3D ordered Mesoporous Si/C Sphere Arrays as High-Volumetric-Capacity and Durable Anode for Lithium-ion Batteries

Micro-nanostructured Si/C composites are recognized as promising anode materials for high-performance lithium-ion batteries (LIBs), but such anodes often result in suboptimal volumetric capacities. Herein, a novel 3D ordered mesoporous Si/N-doped carbon (Si/NC) sphere array (M-Si/NC-SA) as the anode material is introduced. The M-Si/NC-SA anode is designed to address these challenges by combining high compacted density and a mesoporous structure that provides efficient pathways for electrolyte and Li⁺ diffusion, while also accommodating the volume expansion of silicon during cycling. The mesopores within the Si/NC spheres and macropores between the spheres act as buffer zones, preventing pulverization and minimizing particle-level expansion. The optimal M-Si/NC-SA demonstrates outstanding electrochemical performance, delivering a high compacted density of 0.78 mg cm^-3, an impressive volumetric capacity of 2275 mAh cm^-3 at 0.1 A g^-1, and a capacity of 1011 mAh g^-1 at 1 A g^-1 after 1000 cycles. The full-cells paired with lithium iron phosphate cathode can achieve practically relevant attributes. This work provides a kilogram-scale method for producing high-performance Si-based anodes with enhanced volumetric capacity and superior cycling stability, offering a promising approach for next-generation LIBs.