MXene-derived TiSe2/TiO2/C heterostructured hexagonal prisms as high rate anodes for Na-ion and K-ion batteries

Establishing heterostructure is an effective strategy to improve the cycling and rate properties of electrode due to high charge transfer kinetics. Nevertheless, it is still a great challenge to prepare a reasonable heterojunction material with appropriate electrochemical property as anode for Na/K ion batteries. In this work, a novel MXene derivative consisted of TiSe2/TiO2/C heterostructured hexagonal prism has been prepared by a simple solid phase sintering method to converting Ti3C2Tx MXene to TiSe2/TiO2/C. In this composite, TiSe2 and TiO2 with different work functions can induce a built-in electric field in the heterojunction interface, accelerating the electrochemical courses. Serving as an anode material for Na ion batteries, TiSe2/TiO2/C can keep a discharge capacity of 280 mAh g−1 at 5 A g−1 after 1000 cycles and a superior rate capability with 212 mAh g−1 even at 10 A g−1. Even using as anode for K ion batteries, TiSe2/TiO2/C can still retain a capacity of 121 mAh g−1 at 0.1 A g−1 after 800 cycles. This work supplies a simple approach to design metal oxide/selenide heterostructures toward Na/K ion batteries with excellent performance and promotes the application of MXene derivatives in the field of energy storage.