Metal–organic framework assisted synthesis of nitrogen-doped hollow carbon materials for enhanced supercapacitor performance
Nitrogen-doped hollow carbon materials have been facilely fabricated via the simple carbonization process by using ZIF-8 polyhedrons coated with polydopamine (PDA). ZIF-8 polyhedrons can be used as sacrificial templates for the hollow structures and both ZIF-8 polyhedrons and PDA can be used as carbon and nitrogen sources. Due to the synergistic effect of the hierarchical pore structure and high level N doping, the nitrogen-doped hollow carbon materials can serve as ideal electrode materials for supercapacitors, exhibiting an enhanced specific capacitance of 253 F g−1 at a current density of 0.2 A g−1 and excellent rate capability with a capacitance retention of 70% at a high current density of 20 A g−1. Moreover, ZIF-8@PDA-C also shows excellent electrochemical stability with 93% capacitance retention over 10 000 cycles. This will also provide a new strategy for configuring nitrogen-doped hollow carbon electrode materials for supercapacitors and other carbon-based energy storage devices.