Efficient oxygen evolution reaction in SrCo0.8Fe0.2O3-δ perovskite and surface reconstruction for practical zinc-air batteries

Perovskite oxide has attracted wide attention in the field of electrochemistry due to its intrinsic electrocatalytic activity, structural stability and compositional flexibility. Herein, SrCo0.8Fe0.2O3-δ (SCF-0) material is simply heated in a H3BO3 solution to form a synthetic catalyst, exhibiting excellent OER activity. The optimized SCF (SCF-0.2) has an overpotential of 287 mV and a Tafel slope of 50 mV dec−1 at a current density of 10 mA cm−2 (the two items of SCF-0 are 396 mV and 102 mV dec−1). Subsequent material characterization confirmed that, due to the efficient improvement of the surface morphology of the material, the smooth plane generates numerous needle-like nanoflower structures with a size of 30–50 nm, which significantly enhanced the specific surface area of the material, attributed to selective slowly dissolve out of a lot of Sr and a small amount of Fe. In addition to that, the perovskite SCF-0.2 + Pt/C is used as the air cathode in the self-assembled zinc-air battery, which shows excellent peak energy density ~106 mW cm−2 and charge-discharge cycle life. In particular, this simple surface modification method provides an effective optimization strategy for improving the specific surface area and OER performance of the material.