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.