Robust Core-Shell Carbon-Coated Silicon-Based Composite Anode with Electrically Interconnected Spherical Framework for Lithium-Ion Battery

Abstract

Carbon-coated Si/carbon nanotube/graphene oxide (C-Si/CNT/GO) microspheres with a robust core-shell composite structure were successfully fabricated by efficient and scalable spray-drying and chemical vapor deposition (CVD) for application as a lithium-ion battery (LIB) anode. The amphiphilic GO nanoparticles facilitated the uniform dispersion of Si nanoparticles by suppressing the CNT aggregation in the Si/CNT/GO microspheres, efficiently forming a robust Si/CNT/GO microsphere composite structure. The surface of the Si/CNT/GO microsphere composite was coated with carbon using CH4 via CVD to enhance its cycling performance. The four building block components, namely, Si nanoparticles, CNTs, and GO nanoparticles as the core and the carbon-coating layers as the shell, provided high electrochemical capacity, excellent electrical conductivity, efficient buffer space for the volume expansion of the Si nanoparticles, and high structural stability during lithiation/delithiation. The C-Si/CNT/GO composite anode also exhibited excellent electrochemical performance with high specific capacity (2921 mAh g-1 at 100 mA g-1), long cycle life (1542 mAh g-1 at 200 mA g-1 after 100 cycles), and high charge/discharge rate (1506 mAh g-1 at 6 A g-1). This approach for fabricating core-shell structured Si-based composite anodes with excellent electrochemical performance will provide a significant breakthrough for developing next-generation LIBs.