Pore structure and electrochemical properties of CNT-based electrodes studied by in situ small/wide angle X-ray scattering
| Autor: | Evgeny Senokos, Rebeca Marcilla, Cleis Santos, Juan J. Vilatela, Juan Carlos Fernández-Toribio, Alvaro Ridruejo |
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| Rok vydání: | 2021 |
| Předmět: |
Materials science
FOS: Physical sciences 02 engineering and technology Carbon nanotube Applied Physics (physics.app-ph) 010402 general chemistry 7. Clean energy 01 natural sciences Capacitance law.invention law Specific surface area General Materials Science Composite material Porosity Wide-angle X-ray scattering Condensed Matter - Materials Science Renewable Energy Sustainability and the Environment Scattering Small-angle X-ray scattering Materials Science (cond-mat.mtrl-sci) Physics - Applied Physics General Chemistry 021001 nanoscience & nanotechnology 0104 chemical sciences Electrode 0210 nano-technology |
| Zdroj: | Journal of Materials Chemistry A |
| DOI: | 10.48550/arxiv.2107.12792 |
| Popis: | Macroscopic ensembles of nanocarbons, such as fibres of carbon nanotubes (CNT), are characterised by a complex hierarchical structure combining coherent crystalline regions with a large porosity arising from imperfect packing of the large rigid building blocks. Such structure is at the centre of a wide range of charge storage and transfer processes when CNT fibres are used as electrodes and/or current collectors. This work introduces a method based on wide and small-angle X-ray scattering (WAXS/SAXS) to obtain structural descriptors of CNT fibres and which enables in situ characterisation during electrochemical processes. It enables accurate determination of parameters such as specific surface area, average pore size and average bundle size from SAXS data after correction for scattering from density fluctuations arising from imperfect packing of graphitic planes. In situ and ex situ WAXS/SAXS measurements during electrochemical swelling of CNT fibre electrodes in ionic liquid provide continuous monitoring of the increase in effective surface area caused by electrostatic separation of CNT bundles in remarkable agreement with capacitance changes measured independently. Relative contributions from quantum and Helmholtz capacitance to total capacitance remaining fairly constant. The WAXS/SAXS analysis is demonstrated for fibres of either multi- and single-walled CNTs, and is expected to be generally applicable to operando studies on nanocarbon-based electrodes used in batteries, actuators and other applications |
| Databáze: | OpenAIRE |
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