6 results on '"Shrayesh N. Patel"'
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2. Ion Transport in 2D Nanostructured π-Conjugated Thieno[3,2
- Author
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Zhongyang, Wang, Chaoqiuyu, Wang, Yangyang, Sun, Kai, Wang, Joseph W, Strzalka, Shrayesh N, Patel, Paul F, Nealey, Christopher K, Ober, and Fernando A, Escobedo
- Abstract
Leveraging the self-assembling behavior of liquid crystals designed for controlling ion transport is of both fundamental and technological significance. Here, we have designed and prepared a liquid crystal that contains 2,5-bis(thien-2-yl)thieno[3,2
- Published
- 2022
3. Structure Control of a π-Conjugated Oligothiophene-Based Liquid Crystal for Enhanced Mixed Ion/Electron Transport Characteristics
- Author
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Joseph Strzalka, Jens Niklas, Mayank Misra, Shrayesh N. Patel, Fernando A. Escobedo, Oleg G. Poluektov, Ban Xuan Dong, Paul F. Nealey, Ziwei Liu, and Christopher K. Ober
- Subjects
Materials science ,Dopant ,General Engineering ,General Physics and Astronomy ,Ionic bonding ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Microstructure ,01 natural sciences ,0104 chemical sciences ,Ion ,chemistry ,Liquid crystal ,Chemical physics ,X-ray crystallography ,General Materials Science ,Lithium ,Thin film ,0210 nano-technology - Abstract
Developing soft materials with both ion and electron transport functionalities is of broad interest for energy-storage and bioelectronics applications. Rational design of these materials requires a fundamental understanding of interactions between ion and electron conducting blocks along with the correlation between the microstructure and the conduction characteristics. Here, we investigate the structure and mixed ionic/electronic conduction in thin films of a liquid crystal (LC) 4T/PEO4, which consists of an electronically conducting quarterthiophene (4T) block terminated at both ends by ionically conducting oligoethylenoxide (PEO4) blocks. Using a combined experimental and simulation approach, 4T/PEO4 is shown to self-assemble into smectic, ordered, or disordered phases upon blending the materials with the ionic dopant bis(trifluoromethane)sulfonimide lithium (LiTFSI) under different LiTFSI concentrations. Interestingly, at intermediate LiTFSI concentration, ordered 4T/PEO4 exhibits an electronic conductivity as high as 3.1 × 10-3 S/cm upon being infiltrated with vapor of the 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ) molecular dopant while still maintaining its ionic conducting functionality. This electronic conductivity is superior by an order of magnitude to the previously reported electronic conductivity of vapor co-deposited 4T/F4TCNQ blends. Our findings demonstrate that structure and electronic transport in mixed conduction materials could be modulated by the presence of the ion transporting component and will have important implications for other more complex mixed ionic/electronic conductors.
- Published
- 2019
- Full Text
- View/download PDF
4. Intrinsic Ion Transport Properties of Block Copolymer Electrolytes
- Author
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Daniel Sharon, Juan J. de Pablo, Shrayesh N. Patel, Ban Xuan Dong, Paul F. Nealey, Peter Bennington, Michael A. Webb, and Moshe Dolejsi
- Subjects
Materials science ,Ethylene oxide ,General Engineering ,General Physics and Astronomy ,02 engineering and technology ,Electrolyte ,Conductivity ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Lithium-ion battery ,0104 chemical sciences ,Nanomaterials ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Copolymer ,Ionic conductivity ,General Materials Science ,0210 nano-technology ,Ion transporter - Abstract
Knowledge of intrinsic properties is of central importance for materials design and assessing suitability for specific applications. Self-assembling block copolymer electrolytes (BCEs) are of great interest for applications in solid-state energy storage devices. A fundamental understanding of ion transport properties, however, is hindered by the difficulty in deconvoluting extrinsic factors, such as defects, from intrinsic factors, such as the presence of interfaces between the domains. Here, we quantify the intrinsic ion transport properties of a model BCE system consisting of poly(styrene
- Published
- 2020
5. Simultaneous Conduction of Electronic Charge and Lithium Ions in Block Copolymers
- Author
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Gregory M. Stone, Anna E. Javier, Shrayesh N. Patel, Nitash P. Balsara, and Scott Mullin
- Subjects
Time Factors ,Materials science ,Polymers ,General Physics and Astronomy ,chemistry.chemical_element ,Ionic bonding ,Thiophenes ,Lithium ,Imides ,Elementary charge ,Polyethylene Glycols ,Ion ,Electron Transport ,X-Ray Diffraction ,Lamellar phase ,Scattering, Small Angle ,Polymer chemistry ,Copolymer ,Ionic conductivity ,General Materials Science ,Conductive polymer ,Electric Conductivity ,Temperature ,General Engineering ,chemistry ,Chemical engineering - Abstract
The main objective of this work is to study charge transport in mixtures of poly(3-hexylthiophene)-b-poly(ethylene oxide) (P3HT-PEO) block copolymers and lithium bis(trifluoromethanesulfonyl) imide salt (LiTFSI). The P3HT-rich microphase conducts electronic charge, while the PEO-rich microphase conducts ionic charge. The nearly symmetric P3HT-PEO copolymer used in this study self-assembles into a lamellar phase. In contrast, the morphologies of asymmetric copolymers with P3HT as the major component are dominated by nanofibrils. A combination of ac and dc impedance measurements was used to determine the electronic and ionic conductivities of our samples. The ionic conductivities of P3HT-PEO/LiTFSI mixtures are lower than those of mixtures of PEO homopolymer and LiTFSI, in agreement with published data obtained from other block copolymer/salt mixtures. In contrast, the electronic conductivities of the asymmetric P3HT-PEO copolymers are significantly higher than those of the P3HT homopolymer. This is unexpected because of the presence of the nonelectronically conducting PEO microphase. This implies that the intrinsic electronic conductivity of the P3HT microphase in P3HT-PEO copolymers is significantly higher than that of P3HT homopolymers.
- Published
- 2012
- Full Text
- View/download PDF
6. Electrochemically oxidized electronic and ionic conducting nanostructured block copolymers for lithium battery electrodes
- Author
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Anna E. Javier, Shrayesh N. Patel, and Nitash P. Balsara
- Subjects
Battery (electricity) ,Materials science ,Polymers ,Inorganic chemistry ,General Physics and Astronomy ,chemistry.chemical_element ,Thiophenes ,Conductivity ,Lithium ,Electrochemical cell ,Polyethylene Glycols ,Electric Power Supplies ,Materials Testing ,Electrochemistry ,Ionic conductivity ,General Materials Science ,Electrodes ,Conductive polymer ,Ions ,General Engineering ,Electric Conductivity ,Equipment Design ,Lithium battery ,Nanostructures ,Equipment Failure Analysis ,chemistry ,Electrode ,Oxidation-Reduction - Abstract
Block copolymers that can simultaneously conduct electronic and ionic charges on the nanometer length scale can serve as innovative conductive binder material for solid-state battery electrodes. The purpose of this work is to study the electronic charge transport of poly(3-hexylthiophene)-b-poly(ethylene oxide) (P3HT-PEO) copolymers electrochemically oxidized with lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) salt in the context of a lithium battery charge/discharge cycle. We use a solid-state three-terminal electrochemical cell that enables simultaneous conductivity measurements and control over electrochemical doping of P3HT. At low oxidation levels (ratio of moles of electrons removed to moles of 3-hexylthiophene moieties in the electrode), the electronic conductivity (σe,ox) increases from 10(-7) S/cm to 10(-4) S/cm. At high oxidation levels, σe,ox approaches 10(-2) S/cm. When P3HT-PEO is used as a conductive binder in a positive electrode with LiFePO4 active material, P3HT is electrochemically active within the voltage window of a charge/discharge cycle. The electronic conductivity of the P3HT-PEO binder is in the 10(-4) to 10(-2) S/cm range over most of the potential window of the charge/discharge cycle. This allows for efficient electronic conduction, and observed charge/discharge capacities approach the theoretical limit of LiFePO4. However, at the end of the discharge cycle, the electronic conductivity decreases sharply to 10(-7) S/cm, which means the "conductive" binder is now electronically insulating. The ability of our conductive binder to switch between electronically conducting and insulating states in the positive electrode provides an unprecedented route for automatic overdischarge protection in rechargeable batteries.
- Published
- 2013
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