Lithiation mechanism of hierarchical porous MoO2 nanotubes fabricated through one-step carbothermal reduction

Abstract

A one-step carbothermal reduction method has been developed for the preparation of hierarchical porous materials. In this method, CMK-3 acts both as a template casting the hierarchical porous structure and as a reducing agent for the carbothermal reaction. Hierarchical MoO₂ nanotubes prepared through this method exhibit high charge/discharge capacities and rate capabilities when used as an anode material for lithium ion batteries. Cycled at current densities of 0.1 and 1.0 A g⁻¹, the material delivers discharge capacities of 720 and 530 mA h g⁻¹ after 70 cycles, respectively. The Li-ion insertion and extraction processes of MoO₂ nanotubes have been investigated by using an in situ X-ray diffraction technique for the first time to elucidate the Li-ion storage mechanism for the MoO₂ material. We demonstrate that the discharge capacity increase of MoO₂ during the first 30 cycles is attributed to the lithiation transformation of MoO₂.