High-pressure shear-induced construction of a SiOₓ-enriched Si/C Interface for high-performance silicon-based anodes in lithium-ion batteries

To tackle the primary issues of silicon-based anodes, including volumetric expansion, inadequate conductivity, and limited interfacial stability, we utilized high-pressure shear technology to prepare a silicon/hard carbon (Si/HC for short) composite anode, using corn cob-derived biomass hard carbon as the framework and combining it with commercial silicon powder. In the high-pressure shearing process, silicon grains are refined to the nanoscale, resulting in the emergence of a local metastable BC8-Si phase. Simultaneously, shear stress promotes the reconstruction of the silicon surface oxide layer, leading to the formation of a SiO x -enriched region at the silicon‑carbon interface. This configuration establishes a continuous conducting network and mitigates the stress resulting from volumetric expansion. Electrochemical evaluations indicate that the synthesized Si/HC composite electrode attains an initial reversible capacity of 1670 mAh g −1 at a current density of 0.2 A g −1 , and maintains 610 mAh g −1 after 500 cycles. At a 1C rate, it provides a capacity of 547 mAh g −1 , along with favorable rate recovery capabilities. The mechanical analysis and in situ characterization suggest that the cold-welding composite structure contributes to reduced interfacial polarization, promotes the development of a stable solid-electrolyte interphase (SEI) film, and shifts the lithium storage mechanism from diffusion-limited kinetics toward enhanced interfacial reaction contributions. This study presents a potential production method for the application of silicon-based anodes through a synergistic enhancement strategy involving physical compounding and interfacial modification.