Use of Organic Esters as Cosolvents in Electrolytes for Lithium-Ion Batteries with Improved Low Temperature Performance

Abstract

The electrolyte composition plays a strong role in determining the low temperature performance of lithium-ion cells, both in terms of ionic mobility in the electrolyte solution, as well as forming suitable surface films on the electrode surfaces. A series of ester solvents was chosen for incorporation into multicomponent electrolyte formulations due to their favorable physiochemical properties (i.e., low viscosity, low melting point, and high permittivity), as well as good compatibility with carbonaceous anodes and mixed metal cathodes (i.e., LiCoO2 and LiNiCoO2false). In addition to determining the relative facility of lithium intercalation and deintercalation in Li-carbon cells as a function of temperature, a number of conventional electrochemical methods were employed to further enhance the understanding of the nature of the electrode surface films in these ester-based electrolytes, including dc polarization and ac impedance measurements. A distinct trend was observed with respect to the stability of the surface films formed. In solutions containing low molecular weight cosolvents (i.e., methyl acetate and ethyl acetate) the surface films appear resistive and inadequately protective, whereas electrolytes containing higher molecular weight esters resulted in surface films with more desirable attributes. Promising electrolyte formulations were further evaluated in prototype lithium-ion cells (AA-size) and fully characterized in terms of their low temperature discharge performance. © 2002 The Electrochemical Society. All rights reserved.

Lithium-ion polymer cells for military applications

“…The spectrum cannot be fully interpreted without a detailed quantitative study of the various components, which has not been done at this time. However, the presence of CO 2 ,C O and CH 4 indicates that decomposition of EMC has taken place. Ethane should also be a decomposition product of EMC, but the infrared bands of this species would have been obscured by those of EMC, unlike those of methane, which have widely spaced rotational fine structure that stand out over the broader bands of EMC.…”

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Advanced nanostructured carbon materials for electrical double layer capacitors

“…The cyclic voltammograms show that the so-called ideal capacitive behaviour for nanostructured carbons has been established at potential scan rates v ≤ 10 mV s -1 and ΔE ≤ 3.2 V. There is a very well detectable minimum in j,E -curves, corresponding to the total zero charge potential for the non-aqueous electrolyte | nanostructured carbon interface, depending on the carbon and electrolyte used. At higher scan rates the so-called distortion effects [6,10,11,[19][20][21][22][23] were observed in the region of the potential switch-over. The electrochemical characteristics of the electrical double layer capacitor (EDLC) single cell (two-electrode system) based on the nanoporous carbon electrode in 1M (C 2 H 5 ) 3 CH 3 NBF 4 solution in various non-aqueous electrolytes [8,9] using the cyclic voltammetry (CV) and the electrochemical impedance spectroscopy (EIS) methods.…”

The First Lithium-ion Battery with Ionic Liquid Electrolyte Demonstrated in Extreme Environment of Space

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