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[[File:Electric double-layer (BMD model) NT.PNG|thumb|200px|Scheme on double layer on electrode (BMD model).<br/> 1. IHP Inner Helmholtz Layer<br/> 2. OHP Outer Helmholtz Layer<br/> 3. Diffuse layer<br/> 4. Solvated ions<br/> '''5. Specifically adsorptive ions (Pseudocapacitance)'''<br/> 6. Solvent molecule.]] |
[[File:Electric double-layer (BMD model) NT.PNG|thumb|200px|Scheme on double layer on electrode (BMD model).<br/> 1. IHP Inner Helmholtz Layer<br/> 2. OHP Outer Helmholtz Layer<br/> 3. Diffuse layer<br/> 4. Solvated ions<br/> '''5. Specifically adsorptive ions (Pseudocapacitance)'''<br/> 6. Solvent molecule.]] |
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'''Pseudocapacitors''' |
'''Pseudocapacitors''' store electrical energy [[Faradaic current|faradaically]] by electron charge transfer between [[electrode]] and [[electrolyte]]. This is accomplished through [[Capacitive deionization|electrosorption]], reduction-oxidation reactions ([[Redox|redox reactions]]), and [[intercalation (chemistry)|intercalation]] processes,<ref>Marin S. Halper, James C. Ellenbogen, Supercapacitors: A Brief Overview, MITRE, March 2006 [http://www.mitre.org/work/tech_papers/tech_papers_06/06_0667/06_0667.pdf]</ref> termed ''pseudocapacitance''.<ref name="conway1">{{Literatur|Autor=B. E. Conway|Titel=Electrochemical Supercapacitors: Scientific Fundamentals and Technological Applications|Verlag=Springer|Ort=Berlin|ISBN=0306457369|Jahr=1999|Seiten=1-8|Online={{Google books|8yvzlr9TqI0C|page=1|plainurl=yes}}}} See also [http://electrochem.cwru.edu/encycl/art-c03-elchem-cap.htm Brian E. Conway in Electrochemistry Encyclopedia: ''ELECTROCHEMICAL CAPACITORS Their Nature, Function, and Applications'']</ref> |
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A pseudocapacitor is part of an [[Electrochemistry|electrochemical]] [[capacitor]], and forms together with an [[electric double-layer capacitor]] (EDLC) to create a [[supercapacitor]]. |
A pseudocapacitor is part of an [[Electrochemistry|electrochemical]] [[capacitor]], and forms together with an [[electric double-layer capacitor]] (EDLC) to create a [[supercapacitor]]. |
Revision as of 02:40, 11 September 2015
Pseudocapacitors store electrical energy faradaically by electron charge transfer between electrode and electrolyte. This is accomplished through electrosorption, reduction-oxidation reactions (redox reactions), and intercalation processes,[1] termed pseudocapacitance.[2]
A pseudocapacitor is part of an electrochemical capacitor, and forms together with an electric double-layer capacitor (EDLC) to create a supercapacitor.
A pseudocapacitor has a chemical reaction at the electrode, unlike EDLCs where the electrical charge storage is stored electrostatically with no interaction between the electrode and the ions. An example is a redox reaction where the ion is O2+ and during charging, one electrode hosts a reduction reaction and the other an oxidation reaction. Under discharge the reactions are reversed.
Unlike batteries, in faradaic electron charge-transfer ions simply cling to the atomic structure of an electrode. This faradaic energy storage with only fast redox reactions makes charging and discharging much faster than batteries.
Double-layer capacitance and pseudocapacitance combine to produce a supercapacitor's capacitance value. Pseudocapacitance may be higher by a factor of 100 than double-layer capacitance with the same electrode surface.
References
- ^ Marin S. Halper, James C. Ellenbogen, Supercapacitors: A Brief Overview, MITRE, March 2006 [1]
- ^ B. E. Conway (1999), Electrochemical Supercapacitors: Scientific Fundamentals and Technological Applications, Berlin: Springer, pp. 1–8, ISBN 0306457369 See also Brian E. Conway in Electrochemistry Encyclopedia: ELECTROCHEMICAL CAPACITORS Their Nature, Function, and Applications