Modification of Zn₃V₂O₈ through Ni-doping for efficient lithium ions storage

Vanadate is expected to be a promising anode material for lithium-ion batteries (LIBs). Herein, a series of Ni doped Zn₃V₂O₈ continuous solid solution has been synthesized through a simple sol–gel method. The effects of Ni-doping on the microstructure of Zn₃V₂O₈ is systematically investigated. The results show that Ni-doping has almost no influence on the crystalline phase structure and morphology, but has influences on the grain size of the samples. With the increase of Ni-doping amount, the grain size of Ni doped Zn₃V₂O₈ gradually increases. Moreover, the conductivity of Ni doped Zn₃V₂O₈ is also improved. Ni doped Zn₃V₂O₈ has exhibited better electrochemical performance than that of Zn₃V₂O₈. In particular, the sample Zn_2.4Ni_0.6V₂O₈ can deliver a capacity of 452.3 mAh g⁻¹ at a current density of 1 A g⁻¹ after 600 cycles. This should be attributed to the decrease of band gap, leading to the improvement of conductivity, which is more conducive to the transport of lithium ions and electrons.