ORCID Profile
0000-0003-1069-9145
Current Organisations
The University of Edinburgh
,
Northeast Normal University
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Publisher: Elsevier BV
Date: 03-2022
Publisher: Wiley
Date: 25-02-2022
Abstract: Impossible voltage plateau regulation for the cathode materials with fixed active elemental center is a pressing issue hindering the development of Na‐superionic‐conductor (NASICON)‐type Na 3 V 2 (PO 4 ) 2 F 3 (NVPF) cathodes in sodium‐ion batteries (SIBs). Herein, a high‐entropy substitution strategy, to alter the detailed crystal structure of NVPF without changing the central active V atom, is pioneeringly utilized, achieving simultaneous electronic conductivity enhancement and diffusion barrier reduction for Na + , according to theoretical calculations. The as‐prepared carbon‐free high‐entropy Na 3 V 1.9 (Ca,Mg,Al,Cr,Mn) 0.1 (PO 4 ) 2 F 3 (HE‐NVPF) cathode can deliver higher mean voltage of 3.81 V and more advantageous energy density up to 445.5 Wh kg −1 , which is attributed by the erse transition‐metal elemental substitution in high‐entropy crystalline. More importantly, high‐entropy introduction can help realize disordered rearrangement of Na + at Na(2) active sites, thereby to refrain from unfavorable discharging behaviors at low‐voltage region, further lifting up the mean working voltage to realize a full Na‐ion storage at the high voltage plateau. Coupling with a hard carbon (HC) anode, HE‐NVPF//HC SIB full cells can deliver high specific energy density of 326.8 Wh kg −1 at 5 C with the power density of 2178.9 W kg −1 . This route means the unlikely potential regulation in NASICON‐type crystal with unchangeable active center becomes possible, inspiring new ideas on elevating the mean working voltage for SIB cathodes.
Publisher: Elsevier BV
Date: 03-2016
Publisher: Wiley
Date: 24-09-2020
Publisher: American Chemical Society (ACS)
Date: 17-11-2022
Abstract: Stabilizing Na
Publisher: Wiley
Date: 10-11-2022
Abstract: Polyanionic transition metal polyphosphate (TMPO)‐type Na 3 V 2 (PO 4 ) 2 O 2 F (NVPO 2 F) 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 NVPO 2 F (NVPO 2−x Cl x F) cathode material for SIBs. Density functional theory investigation reveals that Cl doping tunes the localized electronic density and structure in NVPO 2 F lattice, causing the electron redistribution on vanadium center and dangling anions. Hence, the NVPO 2−x Cl x F 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 V 4+ /V 5+ redox couple for NVPO 2−x Cl x F cathode is verified. The NVPO 2−x Cl x F 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 NVPO 2−x Cl x F//3DC@Se full cell. This study demonstrates a brand‐new strategy to prepare advanced cathode materials for superior SIBs.
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Xing-Long Wu.