Solid Electrolytes for Rechargeable Batteries

Solid polymeric electrolytes have been prepared for their application in rechargeable batteries using eutectic mixtures. The electrolytes are prepared by polymeric solutions of poly(ethylene oxide) (PEO) in acetonitrile and polymethylmethacrylate (PMMA) and poly(vinylidene fluoride-co-hexafluoruropropylene) (PVDF-HFP) in N, N-dimethylformamide (DMF), to which are added different eutectic liquids, lithium salt and a modified inorganic filler that acts as a compatibilizer to avoid the phase separation. Afterwards, the evaporation of the solvents is carried out in order to achieve solid electrolytes, both thermally and electrochemically stable, that overcome the drawbacks that other types of electrolytes present so far and that may thus be useful for this application, such as the risk of leakage of toxic substances, accidents that bring both electrodes into contact and that can cause short circuits, high raw material costs or difficult preparation and handling methods. A study of its thermal properties and morphology has been carried out using techniques such as TGA, DSC or FTIR, and the ionic conductivity of each electrolyte has been measured in order to achieve solid polymeric electrolytes by replacing RTIL for DES.