively. The XRD results demonstrate that the PBCu phase disappears after the calcination of the mixed SDC-PBCu composite powder at 900 degrees 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 R-P obtained here indicate that the quaternary cobalt-free PBCC PDC-BCC-SBCC-CuO is a preferable alternative for high-performance low-temperature H-SOFCs