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  • Investigating miscibility and lithium ion transport in blends of poly(ethylene oxide) with a polyanion containing precisely-spaced delocalized charges
Title: Investigating miscibility and lithium ion transport in blends of poly(ethylene oxide) with a polyanion containing precisely-spaced delocalized charges
A novel precision single-ion conductor with phenylsulfonyl(trifluoromethylsulfonyl)imide lithium salt covalently bound to every fifth carbon of a polyethylene backbone, p5PhTFSI-Li, was synthesized via ring opening metathesis polymerization (ROMP) followed by post polymerization modification. The conversion of poly(4-phenylcyclopentene), bearing 94% sulfonate anions, to trifluoromethanesulfonimide (TFSI) anions was highly efficient (∼90%) as determined by 19 F NMR analysis and corroborated through other spectroscopic methods. The flexible hydrocarbon backbone combined with a bulky TFSI anion led to an observable glass transition temperature of 199 °C even at these high levels of ionization. A high thermal stability up to 375 °C was also observed. Blending of p5PhTFSI-Li with poly(ethylene oxide) at various compositions was performed to investigate electrochemical performance and transference numbers with respect to the lithium electrode using a combination of impedance and polarization methods. At 90 °C and a 50 : 50 wt% blend composition, this system displayed the highest reported conductivity (2.00 × 10 −4 S cm −1 ) of a system with a demonstrated lithium-ion transference number near unity. Such performance is also atypical of single ion conductors produced through post-polymerization modification, which we attribute to the high yield of TFSI conversion. Investigations into the complex miscibility and phase behavior of these blends at various compositions was also probed by a combination of microscopy and differential scanning calorimetry, which is discussed with reference to computational predictions of how charge correlations affect polymer blend phase behavior.  more » « less
Award ID(s):
1804871
PAR ID:
10347578
Author(s) / Creator(s):
; ; ; ;
Date Published:
Journal Name:
Polymer Chemistry
Volume:
13
Issue:
29
ISSN:
1759-9954
Page Range / eLocation ID:
4309 to 4323
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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