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Effects of Confinement and Ion Adsorption in Ionic Liquid Supercapacitors with Nanoporous Electrodes

Lian, Zengju and Chao, Huikuan and Wang, Zhen-Gang (2021) Effects of Confinement and Ion Adsorption in Ionic Liquid Supercapacitors with Nanoporous Electrodes. ACS Nano, 15 (7). pp. 11724-11733. ISSN 1936-0851. https://resolver.caltech.edu/CaltechAUTHORS:20210709-222308605

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Abstract

We investigate the effects of pore size and ion adsorption on the room-temperature ionic liquid capacitor with nanoporous electrodes, with a focus on optimizing the capacitance and energy storage. Using a recently developed modified BSK model accounting for both ion correlations and nonelectrostatic interactions, we find that ion crowding proximate to the electrode surface induced by the spontaneous charge separation due to strong ion correlations is responsible for the anomalous increase in the capacitance with decreasing pore sizes observed in experiments. Reducing the strength of ion correlations increases the capacitance and suppresses the anomalous size dependence. For a given pore size, the capacitance peak diverges when the ion correlation strength α reaches a critical value, α_(sc,L). The capacitance peak shifts to smaller pore size as α decreases because of rapid decrease of α_(sc,L) with decreasing pore size. Asymmetric preferential ion adsorption is shown to lead to significantly enhanced energy storage close to the transition point for any pore sizes. For a given correlation strength, the energy storage is optimal at a pore size where α = α_(sc,L).


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1021/acsnano.1c02506DOIArticle
ORCID:
AuthorORCID
Lian, Zengju0000-0002-0233-8297
Chao, Huikuan0000-0001-9930-3586
Wang, Zhen-Gang0000-0002-3361-6114
Additional Information:© 2021 American Chemical Society. Received 24 March 2021. Accepted 22 June 2021. Published online 6 July 2021. Z.L. acknowledges financial support from the Fundamental Research Funds for the Provincial Universities of Zhejiang (No.SJLY2020006), Foundation of Zhejiang Educational Committee (No.Y20173 7177), and Natural Science Foundation of Ningbo (No.202003N4106). She also acknowledges support from the K.C.Wong Magna Fund in Ningbo University. Z.-G.W. acknowledges financial support from the Hong Kong Quantum AI Lab Ltd. The authors declare no competing financial interest.
Funders:
Funding AgencyGrant Number
Fundamental Research Funds for the Provincial Universities of ZhejiangSJLY2020006
Foundation of Zhejiang Educational CommitteeY20173 7177
Natural Science Foundation of Ningbo202003N4106
Ningbo UniversityUNSPECIFIED
Hong Kong Quantum AI Lab Ltd.UNSPECIFIED
Subject Keywords:ionic-liquid supercapacitors; energy storage; ion correlations; ion adsorption; confinement effects; surface transition; nanoporous
Issue or Number:7
Record Number:CaltechAUTHORS:20210709-222308605
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20210709-222308605
Official Citation:Effects of Confinement and Ion Adsorption in Ionic Liquid Supercapacitors with Nanoporous Electrodes. Zengju Lian, Huikuan Chao, and Zhen-Gang Wang. ACS Nano 2021 15 (7), 11724-11733; DOI: 10.1021/acsnano.1c02506
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:109767
Collection:CaltechAUTHORS
Deposited By: George Porter
Deposited On:12 Jul 2021 21:59
Last Modified:02 Aug 2021 17:47

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