Rapid synthesis of three-dimensional network structure CuO as binder-free anode for high-rate sodium ion battery

We report on the preparation of the three dimensional (3D) network structure CuO by rapid and facile engraving method and their application as high rate anode for sodium ion battery. The CuO is rapidly synthesized by in-situ etched and oxidated the specified Cu foils within 15 min. It shows the 3D network architecture with flower-like nanosheets connected by nanowires, which provides the porous structure, short ion diffusion pathway and collaborative electronic transmission. Furthermore, the etched CuO can be directly used as anode for sodium ion battery without polymer additions or conductive agents. The electrodes exhibit excellent electrochemical performance with a high capacity of 680 mAh·g−1 at 50 mA g−1 and a reversible capacity of 280 mAh·g−1 at 1000 mA g−1. In addition, the electrochemical reaction and detail charge/discharge process are carefully explored to discover the conversion reaction routes and the recession reason. Thus, the 3D network structure CuO might open an insight for transition-metal oxides as energy storage materials. The 3D network structure CuO with flower-like nanosheets connected by nanowires offers porous architecture, short ion diffusion pathway and collaborative electronic transmission, which exhibits excellent rate performance. [Display omitted] •Three-dimensional network structure CuO can be rapidly synthesized within 15 min.•CuO shows 3D network structure with flower-like nanosheets connected by nanowires.•CuO electrodes prepared in 15 min exhibit excellent electrochemical performance.•Conversion reaction routes and the recession reason have been carefully studied.