Metallic Sb-stabilized porous silicon with stable SEI and high electron/ion conductivity boosting lithium-ion storage performance

Silicon (Si) has mild discharge potential and high theoretical capacity, making it a highly desirable material for lithium-ion batteries (LIBs). Nevertheless, the excessive volume expansion, poor ion/electron conductivity and unstable solid electrolyte interface (SEI) hinder practical application to LIBs. Herein, the metallic antimony (Sb) stabilized porous Si (Si–Sb) composite was prepared by magnesiothermic reduction of Sb₂O₃ and Mg₂Si and chemical etching to remove the by-product of MgO. The highly conductive Sb nanodots embedded in the Si ligaments promote not only the formation of conductive and stable LiF-rich SEI, but also the electron/ion transport ability of Si. Owing to the outstanding bulk/interface stability, excellent conductivity, as well as ideal porous structure, the Si–Sb electrode demonstrates a capacity of 820 mAh·g⁻¹ after undergoing 320 turns at 1000 mA·g⁻¹. Additionally, it exhibits a stable capacity of 675 mAh·g⁻¹ when tested at a higher current density of 5000 mA·g⁻¹. The results reveal a viable solution to solve three problems at the same time, namely the poor conductivity, inferior SEI and excessive volume expansion of Si, boding well for the design of Si-based materials for high-energy LIBs. © Youke Publishing Co., Ltd 2024.