Constructing Covalently Si–O–C Bonded Diatomite-Derived SiO2@C Anode for High-Capacity Lithium-Ion Batteries

Abstract

Silica-based materials, serving as one type of prospective electrode for advanced high-energy density LIBs (lithium-ion batteries), are encountering critical obstacles in commercialization, including inherently poor conductivity, volume expansion and particles pulverization. Herein, a silica composite (DTm@GC) has been synthesized as an anode for LIBs by constructing dense carbon network on the diatomite-derived SiO2 through Si–O–C covalent bonding. The strongly dense Si–O–C covalent bond between carbon network and diatomite accelerate migration of Li+ and alleviate volume variation during lithiation/de-lithiation. The results show that DTm@GC anode delivers a superior discharging specific capacity of 781 mAh g-1 after 100 cycles at 0.1 A g-1, along with approximately 100% capacity retention rate. Furthermore, the synthesized anode can keep a stable specific capacity of 613.79 mAh g-1 after 200 cycles at 0.5 A g-1, and 456.68 mAh g-1 over 1000 consecutive cycles at 1 A g-1. The outstanding electrochemical performance of DTm@GC with strong covalent Si–O–C bond has provided a valuable avenue of fabricating low-cost, high-performance SiO2-based anodes for high-capacity LIBs.