A simple fabrication of a porous carbon electrode material by one-step carbonization and activation of a poly(vinyl alcohol) hydrogel

Abstract

The preparation of porous carbon materials via the carbonization of organic polymer materials is an effective method for controllably fabricating high-performance electrodes for supercapacitors. In this study, porous carbon materials were prepared by carbonizing poly(vinyl alcohol) hydrogel. The poly(vinyl alcohol) hydrogel was synthesized through a simple freeze–thaw cross-linking process. Compared with directly carbonizing poly(vinyl alcohol) powder, the carbonization of the poly(vinyl alcohol) hydrogel produced an excellent hierarchical pore structure. In the sample preparation stage, an integrated carbonization-activation process was adopted. The maximum specific surface area of the obtained porous carbon was 1724.7 m² g⁻¹. The electrochemical performance of the obtained porous carbon electrodes was studied in detail by systematically regulating the relevant parameters in the preparation of the poly(vinyl alcohol) hydrogel. In a 6 M KOH aqueous electrolyte, the porous carbon electrode achieved a maximum specific capacitance of 143 F g⁻¹ at a current density of 1 A g⁻¹, which is 13 times higher than that of the directly carbonized poly(vinyl alcohol) powder (10 F g⁻¹). The obtained porous carbon electrode also showed excellent stability in the long-cycle tests. The large specific surface area is the main factor leading to the high specific capacitance of the obtained electrode. These results provide new insights and effective approaches for the further development of high-performance electrodes for energy storage devices.