Graphene Wrapped Siox/C Hollow Spheres Composites Via Molecular Polymerization As High Performance Libs Anodes

Abstract

High-capacity silicon anodes have attracted researchers’ tremendous interest for next generation lithium-ion batteries (LIBs). However, its further application is limited by the large volume expansion during cycling, causing safety issues. Designing nanostructured silicon is an effective strategy to acquire high-performance anodes, but it will face problems of high cost and poor coulombic efficiency. Silicon dioxide and SiOx show relatively higher specific capacity and lower volume expansion than silicon anodes. So, they are now becoming popular among researchers. Structure design of silicon oxide composite is one of the main experimental schemes, like hollow structures. Within the composite materials, graphene becomes one of the main conductive composite matrixes which is ascribed to its superior conductivity and mechanical property since its application in energy storage areas. Hence, SiOx/C composites have been synthesized with carbon and SiOx dispersed uniformly via a simple template-free aldimine condensation between APTMS and dialdehyde. After freeze drying and pyrolysis, the hollow structure can be obtained, in which silicon oxide is derived from APTMS and carbon is derived from carbon chains from dialdehyde. The hollow structure can effectively buffer the volume expansion of silicon oxide during charging and discharging process. Then the hollow particles are wrapped by electrochemical exfoliated graphene. Optimal graphene contents and graphene layers in the composite will be determined to explore its application in LIBs. The introducing of graphene may suppress the volume expansion and improve the conductivity of composites at the same time. Various characterization methods will be conducted to confirm its electrochemical performance and find its potential as anode materials. Figure 1