Na-C Dynamic Interface-Induced Ion Tunneling for Ultrafast Sodium-Ion Transport in Mesoporous Carbon.

Developing high-performance anode materials is critical for advancing sodium-ion batteries (SIBs), wherein slow ion transport kinetics remains a major bottleneck. Although surface/bulk engineering can reduce Na+ diffusion barriers, current strategies lack clear structure-kinetic correlations. Herein, we fabricate mesoscopic carbon spheres (MCS) via a scalable nano-emulsion co-assembly strategy to construct dynamic active interfaces for efficient Na+ transport. The mesoporous structure enhances Na+ accessibility, induces electron cloud rearrangement, and forms dynamic Na-C coordination channels, leading to a nearly four-order-of-magnitude enhancement in Na+ diffusion compared to non-porous carbon. MCS delivers a high reversible capacity of 336.6 mAh g-1 at 0.1 A g-1 and retains 110.4 mAh g-1 after 1000 cycles at 7.5 A g-1. Multiscale simulations (DFT/MD) reveal that precursor Na+ triggers electron cloud rearrangement at interfaces, forming Na-C channels with covalent characteristics. This reduces the diffusion barrier, enabling an ultrafast "interface-induced ion tunneling" migration. This work provides atomic-level insights into interfacial ion regulation and a scalable strategy for high-rate SIB anodes.