NOVELTY - An electrolyte mixture (M1) comprises a thermally stable ionic liquid, low molecular weight polymer having an ethylene oxide chain, and lithium salt.    USE - As an electrolyte for lithium ion battery and rechargeable lithium ion batteries (claimed) used as power sources especially in portable electronics such as mobile phones and laptop computers.    ADVANTAGE - The electrolyte compositions exhibit both relatively high ionic conductivity, as well as remarkably low viscosity, and improved thermal properties for use both with traditional disposable lithium batteries, and rechargeable lithium ion batteries employing Li electrodes. The electrolyte enables the use of pure lithium metal as a battery electrode material in rechargeable batteries. By enabling the use of pure lithium, significant weight reductions in the case of the negative electrode (the anode) can be achieved. In fact, weight savings of up to 80% of the active material of the negative electrode may be realized. The ionic liquid electrolyte facilitates the use of sulfur as a cathode material. It also improves the safety and maintains the good performance of currently available battery cells that use conventional cathodes such as lithium ion phosphate (LiFePO4), lithium cobalt oxide (LiCoO2). The electrolyte greatly increases the safety of lithium batteries is substantially non flammable. These thermally stable electrolytes don't decompose until they reach high temperatures of 300-400 degrees C. This compares to current electrolytes which decompose and/or react at temperatures approaching 120 degrees C and can ignite at that temperature.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) lithium battery comprising the mixture (M1), a positive electrode, and lithium negative electrode;    (2) making a mixture for uses as an electrolyte in a lithium ion battery involving providing a thermally stable ionic liquid; providing a polymer having an ethylene oxide chain capable of is adsorbed into a lithium metal; providing a lithium salt; and mixing the ionic liquid, the polymer, and the lithium salt;    (3) lithium ion battery comprising a mixture, where the mixture comprises a thermally stable ionic liquid, polymer having an ethylene oxide chain, lithium salt; a lithium negative electrode; and a positive electrode; and    (4) making a rechargeable lithium ion battery involving providing a mixture comprising a thermally stable ionic liquid, polymer having an ethylene oxide chain, lithium salt; providing a positive electrode; providing a lithium negative electrode; providing a cell housing; and assembling the mixture, the positive electrode, and the lithium negative electrode into the cell housing.