Amorphous silicon dioxide-based composites for high-performance Li-ion battery anodes

Highlights: • An amorphous SiO₂-based composite is synthesized in a simple solid state synthetic method. • The amorphous SiO₂-based composite contains dual matrices of inactive FeSi and conducting graphite. • The amorphous SiO₂-based composite is tested for its suitability as an electrode material for Li-ion batteries. • The amorphous SiO₂-based composite electrode exhibited excellent electrochemical performances. To design high performance SiO₂-based anodes for Li-ion batteries (LIBs), an amorphous SiO₂-FeSi-graphite (a-SiO₂/FeSi/G) composite was synthesized by a simple solid state synthetic method using SiO, Fe, and graphite powders. The a-SiO₂/FeSi/G composite was comprised of well dispersed amorphous SiO₂ and tiny (5–10 nm sized) FeSi inactive matrices within the graphite buffering matrices. The a-SiO₂/FeSi/G composite electrode showed excellent electrochemical performance featuring high initial charge capacity of 729 mAh g⁻¹, with high initial Coulombic efficiency of approximately 74%, and long capacity retention of 93.7% after 200 cycles, with a highly reversible capacity of 683 mAh g⁻¹.