Excellent durable supercapacitor performance of hierarchical porous carbon spheres with macro hollow cores

Abstract

Hierarchical porous carbon spheres (HPCS) with 500 nm hollow cores and 100 nm shells have been prepared using hard template method. The synthesized HPCS has specific surface area up to 2489 m2 g−1 and pore volume as high as 1.45 cm3 g−1. The durable supercapacitor performance of HPCS is excellent with capacitance retention up to 99.7% after 10,000 charge/discharge tests at 10 A g−1 from three-electrode testing and 97.1% after 10,000 cycles at 10 mA cm−2 from two-electrode testing in 6 M KOH solution. HPCS also presents good supercapacitor performance with capacitance of 152 F g−1 at scan rate of 2 mV s−1 and keeps this capacitance of 123 F g−1 at 100 mV s−1. From the charge/discharge tests, HPCS displays capacitance up to 167 F g−1 and 132 F g−1 at current density of 0.2 A g−1 and 20 A g−1, respectively. From two-electrode testing, the capacitances of HPCS is 34.2 m F cm−2 at 2 mV s−1 and 37.4 m F cm−2 at 0.5 mA cm−2.