Built-in electric field enhanced ionic transport kinetics in the T-Nb2O5@MoO2 heterostructure

Abstract

Mg²⁺/Li⁺ hybrid ion batteries (MLIBs) are regarded as an emerging candidate for next generation rechargeable batteries. However, realizing superior high-rate performance is still an unremitting challenge for further development of MLIBs. Herein, a rational design of the T-Nb₂O₅@MoO₂ nanorod array heterostructure as the cathode of MLIBs is presented. The resulting heterostructure reinforces structural stability and induces the generation of a built-in electric field, which facilitates ionic transport kinetics, as verified by reaction kinetics analysis, ex situ characterization techniques and density functional theory calculations. As expected, the T-Nb₂O₅@MoO₂ heterostructure delivers a reversible capacity of 250.3 mA h g⁻¹ at 0.5C, excellent rate performance (68.8 mA h g⁻¹ at 10C) and long cycling life (capacity retention of 76.0% at 5C after 1500 cycles). Thus, this strategy paves the way for designing advanced electrode materials with excellent electrochemical performance.