Controllable Synthesis of Hollow Dodecahedral Si@C Core–Shell Structures for Ultrastable Lithium‐Ion Batteries

Abstract Silicon (Si) has attracted considerable attention as a promising alternative to graphite in lithium‐ion batteries (LIBs) because of its high theoretical capacity and voltage. However, the durability and cycling stability of Si‐based composites have emerged as major obstacles to their widespread adoption as LIBs anode materials. To tackle these challenges, a hollow core–shell dodecahedra structure of a Si‐based composite (HD‐Si@C) is developed through a novel double‐layer in situ growth approach. This innovative design ensures that the nano‐sized Si particles are evenly distributed within a hollow carbon shell, effectively addressing issues like Si fragmentation, volume expansion, and detachment from the carbon layer during cycles. The HD‐Si@C composite demonstrates remarkable structural integrity as a LIBs anode, resulting in exceptional electrochemical performance and promising practical applications, as evidenced by tests in pouch‐type full cells. Notably, the composite shows outstanding cycling stability, retaining 85% of its initial capacity (713 mAh g −1 ) even after 3000 cycles at a high current rate of 5000 mA g −1 . Additionally, the material achieves a gravimetric energy density of 369 W h kg −1 , showcasing its potential for efficient energy storage solutions. This research signifies a significant step toward realizing the practical utilization of Si‐based materials in the next generation of LIBs.