Ultrasonic assisted growth of SnO2@carbon hollow nanosphere composites as conductive agent free anode materials for lithium-ion batteries

SnO 2 @carbon hollow nanosphere composite was prepared via saturating carbonaceous hollow nanospheres (CHN) with the desired metal salt solution by an ultrasonic assisted route followed by heating in air. The ultrasonic treatment is used not only to help obtain more acid sites on the surface of CHN but also to help obtain a homogeneous distribution of SnO 2 nanoparticles just anchored on the surface of CHN. The sample exhibits excellent energy storage performance with a specific capacity of 1020 mAh/g after 130 cycles at a current rate of 100 mA/g and very stable cycling performance. The significant improvement may be ascribed to hollow-shell hierarchical structures with a short lithium diffusion path and the better structural stability, as well as the improved reversibility of the conversion reaction. The presented work illustrates a complex lithium storage mechanism in metal oxides and provides a strategy to prepare hierarchical structures with tunable size as a conductive agent free electrode designed for better energy storage properties.