Ultra-fine activated carbon sprinkled on epoxy resin-coated grafoil as current collector. With disposable gloves on, I press the carbon down and sprinkle some more. I leave it 24 hours ar 20 deg C. to cure. My objective is to study selected "deep eutectic solvents" as electrolytes and some gel electrolytes.
Why open factory-issued supercapacitors tof lush out the electrolytes in order to test new ones? I use a CD case and place a strip of polished aluminum in the case. I apply epoxy resin and sprinkle on ultra-fine activated carbon (see above). Strips of "porous surgical tape" are applied over the carbon when dried. This will aloow ion mobility. I also place a thin sheet of paper towel over the surface and a second strip of activated carbon-coated aluminum to complete the candidate supercap. 30% aq. phosphoric acid serves as the electrolyte. In 60 seconds, I observed 1.3V and there is no obvious short.
A range of electrolytes and gel electrolytes will be tested this way before creating cylindrical supercaps.
A sheet of grafoil being cut into test current collectors: