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Three Electron Reversible Redox Reaction in Sodium Vanadium Chromium Phosphate as a High‐Energy‐Density Cathode for Sodium‐Ion Batteries
Author(s) -
Zhao Yongjie,
Gao Xiangwen,
Gao Hongcai,
Jin Haibo,
Goodenough John B.
Publication year - 2020
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201908680
Subject(s) - redox , materials science , cathode , vanadium , sodium , anode , ion , sodium ion battery , energy storage , ionic bonding , inorganic chemistry , chromium , electrode , chemistry , metallurgy , power (physics) , physics , organic chemistry , faraday efficiency , quantum mechanics
A sodium‐ion battery operating at room temperature is of great interest for large‐scale stationary energy storage because of its intrinsic cost advantage. However, the development of a high capacity cathode with high energy density remains a great challenge. In this work, sodium super ionic conductor‐structured Na 3 V 2− x Cr x (PO 4 ) 3 is achieved through the sol–gel method; Na 3 V 1.5 Cr 0.5 (PO 4 ) 3 is demonstrated to have a capacity of 150 mAh g −1 with reversible three‐electron redox reactions after insertion of a Na + , consistent with the redox couples of V 2+ / 3+ , V 3+ / 4+ , and V 4+ / 5+ . Moreover, a symmetric sodium‐ion full cell utilizing Na 3 V 1.5 Cr 0.5 (PO 4 ) 3 as both the cathode and anode exhibits an excellent rate capability and cyclability with a capacity of 70 mAh g −1 at 1 A g −1 . Ex situ X‐ray diffraction analysis and in situ impedance measurements are performed to reveal the sodium storage mechanism and the structural evolution during cycling.