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Effects of polymer matrix and salt concentration on the ionic conductivity of plasticized polymer electrolytes
Author(s) -
Whang WhaTzong,
Lu ChouLing
Publication year - 1995
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1995.070561214
Subject(s) - ionic conductivity , electrolyte , polymer , conductivity , materials science , ethylene oxide , polymer chemistry , ionic bonding , salt (chemistry) , chemical engineering , inorganic chemistry , chemistry , ion , copolymer , organic chemistry , composite material , electrode , engineering
Two polar polymers with different dielectric constants, poly(vinylidene fluoride) (PVDF) and poly(ethylene oxide) (PEO), were each blended with a chlorine‐terminated poly(ethylene ether) (PEC) and one of the two salts, LiBF 4 and LiCF 3 CO 2 , to form PEC plasticized polymer electrolytes. The room‐temperature ionic conductivity of the PEC plasticized polymer electrolytes reached a value as high as 10 −4 S/cm. The room‐temperature ionic conductivity of the PVDF‐based polymer electrolytes displayed a stronger dependence on the PEC content than did the PEO‐based polymer electrolytes. In PVDF/PEC/LiBF 4 polymer electrolytes, the dynamic ionic conductivity was less dependent on temperature and more dependent on the PEC content than it was in PEO/PEC/LiBF 4 polymer electrolytes. The highly plasticized PVDF‐based polymer electrolyte film with a PEC content greater than CF4 (CF4 defined as the molar ratio of the repeat units of PEC to those of PVDF equal to 4) was self‐supported and nonsticky, while the corresponding PEO‐based polymer electrolyte film was sticky. In these highly plasticized PVDF‐based polymer electrolytes, the curves of the room‐temperature ionic conductivity vs. the salt concentration were convex because the number of carrier ions and the chain rigidity both increased with increase of the salt content. The maximum ionic conductivity at 30°C was independent of the PEC content, but it depended on the anion species of the lithium salts in these highly plasticized polymer electrolytes. © 1995 John Wiley & Sons, Inc.