A biodegradable low-cost energy storage material has been obtained by using a self-assembly nanocomposite gelatin and graphene flakes. The blends with various ratio of graphene and gelatin have been prepared and characterized by Raman spectroscopy, cyclevoltammetry measurements, chronopotentiometry measurements and impedance spectroscopy. The ability of the biopolymer to bind the water–glycerol molecules and the graphene flakes leads to an improvement of the dielectric properties with a value of the surface capacitance of about 3 orders higher (10mFcm−2) than that measured for the device based on activated carbon. An electrical oxidation at the anode contact has been observed by applying to the device a higher bias voltage. The modified active material exhibits an enhancement of the cycle stability with a further increase of the surface capacitance (100mFcm−2) and of the respective specific capacitance up to a value of about 380Fg−1.