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Title: Improving accuracy of electrochemical capacitance and solvation energetics in first-principles calculations

Here, reliable first-principles calculations of electrochemical processes require accurate prediction of the interfacial capacitance, a challenge for current computationally efficient continuum solvation methodologies. We develop a model for the double layer of a metallic electrode that reproduces the features of the experimental capacitance of Ag(100) in a non-adsorbing, aqueous electrolyte, including a broad hump in the capacitance near the potential of zero charge and a dip in the capacitance under conditions of low ionic strength. Using this model, we identify the necessary characteristics of a solvation model suitable for first-principles electrochemistry of metal surfaces in non-adsorbing, aqueous electrolytes: dielectric and ionic nonlinearity, and a dielectric-only region at the interface. The dielectric nonlinearity, caused by the saturation of dipole rotational response in water, creates the capacitance hump, while ionic nonlinearity, caused by the compactness of the diffuse layer, generates the capacitance dip seen at low ionic strength. We show that none of the previously developed solvation models simultaneously meet all these criteria. We design the nonlinear electrochemical soft-sphere solvation model which both captures the capacitance features observed experimentally and serves as a general-purpose continuum solvation model.
Authors:
ORCiD logo [1] ;  [2] ; ORCiD logo [3]
  1. Rensselaer Polytechnic Inst., Troy, NY (United States)
  2. Argonne National Lab. (ANL), Argonne, IL (United States)
  3. National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States)
Publication Date:
Grant/Contract Number:
AC02-06CH11357
Type:
Accepted Manuscript
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 148; Journal Issue: 14; Journal ID: ISSN 0021-9606
Publisher:
American Institute of Physics (AIP)
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Scientific User Facilities Division; Rensselaer Polytechnic Institute
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
OSTI Identifier:
1459895
Alternate Identifier(s):
OSTI ID: 1432740

Sundararaman, Ravishankar, Letchworth-Weaver, Kendra, and Schwarz, Kathleen A. Improving accuracy of electrochemical capacitance and solvation energetics in first-principles calculations. United States: N. p., Web. doi:10.1063/1.5024219.
Sundararaman, Ravishankar, Letchworth-Weaver, Kendra, & Schwarz, Kathleen A. Improving accuracy of electrochemical capacitance and solvation energetics in first-principles calculations. United States. doi:10.1063/1.5024219.
Sundararaman, Ravishankar, Letchworth-Weaver, Kendra, and Schwarz, Kathleen A. 2018. "Improving accuracy of electrochemical capacitance and solvation energetics in first-principles calculations". United States. doi:10.1063/1.5024219.
@article{osti_1459895,
title = {Improving accuracy of electrochemical capacitance and solvation energetics in first-principles calculations},
author = {Sundararaman, Ravishankar and Letchworth-Weaver, Kendra and Schwarz, Kathleen A.},
abstractNote = {Here, reliable first-principles calculations of electrochemical processes require accurate prediction of the interfacial capacitance, a challenge for current computationally efficient continuum solvation methodologies. We develop a model for the double layer of a metallic electrode that reproduces the features of the experimental capacitance of Ag(100) in a non-adsorbing, aqueous electrolyte, including a broad hump in the capacitance near the potential of zero charge and a dip in the capacitance under conditions of low ionic strength. Using this model, we identify the necessary characteristics of a solvation model suitable for first-principles electrochemistry of metal surfaces in non-adsorbing, aqueous electrolytes: dielectric and ionic nonlinearity, and a dielectric-only region at the interface. The dielectric nonlinearity, caused by the saturation of dipole rotational response in water, creates the capacitance hump, while ionic nonlinearity, caused by the compactness of the diffuse layer, generates the capacitance dip seen at low ionic strength. We show that none of the previously developed solvation models simultaneously meet all these criteria. We design the nonlinear electrochemical soft-sphere solvation model which both captures the capacitance features observed experimentally and serves as a general-purpose continuum solvation model.},
doi = {10.1063/1.5024219},
journal = {Journal of Chemical Physics},
number = 14,
volume = 148,
place = {United States},
year = {2018},
month = {4}
}

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