Role of FTFSI Anion Asymmetry on Physical Properties of AFTFSI (A=Li, Na and K) Based Electrolytes and Consequences on Supercapacitor Application

Autor: Laure Timperman, Joseph Chidiac, Mérièm Anouti
Rok vydání: 2021
Předmět:
Zdroj: ChemPhysChem. 22:1863-1879
ISSN: 1439-7641
1439-4235
DOI: 10.1002/cphc.202100439
Popis: This study compares the physicochemical properties of six electrolytes comprising of three salts: LiFTFSI, NaFTFSI and KFTFSI in two solvent mixtures, the binary (3EC/7EMC) and the ternary (EC/PC/3DMC). The transport properties (conductivity, viscosity) as a function of temperature and concentration were modeled using the extended Jones-Dole-Kaminsky equation, the Arrhenius model, and the Eyring theory of transition state for activated complexes. Results are discussed in terms of ionicity, solvation shell, and cross-interactions between electrolyte components. The application of the six formulated electrolytes in symmetrical activated carbon (AC)//AC supercapacitors (SCs) was characterized by cyclic voltammetry (CV), galvanostatic cycling with potential limitation (GCPL), electrochemical impedance spectroscopy (EIS) and accelerated aging. Results revealed that the geometrical flexibility of the FTFSI anion allows it to access and diffuse easily in AC whereas its counter ions (Li+ , Na+ or K+ ) can remain trapped in porosity. However, this drawback was partially resolved by mixing LiFTFSI and KFTFSI salts in the electrolyte.
Databáze: OpenAIRE
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