Hemp Battery Technology Hasn't Yet Sparked
Hemp Research in Battery Tech
Industrial hemp has shown promise as a potential ingredient in super batteries that might make it faster to charge your phone or electric vehicle in the future. But getting a hemp battery to market is taking a long time.
Hemp, a cousin of marijuana, was illegal to grow for 80 years in the United States until the passage of the 2018 farm bill.
It's been almost seven years since a group led by Clarkson University engineering professor David Mitlin presented an article published in American Chemical Society's Nano Journal at the society's conference in San Francisco showing that when used in supercapacitors, nanosheets of hemp fiber rivaled the performance of graphene, a conductive mineral compound.
I followed up with Mitlin to find out the current status of hemp batteries.
Graphene, derived from the mineral graphite, is one of the world's best conductors of electricity, but costs thousands of dollars an ounce.
The hemp bark, or bast, used in battery research was a waste product from a nearby Canadian hemp processor in Edmonton near University of Alberta. Canada legalized industrial hemp for fiber and seed production in 1998.
The research showed that using hemp might dramatically bring down the costs of supercapacitors.
Mitlin, who now is a professor of mechanical engineering at the University of Texas, in Austin, says hemp's atomic structure makes it similar to the honeycomb atomic lattice makeup of graphene.
"If you take the structure of hemp fiber, you can exfoliate it to make thin sheets of carbon and it performs similar to graphene," he said. "Hemp is unique from a scientific point of view, and has high performance in supercapacitors."
Hemp Conducts Electricity
Hemp has long been known to be a conductor of electricity, especially when wet. Benjamin Franklin used a hemp twine for his 1752 kite-and-lightning experiment, and noted that the loose filaments suddenly stood erect and moved toward his knuckle, proving the existence of electricity.
Mitlin and his team found that hemp nanosheet electrodes, used with an electrolyte, created supercapacitors with an energy density of 12 watt-hours per kilogram which could recharge in 6 seconds. That energy density was "on par with or better than commercial graphene-based devices," the team's peer-reviewed 2013 paper said.
Battery researchers want to perfect supercapacitors, also called ultracapacitors, because they store static energy in large quantities, and recharge quickly, as opposed to batteries, which work slowly via a chemical reaction, and lose their power over time.
Right now, supercapacitors are used to provide a burst of energy in a mechanical setting, for example regenerative brakes for electric vehicles, or to store energy to direct the blades in wind turbines.
However, researchers at companies like Tesla are trying to meld long-lasting batteries with supercapacitors to create batteries which charge much quicker. The goal would be a cell phone charged in seconds, or an electric car in minutes.
In 2014, Mitlin's team formed a startup, Alta Supercaps[checked], to try to produce hemp-based super capacitors and button cell batteries on a small scale. But the company announced on its website that it was closed in 2015.
Mitlin, who continues to research battery technology, declined to talk about commercial applications of his hemp battery research.
Bio-waste Can Make a Form of Graphene
Twenty-three Alta Supercaps patents for hemp batteries were acquired by publicly traded Rochester N.Y.-based Sparkle Holdings, LLC, which opened in 2018.
"We are creating defect-free two-demensional hemp graphene for batteries," said Sparkle CEO Mick Stadler. The company is developing prototype batteries, supercapacitors, pouch cells and button cells, Stadler said. "We are taking the base science to the next step in battery development."
Sparkle also grows hemp in Rochester and processes it for CBD.
"Making graphene can be a toxic process. Instead of mining graphite, we process a plant, we make the similar material [a bio-based] graphene, from a green process," Stadler said.
Battery scientists, especially in China, are continuing to publish research on supercapacitors using hemp as an alternative for graphene. Researchers are also studying the conductive properties of other bio-waste carbon sources like banana peels, pineapple leaves, peat moss, waste paper pulp and the shells of eggs, peanuts and pistachios.
But as of yet, there are no hemp batteries on the market.
"We believe there is a future for a hemp storage technology combination that will be used in electric cars, or for storing wind or solar energy," Stadler said.
© 2020 Jean Lotus