Testing Electrochemical Capacitors
Cyclic Voltammetry and Leakage Current
Purpose of This Note
This application note is the first part of an overview of electrochemical techniques used to test electrochemical capacitors (ECs). Electrochemical capacitors that are commercially available were tested to explain and discuss the theoretical background of cyclic voltammetry and leakage current measurement.
This application note is part one of 3. Part 2 of this note discusses techniques that are also familiar to battery technologists. Part 3 describes theory and practice of EIS measurements on capacitors.
In contrast to batteries, ECs generally store energy by highly reversible separation of electrical charge while batteries use chemical reactions. ECs consist of two high-surface electrodes immersed in a conductive liquid or polymer called the electrolyte. The electrodes are separated by an ionic-conducting separator that prevents shorts between the two electrodes.