Control of cyclic stability and volume expansion on graphite–SiOx–C hierarchical structure for Li-ion battery anodes

Abstract

To increase the energy density of today's batteries, studies on adding Si-based materials to graphite have been widely conducted. However, adding a Si-based material in the slurry mixing step suffers from low distribution due to the self-aggregation property of the Si-based material. Herein, a hierarchical structure is proposed to increase the integrity by using APS to provide a bonding effect between graphite and SiO_x. Additionally, to endow a protection layer, carbon is coated on the surface using the CVD method. The designed structure demonstrates enhanced integrity based on electrochemical performance. The MSG (methane decomposed SiO_x@G) electrode demonstrates a high ICE of 85.6% with 429.8 mA h g⁻¹ initial discharge capacity. In addition, the MSG anode has superior capacity retention (89.3%) after 100 cycles, with enhanced volumetric expansion (12.7%) after 50 cycles. We believe that the excellent electrochemical performance of MSG is attributed to increased integrity by using APS (3-aminopropyltrimethoxysilane) with a CVD carbon coating.