Cannabis NanoHemp SuperCapacitor
Conventional batteries store large reservoirs of energy and drip-feed it slowly, whereas supercapacitors can rapidly discharge their entire load.
Graphene is considered the best nanomaterial but it costs as much as $2,000 per gram. Industrial hemp waste makes a graphene-like nanomaterial for a fraction of the cost – less than $500 per ton – and actually outperforms graphene.
University of Alberta chemical engineer David Mitlin and his colleagues converted waste from the cannabis plant (Cannabis sativa) into a carbon nanomaterial that had similar properties to graphene and with a much smaller price tag.
Hemp nanomaterial showed “superior electrochemical storage properties” compared to graphene and will eventually be used for a wide range of nanotechnology applications, from flashlights to solar cells.
Hemp bast fibre created unique interconnected partially graphitic carbon nanosheets with high specific surface area, significant volume fraction of mesoporosity, and good electrical conductivity.
The bast’s lignin and hemicellulose break down with heat and carbonizes the cellulose. Treatment with potassium hydroxide causes it to exfoliate into nano-sheets that provide a quick path for charges to move in and out, which is important when a supercapacitor charges and discharges..
The best property of the device, Mitlin says, is its maximum power density, a measure of how much power a given mass of the material can produce. At 60 °C, the material puts out 49 kW/kg; activated carbon used in commercial electrodes supplies 17 kW/kg at that temperature.
Interconnected Carbon Nanosheets Derived from Hemp for Ultrafast Supercapacitors with High Energy
Hemp fibres ‘better than graphene’
Souping-Up Bio-Waste into Supercapacitors
Professor David Mitlin – WIN Seminar Series
Graphene is a two-dimensional atomic crystal extracted from graphite and used for a wide variety of applications, ranging from electronics to composite materials.
Graphene is a ultra-light yet immensely tough allotrope of carbon in a hexagonal lattice of planar sheets at one atom thick.