Encapsulation of SnO2 nanoparticles between the hollow TiO2 nanosphere and the carbon layer as high-performance negative materials for lithium-ion batteries

Abstract SnO2 is regarded as a promising negative material candidate for contemporary lithium-ion batteries (LIBs). However, the nanostructured SnO2 electrodes suffer from rapid capacity fades during lithiation and delithiation at a high-current density due to active materials aggregating and cracking. Herein, we designed and fabricated a novel multilayered hollow TiO2@SnO2@C sphere electrode though a facile three-step sol-gel coating process and hydrothermal strategy. The SnO2 nanoparticles are well confined between an outermost high-conductivity carbon layer and innermost stable hollow TiO2 nanospheres that form the pillar structure of the entire composite. Attributed to the internal spherical titanium dioxide as a support layer, the structural integrity of the composite and the possible anti-inward rupture can be effectively improved. As a result, the as-prepared TiO2@SnO2@C electrode exhibits a remarkable reversible capacity of 484 mAh g−1 at 0.2 A g−1 after 300 cycles and delivers outstanding capacity of 263 mAh g−1 at 3 A g−1. Moreover, this unique SnO2 hollow sphere structure with TiO2 as the innermost stable pillar will have implications for the design of high-power-density negative materials for future lithium-ion batteries.