Jellyfish biomass was prepared from locally collected jellyfish (Mediterranean Sea) according to a previously published method . In short, the upper "umbrella" of the jellyfish was separated and homogenized into a white paste, diluted with ethanol, and centrifuged. The precipitate was then freeze-dried and grounded into a white powder in order to make an accurate assessment of the solid biomass content used in the anode synthesis. It is worth noting that the freeze-drying process was done for optimization only and is not necessary for any future industrialized applications, seeing as how the biomass is re-hydrated directly after.