Abstract
In this work, we investigate the effect of the cation structure on the structure and dynamics of the electrode–electrolyte interface using molecular dynamics simulations. A constant potential method is used to capture the behaviour of 1-ethyl-3-methylimidazolium bis (trifluoromethane)sulfonimide ([Cmim][NTf]) and butyltrimethylammonium bis(trifluoromethane) sulfonimide ([N][NTf]) ionic liquids at varying potential differences applied across the supercapacitor. We find that the details of the structure in the electric double layer and the dynamics differ significantly, yet the charge profile and capacitance do not vary greatly. For the systems considered, charging results in the rearrangement and reorientation of ions within ∼1 nm of the electrode rather than the diffusion of ions to/from the bulk region. This occurs on timescales of (10 ns) for the ionic liquids considered, and depends on the viscosity of the fluid.
Highlights
In today’s modern society, a wide range of electronic products, including mobile phones, laptops, cameras, pacemakers, hearing aids and electric vehicles, heavily rely on the energy storage technology behind them
A striking difference between these two systems is that no chemical reactions occur on the electrodes of an electric double-layer supercapacitors (EDLSC) and energy is stored via ion adsorption on the electrodes, whereas energy is generated through chemical reactions involving the electrodes of a battery
We investigate the effect of the cation structure and dynamics on the layering in the electrode-to-electrolyte interface using molecular dynamics (MD) simulations by studying two ionic liquid electrolytes with planar graphene electrodes
Summary
In today’s modern society, a wide range of electronic products, including mobile phones, laptops, cameras, pacemakers, hearing aids and electric vehicles, heavily rely on the energy storage technology behind them. The mobility of ions, which are related to the electrolyte viscosity or diffusivity, plays a role, on the charge/discharge rate Computer simulations, such as molecular dynamics (MD) simulations, can be used to gain an insight into the atomic-level formation of layers in EDLs. In MD simulations, two techniques have been commonly used to model the charged electrodes: a fixed charge method (FCM) and a constant potential method (CPM) [12,13,14]. Noh and Jung [15] studied the 1-ethyl-3-methylimidazolium thiocyanate ([C2mim][SCN]) IL confined between graphene electrodes These authors applied various potential difference across the simulation cell, with values between 0 and 4 V, to investigate the charge/discharge dynamics of the supercapacitor at 350 K. We investigated the patterns of ILs that form on the electrode surface with varied applied potential and determined the capacitance of the supercapacitors
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
