Reduction effect of irreversible capacity on SiO anode material heat-reacted with Fe2O3

► The charge-discharge efficiency of high capacity SiO anode material is as low as 75% on first cycle. ► To reduce the oxygen defects in SiO structure, Fe2O3 was used as an oxygen source of the redox reaction. ► The charge-discharge efficiency of SiO anode material improves by heat-treated with Fe2O3. ► The one of the factor of good reversibility is an improvement of the Li-extraction performance by surface modification.