On Thursday, August 14, 2014 a group of scientists from the University of Alberta in Edmonton (Canada) presented their research regarding a super-capacitor fabricated with hemp: the hemp battery. The scientists present their results at the 248th National Meeting & Exposition of the American Chemical Society (ACS), the world's largest society of scientists.
On Thursday, August 14th, 2014 a group of scientists from the University of Alberta in Edmonton (Canada) presented their research regarding a super-capacitor fabricated with hemp: the hemp battery. The scientists present their results at the 248th National Meeting and Exposition of the American Chemical Society (ACS), the world’s largest society of scientists, held in San Francisco.
Super-capacitors have seen much development during recent years. It is a method of storing energy, as with batteries, but the energy density of super-capacitors can be a thousand times higher in comparison with conventional capacitors. One of the advantages of this new battery type is that it can be recharged in less than a minute, and over a hundred thousand times. Also, its capacity does not diminish over time.
Super-capacitors are usually made of grapheme, a type of carbon which is a raw material derived from graphite. The race for the ideal super-capacitor is largely focused on this raw material because it is strong and light. Currently scientists are investigating how the electronics industry can benefit from graphene in order to create better solar cells and water filtration systems, improve touch-screen technology, and last but not least, make batteries. However, extracting graphene from graphite is very expensive.
The Mitlin Group, a united group of scientists, has discovered how to extract similar carbon from hemp fibres to make nano-sheets. This is achieved by heating hemp fibres for 24 hours at 176 degrees Celsius, after which the resulting material is briefly blasted with a more intense heat. This process causes the hemp fibres to fan out into nano-sheets of the desired carbon.
Fully assembled, their performance is better than the current commercial super-capacitors in terms of energy density, and the temperature range in which they can work. Hemp devices yielded an energy density of 12 Watt-hours per kilogram, which is two to three times higher than their commercial counterparts. They also continued to work within an impressive temperature range, from freezing to over 90 degrees Celsius.
“We’ve pretty much figured out the secret sauce of it”, says Dr. David Mitlin. “We’re past the proof-of-principle stage for the fully functional super-capacitor. Now we’re gearing up for small-scale manufacturing.”
Industrial hemp is currently emerging again in the United States. The country and industry are increasingly opening up to the many traditional uses of hemp such as food, ropes and paper. Sensi Seeds hopes that this new kind of application will greatly hasten the return of the hemp industry.