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

Due to the synchronous occurrence of densifying process and Ba element segregation under a linear current sweeping technique, a 2 μm thick dense active cathode functional interlayer is formed, outputting 1669 and 905 mW cm −2 at 700 and 600 °C.