A group of American researchers led by David Mitlin found that the waste of hemp fibers, with appropriate processing, can become a material for the manufacture of a supercapacitor, which is in no way inferior to the famous graphene.
Currently, scientists in many countries around the world have focused their efforts on graphene. With all its undoubted advantages, it is quite expensive, at the same time, hemp nanosheets can be produced from biowaste of specialized enterprises in the USA and Canada.
In the course of research, it was found that when hemp fibers are heated to a temperature of 177 ° C during the day, the structure of the material is destroyed, followed by the peeling of carbon nanosheets.
David Mitlin and his colleagues created their supercapacitors using "hemp" carbon as electrodes and an ionic liquid as an electrolyte. The device showed good characteristics: energy density - 12 watt-hour / kg, which is 3 times higher than commercial analogs. Plus, the supercapacitor can operate in a wide temperature range from negative to +90 ° C.
Unlike traditional capacitors, supercapacitors can be charged and discharged in a matter of seconds. Scientists have not yet managed to solve the problem of energy density, which will require the development of special electrodes.