Halogenated and chalcogenated Ti2C MXenes: High capacity electrode materials for lithium-ion batteries

Inspired by the recent successful growth of Ti2C monolayers, we investigated the effects of Ti2CT2 (T = F, Cl, Br, O, S and Se) anode in lithium-ion batteries (LIBs) by first-principles calculations. The results revealed that Ti2CT2 MXenes exhibit metallic conductivity with higher structural stability and mechanical strength than Ti2C. Compared with other Ti2CT2 monolayers, Ti2CS2 monolayer display lower diffusion barrier, larger elastic modulus, lower open circuit voltage and higher storage capacity. Moreover, surface sulfuration yields the expanded interlayer spacing, which can improve Li-ion accessibility in double-layer Ti2CS2.