Three-dimensional honeycomb-like porous carbon derived from Ganoderma lucidum spore for high-performance electrochemical capacitors

Abstract

In this work, we demonstrate that pure three-dimensional honeycomb-like porous carbons (3D-HPC) can be prepared by one-step simultaneous carbonization and activation of Ganoderma lucidum spores (GLS) with KOH active agent. Benefiting from the specific natural morphology of GLS and uniform activation process, the obtained 3D-HPC exhibits pure honeycomb-like hierarchical structures. The obtained 3D-HPC-900 shows the honeycomb-like structures and a high density of narrow mesopores, leading to a high accessible surface area. Combined with high specific surface area of 1995 m2 g−1 and oxygen/nitrogen doping, 3D-HPC-900 exhibits a high specific capacitance of 224 F g−1 at a current density of 0.25 A g−1, an ultrahigh capacitance retention of 75.9% even the current density increased by 80 times, and an excellent cycling stability with 100% capacitance retention after 50,000 cycles. More importantly, the maximum energy density can reach up to 75.7 W h kg−1 at the power density of 1750 W kg−1 in ionic liquid. Meanwhile, the experimental results clearly reveal the exclusive effects of mesopores on improving the rate performance in electrochemical capacitors. Therefore, the work provides a clear method on preparation of high-valued honeycomb-like structured carbon materials to enhance the rate capability of carbon-based electrochemical capacitors.