电化学
钠离子电池
快离子导体
结构精修
钠
阴极
电化学窗口
化学
插层(化学)
材料科学
相(物质)
离子
离子键合
电池(电)
分析化学(期刊)
无机化学
晶体结构
化学工程
离子电导率
电极
结晶学
电解质
物理化学
法拉第效率
热力学
色谱法
有机化学
功率(物理)
工程类
物理
作者
Rachid Essehli,Alaa Alkhateeb,Abdelfattah Mahmoud,Frèdéric Boschini,Hamdi Ben Yahia,Ruhul Amin,Ilias Belharouak
标识
DOI:10.1016/j.jpowsour.2020.228417
摘要
Sodium (Na) super ionic conductor (NASICON) polyanionic compounds have recently attracted much attention from the battery community because of their electroactive properties and reasonably high ionic conductivities, leading to their use as a cathode in sodium-ion batteries. This article describes the compositional optimizations, crystallographic evaluations, and electrochemical behavior of a new mixed NASICON polyanionic compound, NaFe2−xVx(PO4)(SO4)2. By doping the characteristic Fe3+ sites of the FeO6 octahedrons with varying amounts of V3+, the electrochemical stability and charge transport in NaFe2(PO4)(SO4)2 were enhanced. The resulting best composition, with crystal structure NaFe1.4V0.6(PO4)(SO4)2 resolved through the Rietveld method, exhibited a stable capacity compared with the other synthesized compositions. In situ powder x-ray diffraction measurements, a single-phase intercalation/deintercalation mechanism of the NASICON structure in the measured sodium concentration window was observed with no impurity phase formation. Further electrochemical assessments revealed the interfacial charge transfer kinetics to be the rate-limiting step in the sodium concentration window. Also, the measured sodium-ion diffusivity values in the range of 6 × 10−11 to 7 × 10−11 cm2/s in the measured sodium concentration range. The results reported here highlight the potential of compositionally and morphologically optimized NaFe1.4V0.6(PO4)(SO4)2 with higher particle surface areas as a cathode material for high-performance sodium-ion batteries.
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