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Accueil du site > Productions scientifiques > Faits marquants > 2015 > J. Am. Chem. Soc.-2015 : Confinement, Desolvation, And Electrosorption Effects on the Diffusion of Ions in Nanoporous Carbon Electrodes

J. Am. Chem. Soc.-2015 : Confinement, Desolvation, And Electrosorption Effects on the Diffusion of Ions in Nanoporous Carbon Electrodes

par Ali Abou-Hassan - 19 décembre 2016

Confinement, Desolvation, And Electrosorption Effects on the Diffusion of Ions in Nanoporous Carbon Electrodes, J. Am. Chem. Soc., 2015, 137 (39), pp 12627–12632

by Clarisse Pean, Barbara Daffos, Benjamin Rotenberg Pierre Levitz, Matthieu Haefele, Pierre-Louis Taberna, Patrice Simon, and Mathieu Salanne

Contact PHENIX : mathieu.salane@upmc.fr

Abstract : Supercapacitors are electrochemical devices which store energy by ion adsorption on the surface of a porous carbon. They are characterized by high power delivery. The use of nanoporous carbon to increase their energy density should not hinder their fast charging. However, the mechanisms for ion transport inside electrified nanopores remain largely unknown. Here we show that the diffusion is characterized by a hierarchy of time scales arising from ion confinement, solvation, and electrosorption effects. By combining electrochemistry experiments with molecular dynamics simulations, we determine the in-pore conductivities and diffusion coefficients and their variations with the applied potential. We show that the diffusion of the ions is slower by 1 order of magnitude compared to the bulk electrolyte. The desolvation of the ions occurs on much faster time scales than electrosorption.