W-doped VO2(B) nanosheets-built 3D networks for fast lithium storage at high temperatures

Abstract

VO2 as one of the most prospective cathode materials applied for lithium-ion batteries, has appealed increasing attentions owing to its high theoretical specific capacity, unique tunnel structure, as well as low cost. Among multiple methods to optimize the electrochemical performances of VO2(B), heteroatom-doping has attracted increasing interests owing to its efficiently adjusting the microstructure and interplanar distances of VO2(B). Here, W-doped VO2(B) nanosheets-built 3D networks are obtained readily via a hydrothermal route by oxalic acid reduction of vanadium pentoxide. The resultant 3D networks possess ultrathin nanowalls, interconnected structure and enlarged tunnels, which are advantageous for the easy access of electrolyte and fast diffusion of lithium ions. As a consequence, high reversible specific capacity of 304 mAh g−1, ultrahigh rate capability (200 mAh g−1 at 2 A g−1), and high-temperature electrochemical performances are achieved as the 3D networks are applied for lithium storage.