La1.7Sr0.3Co0.5Ni0.5O4+δ layered perovskite as an efficient bifunctional electrocatalyst for rechargeable zinc-air batteries

In this work, a novel La1.7Sr0.3Co0.5Ni0.5O4+δ with a layered perovskite structure was synthesized by the sol-gel method and characterized by the X-ray diffraction (XRD), scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). Catalytic activities of La1.7Sr0.3Co0.5Ni0.5O4+δ toward oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) were systematically investigated by the rotating disk electrode (RDE) technique in alkaline media. Compared to La2NiO4+δ, La1.7Sr0.3Co0.5Ni0.5O4+δ demonstrated more active for ORR in terms of the higher limiting current density (−4.05 mA·cm−2) and higher half-wave potential (0.568 V vs. RHE) at 1600 rpm. Zinc-air batteries using La1.7Sr0.3Co0.5Ni0.5O4+δ as the catalyst exhibited the higher peak power density (60 mW·cm−2), the lower discharge-charge voltage gap (1.26 V) after 100 cycles and good discharge-charge cycling stability than that of La2NiO4+δ.