TEMPO‐Substituted Poly(ethylene sulfide) for Solid‐State Electro‐Chemical Charge Storage

Abstract

A poly(ethylene sulfide) backbone is introduced as the main chain of a radical polymer. Anionic ring‐opening polymerization of an episulfide monomer substituted with 2,2,6,6tetramethylpiperidin1oxyl (TEMPO), a robust nitroxide radical, yields the corresponding polythioether. Compared to the traditional poly(ethylene oxide) backbone, the new polymer shows a lower glass transition temperature (−10 °C), and about threefold higher solid‐state ionic conductivity. The polythioether is also shown to improve the charge/discharge properties of a cathode in solid‐state lithium‐ion batteries.

Recent advances in the ring-opening polymerization of sulfur-containing monomers

“…80 The anionic ROP of various thioglcidyl ether monomers (type M35) has also been reported to obtain polythioethers possessing distinct properties (Scheme 15c/d). [81][82][83][84] For example, (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO)-substituted polythioether polyM35c has demonstrated potential applications in energy storage (Scheme 15c), 81 while phenyl thioglcidyl ether (M35d) underwent ring-expansion polymerization using benzothiazol-2-one (BT) as a cyclic initiator in the presence of tetrabutylammonium chloride (TBAC) as a catalyst (Scheme 15d). 82 The polymerization proceeded in a well-controlled manner to afford polyM35d (M n = 6.15 kg mol −1 , Đ = 1.18) with one BT moiety per macrocycle, as confirmed by MALDI-TOF analysis.…”

Episulfide Anionic Ring-Opening Polymerization Initiated by Alcohols and Primary Amines in the Presence of γ-Thiolactones

“…9,10 In the field of energy storage, polythioethers, especially poly(ethylene sulfide), have a high potential as solid-state electrolytes to replace poly(ethylene oxide) in lithium-ion batteries. 11 In addition, polysulfides are commonly used as oxidation-responsive or antioxidant materials for biomedical applications due to their up to now unique well-controlled oxidation responsive behavior. 3,[12][13][14] For example, PPS nanoparticles or PEG-PPS vesicles can be used for oxidation-driven drug-release due to the ability of the hydrophobic PPS to be oxidized via chemical or enzymatic oxidation to hydrophilic polysulfoxides and/or polysulfones.…”

“…[39][40][41][42][43][44] Living episulfide polymerizations were also obtained using thiol / 1,8-diazabicyclo [5.4.0]undec-7-ene (DBU) as initiating system allowing the preparation of various architectures. 11,19,20,42,45,46 Except for thiol and thiol-derived compounds, carboxylic acid derivatives have been employed as initiators using (Thio)acyl Group Transfer Polymerization developed by Nishikubo and coll. [47][48][49] Alcohol and amine groups are more common chemical moieties and easier to handle than thiol groups.…”

“…They cover a broad range of physicochemical properties, such as high refractivity, heat resistance, heavy metal chelation properties, or enhanced dielectric properties . Therefore, they find applications in a wide range of industrial fields − ranging from commonly used adhesives and sealing agents − to high-tech products, such as optical devices [high-refractive index (RI) polymers], or self-healing materials. , In the field of energy storage, polythioethers, especially poly­(ethylene sulfide), have a high potential as solid-state electrolytes to replace poly­(ethylene oxide) in lithium-ion batteries . In addition, polysulfides are commonly used as oxidation-responsive or antioxidant materials for biomedical applications due to their unique well-controlled oxidation responsive behavior up to now. ,− For example, PPS nanoparticles or polyethylene glycol (PEG)–PPS vesicles can be used for oxidation-driven drug release due to the ability of the hydrophobic PPS to be oxidized via chemical or enzymatic oxidation to hydrophilic polysulfoxides and/or polysulfones. , In addition, PEG–PPS copolymers were also used to prepare protein repellent layers on implants using the metal affinity of the thioether group …”

“…The following initiators were originally used for episulfide polymerization: carbanions (such as naphthalene sodium, , carbazyl sodium, or fluorenyl tetrabutylammonium), thiolates (sodium, potassium, zinc, cadmium, or quaternary ammonium thiolates), − or quaternary ammonium dithiobenzoates. , Thiolate–zinc complexes of N -methylporphyrins are effective for the immortal polymerization of episulfide. , Later, the use of protected thiols (in the form of thioacetates) allowed a better control over polythioether molar mass and dispersity, avoiding thiol easy oxidation to disulfide and subsequent errors in the initiator concentration . The thioacetyl group is cleaved in situ by methanolysis, leading to a thiolate that is able to initiate the controlled AROP of episulfides. − Living episulfide polymerizations were also carried out using thiol/1,8-diazabicyclo[5.4.0]­undec-7-ene (DBU) as an initiating system, allowing the preparation of various architectures. ,,,,, Except for thiol and thiol-derived compounds, carboxylic acid derivatives have been employed as initiators using (thio)­acyl group transfer polymerization developed by Nishikubo et al − …”