Solid-State NMR Study of New Copolymers as Solid Polymer Electrolytes

Abstract

Abstract:We report the analysis of comb-like polymers by solid-state NMR. The polymers were previously evaluated as solid-polymer-electrolytes (SPE) for lithium-polymer-metal batteries that have suitable ionic conductivity at 60 • C. We propose to develop a correlation between 13 C solid-state NMR measurements and phase segregation. 13 C solid-state NMR is a perfect tool for differentiating polymer phases with fast or slow motions. 7 Li was used to monitor the motion of lithium ions in the polymer, and activation energies were calculated.

Use of Solid-State NMR Spectroscopy for the Characterization of Molecular Structure and Dynamics in Solid Polymer and Hybrid Electrolytes

“…Lin et al and Daigle et al have measured variable temperature T 1 in polyethylene glycol (PEG)-based co-polymer systems containing lithium salts [ 31 , 76 ]. In both cases T 1 was observed to decrease with increasing temperature indicating increased mobility of both the polymer segment and the Li + ions.…”

“…These results can often be correlated with conductivity data. In these works, the low temperature portion of the T 1 buildup as a function of temperature curve is used to calculate activation energies for Li + transport in these systems, a method that can be used in samples that are not suitable for analysis via EIS [ 31 ]. It is worth noting that this method does present some challenges as it requires the ability to measure NMR spectra at low temperatures (down to −50 °C in Lin et al [ 76 ]) since temperatures above about −10 °C are around the T 1 minimum where significant changes in T 1 as a function of temperature no longer occur [ 31 ].…”

“…Therefore, in addition to being non-destructive, NMR spectroscopy is an isotopically sensitive method for investigating several nuclei that typically exist in solid electrolytes [ 28 ]. For example, nuclei such as 6 Li, 7 Li, 19 F, and 23 Na are generally used to study dynamic processes whereas 1 H and 13 C tend to be used to characterize polymer structure [ 30 , 31 ]. NMR is particularly suited to this task as it is sensitive to changes in local environments that occur on a microsecond to second timescale [ 30 ].…”

Review of Recent Nuclear Magnetic Resonance Studies of Ion Transport in Polymer Electrolytes

“…A recent study by Daigle et al investigated the Li + ion mobility in comb-like copolymers via solid-state NMR [60]. These comb-like polymers were based on poly(styrene) (PS) backbone fashioned through anionic polymerization.…”

“…Evolution of 7 Li linewidth as a function of inverse temperature for sample 1 ( black triangles ), sample 2 ( open circles ) and sample 3 ( black circles ) [60] (OPEN ACCESS).…”