Three-dimensional honeycomb-like hierarchically structured carbon nanosheets from resin for high-performance supercapacitors

The capacitance of electrode materials is directly influenced by their surface area. In this work, we synthesized three-dimensional interconnected honeycomb-like carbon nanosheets (RTK-3) utilizing a homemade phenolic resin along with KOH etching and in situ doping of thiourea. These nanosheets possess a large surface area (2277.71 m g) and are rich in heteroatoms, which results in outstanding electrochemical performance, with specific capacitances of 349 F g at 0.5 A g and 217 F g at 10 A g. Additionally, the assembled symmetric supercapacitor (RTK-3//RTK-3) exhibits exceptional performance in different aqueous electrolytes. Specifically, it delivers an energy density of 6.11 W h kg at a power density of 249.61 W kg in alkaline electrolytes, while it achieved a preeminent energy density of 36.34 W h kg at 810.11 W kg in neutral electrolytes due to its larger potential window (0-1.8 V). The utilization of resin-based carbon materials to prepare high-performance supercapacitors represents a novel approach and could potentially lead to the application of other large surface area and heteroatom-doped materials in energy storage.