化学
碱金属
电解质
碳酸乙烯酯
无机化学
乙腈
溶剂化
离子
离子键合
电化学
溶剂
离子半径
物理化学
有机化学
电极
作者
Samia Amara,Joël Toulc'Hoat,Laure Timperman,Agnès Biller,Hervé Galiano,Corinne Marcel,Matthieu Ledigabel,Mérièm Anouti
出处
期刊:ChemPhysChem
[Wiley]
日期:2019-01-08
卷期号:20 (4): 581-594
被引量:56
标识
DOI:10.1002/cphc.201801064
摘要
The development of a suitable functional electrolyte is urgently required for fast-charging and high-voltage alkali-ion (Li, Na, K) batteries as well as next-generation hybrids supercapacitors. Many recent works focused on an optimal selection of electrolytes for alkali-ion based systems and their electrochemical performance but the understanding of the fundamental aspect that explains their different behaviour is rare. Herein, we report a comparative study of transport properties for LiPF6 , NaPF6 , KPF6 in acetonitrile (AN) and a binary mixture of ethylene carbonate (EC), dimethyl carbonate (DMC): (EC/DMC : 1/1, weigh) through conductivities, densities and viscosities measurements in wide temperature domain. By application of the Stokes-Einstein, Nernst-Einstein, and Jones Dole equations, the effective ionic solvated radius of cation (reff ), the ionic dissociation coefficient (αD ) and structuring Jones Dole's parameters (A, B) for salt are calculated and discussed according to solvent or cation nature as a function of temperature. From the results, we demonstrate that better mobility of potassium can be explained by the nature of the ion-ion and ion-solvent interactions due to its polarizability. In the same time, the predominance of triple ions in the case of K+ , is a disadvantage at high concentration.
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