Abstract
AbstractPolyanionic transition metal polyphosphate (TMPO)‐type Na3V2(PO4)2O2F (NVPO2F) is promising as cathode for large‐scale sodium‐ion batteries (SIBs) on account of its considerable capacity and highly stable structure. However, the redox of transition metal and phase transitions along with the (de)intercalation of Na+ lead to its slow kinetics and inferior rate performance. Herein, chlorine (Cl) is applied as a heteropical dopant to obtain Cl‐doped NVPO2F (NVPO2−xClxF) cathode material for SIBs. Density functional theory investigation reveals that Cl doping tunes the localized electronic density and structure in NVPO2F lattice, causing the electron redistribution on vanadium center and dangling anions. Hence, the NVPO2−xClxF cathode exhibits a revised redox behavior of vanadium for Na+ extraction/insertion, increases Na+ diffusion rate, as well as lowers charge transfer resistance. A Na+ storage mechanism of reversible transformations between three phases and V4+/V5+ redox couple for NVPO2−xClxF cathode is verified. The NVPO2−xClxF cathode reveals a high rate capacity of ≈63 mAh g−1 at 30C and great cycle stability over 1000 cycles at 10C. More importantly, outstanding rate property (314 Wh kg−1 at 5850 W kg−1) and cycling capability are obtained for the NVPO2−xClxF//3DC@Se full cell. This study demonstrates a brand‐new strategy to prepare advanced cathode materials for superior SIBs.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
