| Full text | |
| Author(s): |
Lemos Pereira, Guilherme Ferreira
[1]
;
Pereira, Rafael Guimaraes
[1]
;
Salanne, Mathieu
[2]
;
Amaral Siqueira, Leonardo Jose
[1]
Total Authors: 4
|
| Affiliation: | [1] Univ Fed Sao Paulo, Lab Mat Hibridos, Dept Quim, Inst Ciencias Ambientais Quim & Farmaceut, Rua Sao Nicolau 210, BR-09913030 Diadema, SP - Brazil
[2] Sorbonne Univ, Physicochim Electrolytes & Nanosyst Interfac, PHENIX, CNRS, F-75005 Paris - France
Total Affiliations: 2
|
| Document type: | Journal article |
| Source: | Journal of Physical Chemistry C; v. 123, n. 17, p. 10816-10825, MAY 2 2019. |
| Web of Science Citations: | 2 |
| Abstract | |
Phosphonium-based ionic liquids with short alkyl chains present low viscosity besides their relative high electrochemical stability. These properties make them good candidates for electrolytes of electrochemical double-layer capacitors (EDLC). We performed molecular dynamics (MD) simulations of (2-methoxyethyl)triethylphosphonium {[}P-222,P-201] his(trifluoromethanesulfonyl)imide {[}NTf2] ionic liquid confined in planar and nanoporous graphene electrode. The electrodes were simulated with a constant potential model, which allows the carbon charges to fluctuate. In spite of the ether function in the longer chain of phosphonium, the ions are organized in layers of alternated charge close to the surface of planar electrodes. The differential capacitance on the negative electrode is lower than in the positive electrode, which reflects the larger size of phosphonium cations. In nanoporous carbons, inside the pores of 8.2 angstrom, there is a monolayer of ions, whereas in larger pores (12 angstrom) there are one layer of N atom of anion and two layers of P atom of phosphonium cations. With both porous electrodes, the ions of the same charge are mostly adsorbed in front of each other across the graphene plane due to high image charges of carbon atoms of the electrode in between the ions. In the electrode of narrower pore, the capacitance varies with the applied voltage, which impacts the overall energy density of the electrode. (AU) | |
| FAPESP's process: | 17/11631-2 - CINE: computational materials design based on atomistic simulations, meso-scale, multi-physics, and artificial intelligence for energy applications |
| Grantee: | Juarez Lopes Ferreira da Silva |
| Support Opportunities: | Research Grants - Research Centers in Engineering Program |