Composite design for electrochemical improvement through prelithiated Li₂SiO₃ in rice husk-derived SiO₂/rGO as lithium-ion battery anode

The formation of a solid-electrolyte interphase (SEI) layer and Li₂O species at an anode driven by thermodynamic spontaneity not only consumes the active Li-ions (Li⁺), but also generates battery capacity loss. The unstable SEI layer growth directly degrades both battery efficiency and cycling stability. Thereby, prelithiated materials were prepared to militate against the enlargement of Li consumption for Li-ion batteries (LIBs). Here, we demonstrated the hydrothermal synthesis of lithium metasilicate (Li₂SiO₃), a prelithiated material, with physical characterizations exposing the microflower-like clusters evolved from the attachment of their high-purity primary plates. The electrochemical performance of the pristine Li₂SiO₃ provided a poor cycling capability in a half coin-cell test with a final discharge capacity of 17 mAh g⁻¹ over 200 cycles, while the silica on reduced graphene oxide (SiO₂/rGO) composite represented only ~ 290 mAh g⁻¹. Conversely, the Li₂SiO₃–SiO₂/rGO composite exhibited excellent cyclability over the pristine and SiO₂/rGO with final discharge specific capacity up to ~ 470 mAh g⁻¹ at the 200th cycle. Despite the revealed similar electrochemical patterns of the obtained cyclic voltammograms (CVs) for these materials, the curiosity of continuously increased capacity for the Li₂SiO₃–SiO₂/rGO composite and Li⁺ compensation mechanisms upon cycling of Li₂SiO₃ were still clearly unsolved. The cycling capacities of the composite were distinctly observed as a great improvement after composite formation between Li₂SiO₃ and SiO₂/rGO.