The use of polymers in Li-S batteries: A review

Recent developments in the use of polymeric materials as device components in lithium sulfur (Li-S) batteries are reviewed. Li-S batteries have generated tremendous interest as a next generation battery exhibiting charge capacities and energy densities that greatly exceed Li-ion battery technologies. In this Highlight, the first comprehensive review focusing on the use of polymeric materials throughout these devices is provided. The key role polymers play in Li-S technology is presented and organized in terms of the basic components that comprise a Li-S battery: the cathode, separator, electrolyte, and anode. After a straightforward introduction to the construction of a conventional Li-S device and the mechanisms at work during cell operation, the use of polymers as binders, protective coatings, separators, electrolytes, and electroactive materials in Li-S batteries will be reviewed. (C) 2017 Wiley Periodicals, Inc.OAIID:RECH_ACHV_DSTSH_NO:T201723059RECH_ACHV_FG:RR00200001ADJUST_YN:EMP_ID:A004677CITE_RATE:2.588FILENAME:The Use of Polymers in Li-S Batteries A Review.pdfDEPT_NM:화학생물공학부EMAIL:[email protected]_YN:YFILEURL:https://srnd.snu.ac.kr/eXrepEIR/fws/file/7bdaf352-9ae0-404a-af19-dee2f7b7daaf/linkY

Inverse vulcanization of elemental sulfur and styrene for polymeric cathodes in Li-S batteries

High sulfur content copolymers were prepared via the inverse vulcanization of elemental sulfur with styrene. This reaction was carried out at a relatively low temperature and invokes a new chain transfer mechanism of abstraction of benzylic protons to form stable copolymers. The use of styrene as a comonomer for inverse vulcanization was attractive due to the low cost and wide spread industrial use of styrenics in free radical processes. The copolymers were used as the active cathode material in Li-S batteries that exhibited outstanding device performance, maintaining 489 mAh/g capacity after 1000 cycles.OAIID:RECH_ACHV_DSTSH_NO:T201611877RECH_ACHV_FG:RR00200001ADJUST_YN:EMP_ID:A004677CITE_RATE:2.952FILENAME:Online_Inverse Vulcanization of Elemental Sulfur and Styrene for Polymeric Cathodes in Li-S Batteries.pdfDEPT_NM:화학생물공학부EMAIL:[email protected]_YN:YFILEURL:https://srnd.snu.ac.kr/eXrepEIR/fws/file/3b64a4a9-231d-44af-b77f-0a56acfae91b/linkY

Elemental Sulfur and Molybdenum Disulfide Composites for Li-S Batteries with Long Cycle Life and High-Rate Capability

The practical implementation of Li−S technology has been hindered by short cycle life and poor rate capability owing to deleterious effects resulting from the varied solubilities of different Li polysulfide redox products. Here, we report the preparation and utilization of composites with a sulfur-rich matrix and molybdenum disulfide (MoS2) particulate inclusions as Li−S cathode materials with the capability to mitigate the dissolution of the Li polysulfide redox products via the MoS2 inclusions acting as “polysulfide anchors”. In situ composite formation was completed via a facile, one-pot method with commercially available starting materials. The composites were afforded by first dispersing MoS2 directly in liquid elemental sulfur (S8) with sequential polymerization of the sulfur phase via thermal ring opening polymerization or copolymerization via inverse vulcanization. For the practical utility of this system to be highlighted, it was demonstrated that the composite formation methodology was amenable to larger scale processes with composites easily prepared in 100 g batches. Cathodes fabricated with the high sulfur content composites as the active material afforded Li−S cells that exhibited extended cycle lifetimes of up to 1000 cycles with low capacity decay (0.07% per cycle) and demonstrated exceptional rate capability with the delivery of reversible capacity up to 500 mAh/g at 5 C. © 2016 American Chemical Society322

Improving the Charge Conductance of Elemental Sulfur via Tandem Inverse Vulcanization and Electropolymerization

The synthesis of polymeric materials using elemental sulfur (S₈) as the chemical feedstock has recently been developed using a process termed inverse vulcanization. The preparation of chemically stable sulfur copolymers was previously prepared by the inverse vulcanization of S₈ and 1,3-diisopropenylbenzene (DIB); however, the development of synthetic methods to introduce new chemical functionality into this novel class of polymers remains an important challenge. In this report the introduction of polythiophene segments into poly­(sulfur-<i>random</i>-1,3-diisopropenylbenzene) is achieved by the inverse vulcanization of S₈ with a styrenic functional 3,4-propylenedioxythiophene (ProDOT-Sty) and DIB, followed by electropolymerization of ProDOT side chains. This methodology demonstrates for the first time a facile approach to introduce new functionality into sulfur and high sulfur content polymers, while specifically enhancing the charge conductivity of these intrinsically highly resistive materials

The use of elemental sulfur as an alternative feedstock for polymeric materials

An excess of elemental sulfur is generated annually from hydrodesulfurization in petroleum refining processes; however, it has a limited number of uses, of which one example is the production of sulfuric acid. Despite this excess, the development of synthetic and processing methods to convert elemental sulfur into useful chemical substances has not been investigated widely. Here we report a facile method (termed ‘inverse vulcanization’) to prepare chemically stable and processable polymeric materials through the direct copolymerization of elemental sulfur with vinylic monomers. This methodology enabled the modification of sulfur into processable copolymer forms with tunable thermomechanical properties, which leads to well-defined sulfur-rich micropatterned films created by imprint lithography. We also demonstrate that these copolymers exhibit comparable electrochemical properties to elemental sulfur and could serve as the active material in Li–S batteries, exhibiting high specific capacity (823 mA h g21 at 100 cycles) and enhanced capacity retention.12622601sciescopu

Directing the Deposition of Ferromagnetic Cobalt onto Pt-Tipped CdSe@CdS Nanorods: Synthetic and Mechanistic Insights

A methodology providing access to dumbbell-tipped, metal–semiconductor and metal oxide–semiconductor heterostructured nanorods has been developed. The synthesis and characterization of CdSe@CdS nanorods incorporating ferromagnetic cobalt nanoinclusions at both nanorod termini (<i>i</i>.<i>e</i>., dumbbell morphology) are presented. The key step in the synthesis of these heterostructured nanorods was the decoration of CdSe@CdS nanorods with platinum nanoparticle tips, which promoted the deposition of metallic CoNPs onto Pt-tipped CdSe@CdS nanorods. Cobalt nanoparticle tips were then selectively oxidized to afford CdSe@CdS nanorods with cobalt oxide domains at both termini. In the case of longer cobalt-tipped nanorods, heterostructured nanorods were observed to self-organize into complex dipolar assemblies, which formed as a consequence of magnetic associations of terminal CoNP tips. Colloidal polymerization of these cobalt-tipped nanorods afforded fused nanorod assemblies from the oxidation of cobalt nanoparticle tips at the ends of nanorods <i>via</i> the nanoscale Kirkendall effect. Wurtzite CdS nanorods survived both the deposition of metallic CoNP tips and conversion into cobalt oxide phases, as confirmed by both XRD and HRTEM analysis. A series of CdSe@CdS nanorods of four different lengths ranging from 40 to 174 nm and comparable diameters (6–7 nm) were prepared and modified with both cobalt and cobalt oxide tips. The total synthesis of these heterostructured nanorods required five steps from commercially available reagents. Key synthetic considerations are discussed, with particular emphasis on reporting isolated yields of all intermediates and products from scale up of intermediate precursors

Colloidal Polymers from Dipolar Assembly of Cobalt-Tipped CdSe@CdS Nanorods

The synthesis of a modular colloidal polymer system based on the dipolar assembly of CdSe@CdS nanorods functionalized with a single cobalt nanoparticle “tip” (CoNP-tip) is reported. These heterostructured nanorods spontaneously self-assembled <i>via</i> magnetic dipolar associations of the cobalt domains. In these assemblies, CdSe@CdS nanorods were carried as densely grafted side chain groups along the dipolar NP chain to form bottlebrush-type colloidal polymers. Nanorod side chains strongly affected the conformation of individual colloidal polymer bottlebrush chains and the morphology of thin films. Dipolar CoNP-tipped nanorods were then used as “colloidal monomers” to form mesoscopic assemblies reminiscent of traditional copolymers possessing segmented and statistical compositions. Investigation of the phase behavior of colloidal polymer blends revealed the formation of mesoscopic phase separated morphologies from segmented colloidal copolymers. These studies demonstrated the ability to control colloidal polymer composition and morphology in a manner observed for classical polymer systems by synthetic control of heterostructured nanorod structure and harnessing interparticle dipolar associations

High Refractive Index Copolymers with Improved Thermomechanical Properties via the Inverse Vulcanization of Sulfur and 1,3,5-Triisopropenylbenzene

The synthesis of a novel high sulfur content material possessing improved thermomechanical properties is reported via the inverse vulcanization of elemental sulfur (S₈) and 1,3,5-triisopropenylbenzene (TIB). A key feature of this system was the ability to afford highly cross-linked, thermosetting materials, where the use of TIB as a comonomer enabled facile control of the network structure and dramatically improved the glass transition temperature (relative to our earlier sulfur copolymers) of poly­(sulfur-random-(1,3,5-triisopropenylbenzene)) (poly­(S-<i>r</i>-TIB)) materials over a range from <i>T</i> = 68 to 130 °C. This approach allowed for the incorporation of a high content of sulfur–sulfur (S–S) units in the copolymer that enabled thermomechanical scission of these dynamic covalent bonds and thermal reprocessing of the material, which we confirmed via dynamic rheological characterization. Furthermore, the high sulfur content also imparted high refractive index (<i>n</i> > 1.75) and IR transparency to poly­(S-<i>r</i>-TIB) copolymers, which offered a route to enhanced optical transmitting materials for IR thermal imaging applications with improved thermomechanical propertie

Elemental Sulfur and Molybdenum Disulfide Composites for Li–S Batteries with Long Cycle Life and High-Rate Capability

The practical implementation of Li–S technology has been hindered by short cycle life and poor rate capability owing to deleterious effects resulting from the varied solubilities of different Li polysulfide redox products. Here, we report the preparation and utilization of composites with a sulfur-rich matrix and molybdenum disulfide (MoS₂) particulate inclusions as Li–S cathode materials with the capability to mitigate the dissolution of the Li polysulfide redox products via the MoS₂ inclusions acting as “polysulfide anchors”. In situ composite formation was completed via a facile, one-pot method with commercially available starting materials. The composites were afforded by first dispersing MoS₂ directly in liquid elemental sulfur (S₈) with sequential polymerization of the sulfur phase via thermal ring opening polymerization or copolymerization via inverse vulcanization. For the practical utility of this system to be highlighted, it was demonstrated that the composite formation methodology was amenable to larger scale processes with composites easily prepared in 100 g batches. Cathodes fabricated with the high sulfur content composites as the active material afforded Li–S cells that exhibited extended cycle lifetimes of up to 1000 cycles with low capacity decay (0.07% per cycle) and demonstrated exceptional rate capability with the delivery of reversible capacity up to 500 mAh/g at 5 C

Elemental Sulfur and Molybdenum Disulfide Composites for Li–S Batteries with Long Cycle Life and High-Rate Capability

The practical implementation of Li–S technology has been hindered by short cycle life and poor rate capability owing to deleterious effects resulting from the varied solubilities of different Li polysulfide redox products. Here, we report the preparation and utilization of composites with a sulfur-rich matrix and molybdenum disulfide (MoS₂) particulate inclusions as Li–S cathode materials with the capability to mitigate the dissolution of the Li polysulfide redox products via the MoS₂ inclusions acting as “polysulfide anchors”. In situ composite formation was completed via a facile, one-pot method with commercially available starting materials. The composites were afforded by first dispersing MoS₂ directly in liquid elemental sulfur (S₈) with sequential polymerization of the sulfur phase via thermal ring opening polymerization or copolymerization via inverse vulcanization. For the practical utility of this system to be highlighted, it was demonstrated that the composite formation methodology was amenable to larger scale processes with composites easily prepared in 100 g batches. Cathodes fabricated with the high sulfur content composites as the active material afforded Li–S cells that exhibited extended cycle lifetimes of up to 1000 cycles with low capacity decay (0.07% per cycle) and demonstrated exceptional rate capability with the delivery of reversible capacity up to 500 mAh/g at 5 C