| Full text | |
| Author(s): |
Total Authors: 3
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| Affiliation: | [1] North Dakota State Univ, Dept Phys, Fargo, ND 58108 - USA
[2] Sao Paulo State Univ UNESP, Dept Phys, Inst Biosci Humanities & Exact Sci, BR-15054000 Sao Paulo - Brazil
Total Affiliations: 2
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| Document type: | Journal article |
| Source: | Journal of Physical Chemistry C; v. 122, n. 50, p. 28537-28544, DEC 20 2018. |
| Web of Science Citations: | 3 |
| Abstract | |
We employ the quasi-chemical approximation to incorporate ion ion correlations into a lattice gas model for the electric double layer formed by a compact, size-symmetric ionic liquid. The resulting differential capacitance, which we calculate for planar and weakly curved electrodes up to first order in curvature, transitions from a bell shape to a camel-shape profile for increasing correlation strength. No such transition is present if the quasi-chemical approximation is replaced by a random mixing approximation. The bell-to-camel shape transition is, up to first order, independent of curvature. If Coulomb interactions dominate on molecular length scales, the differential capacitance has a tendency to adopt a camel-shape profile. Hence, our model offers a physical interpretation for the observed camel shape (or even U-shape) of the differential capacitance in many ionic liquids. Correlations also cause ``underscreening{''} where the characteristic decay length of the electric double layer grows with the correlation strength and can become much larger than the size of a single ion. (AU) | |
| FAPESP's process: | 17/21772-2 - Extensions of the Poisson-Boltzmann Theory to the study of the differential capacitance of an electrical double layer |
| Grantee: | Guilherme Volpe Bossa |
| Support Opportunities: | Scholarships in Brazil - Post-Doctoral |