Microscopic Simulations of Electrochemical Double-Layer Capacitors

Abstract

Electrochemical double-layer capacitors (EDLCs) are devices allowing the storage or production of electricity. They function through the adsorption of ions from an electrolyte on high-surface-area electrodes and are characterized by short charging/ discharging times and long cycle-life compared to batteries. Microscopic simulations are now widely used to characterize the structural, dynamical, and adsorption properties of these devices, complementing electrochemical experiments and in situ spectroscopic analyses. In this review, we discuss the main families of simulation methods that have been developed and their application to the main family of EDLCs, which include nanoporous carbon electrodes. We focus on the adsorption of organic ions for electricity storage applications as well as aqueous systems in the context of blue energy harvesting and desalination. We finally provide perspectives for further improvement of the predictive power of simulations, in particular for future devices with complex electrode compositions.

Understanding the Electric Double-Layer Structure, Capacitance, and Charging Dynamics

“…It should be noted that this review is primarily focused on analytical and semianalytical EDL models derived from a microscopic perspective. Complementary reviews are available summarizing recent research for a better understanding of the EDL through molecular simulation and experiment. − A comprehensive discussion of conventional EDL methods is referred to the classical texts of electrochemistry (e.g., refs − ). In terms of the time frame, this review intends to cover the theoretical progress over the past decade, approximately from 2011 through 2021.…”

Nanostructural Organization in a Biredox Ionic Liquid

“…Molecular dynamics simulation can provide significant information on the structure of electrolytes for supercapacitor applications. 20 Yet, compared to previous studies in which the atomic details of the ionic species were not important for catching the charging mechanisms, 21,22 in the case of BILs they certainly play a key role. Recently, we developed polarizable force fields for the 2,2,6,6-tetramethylpiperidinyl-1-oxyl (TEMPO) and anthraquinone (AQ) groups, 23 which opens the way for the simulation of BILs.…”

MetalWalls: Simulating electrochemical interfaces between polarizable electrolytes and metallic electrodes

“…The simulation of electrochemical systems has become an important topic in chemical physics. This is mainly driven by the need for understanding the molecular mechanisms at play in devices such as batteries, 1 electrocatalysts, 2-5 supercapacitors, 6 etc. Such simulations concern bulk electrode materials 7 and electrolytes, 8 whose properties need to be well characterized and rationalized, but more and more efforts are devoted to the description of electrode/electrolyte interfaces.…”

“…9 Until recently, very little was known of the latter at the molecular scale and the only available picture was provided by theories such as the Gouy-Chapman-Stern one. 6 However, these theories are limited to simple systems, 10 and the use of concentrated electrolytes (e.g. ionic liquids) a) Electronic mail: mathieu.salanne@sorbonne-universite.fr and complex electrode materials in current electrochemical devices requires much more sophisticated techniques, among which molecular dynamics (MD) simulation is the most widespread.…”