13C NMR Spectroscopic, CV, and Conductivity Studies of Propylene Carbonate-based Electrolytes Containing Various Lithium Salts
The ion-solvent and ion-ion interactions, oxidative electrochemical stabilities, and ionic mobilities of a series of lithium salt electrolytes with commonly used electrolyte solvents, propylene carbonate (PC) and dimethyl carbonate (DMC), have been studied using 13C nuclear magnetric resonance (NMR) spectroscopy, cyclic voltammetry (CV), and ionic conductivity measurements. The coordinating ability of PC toward lithium salts is significantly higher than that of DMC as shown by the relatively large deshielding of the carbonyl carbon of PC over that of DMC. We have also prepared a novel electrolyte, lithium tetrakis(trifluoromethanesulfonato)gallate [LiGa(OTf)4], and investigated its relative binding to PC by 13C NMR spectroscopy. The latter salt showed significant deshielding of the carbonyl carbon of PC compared to the other salts studied, including the conventional LiPF6. However, its conductivity is not enhanced to the same extent and is comparable to that of LiBF4. The CVs show their relative stabilities toward oxidation around 4.5 V and reduction close to lithium potentials. All electrolytes studied here have good electrochemical stability from 0.1 to 5.0 V vs. Li+/Li, and are suitable for applications in lithium-ion cells.
P. Reddy et al., "13C NMR Spectroscopic, CV, and Conductivity Studies of Propylene Carbonate-based Electrolytes Containing Various Lithium Salts," Electrochemical and Solid State Letters, The Electrochemical Society (ECS), Apr 2005.
The definitive version is available at http://dx.doi.org/10.1149/1.1904466
Petroleum Research Fund
Library of Congress Subject Headings
Nuclear magnetic resonance
Article - Journal
© 2005 the Electrochemical Society (ECS), All rights reserved.