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

Abstract 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.