Regulation oxygen vacancy in Ba 0.9 La 0.1 Co 0.7 Fe 0.2 Nb 0.1 O 3-s cathode with improved hydration activity for proton ceramic fuel cells

Proton ceramic fuel cells (PCFCs) are gaining attention due to their high energy conversion efficiency. However, the development of PCFCs is hindered by the lack of efficient and robust cathode materials. This article proposes a solution by introducing certain cationic deficiency into the Ba0.9La0.1Co0.7Fe0.2Nb0.1O3-s (BLCFN) cathode matrix, which results in abundance of oxygen vacancies as well as enhanced proton defects. Consequently, the catalytic activity and hydration activity of the BLCFN oxygen electrode are improved during the reduction reaction process. Specifically, the polarization impedance (Rp) of the (Ba0.9La0.1)0.95Co0.7Fe0.2Nb0.1O3-s (BL95CFN) decreases by 20% compared to the pristine BLCFN, reaching 0.12 D center dot cm2 at 700 degrees C in air. The Rp of BL95CFN decreases by 12% in a steam environment of 20 vol%. This enhancement is attributed to the higher concentration of oxygen vacancies, which leads to an improved proton diffusion rate and hydration performance. The peak power density of the anode-supported BL95CFN | BZCYYb | BZCYYb-NiO single cell reaches 641 mW cm-2 at 700 degrees C, and the performance of this single cell remains stable for nearly 100 h. These findings highlight the vital role of adjusting oxygen vacancy and proton diffusion, providing a feasible strategy for improving the performance and stability of PCFC cathode materials.