Carbon-based materials generated from biowaste have recently attracted interest due to their exceptional surface and conductive properties. Cow dung derived porous carbon (CDPC) with a 3D structure and linked pores is synthesised in this study, and it exhibits hierarchal pore size distribution, making it a good electrode material for supercapacitors. The surface charge contribution, on the other hand, has a significant impact on the electrodes' electrochemical performance. Furthermore, a large fraction of surface charge contribution at a high scan rate indicates quick electrochemical kinetics and hence the electrode's capacity to perform at a high charge-discharge rate. Furthermore, utilising a 1M H2SO4 electrolyte, the CDPC electrode has attained a high specific capacitance value of 210 F/g at 0.5 A/g. Furthermore, symmetrical solid-state supercapacitor device displayed high energy density of 40 Wh/kg at good power density of 907 W/kg alongwith remarkable cyclic stability rendering 92.6 % of initial capacitance retention after 10000 cgharge-discharge cycle. As a result, these findings demonstrate that investigating surface and diffusion charge contributions opens up new avenues for tuning supercapacitor electrode electrochemical performance.