(La0.8Sr0.2)0.95Mn0.5Fe0.5O3Perovskite as anEfficient Bi-Functional Electrocatalyst for Oxygen-Involved Reaction and Zn-Air Batteries

The perovskite-type oxide (La0.8Sr0.2)(0.95)Mn0.5Fe0.5O3, synthesized using lanthanum resources recovered from polishing powder waste and manganese resources obtained from zinc anode mud, was obtained via a facile polymer-assisted combustion method, and further applied in zinc-air batteries.The crystal phase and microstructure features of the thus-obtained nanoparticles were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and nitrogen adsorption-desorption measurements. The results showed that the (La0.8Sr0.2)(0.95)Mn0.5Fe0.5O3 particles, with nanoscale size, possess a high specific surface area and a suitable Mn3+/Mn4+ molar ratio, which will benefit both the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER). As expected, the thus-fabricated (La0.8Sr0.2)(0.95)Mn0.5Fe0.5O3 electrode exhibits a high current density of 71.2 and 85.2 mA cm(-2) at -0.2 V and 0.6 V vs. Hg/HgO, respectively, which is superior to that of the commercial Pt/C catalyst (58 and 31 mA cm(-2), respectively).Subsequently, this compound oxide can be an air electrode in a rechargeable zinc-air battery. The assembled battery, using (La0.8Sr0.2)(0.95)Mn0.5Fe0.5O3 as the cathode, exhibits a discharge voltage of 1.05 similar to 1.16 V and a charge voltage of 2.03 similar to 2.13 V under 15 mA cm(-2) for 150 h.The excellent electrochemical results presented in this study highlight the potential of (La0.8Sr0.2)(0.95)Mn0.5Fe0.5O3 as a highly efficient and commercially viable bifunctional electrocatalyst for applications in rechargeable zinc-air batteries.