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

Hybrid solid polymer electrolytes (HSPE) comprising poly(ethyleneoxide) (PEO), LiTFSI, barium titanate (BaTiO3), and viologenare prepared by a facile hot press. The physical properties of theHSPE membranes are studied by using small-angle and wide-angle X-rayscattering, thermogravimetric analysis, differential scanning calorimetry,and tensile strength. The prepared hybrid solid polymer electrolytesare also investigated by means of ionic conductivity and transportnumber measurements. The employed analyses collectively reveal thateach 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+-transportnumber of HSPE are presumably attributed to the electrostatic attractionof TFSI anions and the positive charges of viologen. Synergistically,the added BaTiO3 and viologen improve the electrochemicalproperties of HSPE for the applications in all-solid-state-lithiumpolymer batteries.