Solid-state NMR studies of supercapacitors

Griffin, John Matthew and Forse, Alexander C. and Grey, Clare P. (2016) Solid-state NMR studies of supercapacitors. Solid State Nuclear Magnetic Resonance, 74-75. pp. 16-35. ISSN 0926-2040

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Abstract

Electrochemical double-layer capacitors, or ‘supercapacitors’ are attracting increasing attention as high-power energy storage devices for a wide range of technological applications. These devices store charge through electrostatic interactions between liquid electrolyte ions and the surfaces of porous carbon electrodes. However, many aspects of the fundamental mechanism of supercapacitance are still not well understood, and there is a lack of experimental techniques which are capable of studying working devices. Recently, solid-state NMR has emerged as a powerful tool for studying the local environments and behaviour of electrolyte ions in supercapacitor electrodes. In this Trends article, we review these recent developments and applications. We first discuss the basic principles underlying the mechanism of supercapacitance, as well as the key NMR observables that are relevant to the study of supercapacitor electrodes. We then review some practical aspects of the study of working devices using ex situ and in situ methodologies and explain the key advances that these techniques have allowed on the study of supercapacitor charging mechanisms. NMR experiments have revealed that the pores of the carbon electrodes contain a significant number of electrolyte ions in the absence of any charging potential. This has important implications for the molecular mechanisms of supercapacitance, as charge can be stored by different ion adsorption/desorption processes. Crucially, we show how in situ NMR experiments can be used to quantitatively study and characterise the charging mechanism, with the experiments providing the most detailed picture of charge storage to date, offering the opportunity to design enhanced devices. Finally, an outlook for future directions for solid-state NMR in supercapacitor research is offered.

Item Type:
Journal Article
Journal or Publication Title:
Solid State Nuclear Magnetic Resonance
Additional Information:
This is the author’s version of a work that was accepted for publication in Solid State Nuclear Magnetic Resonance. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Solid State Nuclear Magnetic Resonance, 74-75, 2016 DOI: 10.1016/j.ssnmr.2016.03.003
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/3100/3108
Subjects:
ID Code:
78674
Deposited By:
Deposited On:
09 May 2016 11:00
Refereed?:
Yes
Published?:
Published
Last Modified:
20 Sep 2020 03:23