A Low Cost, High Electrochemical Performance Carbon Coated Zinc Borate Anode Material for Sodium-ion Batteries

Sodium-ion batteries (SIBs) as an ideal candidate for large-scale energy storage have been widely studied due to the low cost and almost unlimited sodium resource on the earth, but the works on exploring the high electrochemical performance anode materials with low-cost and eco-friendly are still urgently needed. Herein, with the assistance of a simple liquid co-precipitation method and subsequent chemical vapor deposition (CVD) treatment, the environmentally friendly, low cost and nontoxic Zn3(BO3)2@C (ZBO@C) composite is directly synthesized and proves to be an ideal anode material for SIBs. As anode material, it demonstrates a high initial reversible discharge specific capacity of 289.8 mAh g-1 with a corresponding Coulombic efficiency of 53.7 % at 0.03 A g-1. Even at 1 A g-1, it still exhibits a reversible specific capacity of 151 mAh g-1 after 500th cycles with almost no capacity losing. The Na-ion full cell (ZBO@C||NaCuFeMnO) exhibits a maximum energy/power density of 119 Wh kg-1/301 W kg-1 based on the total mass loading of anode and cathode. Those results indicate that the ZBO@C is an ideal anode for future large-scale energy storage.