Hemp Batteries: The Future of Sustainable Energy Storage?

As the global demand for sustainable and efficient energy storage solutions grows, researchers are turning to unconventional materials to improve battery performance and sustainability. One such material is industrial hemp, a versatile plant historically used in textiles, construction, and food. Recent breakthroughs suggest that hemp could play a transformative role in the development of advanced batteries, particularly in supercapacitors and lithium-sulfur (Li-S) batteries. This article explores the science behind hemp batteries, their advantages, and their potential impact on the energy storage industry.

 

Hemp-Derived Carbon in Supercapacitors

Supercapacitors are energy storage devices known for their fast charging and discharging capabilities, long lifespan, and high power density. However, they have traditionally suffered from low energy density compared to lithium-ion batteries. A key factor in supercapacitor performance is the electrode material, which directly influences energy storage efficiency.

Hemp as an Alternative to Graphene

Graphene, a single-layer carbon nanostructure, has long been regarded as the gold standard for supercapacitor electrodes due to its high electrical conductivity and large surface area. However, high production costs and complex manufacturing processes have limited its widespread adoption.

Dr. David Mitlin, a professor at Clarkson University, discovered a way to transform hemp bast fibers (the inner bark of the hemp plant) into high-performance carbon nanosheets. By subjecting these fibers to a hydrothermal synthesis process, followed by chemical activation, Mitlin's team produced hemp-derived carbon nanosheets that perform similarly to graphene at a fraction of the cost.

Performance of Hemp-Based Supercapacitors

The results were astonishing:

• Hemp-derived supercapacitors stored up to 12 watt-hours per kilogram (Wh/kg)—more than double the energy density of standard commercial supercapacitors.
• The manufacturing process was significantly cheaper than producing graphene.
• The hemp-based electrodes exhibited excellent stability and conductivity.

Mitlin's research suggests that hemp-based carbon nanosheets could replace graphene in many supercapacitor applications, offering a low-cost, sustainable alternative.

 

Hemp in Lithium-Sulfur Batteries (Li-S Batteries)

Lithium-sulfur (Li-S) batteries have long been considered a promising alternative to lithium-ion batteries due to their:

• Higher theoretical energy density (up to five times greater than lithium-ion).
• Abundant and low-cost sulfur cathode material.
• Lower environmental impact compared to cobalt-based lithium-ion batteries.

However, Li-S batteries suffer from significant technical challenges, including:

• Polysulfide dissolution – Intermediate polysulfides tend to dissolve into the electrolyte, leading to capacity loss.
• Cathode expansion – Sulfur undergoes large volumetric expansion during charge and discharge cycles, reducing battery lifespan.

 

The Role of Hemp in Improving Li-S Batteries

To overcome these issues, researchers at Bemp Research Corp., in collaboration with the University of Wisconsin-Milwaukee and the University of North Texas, have developed a boron carbide (B4C)-hemp composite cathode for Li-S batteries.

• Hemp-derived carbon provides a porous structure, allowing the cathode to accommodate expansion and contraction without degradation.
• The structure traps polysulfides, reducing capacity loss and improving cycling stability.
• Prototypes showed significantly improved performance and lifespan compared to conventional Li-S designs.

These advances suggest that hemp-based materials could revolutionize Li-S batteries, making them a viable alternative to lithium-ion batteries for applications like electric vehicles and grid storage.

 

Advantages of Hemp-Based Batteries

The potential benefits of hemp-derived energy storage include:

1. Cost-Effectiveness

Hemp is a fast-growing, widely available crop, making it a low-cost raw material. Compared to expensive synthetic carbon sources, hemp-derived carbon can be produced cheaply and efficiently.

2. Environmental Sustainability

• Hemp cultivation requires minimal pesticides and herbicides.
• Carbon sequestration – Hemp absorbs large amounts of CO₂ during its growth cycle.
• Biodegradable waste – Unlike synthetic materials, hemp-based carbon is more environmentally friendly.

3. Enhanced Battery Performance

Hemp-derived carbon has demonstrated:

• Higher energy density than traditional activated carbon.
• Greater cycling stability, especially in Li-S batteries.
• Comparable or superior performance to graphene in supercapacitors.

 

Challenges and Future Outlook

Despite its promise, hemp-based battery technology faces several challenges:

1. Scalability

• While lab-scale results are promising, scaling up production for commercial use remains a challenge.
• More research is needed to develop industrial-scale processing techniques for hemp-derived carbon.

2. Market Adoption

• The energy storage industry is dominated by lithium-ion technology.
• Manufacturers and consumers need convincing incentives to switch to hemp-based alternatives.

3. Regulatory Considerations

• While industrial hemp is non-psychoactive, regulations around its cultivation vary worldwide.
• Policy changes may be needed to encourage industrial hemp use in technology applications.

Current Research and Future Directions

• University of Wisconsin-Milwaukee is partnering with Wisconsin Battery Company to develop sodium-ion batteries using hemp-derived carbon.
• Research into alternative electrolytes and cathode structures could further improve hemp-based Li-S batteries.
  

 

Conclusion

Hemp-derived materials are emerging as a serious contender in the future of energy storage. From supercapacitors to next-generation Li-S batteries, hemp offers a sustainable, cost-effective, and high-performance alternative to conventional carbon materials.

While challenges remain in terms of scalability and adoption, continued research and technological advancements could make hemp-based batteries a key component of the global energy transition. If successful, hemp could help revolutionize the battery industry, providing a renewable and environmentally friendly solution to our growing energy storage needs.

 

Sources : 

• IHEMP Washington : HEMP - Batteries
• Energy Tech : Will Hemp Make EV Batteries Better?
• UWN Engineering News - News outlet covers the effort to develop alternative to lithium batteries, using hemp