Hemp-Based Efficient Energy Storage SolutionsSupercapacitors powered by hemp-based carbon nanosheets.
The Future of Hemp is Electric
Biomolecular engineers discovered hemp can be converted into battery materials, specifically carbon nanosheets and supercapacitors, and are being explored as a source of clean, green, renewable energy. Pioneering groups in this field have received sizeable grants to focus on utilizing hemp for supercapacitors and carbon nanosheets to replace graphene, a material more widely known in supercapacitors, yet more expensive to produce.
The supercapacitor innovation comes from the recent discovery of hemp bast – the fiber leftover from processing hemp, now used as a highly efficient electrode. Supercapacitors are similar to typical batteries, with the primary function being to store and discharge electricity. The primary difference between batteries and supercapacitors is that supercapacitors have higher power density, allowing them to release energy more quickly, be recharged faster, ensure more charge cycles, and function more safely under extreme temperatures. These abilities allow supercapacitors to be critical components of more advanced and emerging technologies such as electric cars, trucks, trains, and wind turbines, that smooth intermittent power from wind energy.
Super-Charged Renewable Energy
With the global push towards renewable energy, hemp-based carbon nanosheets are revolutionary, not only for their cost-effectiveness and availability vs the more popular graphene but because of their mass-market potential. Hemp is very environmentally friendly and sustainable, being easy to cultivate, and has been historically utilized in many things such as a source of food, rope, and textiles.
In contrast, graphene as a carbon nanosheet material is monumentally more expensive, requiring the mining of graphite that has caused extensive pollution alerts in many areas of the world, including many rural provinces in China and India. In addition, chemicals used in graphite mining are toxic and extremely harmful to people who are processing the material.
The carbon nanosheet application in itself is derived from heating up hemp bast fibers for 24 hours, allowing the nanosheets to flake off the fibers. This is an ideal production scenario, considering these fibers are deemed as waste materials that most manufacturers consider a by-product.
Hemp-derived carbon nanosheets are expected to be used in much wider applications than supercapacitors, including water and air purification. Mitlin said that he plans to have the business have “graphene performance at activated carbon prices”. The profitability of hemp carbon nanosheets is not limited only to manufacturers but to farmers as well, as their waste products can be converted to a renewable source of energy.
Research for Hemp Battery Potential
Under Clarkson University Professor David Mitlin, some hemp-based supercapacitors have been tested to produce as much as 12 watt-hours per kilogram, outperforming current commercial models by a factor of 2 to 3, and while operating under freezing temperatures of upwards to 200 degrees Fahrenheit (93.3 °C). Though hemp carbon nanosheets cannot do everything that graphene does, it is acknowledged to store energy in equivalent efficiency at a fraction of current costs, between 500 to 1000 USD per metric ton.
More recently, in September 2021, new research published in the Journal of Energy Storage also suggests that hemp fiber may be superior to other materials for solid-state supercapacitors. The study shows that hemp ranked "very high" in comparison to other carbon materials for specific energy. The abstract stated, "Further, the assembled supercapacitor device works until 2V delivering a capacitance retention of ~85% after 10,000 cycles."
The researchers concluded that this particular method could lead to, "developing highly promising sustainable electrodes for high energy, solid state supercapacitor applications."
Hemp-derived carbon products are expected to become mainstream, now putting waste bast fibers in production instead of landfills, and reducing pollution levels in conjunction. With almost all newer technologies hinging on new sources of energy, hemp carbon nanosheets are expected to revolutionize supercapacitor batteries and improve the entire energy industry by becoming standard materials in energy storage.