TY - JOUR
T1 - Molecular response of 1-butyl-3-methylimidazolium dicyanamide ionic liquid at the graphene electrode interface investigated by sum frequency generation spectroscopy and molecular dynamics simulations
AU - Xu, Siyun
AU - Xing, Sirui
AU - Pei, Shin Shem
AU - Ivaništšev, Vladislav
AU - Lynden-Bell, Ruth
AU - Baldelli, Steven
PY - 2015/11/10
Y1 - 2015/11/10
N2 - The ion distribution at the charged three layer graphene-ionic liquid (1-butyl-3-methylimidazolium dicyanamide, [BMIM][DCA]) interface is probed by sum frequency generation spectroscopy (SFG), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The SFG results show the presence of both [BMIM]+ cations and [DCA]- anions at the charged graphene surface, where the anion signal increased with the increasing external potential and the cation signal was little influenced by the external potential. The CV and EIS results suggest that ions form an electrically stable double layer at the charged graphene surface. Molecular dynamics simulations of [BMIM][DCA] near the charged graphene surface suggest that the interface consists of alternating layers of cations and anions that restructure with external potential variation. The experimental data can be interpreted by a double-layer model where the anionic and cationic layers interchange position with each other at the surface depending on the applied potential.
AB - The ion distribution at the charged three layer graphene-ionic liquid (1-butyl-3-methylimidazolium dicyanamide, [BMIM][DCA]) interface is probed by sum frequency generation spectroscopy (SFG), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The SFG results show the presence of both [BMIM]+ cations and [DCA]- anions at the charged graphene surface, where the anion signal increased with the increasing external potential and the cation signal was little influenced by the external potential. The CV and EIS results suggest that ions form an electrically stable double layer at the charged graphene surface. Molecular dynamics simulations of [BMIM][DCA] near the charged graphene surface suggest that the interface consists of alternating layers of cations and anions that restructure with external potential variation. The experimental data can be interpreted by a double-layer model where the anionic and cationic layers interchange position with each other at the surface depending on the applied potential.
KW - graphene-based electrodes
KW - room-temperature ionic liquids
KW - supercapacitors
UR - http://www.scopus.com/inward/record.url?scp=84947758846&partnerID=8YFLogxK
U2 - 10.1021/acs.jpcc.5b08736
DO - 10.1021/acs.jpcc.5b08736
M3 - Article
AN - SCOPUS:84947758846
VL - 119
SP - 26009
EP - 26019
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
SN - 1932-7447
IS - 46
ER -