Electrochemically pre-lithiated SiO₂@C nanocomposite anodes for improved performance in lithium-ion batteries

Silica (SiO₂)-based materials are a promising alternative anode material due to their high specific capacity, abundance, safety, and environmental friendliness. However, the significant volume expansion and the formation of a solid electrolyte interphase (SEI) with electrolytes cause active lithium loss and result in poor Coulombic efficiency of SiO₂-based materials, which hinder their commercial applications. Therefore, pre-lithiation, a method of embedding extra lithium ions in the electrodes prior to cycling, is an effective approach to replenish the largely irreversible lithium loss during cycling and overcomes these challenges. In this study, carbon-coated silica (SiO₂@C) nano composite was synthesized via a sol-gel method and the beneficial impacts of using pre-lithiated SiO₂@C electrodes in coin cells were investigated. It is shown that the carbon coating onto the surface of the SiO₂particles and the pre-lithiation method led to a distinct improvement in the overall capacity and Coulombic efficiency of the cells due to the pre-formed SEI and the presence of a lithium reservoir within the anode. Furthermore, the anodes exhibited excellent cycling stability and good rate capability up to 2 A g^-1.