Apparent Molar Volume, Heat Capacity, and Conductance of Lithium Bis (trifluoromethylsulfone)imide in Glymes and Other Aprotic Solvents

摘要: Lithium bis(trifluoromethylsulfone)imide (LiTFSI) is a promising electrolyte for high-energy lithium batteries due to its high solubility in most solvents and electrochemical stability. To characterize this solution, conductance apparent molar volume heat capacity were measured over wide range of concentration glymes, tetraethylsulfamide (TESA), acetonitrile, γ-butyrolactone, propylene carbonate at 25°C compared with those LiClO4 the same solvents. The glymes or n(ethylene glycol) dimethyl ethers (nEGDME), which have chemical structure CH3−O−(CH2−CH2−O) n −CH3 n = 1 4, are particularly interesting since they electrochemically stable, good redox window, analogs polyethylene oxides used polymer-electrolyte batteries. TESA plasticizer Whenever required, following properties pure measured: compressibilities, expansibilities, temperature pressure dependences dielectric constant, acceptor number, donor number. These data particular calculate limiting Debye-Huckel parameters volumes capacities. infinite dilution LiTFSI quite similar other salts. At low concentrations, strongly associated moderately TESA. intermediate thermodynamic suggests that stable solvate EGDME exists solution state. two salts approach molten reasonably specific conductivity This ions constant charge transfer process rather than migration free ions.