Phase behavior and Li
            <sup>+</sup>
            Ion conductivity of styrene‐ethylene oxide multiblock copolymer electrolytes

Sarapas, Joel M.; Saijo, Kenji; Zhao, Yue; Takenaka, Mikihito; Tew, Gregory N.

doi:10.1002/pat.3753

Cited by 14 publications

(9 citation statements)

References 55 publications

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“…This loss of crystallinity could be due to any combination of three factors: the charged nature of the cation, the presence of the bulky triflate counterion, or the presence of water. The presences of the triflate counterion as well as water were the most likely reasons, since these types of species reduce or fully remove crystallinity in other hydrophilic, crystalline polymers, such as poly(ethylene oxide). − From the scattering profiles in Figure , the d -spacings and q values were determined (Table S3). In general, peaks A through C had average d -spacings of 0.46, 0.39, and 0.36 nm, respectively, which were very similar to the d -spacings reported for the series 1 polymers and for HDPE (Figure ).…”

Section: Resultsmentioning

confidence: 99%

Functional Polyethylenes with Precisely Placed Thioethers and Sulfoniums through Thiol–Ene Polymerization

et al. 2018

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The precise functionalization of polyethylenes, often accomplished through acyclic diene metathesis polymerization (ADMET), is a significant area of research that has improved polyethylene properties and performance. Here, the synthesis of precisely functionalized polyethylenes was accomplished using the thiol–ene step-growth (TES) polymerization. The simplicity and versatility of this technique allowed for the synthesis of a variety of polymers and enabled the study of carbon spacer length between and repeat unit symmetry about the resulting backbone thioether moiety. In addition, the backbone thioethers of some samples were functionalized postpolymerization with methyl triflate to produce polyethylenes containing sulfonium cations. All polymers were then characterized for their thermal stability, crystallinity, and morphology using differential scanning calorimetry (DSC) and X-ray scattering. While the carbon spacer length and repeat unit symmetry had no effect on polymer thermal stability, the incorporation of cationic sulfonium groups reduced the degradation temperature. Most polymers were polymorphic with respect to crystal structure, and increasing the carbon spacer length led to an increase in polymer melting temperature and percent crystallinity. Furthermore, the average carbon spacer length had a larger effect on polymer percent crystallinity and crystal structure than repeat unit symmetry, but the symmetry had a significant impact on polymer crystal melting temperature, as symmetric polymers had higher melting temperatures. Overall, TES polymerization was utilized to fabricate precisely functionalized polyethylenes, where the repeat unit symmetry improved polymer crystal perfection.

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Section: Resultsmentioning

confidence: 99%

Functional Polyethylenes with Precisely Placed Thioethers and Sulfoniums through Thiol–Ene Polymerization

et al. 2018

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“…More recently, we demonstrated the polymerization of numerous dithiols and divinyl ethers, and the potential of these molecules to coordinate and conduct lithium cations as solid polymer electrolytes . By using this same concept, we also demonstrated linear multiblock copolymer formation through the reaction of telechelic dithiol and dinorbornene macromonomers . Herein, we report the TES polymerization of monomers to demonstrate its functional‐group tolerance and spatial control, in addition to its redox responsive behavior.…”

Section: Figurementioning

confidence: 93%

Thiol‐Ene Step‐Growth as a Versatile Route to Functional Polymers

Sarapas

Tew

2016

Angew Chem Int Ed

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A new use of the thiol-ene reaction to generate functional, redox-tunable polymers is described. To illustrate the versatility of this approach, tailored divinyl ether monomers were polymerized with triethylene glycol dithiol to yield polymers containing either a carbonate or zwitterionic phosphocholine within the polymer backbone. Similarly, dithioerythritol was polymerized with triethylene glycol divinyl ether to yield a polymer with pendant diols and show how functional groups can be designed into either the divinyl ether or dithiol monomer. Using the thioether functional group inherent to this polymerization, all three polymers were selectively and quantitatively oxidized to either sulfoxides or sulfones by treatment with dilute hydrogen peroxide or mCPBA, respectively. With these illustrative examples, it is shown that the thiol-ene polymerization is a broad-reaching method to access a class of new redox-active polymers which contain varied and dense functional-group compositions.

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“…Lithium bis(trifluoromethanesulfonyl)imide has been the most commonly used salt in block copolymer electrolyte studies. In the SEO/LiTFSI system, ionic conductivity has been characterized as a function of SEO molecular weight, , block architecture, − end-group chemistry, , morphology, − and salt concentration. ,, It is convenient to express salt concentration in terms of r ≡ [Li]/[EO], the ratio of lithium (Li) to ethylene oxide (EO) moieties. Most studies on block copolymer electrolytes are centered around r = 0.10 as this is the regime wherein the conductivity of homopolymer PEO/LiTFSI electrolytes is maximized .…”

Section: Introductionmentioning

confidence: 99%

Correlations between Salt-Induced Crystallization, Morphology, Segmental Dynamics, and Conductivity in Amorphous Block Copolymer Electrolytes

et al. 2018

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Block copolymer electrolytes have been shown to increase the cycle life of rechargeable batteries that utilize high capacity lithium anodes. Most block copolymer electrolyte studies have been centered on polystyrene-b-poly-(ethylene oxide) (SEO) mixed with lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt and are limited to salt concentrations in the vicinity of r ≡ [Li]/[EO] = 0.1, where [Li] and [EO] are the concentration of lithium and ethylene oxide moieties, respectively, as the conductivity of poly-(ethylene oxide) (PEO) homopolymer electrolytes is maximized at this concentration. In this work, we study the morphology and conductivity of electrolytes derived from a high molecular weight SEO block copolymer over the wide LiTFSI concentration range of 0 ≤ r ≤ 0.550. For electrolytes with r ≥ 0.125, the crystallization of PEO−LiTFSI complexes with stoichiometric ratios of 6:1, 3:1, or 2:1 (EO:Li) is shown to correlate with morphology as determined by small-angle X-ray scattering (SAXS) and scanning transmission electron microscopy (STEM): some samples that are semicrystalline at room temperature exhibit regions of periodic lamellar ordering, whereas those that do not crystallize have aperiodic packed-ellipsoid morphologies. SAXS profiles below and above the melting temperatures of the crystals are identical, indicating that the crystals are confined within the block copolymer domains. The conductivities of SEO/LiTFSI mixtures with r = 0.275, r = 0.300, and r = 0.350 are within experimental error of PEO/LiTFSI at the same salt concentrations, in spite of the presence of insulating polystyrene (PS) domains in the SEO/LiTFSI samples. We attribute this to enhanced segmental dynamics of the PEO chains in the SEO electrolytes, based on differential scanning calorimetry (DSC) measurements of glass transition temperatures. The dependence of ionic conductivity on salt concentration in the SEO/LiTFSI electrolytes at temperatures above the melting temperature of the crystalline complexes shows three local maxima that correlate with the formation of crystalline complexes when r ≥ 0.125. These maxima arise due to a combination of the enhanced segmental dynamics and changes in morphology observed by SAXS and STEM.

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Phase behavior and Li ⁺ Ion conductivity of styrene‐ethylene oxide multiblock copolymer electrolytes

Cited by 14 publications

References 55 publications

Functional Polyethylenes with Precisely Placed Thioethers and Sulfoniums through Thiol–Ene Polymerization

Functional Polyethylenes with Precisely Placed Thioethers and Sulfoniums through Thiol–Ene Polymerization

Thiol‐Ene Step‐Growth as a Versatile Route to Functional Polymers

Correlations between Salt-Induced Crystallization, Morphology, Segmental Dynamics, and Conductivity in Amorphous Block Copolymer Electrolytes

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Phase behavior and Li + Ion conductivity of styrene‐ethylene oxide multiblock copolymer electrolytes

Cited by 14 publications

References 55 publications

Functional Polyethylenes with Precisely Placed Thioethers and Sulfoniums through Thiol–Ene Polymerization

Functional Polyethylenes with Precisely Placed Thioethers and Sulfoniums through Thiol–Ene Polymerization

Thiol‐Ene Step‐Growth as a Versatile Route to Functional Polymers

Correlations between Salt-Induced Crystallization, Morphology, Segmental Dynamics, and Conductivity in Amorphous Block Copolymer Electrolytes

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Phase behavior and Li ⁺ Ion conductivity of styrene‐ethylene oxide multiblock copolymer electrolytes