Hierarchical porous carbon rich in uniform micron-sized, bubble-like pores for improved supercapacitor electrodes

Abstract

Hierarchical porous structures are key to prepare carbon electrodes with high specific surface area. The unique morphology of carbon electrode materials provides a high specific surface area that increases the contact points with charges in the electrolyte, thereby facilitating excellent electrochemical performance. Herein, using KOH as an activator and KH2PO4 as a template agent, a hierarchical porous carbon (denoted as AC-PK) rich in uniform micron-sized, bubble-like pores with the specific surface area of 3011 m2 g−1 was prepared. The abundant micron-sized, bubble-like pores acted as reservoirs for charges from the electrolyte and the inner walls had the effect of disturbing charges, causing the charges to move in all directions, thus, increasing the effectivity of specific surface area. The hierarchical porous carbon material was also decorated with O atoms, which increased the surface wettability and improved the electrochemical performance. As a result, the AC-PK exhibited high capacitance of 336 F g−1 at 0.1 A g−1, good cycling performance of 91.4%, energy density of 11.47 Wh g−1, and power density of 24.79 W g−1. This work opens up a new approach to obtain carbon electrodes with hierarchical pores for supercapacitors.