Investigating the potentials of TiVC MXenes as anode materials for Li-ion batteries by DFT calculations

Abstract

Density functional theory (DFT) were performed to investigate the electronic properties and electrochemical performance of two-dimensional TiVC and TiVCT2 (T = O, F, OH) as lithium-ion anode materials. Two types of TiVC and TiVCT2 (T = O, F, OH) structures, which are ordered double-metal (O-type) and solid-solution metal (S-type), were investigated in the present study. The DOS results reveal that all the TiVC and TiVCT2 in the most favorable configurations exhibit metallic character for two types. The lowest diffusion barriers are 0.027 eV and 0.040 eV on two different sides of O-TiVC in this work, which can provide faster charge and discharge rates. In the aspect of storage capacities, the maximum theoretical capacity among these monolayers is 483 mAh g−1 (for O-TiVC), and TiVC terminated with -O group exhibit relatively high theoretical capacity in O- and S-types (375 mAh g−1). However, the capacity will decrease significantly when terminated with -F and –OH groups on the interface. Our calculations suggest that O-TiVC, O-TiVCO2 and S-TiVCO2 are suitable for lithium-ion batteries.