Anti-perovskite nitrides as chemically stable lithiophilic materials for highly reversible Li plating/stripping

Abstract

Constructing structured anodes with lithiophilic materials has emerged as an essential strategy to stabilize Li deposition and accomplish highly reversible Li metal batteries (LMBs). Nevertheless, a lithiophilic material, which meets the requirements of low cost, excellent electronic conductivity and especially chemical stability, is still absent. Herein, we report the discovery of a new class of lithiophilic anti-perovskite nitrides MNNi₃ (M=Zn, Cu, In) that not only are cost-effective and highly conductive, but also possess excellent stability against Li metal. More specifically, electrochemical tests in combination with density functional theory (DFT) calculations reveal that the lithiophilicity of MNNi₃ arises from unique chemical/physical adsorption rather than the previously proposed alloying or conversion reaction mechanisms. The MNNi₃@CC enabled symmetric cells exhibit better rate capability and longer cycle life than the cells with pure carbon cloth and Ni₃N@CC. More importantly, the excellent electrochemical performances of MNNi₃ anodes are also verified by ZnNNi₃@CC in a LiFePO₄ coupled full cell with minimal capacity degradation of 28% in 1500 cycles under the charge/discharge current of 1C. Beyond offering a new type of non-reactive lithiophilic materials to outstanding achieve battery performance, this study deepens the understanding of the lithiophilic nature of different metal nitrides, which paves a way for developing highly reversible lithium metal anode.