| 研究実績の概要 |
2D functional nanosheets, e.g. representative graphene and boron nitride (BN) nanosheets of boron-carbon-nitrogen system, are outstanding materials. This project focused on the novel syntheses of nanosheets in boron-carbon-nitrogen system, i.e. 3D graphene and BN nanosheets, and realized the graphene-based high-energy high-power supercapacitors as well as BN-based thermo-conductive composites.
Current 3D graphenes suffer from poor electrical conductivity; the interconnected self-supported reproducible 3D graphenes remain unavailable. Here we developed a new synthesis method, i.e. "ammonium-assistant chemical blowing" based on a polymeric predecessor, to produce 3D graphenes. The graphene membranes of the 3D graphenes had higher conductivity than the typical RGO. The method had high yield (16 wt.%) and low cost (0.25-0.75 $/g). The supercapacitors based on such 3D graphenes achieved the maximum-power-density of 1 million W/kg in aqueous system, which is 10-times higher than that of previous 3D graphene. It also realized high the energy density of 50 Wh/kg at the high maximum-power-density of 340 kW/kg in organic system.
BN nanosheets are still hardly produced in large quantity. Here we developed "biomass-directed carbothermal reduction" for producing single-crystalline BN nanosheets. A throughput of ca. 20 g of BN nanosheets per single production run is documented in my lab trial. We further studied highly thermal conductive insulating polymeric composites. 40 wt.% epoxy/BN-nanosheet composites demonstrated a 14-fold increase in thermal conductivity.
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