Monolithic carbon nanosheets with rich pores for high-capacitance supercapacitor

It is a big challenge to fabricate monolithic carbons with abundant active sites for ion adsorption. Herein, monolithic carbon nanosheets (MCNSs) were fabricated from anthracene oil by a Ca(OH)2 template-space-confinement strategy coupled with KOH activation. The as-obtained MCNSs feature unique sheet-like structure with developed micropores, providing abundant active sites for ion adsorption, shortening ion transfer distance, and improving electron conductivity. The MCNS electrode materials exhibit a high specific capacitance of 284 F g−1 at 0.05 A g−1, a remarkable rate performance of 229 F g−1 at 20 A g−1, and a good cycling stability with 94.7% capacitance retention after 10,000 cycles at 5 A g−1 in 6 M KOH electrolyte. This work may provide a facile and cheap approach for the scale-up production of monolithic carbon nanosheets with abundant micropores from the derivates of coal tar for high-performance supercapacitors.