Ab Initio Prediction and Characterization of TiB₂ as a Two-Dimensional Dirac Anode for Metal (Li/Na/Mg) Ion Batteries

Abstract

Two-dimensional (2D) Dirac materials exhibit promising characteristics as anode materials due to their exceptional conductivity and versatile properties. This study explores the potential of TiB2 monolayers as a 2D Dirac anode for both lithium-ion batteries (LIBs) and nonlithium-ion batteries (NLIBs) using density functional theory. Our findings demonstrate that TiB2 monolayers possess outstanding mechanical, dynamic, and thermal stability. The calculated adsorption energy values suggest that the adsorption of Li, Na, and Mg atoms on the TiB2 monolayer is a favorable process. Additionally, the TiB2 monolayer maintains its metallic nature and undergoes minimal volume expansion (<2%) during Li/Na/Mg intercalation, ensuring excellent conductivity and long-term cycle stability. The ultralow barrier energy for Li, Na, and Mg (0.04, 0.06, and 0.07 eV, respectively) along with a suitable open-circuit voltage indicates exceptional charging and discharging capabilities. Moreover, the high specific storage capacities of 771, 771, and 3084 mA h g–1 for Li, Na, and Mg, respectively, surpass those of traditional anode materials like graphite. Ab initio molecular dynamics simulations reveal that the TiB2 monolayer is stable at room temperature. This research offers valuable insights for the development of advanced rechargeable metal-ion batteries with high capacity and a lightweight design.