Effect of LiBF4 Salt Concentration on the Properties of Plasticized MG49-TiO2 Based Nanocomposite Polymer Electrolyte

A nanocomposite polymer electrolyte (NCPE) comprising of 49% poly(methyl methacrylate) grafted natural rubber (MG49) as polymer host, titanium dioxide (TiO 2 ) as a ceramic filler, lithium tetrafluoroborate (LiBF 4 ) as dopant salt, and ethylene carbonate (EC) as plasticizer was prepared by solution casting technique. The ceramic filler, TiO 2 , was synthesized in situ by a sol-gel process. The ionic conductivity, chemical interaction, structure, and surface morphology of nanocomposite polymer electrolyte have been investigated as a function of wt% LiBF 4 . The interaction between lithium ions and oxygen atoms occurred at carbonyl and ether groups. The crystalline phase of polymer host slightly decreases with the addition of salt. TGA and DTG analysis suggested that the thermal stability of the electrolyte decreases with the salt content. The ionic conductivity of the electrolyte was found to increase with the increase of salt concentration and then decreased after an optimum value. The highest conductivity achieved was  S cm −1 at 25 wt% of LiBF 4 .