In‐situ introduction of inorganic SiO x with higher average valence promising core‐shell Si@C anodes toward advanced lithium‐ion batteries

Abstract Si, as the most promising anode with high theoretical capacity for next‐generation lithium‐ion batteries (LIBs), is hampered in commercial application by its poor electrical conductivity and significant volume expansion. Herein, the core‐shell Si@SiO x /C@C‐Ar (SSC‐A) or Si@SiO x /C@C‐H 2 /Ar (SSC‐H) composites are purposefully designed by in situ introduction of inorganic SiO x in pure Ar or H 2 /Ar atmosphere to realize a Si‐based anode for LIBs. By introducing different atmospheres, the valence states of SiO x are regulated. The inorganic transition layer formed by the combination of SiO x with higher average valence and asphalt‐derived carbon demonstrates better performance in both stabilizing the core‐shell structure and inhibiting the agglomeration of Si particles. Given these advantages, the SSC‐A electrode exhibits excellent electrochemical performance (1163 mAh g −1 after 400 cycles at 1 A g −1 ), and the commercial blended graphite‐SSC‐A electrode reaches a specific capacity of 442 mAh g −1 with 74.8% capacity retention under the same conditions. Even the SSC‐A electrode without Super P maintains an ultrahigh discharge specific capacity of 803 mAh g −1 with 60.6% after cycling. Importantly, the full batteries based on SSC‐A without Super P achieve a discharge specific capacity of 126 mAh g −1 with 28.2% capacity decay after 200 cycles, demonstrating the superior commercial application potential.