Hollow Si nanospheres with amorphous TiO2 layer used as anode for high-performance Li-ion battery

Abstract

This work introduces a novel, nanostructured Si-based material comprised of hollow Si spheres encapsulated in an amorphous TiO2 layer (HN-Si@aTiO2). The HN-Si@aTiO2 is prepared by magnesiothermic reduction and sol-gel methods. As an anode material, the composite exhibits high capacity performance and enhanced cycling stability. When tested at a current density of 1 A g−1, the nanocomposite achieves a high initial specific capacity of 2804.6 mA h g−1 with a high initial coulombic efficiency of 78.47% and its discharge capacity is 1196.3 mA h g−1 after 100 cycles. Meanwhile, the HN-Si@aTiO2 electrode exhibits high capacity performance with 524.6 mA h g−1 even after 500 cycles at 5 A g−1. The outstanding cycling stability of HN-Si@aTiO2 is attributed to its hollow core-shell nanostructure. The hollow structure of the anode material provides space for volumetric change of the silicon core, while the amorphous TiO2 coating layer maintains the integrity of the electrode material. Therefore, HN-Si@aTiO2 nanocomposites have great prospects as next-generation lithium-ion anode materials owing to their outstanding electrochemical performance and scalable synthesis methods.