Architected Si/C Micro–Nanostructures with Air Cushion-Inspired Stress Mitigation Strategies for Lithium-Ion Battery Anodes

Silicon/carbon (Si/C) composites have emerged as promising anode materials for next-generation lithium-ion batteries (LIBs) due to their high power and energy density, but managing the stress resulting from the large volume change of Si during charging and discharging remains a major challenge. To address this issue, we present a novel microsized porous Si/C-based anode design (AC_Si/C) that incorporates Si@C core–shell nanoparticles and hollow carbon nanospheres as deformable cushions fabricated using a scalable microemulsion approach. Our hybrid anode material system offers high ion and electron conductivity and efficient stress mitigation via the deformable hollow carbon nanospheres, resulting in improved cycling and rate performance. Finite element simulations reveal the stress mitigation mechanisms of the hollow carbon nanospheres, and the AC_Si/C nanostructure exhibits a high reversible specific capacity (855.3 mA h g –1 at 2 A g –1 over 500 cycles) and good capacity reservation for rate performance tests under various current densities. The microemulsion-based synthesis method enables large-scale production of porous Si/C nanocomposites as high-performance commercial anode material systems, demonstrating the potential of this air cushion-inspired design for the development of next-generation high-performance LIBs.