Niobium tungsten oxide Nb₁₄W₃O₄₄ was synthesized by hydrothermal reaction of niobium oxalate and ammonium tungstate and subsequent calcination, and the synthetic conditions and structure were optimized for its use as an anode material in lithium-ion batteries. The nearly pure phase Nb₁₄W₃O₄₄ with a particle size of 1–2 μm shows good rate performance and cycle stability with high capacity retention.

Abstract

Niobium tungsten oxide is a potential replacement for graphite in fast-charge lithium-ion batteries due to its high rate performance and high stability. Herein, Nb₁₄W₃O₄₄ anode was synthesized by hydrothermal reaction of niobium oxalate and ammonium tungstate and sequent calcination of niobium tungsten oxide precursors. Compared with the traditional solid-state method, the particle size and calcination time of Nb₁₄W₃O₄₄ obtained by the modified method are greatly reduced. Through orthogonal experiments, the optimal synthesis conditions were determined, and it was found that hydrothermal conditions have an important influence on the particle size of the final product, while the calcination temperature and time greatly affect the purity of the product and thus influence its specific capacity during cycles.