Effect of LiF‑introduced on electrochemical properties of carbon coated silicon suboxide anode material for lithium-ion batteries

Though silicon suboxide (SiOx, 0 < x < 2) has been considered a new generation of anode material for lithium-ion batteries, the large volume expansion and intrinsic conductivity hinder its commercial applications. In this work, silicon dioxide (SiO2) was prepared via tetraethyl orthosilicate (TEOS) hydrolyzed, and lithium fluoride (LiF) was introduced in situ, and then SiO2/LiF was covered with pyrolyzed sucrose to obtain SiOx/LiF@C. Large elastic modulus, low solubility in a carbonate solution, and high chemical stability LiF was designed to induce the formation of a stable solid-electrolyte interface (SEI) layer on the electrode surface. The more stable interface minimizes the continuous growth of the SEI layer, thereby reducing the resistance and the irreversible decay of capacity. Compared with SiOx@C-3, the SiOx/LiF@C-3 anode displays better electrochemical performance, especially cycle performance at high current density. Benefiting from the cooperation of amorphous carbon coating and stable SEI layer, SiOx/LiF@C-3 activated by low current maintains a specific capacity of 504.2 mAh g−1 and a capacity retention rate of 96% after 300 cycles at a current density of 0.3 A g−1. The great potential of LiF‑introduced for silicon suboxide anode is demonstrated.