Molecular bridge-guided conformal carbon coating on SiO for mechanically robust and electrochemically stable anodes

The development of high-performance anode materials is essential for advancing lithium-ion batteries (LIBs) with higher energy density and faster charging capability. Silicon monoxide (SiO) has attracted considerable attention because of its high theoretical capacity. However, its practical application is hindered by significant volume expansion, poor electronic conductivity and an unstable solid electrolyte interphase (SEI). In this work, we propose a molecular bridge strategy based on oleic acid (OA) that covalently anchors SiO particles within asphalt and directs the self-assembly of a uniform, conformal and mechanically robust carbon coating during carbonization. This tailored carbon layer effectively suppresses the formation of a thick SiO₂ shell, improves electrical conductivity and promotes the formation of a stable SEI. The resulting OA-SiO/C anode delivers a high reversible capacity of more than 530 mAh g^-1 after 1000 cycles at 1 A g^-1 with 97.6% capacity retention. Comprehensive electrochemical and structural analyses demonstrate that the uniform carbon coating enhances interfacial charge transfer kinetics, maintains robust electronic pathways throughout the electrode and mitigates mechanical stress. This study provides a scalable and effective approach for the design of high-performance SiO-based anodes for next-generation LIBs.