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Park S, McDaniel JG. Generalized Helmholtz model describes capacitance profiles of ionic liquids and concentrated aqueous electrolytes. J Chem Phys 2024; 160:164709. [PMID: 38651812 DOI: 10.1063/5.0194360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Accepted: 03/21/2024] [Indexed: 04/25/2024] Open
Abstract
In this work, we propose and validate a generalization of the Helmholtz model that can account for both "bell-shaped" and "camel-shaped" differential capacitance profiles of concentrated electrolytes, the latter being characteristic of ionic liquids. The generalization is based on introducing voltage dependence of both the dielectric constant "ϵr(V)" and thickness "L(V)" of the inner Helmholtz layer, as validated by molecular dynamics (MD) simulations. We utilize MD simulations to study the capacitance profiles of three different electrochemical interfaces: (1) graphite/[BMIm+][BF4-] ionic liquid interface; (2) Au(100)/[BMIm+][BF4-] ionic liquid interface; (3) Au(100)/1M [Na+][Cl-] aqueous interface. We compute the voltage dependence of ϵr(V) and L(V) and demonstrate that the generalized Helmholtz model qualitatively describes both camel-shaped and bell-shaped differential capacitance profiles of ionic liquids and concentrated aqueous electrolytes (in lieu of specific ion adsorption). In particular, the camel-shaped capacitance profile that is characteristic of ionic liquid electrolytes arises simply from combination of the voltage-dependent trends of ϵr(V) and L(V). Furthermore, explicit analysis of the inner layer charge density for both concentrated aqueous and ionic liquid double layers reveal similarities, with these charge distributions typically exhibiting a dipolar region closest to the electrode followed by a monopolar peak at larger distances. It is appealing that a generalized Helmholtz model can provide a unified description of the inner layer structure and capacitance profile for seemingly disparate aqueous and ionic liquid electrolytes.
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Affiliation(s)
- Suehyun Park
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, USA
| | - Jesse G McDaniel
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, USA
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Shen G, Zhang D, Hu Y, Zhang X, Zhou F, Qian Y, Lu X, Ji X. Effect of surface roughness on partition of ionic liquids in nanopores by a perturbed-chain SAFT density functional theory. J Chem Phys 2022; 157:014701. [DOI: 10.1063/5.0098924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In this work, the distribution and partition behavior of ionic liquids (ILs) in nanopores with rough surfaces are investigated by a two-dimensional (2D) classical density functional theory (DFT) model. The model is consistent with the equation of state (EoS) that combines the perturbed-chain statistical associating fluid theory (PC-SAFT) and the mean spherical approximation (MSA) theory for bulk fluid. Its performance is verified by comparing the theoretical predictions to the results from molecular simulations. The fast Fourier transform (FFT) and a hybrid iteration method of Picard iteration and Anderson mixing are used to efficiently obtain the solution of density profile for the sizeable 2D system. The molecular parameters for IL-ions are obtained by fitting to experimental densities of bulk ILs. The model is applied to study the structure and partition of the ILs in nanopores. The results show that the peak of the density profile of counterions near a rough surface is much higher than that near a smooth surface. The adsorption of counterion and removal of coions are enhanced by surface roughness. Thus the nanopore with rough surfaces can store more charge. At low absolute surface potential, the partition coefficient for ions on rough surfaces is lower than that on smooth surfaces. At high absolute surface potential, increasing surface roughness leads to an increase in partition coefficient for counterions and a decrease in partition coefficient for coions.
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Affiliation(s)
| | - Di Zhang
- Huaiyin Institute of Technology, China
| | - Yongke Hu
- Huaiyin Institute of Technology, China
| | | | - Feng Zhou
- Huaiyin Institute of Technology, China
| | | | - Xiaohua Lu
- Department of Chemical Engineering, Nanjing University of Technology, China
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Hydrogen Bond Donors Influence on the Electrochemical Performance of Composite Graphene Electrodes/Deep Eutectic Solvents Interface. ELECTROCHEM 2022. [DOI: 10.3390/electrochem3010009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The development of energy storage devices with better performance relies on the use of innovative materials and electrolytes, aiming to reduce the carbon footprint through the screening of low toxicity electrolytes and solvent-free electrode design protocols. The application of nanostructured carbon materials with high specific surface area, to prepare composite electrodes, is being considered as a promising starting point towards improving the power and energy efficiency of energy storage devices. Non-aqueous electrolytes synthesized using greener approaches with lower environmental impact make deep eutectic solvents (DES) promising alternatives for electrochemical energy storage and conversion applications. Accordingly, this work proposes a systematic study on the effect of the composition of DES containing a diol and an amide as HBD (hydrogen bond donor: 1,2-propylene glycol and urea), on the electrochemical performance of graphene and graphite composite electrodes/DES electrolyte interface. Glassy carbon (GC) was selected as the bare electrode material substrate to prepare the composite formulations since it provides an electrochemically reproducible surface. Gravimetric capacitance was measured for commercial graphene and commercial graphite/GC composite electrodes in contact with choline chloride, complexed with 1,2-propylene glycol, and urea as the HBD in 1:2 molar ratio. The electrochemical stability was followed by assessing the charge/discharge curves at 1, 2, and 4 A g−1. For comparison purposes, a parallel study was performed using commercial graphite. A four-fold increase in gravimetric capacitance was obtained when replacing commercial graphite (1.70 F g−1) by commercial graphene (6.19 F g−1) in contact with 1,2-propylene glycol-based DES. When using urea based DES no significant change in gravimetric capacitance was observed when commercial graphite is replaced by commercial graphene.
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Shen G, Sun Y, Wang Y, Lu X, Ji X. Interfacial structure and differential capacitance of ionic liquid/graphite interface: A perturbed-chain SAFT density functional theory study. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2020.113199] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Electric double layer structure and capacitance of imidazolium-based ionic liquids with FSI− and Tf− anions at graphite electrode by molecular dynamic simulations. J Electroanal Chem (Lausanne) 2019. [DOI: 10.1016/j.jelechem.2019.113452] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Patil SK, Bhise SC, Awale DV, Vadiyar MM, Patil SA, Gunjal DB, Kolekar GB, Ghorpade UV, Kim JH, Kolekar SS. “Seems Bad Turns Good” – traces of precursor in dicationic ionic liquid lead to analytical application. RESEARCH ON CHEMICAL INTERMEDIATES 2018. [DOI: 10.1007/s11164-018-3489-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Ruzanov A, Lembinen M, Jakovits P, Srirama SN, Voroshylova IV, Cordeiro MNDS, Pereira CM, Rossmeisl J, Ivaništšev VB. On the thickness of the double layer in ionic liquids. Phys Chem Chem Phys 2018; 20:10275-10285. [DOI: 10.1039/c7cp07939g] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The Au(111)|BF4−interface model in which BF4−reorients and spontaneously dissociates at surface coverageθ= 1/3.
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Affiliation(s)
- Anton Ruzanov
- Institute of Chemistry, University of Tartu
- 50411 Tartu
- Estonia
| | - Meeri Lembinen
- Institute of Physics, University of Tartu
- 50411 Tartu
- Estonia
| | - Pelle Jakovits
- Mobile & Cloud Computing Laboratory, Institute of Computer Science, University of Tartu
- 50409 Tartu
- Estonia
| | - Satish N. Srirama
- Mobile & Cloud Computing Laboratory, Institute of Computer Science, University of Tartu
- 50409 Tartu
- Estonia
| | - Iuliia V. Voroshylova
- Departamento de Química e Bioquímica, LAQV@REQUIMTE, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre
- Porto
- Portugal
- Departamento de Química e Bioquímica, CIQ(UP), Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre
- Porto
| | - M. Natália D. S. Cordeiro
- Departamento de Química e Bioquímica, LAQV@REQUIMTE, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre
- Porto
- Portugal
| | - Carlos M. Pereira
- Departamento de Química e Bioquímica, CIQ(UP), Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre
- Porto
- Portugal
| | - Jan Rossmeisl
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, København
- Denmark
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The electrochemical interface of Ag(111) in 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ionic liquid—A combined in-situ scanning probe microscopy and impedance study. Electrochim Acta 2016. [DOI: 10.1016/j.electacta.2015.12.227] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Insight on the effect of surface modification by carbon materials on the Ionic Liquid Electric Double Layer Charge Storage properties. Electrochim Acta 2015. [DOI: 10.1016/j.electacta.2015.06.142] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Affiliation(s)
- Robert Hayes
- Discipline
of Chemistry, The University of Newcastle, NSW 2308, Callaghan, Australia
| | - Gregory G. Warr
- School
of Chemistry, The University of Sydney, NSW 2006, Sydney, Australia
| | - Rob Atkin
- Discipline
of Chemistry, The University of Newcastle, NSW 2308, Callaghan, Australia
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Costa R, Pereira CM, Silva AF. Charge Storage on Ionic Liquid Electric Double Layer: The Role of the Electrode Material. Electrochim Acta 2015. [DOI: 10.1016/j.electacta.2015.02.180] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Measurements of the potential of zero charge in room temperature ionic liquids at Ag electrode by surface-enhanced Raman spectroscopy. J Electroanal Chem (Lausanne) 2014. [DOI: 10.1016/j.jelechem.2014.06.021] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Vatamanu J, Xing L, Li W, Bedrov D. Influence of temperature on the capacitance of ionic liquid electrolytes on charged surfaces. Phys Chem Chem Phys 2014; 16:5174-82. [DOI: 10.1039/c3cp54705a] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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