In situ growth of silicon carbide interface enhances the long life and high power of the mulberry-like Si-based anode for lithium-ion batteries

Silicon (Si) attracts attention for its ultra-high theoretical specific capacity (3579 mAh g −1 ) as anodes for lithium-ion batteries (LIB). However, adjusting the contradiction between long life and volume expansion has always been a great challenge for Si-based anodes. In this work, we designed a mulberry-like Si-based anode material (p-SiO x /SiC@C) by an in situ self-assembly and magnesium reduction approach. The most outstanding advantage of this strategy is the formation of silicon carbide (SiC) interlayer between SiO x and carbon coating, which hinders the further reduction of SiO x and realizes controllable specific capacity. The SiC interlayer on the SiO x surface can effectively prevent the electrolyte from penetrating and stabilize the solid electrolyte interphase (SEI) well. As a result, p-SiO x /SiC@C shows stable Li + storage performance and ultra-long cycle stability. Even after 2000 cycles under 2.0 A g −1 , p-SiO x /SiC@C still maintains a complete morphology; the capacity retention rate is about 79%; the capacity loss rate is only 0.01% per cycle on average; and it is even more gratifying that the average coulombic efficiency reaches 99.7%. This work opens up a new direction for the practical application of Si-based anode materials.