Two-dimensional Dirac TiB2C2 as a potential anode material for Li-ion batteries: a first-principles study

Abstract

The development and design of anode materials with good stability, high capacity, low diffusion barrier and excellent cyclability is an important challenge for further improvement of the battery industry. In this context, a promising 2D anode material TiB₂C₂ with Dirac cone states is investigated through the first-principles prediction. We found this material to be thermodynamically, dynamically, and thermally stable, suggesting the possibility of its experimental synthesis. Considering its lightweight, planar structure and Dirac cone features, we systematically investigated the feasibility of the TiB₂C₂ monolayer as an anode material for Li-ion batteries (LIBs). Based on the adsorption energy of lithium on the monolayer surfaces, we determined the sites that can hold lithium ions with high adsorption energy. Moreover, TiB₂C₂ exhibits good ionic and electronic conductivity, a suitable voltage profile, and high structural stability upon the Li-loading process; it also shows 1.12% change in cell parameters. Importantly, a high storage capacity of up to 1075 mA h g⁻¹ was found. All these criteria conclude the appealing electrochemical performance of the TiB₂C₂ monolayer as a promising anode material for LIBs.