Rechargeable Zn-Air Batteries with Outstanding Cycling Stability Enabled by Ultrafine FeNi Nanoparticles-Encapsulated N-Doped Carbon Nanosheets as a Bifunctional Electrocatalyst.

Despite grand advances in Zn-air batteries in recently years, their commercialization remains challenging due largely to the lack of efficient bifunctional oxygen catalysts. Herein, we report the crafting of a bifunctional electrocatalyst comprising ultrafine alloyed FeNi nanoparticles encapsulated within N-doped layered carbon nanosheets (denoted FeNi/N-LCN) for high-efficiency Zn-air batteries. The FeNi/N-LCN electrocatalyst is yielded via the coordination of triphenylimidazole-containing polyaniline (TPANI) oligomer with Fe- and Ni-containing precursors, followed by hydrogen binding with melamine and subsequent pyrolysis. The as-constructed FeNi/N-LCN manifests outstanding activity and stability toward both the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). The primary Zn-air battery assembled with FeNi/N-LCN delivers both high specific capacity and peak power density. Remarkably, the rechargeable Zn-air battery can be repeatedly charged and discharged for 1100 h at 5 mA cm and for 600 h at 10 mA cm, representing the highest cycling stability among various reported Zn-air batteries.