Facile hydrothermal synthesis of double shelled Si@SnO2@C as advanced cathode for high-temperature lithium batteries

The elaborately prepared Si-based composites with core-shell structure have greatly optimized the issues of Si electrode volume expansion. However, the preparation processes of most of them are tedious and the solvents used to remove templates is harmful, which affects the development and application of Si-based electrode materials. Herein, a novel double-shelled Si@SnO2@C composite is successfully designed in one-step by hydrothermal method and verified by X-ray diffraction analysis combined with X ray photoelectron spectroscopy analysis. As the cathode of high-temperature battery, the discharge behavior of Si@SnO2@C composite in the Li–Mg–B alloy/LiNO3–KNO3/Si@SnO2@C battery system has been carried out. It is demonstrated that the as-prepared Si@SnO2@C composite has excellent discharge performance at current densities of 10 mA cm−2 and the specific capacity can be achieved 782.12 mAh g−1 at 200 °C. Even at a much higher temperature of 300 °C, the capacity can still reach 613.67 mAh g−1, and these favorable properties are mainly due to outstanding structure characteristics. The synthesis process is simple and economical, which provides a feasible alternative method for preparation of advanced silicon-based electrode materials to alleviate violent volume expansion. •A unique Si@SnO2@C composite with core-shell structure had been prepared facilely.•Discharge performance of Li–Mg–B alloy/LiNO3–KNO3/Si@SnO2@C cells as high temperature lithium battery is investigated.•The battery exhibits excellent safety from room temperature to 300 °C.