Abstract
Molecular dynamics (MD) simulations using the constant potential method (CPM) can provide nanoscale insight to explain and optimize supercapacitor charging dynamics and charge storage. We report CPM MD operando simulations for charging of nanoporous carbide-derived carbon supercapacitors with four distinct electrolytes, including ionic liquid (IL), mixed IL-solvent, and solvent-in-salt electrolytes. Instead of employing a coarse-grained model, we used an all-atom model for the electrolytes, allowing us to uncover the essential effects of solvents on the charging mechanism. We find that the water-in-salt electrolyte, lithium bis(trifluoromethanesulfonyl)imide / water, leads to the greatest charge storage among the studied combinations and exhibits a significantly higher integral and differential capacitance on the negative electrode, associated with a strong cation-driven charging mechanism. Our simulations also demonstrate the varying contributions of the different electrode regions to supercapacitor performance, with an especially high local capacitance (up to ∼250 F/g) within the interfacial region of the electrodes. These molecular insights provide important guidance for optimizing supercapacitor performance by carefully tuning electrode nanostructure and electrolyte composition.
| Original language | English |
|---|---|
| Article number | 143500 |
| Journal | Electrochimica Acta |
| Volume | 474 |
| DOIs | |
| State | Published - Jan 10 2024 |
Funding
This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy (DOE). The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The DOE will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan ( https://www.energy.gov/doe-public-access-plan ). X.B. and P.T.C. gratefully acknowledge the support provided by the Fluid Interface Reactions, Structures and Transport (FIRST) Center, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences. X.B. and P.T.C. also extend their appreciation to the National Energy Research Scientific Computing Center (NERSC), a U.S. Department of Energy Office of Science User Facility located at Lawrence Berkeley National Laboratory for providing computational resources. S.R.T. and D.J.S. gratefully acknowledge the Australian Research Council for its support through the Discovery program (FL19010008) and would like to thank the Pawsey Supercomputing Research Centre and the University of Queensland's Research Computing Centre (RCC) for its support in this research by providing computational resources. This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy (DOE). The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The DOE will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (https://www.energy.gov/doe-public-access-plan). During the preparation of this work the authors used ChatGPT in order to improve language and readability. After using this tool/service, the authors reviewed and edited the content as needed and take full responsibility for the content of the publication. X.B. and P.T.C. gratefully acknowledge the support provided by the Fluid Interface Reactions, Structures and Transport (FIRST) Center, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences. X.B. and P.T.C. also extend their appreciation to the National Energy Research Scientific Computing Center (NERSC) , a U.S. Department of Energy Office of Science User Facility located at Lawrence Berkeley National Laboratory for providing computational resources. S.R.T. and D.J.S. gratefully acknowledge the Australian Research Council for its support through the Discovery program ( FL19010008 ) and would like to thank the Pawsey Supercomputing Research Centre and the University of Queensland's Research Computing Centre (RCC) for its support in this research by providing computational resources.
Keywords
- Charging mechanism
- Nanoporous supercapacitor
- Performance optimization
- Solvent-in-salt electrolyte