Nickel-Doped Cobalt Phosphide with Phosphorus-Vacancy-Abundant As an Efficient Catalyst For Non-Aqueous and Quasi-Solid-State Li-O2 Batteries

Abstract

Designing electrocatalysts with superior performance is widely recognized as one of the main strategies to address the practical challenges faced by Li-O2 batteries. Elemental doping and vacancy engineering can alter the local electronic structure, thereby influencing the adsorption and catalytic activity of reaction products. This manipulation is critical for improving the overall performance of Li-O2 batteries. Nickel-doped cobalt phosphide with abundant phosphorus-vacancy were synthesized as electrocatalysts to enhance the electrochemical efficiency of Li-O2 batteries by increasing phosphorus vacancies. The resulting nanocomposites as the electrocatalysis in the non-aqueous Li-O2 batteries exhibited outstanding electrochemical performance, including low overpotential and impressive cycling stability up to 741 cycles at a current density of 500 mA g-1. What is more, with quasi-solid-state electrolytes, the assembled Li-O2 batteries still can work up to 91 cycles. This study demonstrates that the appropriate element doping and vacancy construction of transition-metal-phosphides could be a favorable approach to develop Li-O2 batteries.

Keywords: Li-O2 Batteries, Nickel-Doped Cobalt Phosphide, Phosphorus-Vacancy, Quasi-Solid-State Electrolytes