Two-step ball-milling synthesis of a Si/SiOx/C composite electrode for lithium ion batteries with excellent long-term cycling stability

Abstract

SiO_x-based anodes have attracted tremendous attention owing to their low cost, higher theoretical capacity than graphite and lower volume expansion than pure silicon. In this work, a simple and cost-effective two-step ball-milling method was proposed to fabricate Si/SiO_x/C composites by using commercial SiO and graphite carbon as raw materials. The two-step ball-milling synthesis of the Si/SiO_x/C composites can avoid the generation of an inert SiC phase and realize the uniform dispersion of Si/SiO_x in graphite carbon, which offers good electrical conductivity and relieves the volume expansion of the Si/SiO_x phase. Owing to the synergistic effect of the Si/SiO_x phase and the graphite carbon, the typical Si/SiO_x/C electrode exhibits a stable and high capacity of 726 mA h g⁻¹ after 500 cycles at a current density of 0.1 A g⁻¹ with a capacity retention of 82%. The two-step ball-milling preparation of the Si/SiO_x/C composite provides a facile approach to fabricate high-performance SiO_x-based anode materials.