Synthesis of ultrafine ZnO nanoparticles supported on nitrogen-doped ordered hierarchically porous carbon for supercapacitor

Abstract

This paper reports on the synthesis of ZnO/nitrogen-doped hierarchically porous carbon (ZnO/N–OHPC) and its application as electrode for supercapacitor. N–OHPC having large surface area, 3D ordered macropores and ordered mesopores in the carbon skeleton is fabricated from dual-templates with dicyandiamide as the nitrogen source. Through a convenient in situ solution growth way, ultrafine ZnO nanoparticles (∼3.2 nm) are evenly distributed on the macroporous walls of N–OHPC. The as-synthesized ZnO/N–OHPC (38.6 wt% ZnO) exhibits a maximum gravimetric capacitance of 720 F g−1 at 1 A g−1 within the potential window of 0.1–0.5 V. In addition, it exhibits a great rate ability (66% capacitance retention at 10 A g−1) and durability (90% of the initial capacitance was obtained after 30,000 cycles). The superior electrochemical performance is due to the synergistic effects of small ZnO nanoparticles and N-doped ordered hierarchically porous carbon.