Hemp Supercapacitors Bring Green Tech To A Higher Level

Outperforming standard supercapacitors up to 200 percent, hemp-based supercapacitors could be the future of green technology.

At the Ministry of Hemp, we’re a little biased about our favorite plant in the world: hemp. But it seems like everyday we find newer and better ways that it can be used.

One innovation we recently discovered? Scientists discovered how to use hemp in supercapacitor electrodes. A supercapacitor is the lesser-known alternative to traditional electrical energy storage. Right now, a supercapacitor is the second best option for storing power, after batteries. However, more research could change that.

Below we’ll introduce you to hemp supercapacitors and how hemp could play a part in our energy future.

WHAT’S A SUPERCAPACITY, ANYWAYS?

The most famous form of energy storage is the battery, an object that contains two opposing electrical terminals separated by electrolytes. When you turn on the power, a chemical reaction occurs between the electrolytes and electrodes, producing electric energy for your device. Since batteries rely on electrolyes, and electrolytes wear out, all batteries need to be replaced. In addition, batteries take a very long time to fully charge. Today, we use batteries everywhere; in our phones, laptops, and more recently, our cars.

Capacitors work very differently from the traditional battery. In short, a normal capacitor is comprised of two metal plates and an insulating material between the plates called a dielectric. In a capacitor, positive & negative build up on the plates. Rather than electrolytes, capacitors store electrical energy within the plates.

Supercapacitors on the other hand, are different for two ways. Their plates have a “bigger” surface area and the distance between the plates is much shorter. Supercapacitors are usually coated in a porous substance such as activated charcoal. These coatings are called the “supercapacitor electrodes.”  The electrodes serve as more storage on the plates, giving them more surface area to store electricity. Think of normal non-coated capacitors as mops; which can only absorb so much water, and supercapacitors as sponges, soaking up much more water than its surface area. The website Explain That Stuff published a great explanation of supercapacitorsin August.

Unlike batteries, supercapacitors charge almost instantaneously and last much longer than batteries. Their biggest drawback, preventing them from being the popular choice, is the amount of energy that is able to be stored within them. Right now, supercapacitors only store a fraction of the power of a traditional battery, but scientists are working hard to find a way around this problem.

THE MIGHTY HEMP SUPERCAPACITOR

Today’s supercapacitors commonly use graphene, a carbon nanomaterial to create electrodes. But making graphene costs up to $2000 per gram.

In 2013, Researchers at the University of Alberta National Institute for Nanotechnology found a more economical material in hemp. These scientists discovered how to process raw hurds (the plant’s woody core) into activated carbons through hydrothermal processing and chemical activation. The final product is one that’s able to soak up more electricity, providing better energy capacity. The solution produces not only a cheaper material — $5000 per ton — but one that performs up to four times better than graphene. Better yet, the solution uses the hemp stems, the part that is often left unused during other forms of hemp processing. With this, the entire plant is used, and no part is left to waste!