Dielectric properties of sulfonated poly(ether ether ketone) (SPEEK) electrolytes with 1-ethyl-3-methylimidazolium tetrafluoroborate salt: Ionic liquid-based conduction pathways


YILMAZOĞLU M., Bayiroglu F., ERDEMİ H., Abaci U. , GÜNEY H. Y.

COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS, vol.611, 2021 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 611
  • Publication Date: 2021
  • Doi Number: 10.1016/j.colsurfa.2020.125825
  • Title of Journal : COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS

Abstract

In this study, dielectric properties of sulfonated poly(ether ether ketone) (SPEEK) solid polymer electrolytes (SPEs) containing room-temperature molten salt, 1-ethyl-3-methylimidazolium tetrafluoroborate were investigated. Additionally, the effects of ionic liquid (IL) addition on the thermomechanical properties and the microstructure of composite electrolytes (SPEEK-30 x 1IM and SPEEK-30 x 2IM) were studied. The characteristics of the SPEs were investigated by FTIR, SEM, TGA, DSC and DMA measurements. FTIR analysis confirmed the success of the sulfonation process and IL/sulfonated polymer interactions. IL addition caused changes in the crystalline structure and surface morphology of the SPEs. It was observed that SPEEK-30 x 1IM and SPEEK-30 x 2IM electrolytes have lower glass transition temperatures (T-g) and crystallinity than that of pure SPEEK-30. Due to the amorphous character formed by IL, proton conduction paths in which ILs exhibit enhanced conductivity have been formed. Among the composite electrolytes, SPEEK-30 x 2IM demonstrated an ionic conductivity (5.45 x 10(-4) Scm(-1)) more than 20 times higher than SPEEK-30.