Rational Synthesis of "Grape-like" Ni₂ V₂ O₇ Microspheres as High-capacity Anodes for Rechargeable Lithium Batteries

Vanadates have received booming attention recently as promising materials for extensive electrochemical devices such as batteries and electrocatalysis. However, the enormous difficulties of achieving pure-phase transition metal vanadates, especially for nickel-based, hinder their exploitations. Herein, for the first time, by controlling the amount of ethylene glycol (EG) and reaction time, grape-like Ni₂ V₂ O₇ (or V₂ O₅ /Ni₂ V₂ O₇ ) microspheres were rationally fabricated. It is demonstrated that the EG can chelate both Ni²⁺ and VO₃ ^- to form organometallic precursors. As anode in lithium-ion batteries (LIBs), it could deliver superior reversible capacity of 1050 mAh/g at 0.1 A/g and excellent rate capability of 600 mAh/g at 4 A/g. The facile hydrothermal synthesis broadens the material variety of nickel vanadates and offers new opportunities for their wider applications in electrochemistry.