MoO2@carbon hollow microspheres with tunable interiors and improved lithium-ion battery anode properties

Abstract

MoO₂ hollow microspheres with tunable inner space have been synthesized through a hydrothermal process using MoO₃ microbelts instead of bulk MoO₃ as the precursor. It is found that the reactant morphology has a great impact on the product morphology and the inner space can be tuned by changing the amount of NaOH aqueous solution. An interesting evolutional process from MoO₃ microbelts through a rose-like intermediate to MoO₂ hollow microspheres has been clearly observed, and thus the possible formation mechanism is revealed. One layer of amorphous carbon has been subsequently coated on the surface of MoO₂ hollow microspheres through a simple hydrothermal approach followed by annealing in argon. As the anode material for lithium ion batteries, MoO₂@C hollow microspheres manifest excellent lithium-storage properties, such as high capacity (677 mA h g⁻¹) and good cycling stability (negligible capacity fading even after 80 cycles). The significantly enhanced performance of MoO₂@C hollow microspheres can be attributed to its unique structures, such as nanoscaled primary building blocks, carbon coating, hollow structure, and especially the synergy between the carbon coating and hollow structure.