Influence of solvent evaporation temperature on the performance of ternary solid polymer electrolytes based on poly(vinylidene fluoride-co-hexafluoropropylene) combining an ionic liquid and a zeolite

• Main Author: Barbosa, João C.
• Publication Date: 2023
• Other Authors: Correia, Daniela Maria Silva, Fidalgo-Marijuan, Arkaitz, Gonçalves, Renato Ferreira, Ferdov, Stanislav, de Zea Bermudez, Verónica, Costa, Carlos Miguel Silva, Lanceros-Méndez, S.
• Format: Article
• Language: eng
• Source: Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)
• Download full: https://hdl.handle.net/1822/93604
• topic: evaporation temperature; lithium-ion batteries; PVDF-HFP; solid polymer electrolytes; ternary composites; Ciências Naturais::Ciências Químicas; Energias renováveis e acessíveis

Solid polymer electrolytes (SPEs) will allow improving safety and durability in next-generation solid-state lithium-ion batteries (LIBs). Within the SPE class, ternary composites are a suitable approach as they provide high room-temperature ionic conductivity and excellent cycling and electrochemical stability. In this work, ternary SPEs based on poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) as a polymer host, clinoptilolite (CPT) zeolite, and 1-butyl-3-methylimidazolium thiocyanate ([Bmim][SCN])) ionic liquid (IL) as fillers were produced by solvent evaporation at different temperatures (room temperature, 80, 120, and 160 °C). Solvent evaporation temperature affects the morphology, degree of crystallinity, and mechanical properties of the samples as well as the ionic conductivity and lithium transference number. The highest ionic conductivity (1.2 × 10-4 S·cm-1) and lithium transference number (0.66) have been obtained for the SPE prepared at room temperature and 160 °C, respectively. Charge-discharge battery tests show the highest value of discharge capacity of 149 and 136 mAh·g-1 at C/10 and C/2 rates, respectively, for the SPE prepared at 160 °C. We conclude that the fine control of the solvent evaporation temperature during the preparation of the SPE allows us to optimize solid-state battery performance.