Nitrogen-enriched hierarchically porous carbon sheets anchored with ZIF-derived carbon for supercapacitors

Zeolitic imidazolate frameworks (ZIF)-derived carbon nanomaterials have been proposed as one of the promising electrochemically active materials for supercapacitors owing to its high specific surface area, rich surface functional groups and tunability on the structure. However, the discontinuous and dominantly microporosity structure of most ZIF-derived carbon materials determines limited active surface and diffusion kinetics. Herein, we prepared nitrogen-enriched hierarchically porous carbon sheets (NHPCS) anchored with ZIF-derived carbon. The mesoporous carbon sheets saved as reinforcing materials incorporate with ZIF-derived carbon materials to effectively convert ZIF-8 derived dispersed dodecahedron carbon to continuous and hierarchically porous structure with macropores and micropores on mesoporous sheets, more nitrogen content, enhanced specific surface area and pore volume of the NHPCS. As an electrode for supercapacitors, optimized NHPCS can reach a considerable specific capacitance of 305 F g−1 at 1 A g−1 with a superior stability of 90.0% capacitive retention after 10,000 cycles at 5 A g−1 in 6.0 M KOH solution. Such enhanced performances can be ascribed to the fully exposed active sites with fast diffusion kinetics and stable interconnected structure consisting of NHPCS, thereby leading to durable electrochemically activity.