ELECTROLYTE COMPOSITION HAVING EXCELLENT HIGH-TEMPERATURE STABILITY AND PERFORMANCE AND ELECTROCHEMICAL DEVICE INCLUDING SAME

摘要

The present invention relates to an electrolyte composition comprising: (i) a solvent; (ii) a lithium sa and (iii) an additive in the form of a polymer, oligomer, or a mixture thereof which causes physical or chemical gelation at 30-80°C, wherein the ionic conductivity of the electrolyte composition after gelation is 90% or more based on the ionic conductivity of the electrolyte composition which does not include the additive, and the lithium ion transference number is 0.5 or more. The electrolyte composition according to the present invention has a viscosity as low as that of a liquid during the injection of an electrolyte at room temperature such that the electrolyte is easily immersed into an anode/cathode and a separation membrane so as to result in high wettability (wetting property). However, during high-temperature storage after the injection of the electrolyte, the state of the electrolyte composition is transformed to an irreversible gel state so as to prevent the degeneration of the electrolyte and the generation of gases. Therefore, the electrolyte composition of the present invention can impart excellent battery performance and stability and also have ionic conductance as high as a liquid, and thus can be effectively used in the preparation of an electrochemical device.