Understanding the Li/Na intercalation mechanism in MoS2/Ti2BT2 (T = Se Te) heterostructures: An atomic-scale investigation

Layered van der Waals (vdW) heterostructures are widely considered as exceptional anode materials of lithium (LIBs) /sodium (SIBs) ion batteries, which can integrate the desirable characteristics and break the limitation of parent structures. Herein, using first principles calculations, we report MoS2/MBene heterostructures (MoS2/Ti2BT2, T = Se, Te) and investigate their potential as the anodes of LIBs/SIBs. Our computational results confirm that the designed heterostructures exhibit intrinsically metallic behavior with excellent thermal, dynamical and mechanical stability. Their mechanical stiffness (Young's moduli > 240 N/m) is dramatically enhanced after the incorporation of Ti2BT2 layer, which can successfully address the soft problem of MoS2. Moreover, both MoS2/Ti2BSe2 and MoS2/Ti2BTe2 exhibit rapid ion diffusivity with Li (Na) diffusion barriers of 0.21 (0.09) and 0.17 (0.07) eV. The computed average open circuit voltages are 0.61 (0.32) and 0.39 (0.18) V, respectively, making them suitable for high-charging-voltage application. Importantly, the two heterostructural anodes also show acceptable Li (Na) storage capacities of 315.65 (256.81) and 252.52 (154.08) mA h/g. These fascinating results demonstrate that MoS2/Ti2BT2 heterostructures exhibit great promise to be appealing anode candidates for LIBs/SIBs.