Shell-like hierarchical porous carbons for high-rate performance supercapacitors

Shell-like hierarchical porous carbons (SHPCs) were prepared from petroleum pitch by a nano-ZnO-template strategy coupled with in-situ KOH activation technique. The as-made SHPCs feature interconnected thin carbon shells and abundant short hierarchical pores, which are favorable for both the rapid transfer of electrons and ions during the charge-discharge process. The SHPCs made under optimal conditions show a specific surface area up to 2646 m 2  g −1 . As electrodes for supercapacitors , SHPCs exhibit a high specific capacitance up to 296 F g −1 at 0.05 A g −1 in 6 M KOH electrolyte, good rate performance remaining at 237 F g −1  at 20 A g −1 and a good cycle stability with over 96.5% capacitance retention after 5000 cycles. This work suggests a facile strategy for high-efficiency synthesis of SHPCs from petroleum pitch as electrode materials for supercapacitors and other energy stotage devices.