<p>Porous carbon has long been a research focus in the field of supercapacitor electrodes. In this work, we aim to adjust the porous structure and surface oxygen-containing groups (or oxygen heteroatoms) by optimizing the ratio of acrylamide monomer to polyvinyl alcohol in the hydrogel system, followed by an activation process. As the ratio of acrylamide monomer to polyvinyl alcohol varies, the resulting materials maintain a porous carbon morphology with no significant changes. The optimized sample, PCK-1:5, exhibits a high specific capacitance of 396 F g⁻¹ at 0.5 A g⁻¹, which is much higher than that of PC-1:5 (29.6 F g⁻¹) before activation. Furthermore, the PCK-1:5//PCK-1:5 supercapacitor device achieves a high energy density of 16.5 Wh kg⁻¹ along with a long cycle life.</p>