Advancing cathodic electrocatalysis via an in situ generated dense active interlayer based on CuO5 pyramid-structured Sm2Ba1.33Ce0.67Cu3O9

Abstract

Tailoring electrode–electrolyte interphases could potentially enhance the interfacial reaction for protonic ceramic fuel cells (PCFCs), and an in situ generated dense active cathode functional interlayer (CFI) via a low-cost linear current sweeping (LCS) method is developed based on the perovskite-related Sm₂Ba_1.33Ce_0.67Cu₃O₉ (SBCC) cathode material. Due to the simultaneous occurrence of Ba element segregation and the densifying process at the SBCC/BZCY interface during the LCS procedure, the Ba(Zr,Ce)_1−x(Sm,Y,Cu)_xO_3−δ (BZCSYC) phase is formed and sandwiched between two SBCC phases in the 2 μm thick CFI, promoting the protolysis to the SBCC@BZCSYC CFI–cathode interface. When assessing the SBCC cathode accompanied by the CFI based on a BaZr_0.1Ce_0.7Y_0.2O_3−δ-based single-cell, exhilarating cell performance with peak power densities (PPDs) of 1669 and 905 mW cm⁻², corresponding to the interfacial polarization resistance (R_P) values of 0.027 and 0.115 Ω cm² at 700 and 600 °C, respectively, is attained. The superior cell performance, including the remarkably high PPD and the notably low R_P, clearly state that SBCC is a preferential cathode alternative. The LCS technique is an advanced method to optimize the electrode interface for high-performance low-temperature PCFCs.