Facile synthesis of pomegranate-like structured SiOx composite spheres with internal carbon conductive network for lithium-ion batteries

Abstract

Incorporating carbon into unique structural particles is an effective way to further enhance cycle stability, the number of lithium-ion transfer channels within particles, and diffusion rate, but the procedure is intricate and challenging. The introduction of carbon into pomegranate-like SiO2 nanospheres is achieved by co-depositing SiO2 with carbon precursors to produce ultra-fine SiO2/C composite nanoparticles that replace the SiO2 nanoparticles that make-up the pomegranate spheres. The ultrafine SiO2/C composite nanoparticles encapsulated inside the sphere are connected to each other, creating a carbon-conductive network within the sphere. A mechanically stable outer carbon layer containing nitrogen is coated on the surface to form the (P-SiOx/CN)@CN composite material. The mechanically stable outer carbon layer, the reserved void space within the sphere, the core constructed by interconnected nanoparticles, and the carbon conductive network inside the sphere work together to endow the composite with superior electrochemical properties. The (P-SiOx/CN)@CN composite delivers high reversible mass discharge specific capacity of 970 mA h g−1 at 1.0 A g−1 over 500 cycles. This work develops a new approach to the facile synthesis of high-performance SiO2 anode materials for lithium-ion batteries.