This study is financially supported by the Natural Science Foundation of Guangdong Province (2021A1515010395), the National Natural Science Foundation of China (22179039 and 22005105), the Fundamental Research Funds for the Central Universities (2022ZYGXZR002), the Pearl River Talent Recruitment Program (2019QN01C693), and the Introduced Innovative R&D Team of Guangdong (2021ZT09L392). K.P. appreciates the support of the China Postdoctoral Science Foundation Project (2020M682700). S.L. appreciates the support of the Science and Technology Innovation Program of Hunan Province (2021RC2007). ICN2 acknowledges funding from Generalitat de Catalunya 2021SGR00457. This study was supported by MCIN with funding from European Union NextGenerationEU (PRTR-C17. I1) and Generalitat de Catalunya. This research is part of the CSIC program for the Spanish Recovery, Transformation, and Resilience Plan funded by the Recovery and Resilience Facility of the European Union, established by the Regulation (EU) 2020/2094. The authors thank the support from the project NANOGEN (PID2020-116093RB-C43), funded by MCIN/ AEI/10.13039/501100011033/ and by “ERDF A way of making Europe”, by the “European Union”. ICN2 is supported by the Severo Ochoa program from Spanish MCIN/AEI (Grant No.: CEX2021-001214-S) and is funded by the CERCA Programme / Generalitat de Catalunya.

The reversible protonic ceramic electrochemical cells (R-PCECs) can efficiently and cost-effectively store and convert energy at low-intermediate temperatures (400-700 oC). Their widespread commercialization is mainly limited by the challenges of oxygen electrodes due to the slow oxygen reaction kinetics and poor durability. In this study, we first enhance the reaction activity and surface stability of a double-perovskite PrBaCo2O5+δ (PBC) oxygen electrode by employing a fluorite-based Pr0.1Ce0.9O2+δ (PCO) catalyst coating. The PCO-coated PBC (PCO-PBC) oxygen electrode shows a much-reduced area-specific resistance of 0.096 Ωcm2 and good performance on a fuel-electrode supported single cell at 650 oC, displaying a typical peak power density of 1.21 Wcm-2 (in fuel cell mode) and a typical current density of 2.69 Acm-2 at 1.3 V (in electrolysis mode) with reasonable faradaic efficiencies and durability. PCO coating has significantly improved the surface exchange process, facilitated ion diffusion, and suppressed the Ba-segregation of PBC, as confirmed by the analyses of electrochemical performance and TEM.

With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2021-001214-S)

Peer reviewed