Preparation and electrochemical characterization of ultrathin WO3−x /C nanosheets as anode materials in lithium ion batteries

Ultrathin two-dimensional (2D) nanomaterials offer unique advantages compared to their counterparts in other dimensionalities. O-vacancies in such materials allow rapid electron diffusion. Carbon doping often improves the electric conductivity. Considering these merits, the WO3−x /C ultrathin 2D nanomaterial is expected to exhibit excellent electrochemical performance in Li-ion batteries. Here, ultrathin WO3−x /C nanosheets were prepared via an acid-assisted one-pot process. The as-prepared WO3−x /C ultrathin nanosheets showed good electrochemical performance, with an initial discharge capacity of 1,866 mA·h·g−1 at a current density of 200 mA·g−1. After 100 cycles, the discharge and charge capacities were 662 and 661 mA·h·g−1, respectively. The reversible capacity of the WO3−x /C ultrathin nanosheets exceeded those of WO3 and WO3−x nanosheets. The electrochemical testing results demonstrated that WO3−x /C ultrathin nanosheets are promising alternative anode materials for Li-ion batteries.