Electrochemical behaviour of hybrid devices based on NaSO and RbSO neutral aqueous electrolytes and carbon electrodes within wide cell potential region.

Focused ion beam scanning electron microscopy (FIB-SEM), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller gas adsorption methods have been used for the characterisation of physical properties of microporous carbide-derived carbon electrodes, prepared from MoC at 600 °C (noted as MoC-CDC) before and after electrochemical tests conducted within a very wide two-electrode cell potential region. Cyclic voltammetry, constant current charge/discharge and impedance data have been analysed to establish the electrochemical characteristics of the hybrid devices consisting of the 1 M NaSO and 1 M RbSO aqueous electrolytes and MoC-CDC electrodes within the very wide cell potential region (Δ E ≤ 2.4 V). The influence of cation chemical composition on the electrochemical characteristics of supercapacitors/electrochemical hybrid devices has been analysed. The complex kinetics behaviour of completed devices (adsorption, blocking adsorption and intercalation of Na and Rb ions; faradic and mass transfer; gas adsorption; etc.) has been established at Δ E ≥ 1.5 V. At least three different characteristic time constants dependent on the electrolyte cation composition and cell potential applied have been established. [ABSTRACT FROM AUTHOR]