How chemical defects influence the charging of nanoporous carbon supercapacitors

Romain Dupuis (1, 2, 3, 4) , Pierre-Louis Valdenaire (4) , Roland Pellenq (4, 5) , Katerina Ioannidou (3, 4)

1 IEM - Institut Européen des membranes
2 ICGM - Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier
3 PMMD - Physique et Mécanique des Milieux Divisés
4 MSE 2 - Multiscale Material Science for Energy and Environment
5 GW - The George Washington University

Significance Nanoporous carbon texture makes fundamental understanding of the electrochemical processes challenging. Based on density functional theory (DFT) results, the proposed atomistic approach takes into account topological and chemical defects of the electrodes and attributes to them a partial charge that depends on the applied voltage. Using a realistic carbon nanotexture, a model is developed to simulate the ionic charge both at the surface and in the subnanometric pores of the electrodes of a supercapacitor. Before entering the smallest pores, ions dehydrate at the external surface of the electrodes, leading to asymmetric adsorption behavior. Ions in subnanometric pores are mostly fully dehydrated. The simulated capacitance is in qualitative agreement with experiments. Part of these ions remain irreversibly trapped upon discharge.

Mots clés: atomistic simulations; energy storage; supercapacitors; nanoporous carbon; ionic adsorption

Domaines: Science des matériaux [cond-mat.mtrl-sci]; Energie électrique

Romain Dupuis, Pierre-Louis Valdenaire, Roland Pellenq, Katerina Ioannidou. How chemical defects influence the charging of nanoporous carbon supercapacitors. Proceedings of the National Academy of Sciences of the United States of America, 2022, 119 (17), pp.121945119. ⟨10.1073/pnas.2121945119⟩. ⟨hal-03920236v2⟩