Nuclear magnetic relaxation study of poly(ethylene oxide)–lithium salt based electrolytes

Donoso, José Pedro; Bonagamba, Tito J.; Panepucci, Horácio Carlos; Oliveira, Lucas Nonato de; Gorecki, W.; Berthier, Y.; Armand, Michel

doi:10.1063/1.464435

Cited by 95 publications

(79 citation statements)

References 32 publications

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“…As observed in Fig 3, between 200 K and 280 K for HEC/DPEO (220 K and 300 K for the polymer electrolyte) the linewidth decreases sharply to 0.6 kHz and then remains constant up to 350 K. It is clear from the data that the onset of the motional narrowing occurs near the T g of the HEC/polyether ®lms (Table 1). Similar behaviour has been observed in polyethers and polymer electrolytes, 11,13 where the line narrowing at T g is attributed to the onset of local segmental motion in the polymer chain. The fact that 1 H linewidth reduction occurs close to T g is clear evidence that the line transition is really associated with the polymer dynamics occurring above T g .…”

Section: Resultssupporting

confidence: 66%

“…The molar substitution (MS = 0.58) valued of the HEC sample were determined from the 1 H NMR spectra, quantifying the peak areas from 3.5 to 4.4 ppm and from 4.3 to 5.8 ppm. 6,7 The degrees of substitution (DS = 0.34) were obtained from MS results and the peak areas at 69.7 and 60.0 ppm in the corresponding 13 C NMR spectra. 7,8 The weight average degree of polymerization (DP = 850) was determined through the Mark± Houwinck±Sakurada equation (K = 1.1 Â 10 À2 and a = 0.87) 7,9 using intrinsic viscosity values determined with a capillary viscometer.…”

Section: Methodsmentioning

confidence: 99%

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DSC and solid state NMR characterization of hydroxyethylcellulose/polyether films

Regiani¹,

Tambelli²,

Pawlicka³

et al. 2000

Polym. Int.

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Section: Resultssupporting

confidence: 66%

Section: Methodsmentioning

confidence: 99%

DSC and solid state NMR characterization of hydroxyethylcellulose/polyether films

Regiani¹,

Tambelli²,

Pawlicka³

et al. 2000

Polym. Int.

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“…[15][16][17] In particular, fluoride glasses have been investigated by 19 F NMR for more than 15 years. Most of the works were focused on ZrF 4 -based glasses, concerning temperature dependence of the 19 F linewidth and nuclear relaxation times.…”

Section: Nuclear Magnetic Resonancementioning

confidence: 99%

Differential scanning calorimetry, x-ray diffraction and F19 nuclear magnetic resonance investigations of the crystallization of InF3-based glasses

Franco

Tambelli

Magon

et al. 1998

The Journal of Chemical Physics

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Results of differential scanning calometry ͑DSC͒, x-ray diffraction ͑XRD͒, and 19 F nuclear magnetic resonance ͑NMR͒ of InF 3 -based glasses, treated at different temperatures, ranging from glass transition temperature (T g ) to crystallization temperature (T c ), are reported. The main features of the experimental results are as follows. DSC analysis emphasizes several steps in the crystallization process. Heat treatment at temperatures above T g enhances the nucleation of the first growing phases but has little influence on the following ones. XRD results show that several crystalline phases are formed, with solid state transitions when heated above 680 K. The 19 F NMR results show that the spin-lattice relaxation, for the glass samples heat treated above 638 K, is described by two time constants. For samples treated below this temperature a single time constant T 1 was observed. Measurements of the 19 F spin-lattice relaxation time (T 1 ), as a function of temperature, made possible the identification of the mobile fluoride ions. The activation energy, for the ionic motion, in samples treated at crystallization temperature was found to be 0.18Ϯ0.01 eV.

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“…Since the binding energy between Li þ and oxygen is very large [15], Li þ ions are predominantly complexed with the EO groups [11,16]. We therefore assume that all Li þ ions reside on the PEO chains.…”

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confidence: 99%

Thermodynamics of Ion-Containing Polymer Blends and Block Copolymers

2011

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We develop a theory for the thermodynamics of ion-containing polymer blends and diblock copolymers, taking polyethylene oxide (PEO), polystyrene and lithium salts as an example. We account for the tight binding of Li þ ions to the PEO, the preferential solvation energy of anions in the PEO domain, the translational entropy of anions, and the ion-pair equilibrium between EO-complexed Li þ and anion. Our theory is able to predict many features observed in experiments, particularly the systematic dependence in the effective parameter on the size of the anions. Furthermore, comparison with the observed linear dependence in the effective on salt concentration yields an upper limit for the binding constant of the ion pair. DOI: 10.1103/PhysRevLett.107.198301 PACS numbers: 83.80.Uv, 77.22.Àd, 82.35.Rs, 83.80.Sg There is much current interest in ion-containing polymers as materials for energy applications [1]. Of particular interest for rechargeable battery applications are block copolymers [2][3][4] of an ion-dissolving block, typically polyethylene oxide (PEO), and a nonconducting block such as polystyrene (PS), doped with lithium salts. The lithium ions are complexed with EO groups [5], and together with their counterions, provide the charge carriers [6]. The nonconducting block can be tuned to confer other functions, such as mechanical robustness [3,4,6].Experimentally, the addition of lithium salts has been shown to have significant effects on the order-order and order-disorder transitions in block copolymers [3,7,8]. Among other effects, it is found that the effective parameter characterizing the immiscibility of the two blocks increases linearly with salt concentration [9,10],where is the intrinsic Flory-Huggins parameter for the salt-free system, r is the molar ratio of Li þ ions to EO monomers, and the slope m depends on the anion type. Wanakule et al. [10] found that m decreases with increasing anion radius a. No existing theory describes this behavior. Since the Li þ ions are strongly bound to the EO groups [11], one may consider the PEO with its bound Li þ ions as an effective polyelectrolyte, with the anions acting as the counterions. However, existing theories for diblock copolymers with a charged block and a neutral block [12,13] predict enhanced miscibility between the blocks relative to the uncharged system, opposite to experimental observations; there is also no dependence on the radius of the counterions.The strong binding of Li þ to the EO groups clearly will affect the thermodynamics of PEO-PS diblock copolymers. However, as suggested in Ref.[10] and demonstrated here, a key effect in these ion-containing polymers is the solvation energy of the anions, which has been ignored in all existing theories of ion-containing polymers. An earlier theory developed by one of us [14], taking into account the effects of ion solvation, predicted that adding salts to binary polymer blends can decrease the miscibility between the two polymers. However, that theory assumed the salt ions to be fully dissociated a...

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Nuclear magnetic relaxation study of poly(ethylene oxide)–lithium salt based electrolytes

Cited by 95 publications

References 32 publications

DSC and solid state NMR characterization of hydroxyethylcellulose/polyether films

DSC and solid state NMR characterization of hydroxyethylcellulose/polyether films

Differential scanning calorimetry, x-ray diffraction and F19 nuclear magnetic resonance investigations of the crystallization of InF3-based glasses

Thermodynamics of Ion-Containing Polymer Blends and Block Copolymers

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