Synthesis of Hierarchically Porous Carbon with Tailored Porosity and Electrical Conductivity Derived from Hard–Soft Carbon Precursors for Enhanced Capacitive Performance

Abstract

Porous carbon has been one of the most promising electrode materials for supercapacitors, and the carbon precursor has a significant impact on the properties of final products. Herein, we report an efficient method to prepare hierarchically porous carbon (HPC) using a hard–soft carbon precursor by mixing biomass and pitch, following with carbonization and KOH activation. Combining the advantages of each single precursor, the resultant RH1SP1-HPC presents a high surface area of 2996 m2 g–1 with the fabrication of a 3D interconnected porous structure and good conductivity. Benefiting from these features, RH1SP1-HPC exhibits a superior electrochemical performance compared with the samples derived from a single precursor with a high specific capacitance of 340 F g–1 at 0.5 A g–1 in a two-electrode system and outstanding rate capability of 87.6% capacitance retention at 20 A g–1. The enhanced capacitive performance demonstrates that the hard–soft carbon precursor is desirable to synthesize porous carbons for energy storage.