The Charge Self‐Regulation Effect Induced by Microcrystalline‐Amorphous Heterointerface Network Toward Fast Charging Sodium Ion Batteries

Abstract Sodium‐ion batteries (SIBs), recognized for their abundant resource availability, are emerging as a viable alternative to conventional batteries. Nevertheless, sluggish electrons/ions kinetics impedes further advancement in SIBs technology. Herein, a novel microcrystalline‐MoSe₂/amorphous‐MoSe_xO_y (C‐MoSe₂/A‐MoSe_xO_y) is developed through in situ low‐temperature oxidation of crystalline MoSe₂. The microcrystalline MoSe₂ acts as a robust framework, while the amorphous MoSe_xO_y phase fills the interstitial spaces. This anode material is characterized by an optimized microcrystalline‐amorphous heterointerface. The resultant charge self‐regulation effect can be exploited to modulate active electron states, thereby ensuring high‐speed and stable sodium storage performance. The heterointerface demonstrates an ultrahigh specific capacity (641.0 mAh g⁻¹ at 0.5 A g⁻¹) and maintains splendid rate performances up to 100 A g⁻¹ (324.2 mAh g⁻¹). Detailed theoretical and experimental researches indicate that the enhanced performance results from the production of active electronic states, which are initiated by the charge self‐regulation effect at the microcrystalline‐amorphous heterointerface in C‐MoSe₂/A‐MoSe_xO_y, featuring active Mo─Se bonds, which regulates the interfacial charge redistribution and facilitate electron transfer across the active interface between the microcrystalline and amorphous phases. The findings suggest that the charge self‐regulation effect, prompted by the heterointerface network, inherently accelerates electron/ion transport, offering a promising electrode design strategy for fast‐charging batteries.