The company AkKo Lab LLC (Russia, Moscow) is specialized in the development and production of graphene materials. Employees of "AkKo Lab" developed and announced a thin film capacitor based on graphene oxide (GO).
Graphene oxide, by AkKo Lab LLC, was used to development this capacitor. The lateral size of graphene flakes is up to 2 microns and thickness of 1-2 nm (fig. 1 above).
The results of investigation has shown that a graphene oxide gel exhibits a good adhesion to a variety of current collectors. And graphene oxide films have the necessary mechanical properties for forming separate electrode materials. It should be noted graphene oxide electrodes require no binder additive. This feature make easy a number of technological operations during assembly of capacitors. The authors found that electrodes of this capacitor are formed in the cell as a result of the electrochemical reduction of graphene oxide for producing reduced graphene oxide (rGO) fig. 2.
Fig. 2 - Scheme of the graphene oxide electrochemical reduction in capacitor cell
Cyclic voltammogram of GO film polarization for the contact group Graphite / GO / graphite in a symmetrical cell without electrolyte is shown at fig. 3 (speed sweep voltage - 100 mV/s).
Fig. 3 - Cyclic voltammogram of GO film polarization
In conclusion, the authors have developed capacitors without electrolyte with thickness of the membrane-electrode layer up to 3 microns and a capacity - 1 mF/cm2 with an operating voltage up to 1.5 V. Thus, there is a huge potential of graphene oxide materials in the creation of ultra-thin energy storage. Capacity and self-discharge of such systems are determined primarily by the quality and uniformity of the GO film.
Source and top image: AkKo Lab LLC
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