Mxene-Derived Tise2/Tio2/C Heterostructured Hexagonal Prisms As High Rate Anodes for Na-Ion And K-Ion Batteries

Abstract

Establishing heterostructure is the effective strategy to improve the cycling and rate properties of electrode due to the 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, TiO2 with lower work functions can inject electrons to TiSe2 surfaces in order to achieve electron balance 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.

Keywords: Na ion battery, K ion battery, heterogenous composite, TiSe2/TiO2/C, MXene derivatives.