Encapsulating Si nanoparticles in multi-shell hollow spheres: An effective approach to boost the cyclability

Silicon is an appealing lithium-ion battery anode material; unfortunately, it is confronted with unsatisfactory cyclability owing to its large volume change. Herein, we design a unique ternary composite anode material (Si/Cr2O3/C), where the Si nanoparticles are confined in carbon-coated chromium oxide multi-shell hollow spheres (MSHSs). Encapsulating the Si nanoparticles in the MSHSs effectively boosts the cyclability owing to the available free space for volume change buffering and the ideal structural stability of the Cr2O3/C hybrid matrix. The rationally designed Si/Cr2O3/C ternary composite demonstrates not only high reversible capacity (1351 mA h g(-1) at 100 mA g(-1)) but also stable cycling (716 mA h g(-1) after 300 cycles at 500 mA g(-1)). This contribution proposes a novel multi-shell hollow structure design to solve the poor cyclability problem of Si-based anode materials.