I have prepared activated carbon/iron oxide nanocomposites with different shape of metal oxide. i.e. spherical and rod shape of metal oxide nanoparticles were encapsulated carbon material. I have measured the specific capacitance for the same samples. Rod shape particles are less capacitance values than spherical shaped particles.
So give me an idea about relation between shape and specific capacitance.
Many thanks in advance!
Dear Dr. Ranjithkumar:
There is a wide set of particular parameters that should be take in account to a functional comparision between specific capacitance of two nanocomposite powder.
But, if both carbonaceous structure are considered equals, thus the changing of capacitance can be addessed to oxide particle morphology.
The great values of capacitance value of kind of nanocomposite can be assigned to the interface carbon/surface oxide. In this sense, the highest capacitance value can be indexed to the powder with highest surface area (BET surface area).
Also, it is possible that changing in the valence of cations components gives rise some modification for capacitance, this find should be verifyed.
Particles with high aspect ratio can present some preferential crystallographic plane, which can not be favorable to the charging phenomenon.
Kind regards
Marcos Nobre
Dear Dr. Ranjithkumar, I would like to shortly comment that a possibly higher conductivity and a higher specific surface area of active material(herein, the metal oxide) are important for electrochemical capacitors. Thus, you would better check out what structure of nanocomposte is efficient to keep higher conductivity and specific surface area.
Dear Dr. Ranjithkumar
First you should make sure what are the changes in the porous structure of the hosting carbon material, caused by the impregnation of the oxides. One possibility is that the Rod Shape are either more destructive or clogging the porous structure.
Second, you should make sure to have similar loading amounts for "fare" normalization.
The kinetics of adsorption can also be highly important in your case, you can test adsorption kinetics in gaseous phase and not only BET.
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