| 摘要 |
The present invention relates to a porous carbon nanosheet which is capable of becoming an energy-storing material and, more specifically, to a porous carbon nanosheet which has an excellent electrochemical performance and is produced by mixing with an alkaline activator and a heat treatment after peeling and freeze-drying of coffee grounds available in quantity in the coffee industry and a porous carbon nanosheet which is capable of becoming an energy-storing material with regard to a method for manufacturing the same. A nano-structured carbon material produced from the coffee grounds according to the present invention has an amorphous carbon structure made up of small carbon crystals with little three-dimensional stacking, has an atypical plate-shaped structure, has a thickness as small as 9 nm, and has a side surface size of several micrometers with a significant aspect ratio. The nano-structured carbon material produced from the coffee grounds according to the present invention exhibits an excellent electrical property equivalent to an electrical conductivity of 120 S cm^-1 and has a very large capacity and an excellent rate capability at the same time. Specifically, the material shows a very high level of energy density of at least 100 Wh/kg even at a rapid output at which charging and discharging can be carried out in three seconds. In the case of FP-CNS-1200 produced on a 1,200C KOH 0.5 times basis, a super capacitor produced based on this as an electrode material shows an excellent life characteristic of 90.5% after 5,000 cycles. The present invention relates to a method for recycling coffee grounds, which can be economically and easily obtained after generation in quantity as wastes in the coffee industry, and thus is environment-friendly. The porous carbon nanosheet produced in this manner can be used as a material such as an electrode as well as a material for energy storage purposes. |
