Electrochemical stability of steel, Ti, and Cu current collectors in water-in-salt electrolyte for green batteries and supercapacitors

Abstract

The electrochemical behaviour of steel, copper, and titanium current collectors was studied in aqueous solutions of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) at various concentrations, from 0.5 up to 20 m. As the concentration of the electrolyte increases, the electrochemical window of water stability widens according to the “water-in-salt” concept. The metal grids have been studied electrochemically, both under anodic and cathodic conditions, by means of cyclic voltammetry and chronoamperometry. Subsequently, a microscopic analysis with SEM and compositional analysis with XPS was carried out to evaluate the surface modifications following electrochemical stress. We found that copper is not very suitable for this kind of application, while titanium and steel showed interesting behaviour and large electrochemical window.

Nanohollow Titanium Oxide Structures on Ti/FTO Glass Formed by Step-Bias Anodic Oxidation for Photoelectrochemical Enhancement

“…First, CV curves without UV illumination presented the typical behaviors, which could be used to check the surface material and its oxidation and reduction peaks, as shown in Figure 8 a. The sample with the FTO surface had a typical CV curve and clear peaks, and the samples with the Ti or ALD TiO 2 surfaces both showed no oxidation nor reduction peaks, which matched the results reported in the literature [ 44 , 45 ]. For the CBAO-Ti50n sample, the peak currents for oxidation and reduction both showed similar behaviors but with smaller values than those obtained for the FTO sample.…”

An All‐Fluorinated Electrolyte Toward High Voltage and Long Cycle Performance Dual‐Ion Batteries

“…To evaluate the anodic stability of electrolytes against oxidation under high voltage, linear sweep voltammetry (LSV) on an inert working electrode of titanium was performed, as presented in Figure 1b. [12] A decomposition potential of ≈5.0 V is observed for 1 m LiPF 6 -EMC electrolyte, whereas FEC and FEMC effectively expand the electrochemical stability window up to 5.5 V, which is well consistent with the DFT calculation. [13] Owing to the excellent anti-oxidation stability, FEC and FEMC solvents are therefore expected to have lower reactivity with the cathode under high voltage.…”

Circumneutral concentrated ammonium acetate solution as water-in-salt electrolyte

“…On the contrary, for titanium it increases to +2.60 V vs SCE. Such a wide anodic range of titanium has been already observed in LiTFSI-based WISE and attributed to the formation of a surface Ti-oxide film that partially passivates the grids and hinders electrolyte decomposition [38,39]. Accordingly, using titanium and 26.4 m AmAc an outstanding ESW of 3.4 V should be feasible.…”