A low-cost and advanced SiOx–C composite with hierarchical structure as an anode material for lithium-ion batteries

Abstract

A cost-efficient and scalable method is designed to prepare a SiO_x–C composite with superior cyclability and excellent rate performance. The glucose addition in a two-step way induces a hierarchical structure, where individual SiO_x nanoparticles are wrapped by a conductive carbon layer and these agglomerated particles are further wrapped by a carbon shell functioning as an electrolyte blocking layer. Instrumental analysis indicates that the SiO_x domains are comprised of SiO₂ and SiO. The SiO_x–C anode exhibits a high reversible specific capacity of 674.8 mA h g⁻¹ after 100 cycles at 100 mA g⁻¹ with a capacity retention of about 83.5%. The excellent electrochemical performance is due to the hierarchical structure, the well-dispersed conductive carbon network, and the Li₂O and Li₄SiO₄ generated in the initial discharge process, all of which can immensely relieve the volume expansion induced by the lithiation of silicon. This hierarchical SiO_x–C composite has a promising prospect of practical application given its adequate storage capacity, good cycling stability, commercially available materials and simple equipment.