Multifunctional composites as Solid-Polymer-Electrolytes (SPE) for Lithium Ion Battery (LIB)

Abstract

Abstract. Novel solid-polymer-electrolytes (SPE) have been formulated as key components of structural multifunctional materials to develop Lithium Ion Battery (LIB). To this aim, SPE blends based on polyethylene oxide (PEO), different molecular weights polyethylene glycole (PEG), PEG-modified sepiolite (SEP) and lithium triflate have been prepared by one pot melt mixing. The films were obtained by compression moulding following a method easily scalable to industrial level. The different films have been characterized by structural (FTIR-ATR), thermal (DSC, TGA), morphological (SEM) and mechanical (tensile tests) analysis. The different properties could be mainly addressed to the diverse PEG both amounts and molecular weight and to the specific physical interaction occurring between PEO, PEG sepiolite and lithium ions strongly influencing crystallinity, thermal stability and mechanical response. Thus, SPE2 sample evidenced the highest both crystallinity and mechanical stiffness and toughness, whereas SPE1 and SPE3 film showed the best compromise between molecular crystallinity and mechanical performances, mostly as strain at break are concerned. Finally, SPE4 film, including the highest amount of PEG showed a peculiar increasing of mechanical rigidity in opposition to molecular plasticization effect exploited by PEG. The many features of SPE systems requires special attention and further research when it comes time to design structural multifunctional materials for LIB based batteries of Type-III.