Open AccessHow chemical defects influence the charging of nanoporous carbon supercapacitors
Author(s) -
Romain Dupuis,
Pierre-Louis Valdenaire,
Roland J.M. Pellenq,
Katerina Ioannidou
Publication year - 2022
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.2121945119
Subject(s) - supercapacitor , nanoporous , ion , chemical physics , electrode , materials science , carbon fibers , adsorption , capacitance , electrochemistry , surface charge , charge (physics) , density functional theory , nanotechnology , charge density , ionic bonding , chemical engineering , chemistry , composite material , computational chemistry , physics , organic chemistry , quantum mechanics , composite number , engineering
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.