I have tested 'graphene powder' as an electrode material for supercap. The graphene power was coated on the commercial carbon paper as current collector. Electrolyte is 0.5 M KOH and referece electrode is Ag/AgCl or Hg/HgO. In the potential window of 1 V, the bubbles were observed on the surface of Pt mesh. How can I remove the bubbles?
I guess water or electroylte decomposition in that voltage is the reason for the bubble,handling in an extreme inert atm may be a solution.
Thank you for your answers. I have one more question. How can I find optimized potential range for my sample? I have tried to change the potential range within 1 V [due to aqueous solution], However, I have never obtained an rectangular shaped graph. Thanks all reply in advance.
If you want to obtain rectangular curve ,you better use some neutral electrolyte rather than KOH,if you didnt get the rectangular shape, minimize the potential range,then try again.
Dear Park! You should use higher surface for counter electrode in order to answer to working electrode. Sometimes You can see bubbles, unless counter electrode has enough size. (Counter must be enough surface area according to working electrode). To optimize potential range, you can use CV (cyclic Voltametry) gradually both by changing potantial range and by trying with different electrolytes or pH. it may be better idea .
I think graphene is negative electrode material, so proper three electrode cell configuration is more important, in order to get the rectangular shape of CV curve or linear triangular nature of galvanostatic charge-discharge curve.
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