A new type of composite supercapacitive material was developed by applying graphene nanoplatelets to non-woven carbon fiber (CNW) reinforced with polyvinyl butyral (PVB). Basic mechanical resistance of the graphene-reinforced material was examined through the tensile test. The capacitive properties of the resulting CNW/PVB/graphene composite were investigated by cyclic voltammetry and electrochemical impedance spectroscopy techniques in three electrode system, with performance compared to those of neat carbon non-woven and PVB-reinforced carbon non-woven fabrics. The specific capacitances of carbon mat, carbon mat/PVB and carbon mat/PVB/graphene, obtained from CV response registered at 50 mVs^-1, were 1.30 x 10^-4, 3.00 x 10^-4 and 3.33 x 10^-4 F cm^-2, respectively. Beyond capacitance magnitude, the graphene-modified composite also exhibited a more ideal rectangular CV shape with suppressed faradaic activity and presented a steeper low-frequency slope in Nyquist plots, indicative of improved ion diffusion kinetics and overall rate capability. These findings position the developed graphene/PVB/CNW composite as a promising, flexible electrode material for supercapacitor applications.