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Carbons with Regular Pore Geometry Yield Fundamental Insights into Supercapacitor Charge Storage

Liu, Yifei Michelle and Merlet, Céline and Smit, Berend Carbons with Regular Pore Geometry Yield Fundamental Insights into Supercapacitor Charge Storage. (2019) ACS Central Science, 5 (11). 1813-1823. ISSN 2374-7943

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Official URL: https://doi.org/10.1021/acscentsci.9b00800

Abstract

We conduct molecular dynamics simulations of electrical double-layer capacitors (EDLCs) using a library of ordered, porous carbon electrode materials called zeolite templated carbons (ZTCs). The well-defined pore shapes of the ZTCs enable us to determine the influence of pore geometry on both charging dynamics and charge storage mechanisms in EDLCs, also referred to as supercapacitors. We show that charging dynamics are negatively correlated with the pore-limiting diameter of the electrode material and display signatures of both progressive charging and ion trapping. However, the equilibrium capacitance, unlike charging dynamics, is not strongly correlated to commonly used, purely geometric descriptors such as pore size. Instead, we find a strong correlation of capacitance to the charge compensation per carbon (CCpC), a descriptor we define in this work as the average charge of the electrode atoms within the coordination shell of a counterion. A high CCpC indicates efficient charge storage, as the strong partial charges of the electrode are able to screen counterion charge, enabling higher ion loading and thus more charge storage within the electrode at a fixed applied voltage. We determine that adsorption sites with a high CCpC tend to be found within pockets with a smaller radius of curvature, where the counterions are able to minimize their distance with multiple points on the electrode surface, and therefore induce stronger local partial charges.

Item Type:Article
Additional Information:This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposes
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Other partners > Collège de France (FRANCE)
Other partners > Ecole Nationale Supérieure de Chimie de Paris - ENSCP (FRANCE)
Other partners > Ecole Polytechnique Fédérale de Lausanne - EPFL (SWITZERLAND)
Other partners > Ecole Nationale Supérieure de Chimie de Montpellier - ENSCM (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - INPT (FRANCE)
Other partners > Institut polytechnique de Grenoble (FRANCE)
Other partners > Sorbonne Université (FRANCE)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UPS (FRANCE)
Other partners > Université de Nantes (FRANCE)
Other partners > Université de Picardie Jules Verne (FRANCE)
Other partners > University of California - UC Berkeley (USA)
Other partners > Université de Pau et des Pays de l'Adour - UPPA (FRANCE)
Other partners > Université de Haute Alsace - UHA (FRANCE)
Other partners > Université de Montpellier (FRANCE)
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Deposited By: cirimat webmestre
Deposited On:02 Dec 2019 11:02

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