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

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 m(2) 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.