In this programme, three types of electrodes with different
active layers were used: they were produced by (type 1) pressing
a piece of 40 ppi nickel foam, initial thickness 1.8 mm into
the plate with a pressure of 6 kg cm2 (type 2) pressing a piece
of 70 ppi reticulated vitreous carbon, initial thickness 1.5 mm
into the plate with a pressure of 6 kg cm2 (type 3) taking an
electrode of type 2 and scraping away the reticulated carbon
layer with a knife.