Quantum-continuum simulation of the electrochemical response of pseudocapacitor electrodes under realistic conditions

Nathan Keilbart, Yasuaki Okada, Aion Feehan, Shin'ichi Higai, and Ismaila Dabo
Phys. Rev. B 95, 115423 – Published 20 March 2017

Abstract

Pseudocapacitors are energy-storage devices characterized by fast and reversible redox reactions that enable them to store large amounts of electrical energy at high rates. We simulate the response of pseudocapacitive electrodes under realistic conditions to identify the microscopic factors that determine their performance, focusing on ruthenia (RuO2) as a prototypical electrode material. Electronic-structure methods are used together with a self-consistent continuum solvation (SCCS) model to build a complete data set of free energies as the surface of the charged electrode is gradually covered with protons under applied voltage. The resulting data set is exploited to compute hydrogen-adsorption isotherms and charge-voltage responses by means of grand-canonical sampling, finding close agreement with experimental voltammetry. These simulations reveal that small changes on the order of 5μF/cm2 in the intrinsic double-layer capacitance of the electrode-electrolyte interface can induce variations of up to 40μF/cm2 in the overall pseudocapacitance.

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  • Received 5 January 2017
  • Revised 24 February 2017

DOI:https://doi.org/10.1103/PhysRevB.95.115423

©2017 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Nathan Keilbart1,*, Yasuaki Okada1,2, Aion Feehan1,3, Shin'ichi Higai2, and Ismaila Dabo1

  • 1Department of Materials Science and Engineering, Materials Research Institute, and Penn State Institutes of Energy and the Environment, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
  • 2Murata Manufacturing Co., Ltd., 10-1, Higashikotari 1-chome, Nagaokakyo-shi, Kyoto 617-8555, Japan
  • 3École Centrale Paris, Grande Voie des Vignes, 92290 Châtenay-Malabry Cedex, France

  • *nathan.keilbart@psu.edu

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Issue

Vol. 95, Iss. 11 — 15 March 2017

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