Researchers have been trying to use hemp as a low cost, high energy density battery material for a decade. Are they getting anywhere close?
Ever since the movie Reefer Madness was released in 1936, Americans have had a pathological fear of hemp. Because of it, the lowly hemp plant, which may have more uses than any other crop, has been treated with scorn. And yet, it could be a key component of future batteries, making them more energy dense and lowering their cost significantly.
One of the first researchers to delve into the benefits of hemp was Dr. David Mitlin of Clarkson University in New York, who lead a team that “cooked” hemp bark and turned it into artificial graphene. His work was published in the journal of the American Chemical Society in 2014.
Mitlin told the BBC, “People ask me: why hemp? I say, why not? We’re making graphene-like materials for a thousandth of the price — and we’re doing it with waste.”
Hemp In Texas
Fast forward nearly a decade, and Texas-based Bemp Research says it has developed a lithium sulfur battery that also relies on hemp that it calls B4C-hemp, which is short for “boron carbide made from hemp.” It says its battery would overcome many lithium-ion battery challenges in terms of cost, weight, scalability, performance, and recyclability. Its website is painfully short of details, but founder Son Nguyen gave an interview to Energy Tech recently in which he explained more about this new technology.
EnergyTech — Please describe your LiS technology, its intended applications, and why LiS/B4C-hemp is superior to Li-ion batteries.
Nguyen — LiS/B4C-hemp is superior to Li-ion batteries in terms of gravimetric energy density, safety, and, most importantly, costs and environmental friendliness. Our chemistry uses lightweight and abundant materials such as sulfur, boron, and carbonized hemp – instead of heavy metals such as nickel and cobalt. LiS/B4C-hemp batteries will be great for heavy-duty trucks and electric airplanes.
Energy Tech — What is hemp’s function in the technology, and why is hemp the right material choice?
Nguyen — Hemp was chosen as one of the core materials due to its durability, porosity, and low costs. LiS batteries have problems such as the cathode contracting/expanding during charging/discharging, and the cathode’s polysulfides shuttling to the anode and hurting the batteries’ performance. Researchers could solve these problems using expensive materials such as graphene, but graphene is impossible to mass-produce. Hemp is a better, lower-cost solution. Hemp’s durability can help the cathode withstand hundreds of cycles of contraction and expansion. Hemp’s porous structure can help “trap” the polysulfides from shuttling to the anode.
Energy Tech — Significant supply chain bottlenecks exist across the manufacturing spectrum, including Li-ion battery manufacturing. Would your LiS/B4C-hemp batteries overcome any Li-ion supply chain challenges?
Nguyen — Sulfur is very abundant. Boron is also relatively abundant, with the biggest boron mine being in California. We also have a strategic partnership with Delta Agriculture, the biggest hemp producer in the USA. Delta Agriculture highlights that hemp is a legal crop that requires little water, no pesticides, and is better at carbon sequestration than trees. Being an American company, our focus right now is to make batteries for American electric vehicles, and we do not see any supply chain problems. Bemp batteries are less reliant on rare earth metals from around the globe and thus will help U.S. national security.
Energy Tech — Why is LiS/B4C-hemp better than Li-ion from safety and environmental/recycling standpoints?
Nguyen — LiS/B4C-hemp is safer than Li-ion because if the battery is damaged, punctured, bent, or crushed, sulfur will immediately react with lithium to form a passive layer – so it will not combust. Also, there is no metallic oxide in our chemistry so there is no risk of thermal runaway like in Li-ion chemistries. Since there is no cobalt or nickel, and lithium is the only valuable metal in our chemistry, recycling can be done much more easily compared to Li-ion. We just need to recover the lithium, and that is it.
Energy Tech — How far along are you in developing the technology, and what’s the next step?
Nguyen — We have done many stress tests to see how our LiS/B4C-hemp batteries perform at different charge/discharge rates. They can be fully charged in 20 minutes and will still have double the gravimetric energy density of the best Li-ion batteries. At slower charge rates, the gravimetric energy density can be even higher. This means doubling or tripling the range per charge for electric vehicles. The cycle life is also very good for lithium sulfur engineering, and we estimate our batteries will be good for 100,000 miles being fast-charged, longer for slow charging, before being recycled.
The next step is to make bigger cells and battery packs and do even more stress tests. Our batteries performed well in a very wide temperature range in the lab, for example, but we need to let them cycle longer in extremely cold and extremely hot temperatures to verify our findings.
Energy Tech — When might your technology become commercially available, and what would likely be the first commercial applications?
Nguyen — We plan to mass produce our batteries before 2026. The first applications will be for drones and heavy-duty electric vehicles such as buses and trucks.
The Takeaway
We don’t know who will solve the riddle of low cost, high energy batteries, but we are convinced someone will in the next 2 to 3 years. There is simply too much money piling into the field and too many researchers putting their shoulders to the wheel for it not to happen.
Frankly, we can’t say whether graphene made from hemp will be part of the solution, but it is certainly an appealing alternative. Hemp grows just about anywhere it is planted. It needs little water and no pesticides. It could be a tremendously appealing cash crop for farmers. Who knows? It could even replace corn in the agrarian economies of the Midwest. Think what a revolution that would be.
The lack of foundational data from Bemp Research is troubling. They are aggressively seeking funding to pursue their quest to transition from concept to commercialization. Perhaps they are keeping their cards close to their vest so as not to tip off the competition, or maybe this is all smoke and mirrors designed to secure a big payday for the founder and his team before moving on to something else.
Our mission is to keep our readers informed about new developments in the EV revolution. If we hear any more about graphene and hemp, we will be sure to share it with you.
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Source: Clean Technica