阴极
电化学
水溶液
快离子导体
材料科学
无机化学
化学工程
化学
物理化学
电极
电解质
工程类
作者
Jiasheng Yue,Shuqiang Li,Shi Chen,Feng Wu,Jingjing Yang,Xueying Lu,Yu Liu,Ran Zhao,Chuan Wu,Ying Bai
标识
DOI:10.34133/energymatadv.0050
摘要
Sodium superionic conductor (NASICON) is a class of compounds with robust polyanionic frameworks and high thermal stability, which are regarded as prospective cathodes candidates for secondary batteries. However, NASICON cathodes typically have low discharge plateaus and low practical capacities in aqueous electrolytes. Here, Na 3 V 1.75 Fe 0.25 (PO 4 ) 2 F 3 is investigated as a cathode material for the aqueous zinc/sodium batteries. While the addition of F helps with the improvement of NASICON structural stability, the low-cost Fe substitution has a positive impact on the capacity increment, reaction voltage increases, and cycling stability improvement. Because the Fe 3+ substitution could induce a change in the spin magnetic moments of the 3d orbitals of the VO 4 F 2 and FeO 4 F 2 octahedra, the 2-electron reaction of V is activated, which are V 4+ /V 3+ and V 5+ /V 4+ redox couples. As a result, the novel Na 3 V 1.75 Fe 0.25 (PO 4 ) 2 F 3 cathode delivers a high operating voltage of 1.7 V, a high energy density of 209 W·h·kg −1 and stable lifespan (83.5% capacity retention after 6,000 cycles at 1 A·g −1 ) in the aqueous zinc/sodium batteries. This research demonstrates the practicality of activating multielectron reactions to optimize the electrochemical properties of NASICON cathodes for aqueous secondary batteries.
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