VOC Bonding of Heterointerface Boosting Kinetics of Free‐Standing Na5V12O32 Cathode for Ultralong Lifespan Sodium‐Ion Batteries

The flexible free‐standing cathodes with high energy density have been challenging toward wearable sodium‐ion batteries (SIBs). Herein, Na5V12O32 nanobelts (NVO‐NBs)‐based heterostructure is fabricated with boosting the sodium‐ion kinetic characteristics to address the challenges. In the heterostructure, the controllable VOC bonds are generated at the interface originating from the chemical conversion of functional groups of the reduced graphene oxides (rGOs) with VO bonding of NVO through interfacial electronic interactions. The interfacial synergistic between the brilliant bonding properties and the inherent formation of a stress field at the heterointerface motivated by work function difference can reduce the Na+ diffusion barrier, facilitate charge transfer, hence accelerates reaction kinetics and electron/ion transport, as well as modifying the electronic structure to realize a cherished adsorption energy of Na+. Therefore, the optimized NVO‐NBs‐based heterostructure exhibits exceptional rate capability (213 mAh g−1 at 0.2 C with 100 mAh g−1 at 10 C) and ultralong cycling stability (95.4%, 3000 cycles at 5 C). This work demonstrates that the controllable heterostructure interface with abundant chemical bonds is an effective approach to exploit potential cathodes for rechargeable batteries. The controllable VOC bonds constructed at the heterostructure‐interface effectively drives the charge transfer and enhances the reaction kinetics. Intensive built‐in electric field are successfully induced at the surface of heterostructure, which qualitatively tune the properties of interfacial charges and provide additional driving forces for facilitating electron transfer and accelerating reaction kinetics and electron/ion transport.