Silicon Monoxide Anodes Co-Modified with ZnS and Nitrogen-Doped Carbon via Facile Synthesis: Toward High-Energy Lithium-Ion Battery Applications

Silicon monoxide (SiO) has emerged as a promising silicon-based anode material owing to its high theoretical specific capacity and extended cycle life. Nevertheless, its practical application is hindered by significant volume expansion and insufficient cycling stability. In this study, a composite material of SiO coated with zinc sulfide and nitrogen-doped carbon (ZnS&NC/SiO) was successfully prepared via a developed method of in situ conversing MOFs into nitrogen-doped carbon and ZnS. As an anode of lithium-ion batteries, the ZnS&NC/SiO composite exhibited superior reversible capacity (748 mAh·g^-1 after 1000 cycles at 1.0 A·g^-1) and ultralower electrochemical impedance spectra (Rct = 62 Ω). The performance is much superior to that of the reported SiO-based anode materials, which is attributed to the special coating structure that relieves volume expansion and improves the inherently low electrical conductivity, the doped N atoms that provide more active sites, and the SiO and ZnS enables one of them to serve as a buffer medium for more stable structure due to the different lithium intercalation potential. The designed structure could provide a promising strategy for other electrode materials.