Different compositions of a ternary solid polymer electrolyte (SPE) system consisting solely of poly(ethylene oxide), lithium bis(trifluoromethansulfonyl)imide (LiTFSI) and the ionic liquid N-methyl-N-butyl-pyrrolidinium bis(trifluoromethane-sulfonyl) imide (Pyr14TFSI) were tested. Differential scanning calorimetry shows that a few ternary polymer electrolytes with selected salt and ionic liquid contents are amorphous at room temperature. The Li+ coordination in the ternary electrolytes was analyzed by Raman spectroscopy while the Li+ transport properties were investigated by means of pulsed-field-gradient NMR (PFG-NMR), impedance spectroscopy and DC methods.