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Phase behavior of binary and ternary fluoropolymer (PVDF-HFP) solutions for single-ion conductors

A fluoropolymer poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) has a dielectric constant of ∼11, providing charge screening effects. Hence, this highly polar PVDF-HFP material has been employed as a matrix for solid polymer electrolytes (SPEs). In this study, the phase behavior of binar...

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Detalles Bibliográficos
Autor principal: Kim, Jung Yong
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The Royal Society of Chemistry 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9344283/
https://www.ncbi.nlm.nih.gov/pubmed/35975057
http://dx.doi.org/10.1039/d2ra04158h
Descripción
Sumario:A fluoropolymer poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) has a dielectric constant of ∼11, providing charge screening effects. Hence, this highly polar PVDF-HFP material has been employed as a matrix for solid polymer electrolytes (SPEs). In this study, the phase behavior of binary PVDF-HFP solutions was analyzed using the Flory–Huggins theory, in which ethylene carbonate, propylene carbonate, dimethyl carbonate, γ-butyrolactone, and acetone were employed as model solvents. In particular, for the binary PVDF-HFP/acetone system, the solid–liquid and liquid–liquid phase transitions were qualitatively described. Then, the phase diagram for ternary acetone/PVDF-HFP/polyphenolate systems was constructed, in which the binodal, spinodal, tie-line, and critical point were included. Finally, when a polyelectrolyte lithium polyphenolate was mixed with the PVDF-HFP matrix, it formed a single-ion conductor with a Li(+) transference number of 0.8 at 23 °C. In the case of ionic conductivity, it was ∼10(−5) S cm(−1) in solid state and ∼10(−4) S cm(−1) in gel state, respectively.