The facile synthesis and electrochemical performance of Ni2V2O7 as a novel anode material for lithium-ion batteries

Abstract

The single-phase binary nickel vanadate Ni₂V₂O₇ was successfully synthesized by a simple solid-state method to explore novel anode materials for lithium-ion batteries. After an activation process, the Ni₂V₂O₇ electrode exhibited excellent electrochemical performance with a stable, high specific capacity of about 960 mA h g⁻¹ at a current density of 100 mA g⁻¹, which is attributed to the multiple valence states and the synergistic effect of the transition elements V and Ni. Even at a high current density of 2000 mA g⁻¹, a stable specific capacity of about 400 mA h g⁻¹ was still obtained. Considering the influence of the activation process on the electrochemical performance of the Ni₂V₂O₇ electrode, we studied the origin of the excellent electrochemical performance, where the improved lithium diffusion coefficient and increased pseudocapacitive contribution caused by the activation process led to a significant improvement in the electrochemical performance, including rate capacity and cycle stability. By combining in situ X-ray diffraction (XRD) and ex situ X-ray photoelectron spectroscopy (XPS) methods, for the first time, we illustrate the detailed lithium storage mechanism of the Ni₂V₂O₇ electrode during the lithium insertion/extraction process.