Preparation of Zn3Nb2O8 anode material for high-performance lithium/sodium-ion batteries†

Niobium-based oxides (M-Nb-O) as promising lithium/sodium-ion storage anode materials have attracted much attention. More types of niobium-based oxides are prepared in order to provide more candidates for anode materials. Herein, Zn₃Nb₂O₈ as a novel intercalation-type anode material has been reported for the first time. Arborescent Zn₃Nb₂O₈ particles (Zn₃Nb₂O₈-A) and stump-like Zn₃Nb₂O₈ particles (Zn₃Nb₂O₈-B) have been prepared by solid-state and solvothermal methods, respectively. Benefiting from the microsized stump-like structure and the exposure of the (110) facet, Zn₃Nb₂O₈-B delivers superior long-term cycling stability with a 139.6% capacity retention (291.8 mA h g⁻¹) over 650 cycles at 0.5 A g⁻¹ and a large reversible specific capacity of 91.4 mA h g⁻¹ at 4.0 A g⁻¹ in lithium-ion batteries. Furthermore, the Zn₃Nb₂O₈-B electrode exhibits outstanding cycling stability (100.1 mA h g⁻¹ with 94.5% capacity retention after 400 cycles at 0.5 A g⁻¹) in sodium-ion batteries. The excellent electrochemical performance of the stump-like Zn₃Nb₂O₈-B materials can be attributed to the exposure of the (110) facet, enlarged interlayer spacing, small charge transfer resistance, and high pseudocapacitive contribution. Therefore, Zn₃Nb₂O₈-B has great application prospects as an anode material for lithium/sodium-ion storage.