Freeze-drying-assisted Synthesis of Mesoporous CoMoO4 Nanosheets as Anode Electrode Material for Enhanced Lithium Batteries

A facile and green freeze-drying-assisted method was proposed to synthesize CoMoO₄ mesoporous nanosheets(MPNSs). The resulting product exhibits a high specific capacity and good rate performance when evaluated as an anode material for lithium-ion batteries(LIBs). The reversible specific capacity can be kept at 1105.2 mA·h·g^-1 after 100 cycles at a current density of 0.2 A/g. Even at the current densities of 1 and 4 A/g, the CoMoO₄ MPNSs electrode can still retain the reversible capacities of 1148.7 and 540 mA·h·g^-1, respectively. Furthermore, the full cell(LiFePO₄ cathode/CoMoO₄ MPNSs anode) displays a stable discharge capacity of 146.7 mA·h·g^-1 at 0.1 C (1 C=170 mA/g) together with an initial coulombic efficiency of 98.2%. In addition, the CoMoO₄ crystal structure is destroyed and reduced into Co⁰ and Mo⁰ in the first discharge process. In the subsequent cycles, the attractive Li storage properties come from the reversible conversions between Co/Co²⁺ and Mo/Mo⁶⁺. The improved electroche-mical performance of CoMoO₄ MPNSs is mainly attributed to their unique porous structures, which not only possess a good ion diffusion and electronic conduction pathway, but also provide many cavities to alleviate the volume changes during repeated cycling. This work offers a new perspective to the design of other porous electrode materials with a good energy storage performance.