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Choudhury S, Akef M, Seifert A, Göbel M, Gruschwitz M, Matsidik R, Tegenkamp C, Sommer M. Hybrid Organosulfur Network/MWCNT Composite Cathodes for Li-S Batteries. ACS APPLIED MATERIALS & INTERFACES 2024; 16:6301-6314. [PMID: 38265883 DOI: 10.1021/acsami.3c09316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2024]
Abstract
Lithium-sulfur (Li-S) batteries hold a promising position as candidates for next-generation high-energy storage systems. Here, we combine inverse vulcanization of sulfur with multiwalled carbon nanotubes (MWCNTs) to increase the conductivity of cathode materials for Li-S batteries. The mixing process of inversely vulcanized sulfur copolymer networks with MWCNTs is aided by shear in a two-roll mill to take advantage of the soft nature of the copolymer. The high-throughput mixing method demands a source of conductive carbon that can be intimately mixed with the S copolymer, rendering MWCNTs an excellent choice for this purpose. The resulting sulfur copolymer network-MWCNTs composites were thoroughly characterized in terms of structure, chemical composition, thermal, and electronic transport properties, and finally evaluated by electrochemical benchmarking. These promising hybrids yielded electrodes with high sulfur content and demonstrate stable electrochemical performance exhibiting a specific capacity of ca. 550 mAh·gsulfur-1 (380 mAh·gelectrode-1) even after 500 charge-discharge cycles at specific current of 167 mA·g-1 (corresponds to 0.1C discharge rate), and thus are superior to melt-infiltrated reference samples.
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Affiliation(s)
- Soumyadip Choudhury
- Rubber Technology Centre, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
- Institut für Chemie, Technische Universität Chemnitz, Strasse der Nationen 62, Chemnitz 09111, Germany
| | - Mohamed Akef
- Institut für Chemie, Technische Universität Chemnitz, Strasse der Nationen 62, Chemnitz 09111, Germany
| | - Andreas Seifert
- Institut für Chemie, Technische Universität Chemnitz, Strasse der Nationen 62, Chemnitz 09111, Germany
| | - Michael Göbel
- Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Str. 6, Dresden 01069, Germany
| | - Markus Gruschwitz
- Institut für Physik, Technische Universität Chemnitz, Reichenhainer Str. 70, Chemnitz 09126, Germany
| | - Rukiya Matsidik
- Institut für Chemie, Technische Universität Chemnitz, Strasse der Nationen 62, Chemnitz 09111, Germany
- Center for Materials, Architectures and Integration of Nanomembranes (MAIN), Chemnitz University of Technology, Chemnitz 09126, Germany
| | - Christoph Tegenkamp
- Institut für Physik, Technische Universität Chemnitz, Reichenhainer Str. 70, Chemnitz 09126, Germany
| | - Michael Sommer
- Institut für Chemie, Technische Universität Chemnitz, Strasse der Nationen 62, Chemnitz 09111, Germany
- Center for Materials, Architectures and Integration of Nanomembranes (MAIN), Chemnitz University of Technology, Chemnitz 09126, Germany
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de Sousa RR, Heinze DA, Sacramento JB, Lanfredi AJC, Carastan DJ. Electrical Conductivity and In Situ SAXS Probing of Block Copolymer Nanocomposites Under Mechanical Stretching. ACS APPLIED MATERIALS & INTERFACES 2023. [PMID: 37235644 DOI: 10.1021/acsami.3c03573] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Elastomers based on block copolymers can self-organize into ordered nanoscale structures, making them attractive for use as flexible conductive nanocomposites. Understanding how ordered structures impact electrical properties is essential for practical applications. This study investigated the morphological evolution of flexible conductive elastomers based on polystyrene-b-poly(ethylene-co-butylene)-b-polystyrene (SEBS) block copolymers with aligned single- or multi-wall carbon nanotubes (SWCNTs or MWCNTs) and their electrical conductivity under large deformations. Oriented nanocomposites were obtained through injection molding and characterized using two different setups: tensile testing monitored by in situ small-angle X-ray scattering (SAXS) and tensile testing with simultaneous electrical conductivity measurements. Our findings demonstrate that structural orientation significantly influences electrical conductivity, with higher conductivity in the longitudinal direction due to the preferred orientation of carbon nanotubes. Tensile testing demonstrated that carbon nanotubes accelerate the process of realignment of the ordered structure. As a consequence, higher deformations reduced the conductivity of samples with longitudinal alignment due to the disruption of percolation contacts between nanotubes, while in samples with a transverse alignment the process promoted the formation of a new conductive network, increasing electrical conductivity.
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Affiliation(s)
- Rogerio R de Sousa
- Center for Engineering, Modeling and Applied Social Sciences, Federal University of ABC (UFABC), Av. Dos Estados, 5001, Santo André, São Paulo 09210-580, Brazil
| | - Daniel A Heinze
- Center for Engineering, Modeling and Applied Social Sciences, Federal University of ABC (UFABC), Av. Dos Estados, 5001, Santo André, São Paulo 09210-580, Brazil
| | - Joana B Sacramento
- Center for Engineering, Modeling and Applied Social Sciences, Federal University of ABC (UFABC), Av. Dos Estados, 5001, Santo André, São Paulo 09210-580, Brazil
| | - Alexandre J C Lanfredi
- Center for Engineering, Modeling and Applied Social Sciences, Federal University of ABC (UFABC), Av. Dos Estados, 5001, Santo André, São Paulo 09210-580, Brazil
| | - Danilo J Carastan
- Center for Engineering, Modeling and Applied Social Sciences, Federal University of ABC (UFABC), Av. Dos Estados, 5001, Santo André, São Paulo 09210-580, Brazil
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Influence of CNT Length on Dispersion, Localization, and Electrical Percolation in a Styrene-Butadiene-Based Star Block Copolymer. Polymers (Basel) 2022; 14:polym14132715. [PMID: 35808760 PMCID: PMC9268902 DOI: 10.3390/polym14132715] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 06/23/2022] [Accepted: 06/28/2022] [Indexed: 02/04/2023] Open
Abstract
This study followed the approach of dispersing and localizing carbon nanotubes (CNTs) in nanostructured domains of block copolymers (BCPs) by shortening the CNTs via ball milling. The aim was to selectively tune the electrical and mechanical properties of the resulting nanocomposites, e.g., for use as sensor materials. Multiwalled carbon nanotubes (MWCNTs) were ground into different size fractions. The MWCNT length distribution was evaluated via transmission electron microscopy and dynamic light scattering. The nanostructure of the BCPs and the glass transition temperatures of the PB-rich and PS phases were not strongly affected by the addition of CNTs up to 2 wt%. However, AFM and TEM investigations indicated a partial localization of the shortened CNTs in the soft PB-rich phase or at the interface of the PB-rich and PS phase, respectively. The stress-strain behavior of the solution-mixed composites differed little from the mechanical property profile of the neat BCP and was largely independent of CNT amount and CNT size fraction. Significant changes could only be observed for Young’s modulus and strain at break and may be attributed to CNT localization and small changes in morphology. For nanocomposites with unmilled CNTs, the electrical percolation threshold was less than 0.1 wt%. As the CNTs were shortened, the resistivity increased and the percolation threshold shifted to higher CNT contents. Composites with CNTs ground for 7.5 h and 13.5 h showed no bulk conductivity but significantly decreased surface resistivity on the bottom side of the films, which could be attributed to a sedimentation process of the grind and thereby highly compressed CNT agglomerates during evaporation.
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Mechanism of strengthening and toughening of a nanostructured styrene-butadiene based block copolymer by oligostyrene-modified montmorillonites. POLYMER 2021. [DOI: 10.1016/j.polymer.2020.123328] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Design, Preparation and Thermal Characterization of Polystyrene Composites Reinforced with Novel Three-Cages POSS Molecules. Molecules 2020; 25:molecules25132967. [PMID: 32605259 PMCID: PMC7412199 DOI: 10.3390/molecules25132967] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 06/18/2020] [Accepted: 06/19/2020] [Indexed: 11/24/2022] Open
Abstract
Novel polystyrene (PS)/polyhedral oligomeric silsequioxanes (POSSs) nanocomposites were designed and prepared by in situ polymerization, using, for the first time, three-cage POSS molecules. The synthesized compounds were first characterized by Fourier transform infrared spectroscopy (FTIR) and 1H NMR spectroscopy to verify the obtaining of the designed products before their thermal performance was evaluated and compared with those of pristine PS and the corresponding single-cage POSSs nanocomposites. The thermal behaviour was checked by the means of the differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Scanning electron microscopy (SEM) was also used to confirm the hypothesis about the dispersion/aggregation of the POSS molecules into the polymer matrix. The parameters chosen to evaluate the thermal stability of the investigated compounds, namely temperature at 5% of mass loss (T5%) and solid residue at 700 °C, showed a significant increase in the stability of the polymers reinforced with the three-cages POSS, in comparison to both PS and single-cage POSS reinforced PSs, which therefore turn out to be promising molecular fillers for nanocomposite production.
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