Hyper-cross-linked (HCL) styrene-based resins filled with graphite nanoplatelets (GNP) at two different GNP concentrations were synthesized by means of a facile and efficient modified Davankov procedure. Firstly, the synthesized samples were broadly characterized by means of transmission electron microscopy (TEM) and thermogravimetric analysis (TG-DTG), and their BET surface areas were also evaluated. Afterwards, capacitance performance of the synthesized electrode materials was investigated by cyclic voltammetry in a 0.5 M H2SO4 solution at different scan rates, also exploring the effects of GNPs concentration. The synthesized materials showed high specific capacitances (Csp) of 52.1 F/g and 60.4 F/g, values obtained with a concentration of the GNP fillers equal to 7.5 wt% and 10 %wt respectively. Moreover, the synthesized nanocomposites exhibited a high capacitance retention up to 97 % over 10000 cycles, thus confirming their excellent performances as robust EDLC electrode materials.