Understanding the electrochemistry of “water-in-salt” electrolytes: basal plane highly ordered pyrolytic graphite as a model system

Abstract

The stability of water-in-salt electrolyte systems is investigated using highly concentrated solutions of KF(aq) with graphite as a model system.

Controlling the flake size of bifunctional 2D WSe2 nanosheets as flexible binders and supercapacitor materials

“…13 However, graphene stores the charge through a build-up in the electrical double layer, which can limit the energy density of the energy storage. 4,14,15 There are many 2D materials apart from graphene that can be used, such as transition metal dichalcogenides (TMDs, also called MX 2 ), 16 which provide outstanding electrochemical properties in terms of energy storage. 17 This is due to the charge storage mechanism of these materials based on both faradaic and non-faradaic processes.…”

Physicochemical and Electrochemical Properties of Water‐in‐Salt Electrolytes

“…The cut‐off criterion (e. g., 1 vs. 100 μA cm −2 ) could lead to huge ESW measurement differences, potentially explaining how some of the studies could not perform within the determined ESW (cycling stability/coulombic efficiency) as one might have expected [94] . In order to avoid these discrepancies, electrochemical impedance spectroscopy (EIS) measurements have been used to find the potential range in which no faradaic reaction (mainly hydrogen and oxygen evolutions) happen and the impedance spectrum is only capacitive in nature [95] …”

“…Finally, the electron transfer properties of redox probes could be influenced by the nature of water‐in‐salt and the structure of the electrified interfaces. Preliminary investigations with model redox systems such as ferricyanide/ferrocyanide in water‐in‐salt electrolytes have been recently reported [75,95] and can serve as basis for further studies involving electron transfer processes within the electrochemical stability window. In summary, despite interest of water‐in‐salt electrolytes for electrochemical energy storage, detailed fundamental studies are needed to get a better understanding of this new class of materials.…”

First Scalable 18650 Aqueous-based Supercapacitors Using Hydrophobicity of Anti-corrosion Graphite Passivation Layer

“…1 Additionally, they provide higher power density (>10 kW kg -1 ) than those using organic electrolytes, 2 ionic liquids, 3 and water-in-salt electrolytes due to the high ionic conductivity of aqueous solutions. 4,5 However, one of the key challenges limiting practical and commercial aqueous-based supercapacitors is a corrosion issue of metal current collectors in aqueousbased electrolytes. Recently, the surface modi cation of metals with carbon materials (i.e., graphite, 6,7 graphene, 8,9 and carbon nanotubes 10 ) has attracted great attention for many other applications.…”