Exploring the potential of Ti₂BT₂ (T = F, Cl, Br, I, O, S, Se and Te) monolayers as anode materials for lithium and sodium ion batteries

Introducing functional groups to two-dimensional transition metal borides (MBenes) is an effective way to ameliorate the properties of MBenes as electrode materials for rechargeable lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). Herein, we investigated the electrochemical performances of Ti₂BT₂ (T = F, Cl, Br, I, O, S, Se and Te) as anode materials for LIBs and SIBs using first-principles calculations. Firstly, the metallic nature of Ti₂BT₂ endows them with excellent conductivities. Besides, the phonon dispersions and ab initio molecular dynamics simulations (AIMD) were conducted to estimate the dynamic and thermal stability of Ti₂BT₂. Additionally, Ti₂BSe₂ has slight high specific capacity of 405 mA h g⁻¹ for LIBs and Ti₂BS₂ possesses ultra-high specific capacity of 942 mA h g⁻¹ for SIBs. Furthermore, the low diffusion energy barriers endow ultra-high charge/discharge rate and suitable open circuit voltages ensure the safety of battery performance. The encouraging results indicate that Ti₂BSe₂ and Ti₂BS₂ are outstanding candidates as electrode materials for LIBs and SIBs, respectively. Our work not only screened out excellent electrode materials for metal-ion batteries, but also provided constructive suggestions for the development of next-generation high-performance electrode materials.