Pseudocapacitance

Simplified view of a double-layer with specifically adsorbed ions which have submitted their charge to the electrode to explain the faradaic charge-transfer of the pseudocapacitance.

Pseudocapacitance is the electrochemical storage of electricity in an electrochemical capacitor known as a pseudocapacitor. This faradaic charge transfer originates by a very fast sequence of reversible faradaic redox, electrosorption or intercalation processes on the surface of suitable electrodes.[1][2][3] Pseudocapacitance is accompanied by an electron charge-transfer between electrolyte and electrode coming from a de-solvated and adsorbed ion. One electron per charge unit is involved. The adsorbed ion has no chemical reaction with the atoms of the electrode (no chemical bonds arise[4]) since only a charge-transfer takes place.

Faradaic pseudocapacitance only occurs together with static double-layer capacitance. Pseudocapacitance and double-layer capacitance both contribute inseparably to the total capacitance value.

The amount of pseudocapacitance depends on the surface area, material and structure of the electrodes. Pseudocapacitance may contribute more capacitance than double-layer capacitance for the same surface area by 100x.[1]

The amount of electric charge stored in a pseudocapacitance is linearly proportional to the applied voltage. The unit of pseudocapacitance is farad.

  1. ^ a b B. E. Conway (1999), Electrochemical Supercapacitors: Scientific Fundamentals and Technological Applications (in German), Berlin: Springer, pp. 1–8, ISBN 978-0306457364 see also Brian E. Conway in Electrochemistry Encyclopedia: ELECTROCHEMICAL CAPACITORS Their Nature, Function, and Applications Archived 2012-04-30 at the Wayback Machine
  2. ^ Marin S. Halper, James C. Ellenbogen (March 2006). Supercapacitors: A Brief Overview (PDF) (Technical report). MITRE Nanosystems Group. Archived from the original (PDF) on 2014-02-01. Retrieved 2014-01-20.
  3. ^ E. Frackowiak, F. Beguin: Carbon Materials For The Electrochemical Storage Of Energy In Capacitors. In: CARBON. 39, 2001, S. 937–950 (PDF[permanent dead link]) E. Frackowiak, K. Jurewicz, S. Delpeux, F. Béguin: Nanotubular Materials For Supercapacitors. In: Journal of Power Sources. Volumes 97–98, Juli 2001, S. 822–825, doi:10.1016/S0378-7753(01)00736-4.
  4. ^ Garthwaite, Josie (12 July 2011). "How ultracapacitors work (and why they fall short)". Earth2Tech. GigaOM Network. Archived from the original on 22 November 2012. Retrieved 23 April 2013.