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

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.