Improving the Electrochemical Properties of SiO Anode for High-Performance Lithium-Ion Batteries by Magnesiothermic Reduction and Prelithiation.

For lithium-ion batteries, silicon monoxide is a potential anode material, but its application is limited by its relatively large irreversible capacity loss, which leads to its low initial Coulombic efficiency (ICE). In this study, we conduct a two-step reaction for the formation of silicon oxide-based materials, including a magnesiothermic reduction of SiO with Mg, followed by the solid-state lithiation of silicon oxide with LiCO. Our results demonstrate that Mg can reduce SiO to Si and form MgSiO, while LiCO reacts with SiO to form LiSiO. MgSiO and LiSiO on the surface of SiO can effectively mitigate the irreversible loss of lithium ions, thus enhancing the ICE of SiO. The resulting SiO-Mg-LiCO-C nanostructure has an ICE of up to 91.1% and a relatively stable cycle performance. After 100 cycles at 0.5 C, the capacity is still 894.5 mAh g, and the capacity retention rate is 87.9%. A lithium-ion full battery with the commercial LiNiMnCoO (NCM811) as the cathode was assembled to test its practical applicability. The full cell exhibits a stable discharge capacity of 91.4 mAh g after 100 cycles at 1 C, with a capacity retention of 79.9%.