Frontispiece: New Insights into the Operating Voltage of Aqueous Supercapacitors

Abstract

Implementation of aqueous supercapacitors (SCs) in industrial production is within reach and will be facilitated through further expanding their operating voltages. This Concept article by X. Lu et al. on page 3639 ff. deals with the recent understanding of factors relevant to the operating voltages of SCs, and novel strategies that have been identified to increase the stable voltages of SCs. From the aspect of suppressing water electrolysis, important roles of both electrolyte and electrode surface are evident.

Design and Mechanisms of Asymmetric Supercapacitors

“…Both the electrode and the electrolyte can affect the cell operating voltage. For aqueous electrolytes, the pH, i.e., the concentration of H + and OH – in the electrolyte, plays a crucial role in determining the final stable potential range of electrolytes . This is mainly because the pH has a great influence on the redox reactions and electrolyte decomposition including the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER).…”