Pomegranate–Like Nano‐Confined Silicon Inside Conductive Carbon Black as Anode Materials for Lithium‐Ion Batteries

Abstract Si materials possess a high theoretical specific capacity when used as anode material in lithium‐ion batteries (LIBs). Si/C composites mitigate volume expansion and enhance conductivity, thus achieving improved electrochemical performance in LIBs. Herein, we report a new strategy for preparing pomegranate‐like Si/C nanocomposites based on low‐cost, readily available conductive carbon black (XC) by using a combination of wet chemical reduction and chemical vapor deposition (CVD) techniques. The preparation first involves a facile wet chemical approach to controlled hydrolysis of SiCl 4 within XC. Subsequently, the obtained SiO 2 /XC precursor is reduced to highly crystalline Si particles within XC (Si/XC) using a novel ionic liquid‐magnesium reduction system, avoiding unwanted byproducts associated with conventional high‐temperature magnesium reduction. Finally, a pomegranate‐like Si/XC composite is coated with an outer carbon layer via CVD, forming a nano‐confined Si/C structure. The composites exhibit excellent reversible capacity and good cycle stability in LIBs. At 1 A g −1 after 400 cycles, the Si/XC@C‐0.5 composite delivered the highest specific capacity of 835 mA h g −1 , exhibiting a capacity retention rate of 121% compared to the first cycle after activation (688 mA h g −1 ). This work provides reproducible and scalable means to prepare high‐performance Si/C composites for LIBs.