Kohlenstoffartige Materialien durch Pyrolyse von Polymeren und ihre Anwendung im elektrochemischen Doppelschichtkondensator

Electrochemical double-layer capacitors have, in comparison to batteries, a relatively high power density. As electrode materials mostly carbonaceous materials are used. The specific surface area of this materials should be as high as possible, because the specific capacitance is proportional to it. In this work the preparation and development of carbonaceous materials by pyrolysis of polymers were examined. As starting materials polyacrylonitrile and phenol/formaldehyd-resins (novolacs) were used. The high surface area were achieved by pyrolysis with co-substances (chemical activation) like alkali- and earth-alkaline carbonates and carbon blacks or by activation with reactive gases (physical activation) like water vapor and carbon dioxide. The electrochemical characterization were conducted in 10 molar sulfuric acid. Specific surface areas of up to 2900 m2/g and specific capacitances for single electrodes of up to 275 F/g could be obtained. A test cell with a specific capacitance of 68 F/g could be cycled over 2000 cycles, without a decrease in the capacitance. The self discharge and the electrochemical activation by shifting of the potential range were examined.


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