Hemp Batteries - Possible alternative to Graphene and Lithium?
The fibers of the hemp plant could be used to make cheaper, more powerful and less polluting batteries, researchers say. They can be converted into high-performance energy storage devices, for example for electric cars.
Over the next few decades, the world will need many batteries to power its vehicles, homes, and cities. Batteries offer growing hope as the world transitions from non-renewable energy sources like natural gas and coal to a more sustainable energy grid. They pave the way to a future without dependence on fossil fuels. Scientists have long struggled to develop power solutions and capacitors that can keep up with the current pace of electronic component development. Many types of (non-hemp) batteries, while capable of storing large amounts of energy, are very large, very heavy, and release their energy relatively slowly.
One of the best ways to accelerate the adoption of battery-powered energy grids and vehicles is by using hemp batteries. Today, most car batteries are made from lithium-ion, an expensive material. Research and experiments have already proven that the hemp plant can be used as a sustainable alternative to efficiently power homes and electric cars. Hemp batteries are more environmentally friendly than metal or plastic batteries, which are toxic and non-biodegradable.
A group of American and Canadian researchers found that the hemp bast fibers can be recycled into supercapacitors. Bast fibers are the inner bark of the plant, which is usually cosidered a waste product. Through the process of hydrothermal synthesis, those fibers were heated and processed into carbon nanosheets, which were used to build graphene-like materials. It has been found that hemp has more capacity to store electricity and can provide more energy at a fraction of the price of lithium batteries.
Max Wölk
Supercapacitors are used to store energy in the form of batteries, which we use to power various things in our daily lives. These types of batteries, unlike lithium-ion batteries, can quickly discharge their entire energy charge to provide a large burst of energy. This is exactly what an electric vehicle needs for rapid acceleration. While supercapacitors don't hold a charge long, they can absorb regenerative energy during braking.
Supercapacitors are a great alternative to store energy efficiently apart from the traditional electrical energy storage method. However, due to their extremely high cost and low energy density, they have tended to be left on the sidelines. However, the use of hemp bast fibers could drastically reduce the cost (and energy density) of supercapacitors.
Common supercapacitors are made entirely of graphene, a carbon nanomaterial that is considered to be one of the ideal materials for supercapacitor electrodes. However, one of the biggest disadvantages of graphene is that it is difficult to produce in large quantities. Hemp, on the other hand, can grow to maturity within a few months and therefore has a high availability. The plant is also known for its ability to grow in many different types of soil, including soil that other plants cannot support.
A study compared the performance of hemp and graphene batteries and concluded that hemp is similar to graphene batteries in terms of weight and energy storage, but manufacturing hemp batteries proves to be more economical. Compared to graphene, hemp is less expensive and works just as well for energy storage.
Another advantage of hemp-based batteries is that, according to researchers, they have extremely good conductivity and are also very temperature-resistant. Even in hot and cold temperatures, the conductivity of hemp batteries remains high. This is particularly important considering that this technology could one day find its way into vehicles that need to function in a variety of climatic conditions.
Many hemp processing plants consider hemp bast fiber a waste product and don't know what to do with it. However, growers are increasingly interested in growing hemp for multiple uses and are now finding more and more options when it comes to creating a secondary income stream from their hemp biomass. Using hemp for batteries could reduce plant waste and minimize the labor and cost of harvesting.
Kathrin Ranegger