Nanoantenna Featuring Carbon Microtubes Derived from Bristle Fibers of Plane Trees for Supercapacitors in an Organic Electrolyte

Plane trees are prevalent and widely distributed in the Northern Hemisphere. Their fruits release massive thin bristle fibers in the autumn that cause asthma, allergies, and eye problems in certain circumstances. In this work, using the bristle fibers as the precursor, hierarchically porous N-doped carbon microtubes covered with carbon nanocones were successfully synthesized by a one-step etching and growing process. These thin carbon nanocones, which appeared like nanoantennas on the outer surface of carbon microtubes, enhanced the electrode/electrolyte interfacial area and enabled faster electron transfer. Serving as electrodes in an organic electrolyte, the hierarchically porous biomass-derived carbon nanocone@microtubes delivered a high specific capacitance of up to 240.5 F g –1 at a current density of 1 A g –1 and an energy density of up to 52.2 Wh kg –1 at a power density of 1250 W kg –1 . This work is a successful case to take full advantage of pollution-carrying biomass via a simple strategy to accomplish both energy sustainable development and environmental protection.