Oxygen-tailoring in SiOX/C with a covalent interface for high-performance lithium storage

Oxygen-tailoring in silicon suboxide (SiOX) can relieve its volume variation for highly structural integrity and form a stable solid electrolyte interface (SEI) layer. Herein, we propose the preparation of hierarchical SiOX/C with different oxygen contents and interfacially covalent Si-O-C bonds for advanced lithium ion batteries (LIBs). Oxygen-manipulating projects are performed to adjust the oxygen content in SiOX for low volume expansion (mechanical stress), in agreement with our experiment, stress distribution simulations and density functional theory analysis. The covalent Si-O-C bonds in metastable SiOX/C are constructed to enhance the adsorption of ethylene carbonate for a stable SEI layer and re-assemble the electrical field for fast interfacial charge responses. These synthetic advantages in hierarchical SiOX/C are beneficial for the structural integrity and the construction of a stable SEI layer. Prepared SiOX/C exhibits excellent electrochemical performance in terms of cyclic stability (1010.4 mA h g(-1) after 300 cycles at 1 A g(-1)), highly stable coulombic efficiency and rate capability (413.6 mA h g(-1) at 4 A g(-1)). The work based on oxygen-manipulating projects and interfacial covalent bonds provides deep insights into the preparation of durable SiOX-based anodes with a long lifespan and stable coulombic efficiency.