Redox enhanced energy storage in an aqueous high-voltage electrochemical capacitor with a potassium bromide electrolyte
Artikel i vetenskaplig tidskrift, 2017

This paper reports a detailed electrochemical investigation of a symmetric carbon-carbon electrochemical device with a potassium bromide (KBr) electrolyte. Below 1.6 V, KBr gives electrochemical double layer behavior. At higher voltages the Br-/Br-3 redox reaction comes into effect and enhances the energy storage. The redox-enhanced device has a high energy density, excellent stability, as well as high coulombic and energy efficiencies even at 1.9 V. More importantly, the redox contribution can be “triggered” by pre-cycling at 1.9 V, and remains beneficial after switching to 1.6 V. The triggering operation leads to a 22% increase in stored energy with negligible sacrifice of power. The intriguing behavior is accompanied by a series of complex variations including the shifts of electrode potential limits and the shift of potential of zero voltage. The electro-oxidation of the positive electrode and kinetics of the Br-/Br-3 electrode reactions are proposed to be the main causes for the triggering phenomenon. These findings provide means to improve the design and operation of devices that contain bromine, or other redox species with a comparably high electrode potential.

redox electrolyte

high voltage

electrode potential


aqueous supercapacitor


Qi Li

Elektronikmaterial och system

Mohammad Mazharul Haque

Elektronikmaterial och system

Volodymyr Kuzmenko

Elektronikmaterial och system

Namrata Ramani

University of California

Per Lundgren

Elektronikmaterial och system

Anderson David Smith

Elektronikmaterial och system

Peter Enoksson

Elektronikmaterial och system

Wallenberg Wood Science Center (WWSC)

Journal of Power Sources

0378-7753 (ISSN)

Vol. 348 219-228


Hållbar utveckling


Nanovetenskap och nanoteknik







Elektroteknik och elektronik