Rationally designed hollow precursor-derived Zn₃V₂O₈ nanocages as a high-performance anode material for lithium-ion batteries

Transition metal oxides have attracted much interest for their high energy density in lithium-ion batteries. However, large volume expansion during the lithiation process limits their practical applications. Hollow structures with porous shell (such as nanocages) can provide sufficient void space to accommodate the volume expansion during the lithiation/delithiation processes. Herein, we developed a novel two-step method to prepare Zn₃V₂O₈ nanocages, in which a hollow precursor first was obtained by a solvothermal method and then was calcined in air atmosphere. Importantly, it is found that the resultant Zn₃V₂O₈ nanocages possess impressive lithium storage performance in terms of high specific capacity, superior rate capability and excellent cycling stability. The excellent lithium storage performance is attributed to easy electrolyte permeability, shorter Li⁺ and electron diffusion pathways, and effective alleviation of the volume expansion provided by the cage-like hollow structure. When coupled with commercially available LiFePO₄ cathode, the full cell exhibits remarkable lithium storage performance. The Zn₃V₂O₈ nanocages demonstrate a great potential as an anode material for high-performance lithium-ion batteries. In addition, the electrochemical reaction mechanism of the Zn₃V₂O₈ nanocages as an anode material was systematically investigated based on ex-situ X-ray diffraction, X-ray photo electron spectroscopy, and transmission electron microscopy.