Dual-Donor Doped Perovskite as Bifunctional Oxygen Electrode Catalyst for Reversible Protonic Ceramic Electrochemical Cell
Wenwen Zhang, Shuo Wang, Chenhui Yang, Jingrong Yu, Yige Guo, Shaowei Zhang, Yuefeng Song, Xiaomin Zhang, Guoxiong Wang, Xinhe Bao
Abstract
Developing high-performance bifunctional oxygen electrodes is crucial for advancing the reversible protonic ceramic electrochemical cell (R-PCEC). Here, we report a novel Nb–Ta codoped BaCoO 3−δ perovskite oxygen electrode that exhibits enhanced bifunctional catalytic activity, enabled by modulation of metal–oxygen bonding. Dual-donor doping with Nb and Ta suppresses Co–O hybridization, thereby weakening Co–O bonds and promoting both oxygen activation and vacancy formation. The increased oxygen vacancy concentration, coupled with reduced hydration energy and a proton hopping barrier, synergistically enhances proton hydration and migration. Consequently, the R-PCEC with the BaCo 0.8 Nb 0.1 Ta 0.1 O 3−δ oxygen electrode achieves remarkable performance, with a peak power density of 1.20 W cm –2 in fuel cell mode and a current density of 1.32 A cm –2 at 1.3 V in electrolysis cell mode at 650 °C. This work elucidates the underlying mechanism by which dual-donor doping modulates defect chemistry and transport properties in perovskite catalysts, offering a rational design strategy for efficient oxygen electrodes in R-PCEC and broader energy conversion technologies.