Sn-doped cobalt containing perovskite as the air electrode for highly active and durable reversible protonic ceramic electrochemical cells

One potential solution to the problems of energy storage and conversion is the use of reversible protonic ceramic electrochemical cells (R-PCEC), which are based on the solid oxide fuel cell (SOFC) technology and offer a flexible route to the generation of renewable fuels. However, the R-PCEC development faces a range of significant challenges, including slow oxygen reaction kinetics, inadequate durability, and poor round-trip efficiency resulting from the inadequacy of an air electrode. To address these issues, we report novel B-sites doped Pr_0.5Ba_0.5Co_0.7Fe_0.3O_3−δ (PBCF) with varying amounts of Sn as the air electrode for R-PCEC to further enhance electrochemical performance at lower temperatures. At 600 ℃, R-PCEC with an air electrode consisting of Pr_0.5Ba_0.5Co_0.7Fe_0.25Sn_0.05O_3+δ has achieved peak power density of 1.12 W∙cm⁻² in the fuel cell mode and current density of 1.79 A∙cm⁻² in the electrolysis mode at a voltage of 1.3 V. Moreover, R-PCECs have shown good stability in the electrolysis mode of 100 h. This study presents a practical method for developing durable high-performance air electrodes for R-PCECs.