Regulating the electronic structure of MoO2/Mo2C/C by heterostructure and oxygen vacancies for boosting lithium storage kinetics

Abstract

The electronic structure regulation of electrode materials can improve the ion/electron kinetics, which is beneficial to the cyclic performance and rate capability for lithium ion batteries (LIBs). Herein, we propose a facile strategy to achieve a MoO₂/Mo₂C/C heterostructure with abundant oxygen vacancies. Density functional theory calculations indicate that the heterostructure of MoO₂/Mo₂C/C can significantly promote the Li⁺/charge transfer and reduce the Li adsorption energy, and the abundant oxygen vacancies in MoO₂/Mo₂C/C can improve the intrinsic electronic conductivity and reduce the Li⁺ diffusion barrier. Benefiting from the multiscale coordinated regulation, the obtained MoO₂/Mo₂C/C film exhibits outstanding high rate capability (454.7 mA h g⁻¹ at 5 A g⁻¹) and remarkable cyclic performance (retaining 569 mA h g⁻¹ over 1000 cycles at 2 A g⁻¹). The insightful findings in this study can shed light on the behavior of the electron/ion structure regulation by the heterostructure and oxygen vacancies, which can guide future studies on designing other electrode materials with high-performance lithium-ion storage.