Simultaneous Effects of C‐N‐V Bonds and Multiple Sulfides Anchoring Active V and Na Enables Honeycomb‐Like Porous Na ₃ V ₂ (PO ₄ ) ₃ with Non‐Attenuation Characteristics for Na‐Ion Batteries

For Na₃V₂(PO₄)₃ (NVP) cathode, the activity and utilization rate of Na and V is the key to affecting its electrochemical properties. However, few studies can simultaneously optimize both. Currently, a facile hydrothermal route is proposed to successfully synthesize the honeycomb-like porous NVP@CHSLS cathodes possessing anchoring effects to enhance the immobilization of active Na/V through in situ carbonation with chitosan and sodium lignosulfonate. DFT calculations demonstrate the N/S co-doped carbon skeleton gains more electrons and behaves with superior charge transfer capability. Accordingly, XAFS verifies the existence of hypervalent V⁴⁺ for the charge balance, as well as a newly generated C-N-V bond inside the bulk, which significantly inhibits the dissolution of V in the electrolyte. Moreover, ex-situ and after-cycled XRD verifies beneficial electrochemical intermediums such as Na₂S manifest extra sodium fixation characteristics, which not only enter into the CEI membrane to reduce the loss of Na⁺, but also participate in the de-intercalation of Na⁺. Furthermore, honeycomb-like porous morphology enriches the active sites for Na⁺ migration and improves the wettability of electrolytes, demonstrated by contact Angle and AFM tests. Consequently, the optimized NVP@CHSLS-2 reveals a high postactivated capacity of 104.5 mAh g^-1 at 60 C, and it remains at 98.8% after 10 000 cycles at 60 C.