Enhanced Electrochemical Performance of Hybrid Solid Polymer Electrolytes Encompassing Viologen for All-Solid-State...

Hybrid solid polymer electrolytes (HSPE) comprising poly(ethylene oxide) (PEO), LiTFSI, barium titanate (BaTiO₃), and viologen are prepared by a facile hot press. The physical properties of the HSPE membranes are studied by using small-angle and wide-angle X-ray scattering, thermogravimetric analysis, differential scanning calorimetry, and tensile strength. The prepared hybrid solid polymer electrolytes are also investigated by means of ionic conductivity and transport number measurements. The employed analyses collectively reveal that each additive in the PEO host contributes to a specific property: LiTFSI is essential in providing ionic species, while BaTiO₃ and viologen enhance the thermal stability, ionic conductivity, and transport number. The enhanced value in the Li⁺-transport number of HSPE are presumably attributed to the electrostatic attraction of TFSI anions and the positive charges of viologen. Synergistically, the added BaTiO₃ and viologen improve the electrochemical properties of HSPE for the applications in all-solid-state-lithium polymer batteries.