High-rate sodium insertion/extraction into silicon oxycarbide-reduced graphene oxide

Abstract

Silicone oxycarbide (SiOC) is gaining attention as a potential anode material for lithium-ion batteries due to its higher reversible capacity and high-rate capability. However, the employment of SiOC in sodium-ion batteries (SIBs) has remained unclear. Here, the electrochemical performance of SiOC derived from phenyl-rich silicone oil and present with graphene as an anode for SIBs is investigated. 1 M NaClO4 dissolved in propylene carbonate (PC) is used as an electrolyte with and without fluorinated ethylene carbonate (FEC) and its effect on electrochemical performance has been studied. The FEC additive electrolyte shows high electrochemical performance where it delivers high charge capacities of 233, 198, 170, 103, 64, and 32 mA h g-1 compared to 218, 126, 101, 52, 27, and 10 mA h g-1 without additive at current densities of 20, 50, 100, 500, 1000, and 2000 mA g-1, respectively. The sodium diffusion coefficient in a high-performance SiOC anode with an FEC additive electrolyte is calculated to be 1.73 × 10-16 cm2 s-1.