Designing different carbon capping amorphous MoO2 to enhance electrochemical performance in lithium-ion batteries

Abstract

Transition metal oxides (TMOs) are considered promising anode materials for lithium-ion batteries (LIBs) because of their high theoretical capacity. However, their use in LIBs is limited by factors such as low initial coulombic efficiency, substantial volume changes, and low electrical conductivity. Here, amorphous MoO₂ capped with different carbon sources is ingeniously designed by controlling the calcination temperature and different carbon sources. Electrochemical kinetics and material characterization show that the amorphous structure not only enhances its electronic conductivity, but also optimizes the lithium-ion (Li⁺) migration mode, thus improving its rate performance. Furthermore, the pore sizes produced by different carbon sources were found to have different effects on the performance of LIBs. Meanwhile, the Li⁺ storage mechanism of the amorphous MoO_2−x@C was revealed by in-situ XRD analysis. As expected, the amorphous MoO_2−x@C exhibits excellent cycling stability, maintaining a discharge specific capacity of 601.4 mA h g⁻¹ at 5.0 A g⁻¹ for 800 cycles. In particular, the MoO_2−x@C||LiCoO₂ full cell still possesses a capacity of 109.8 mA h g⁻¹ at 0.2 C for 80 cycles. This endeavor will provide an experimental idea for molybdenum-based oxide high-performance anode materials.