All these stories we hear about the miracle material graphene, and everything it can do especially when it comes to energy storage, somehow miss to tell us that it comes at quite a huge price. This is why finding an affordable alternative was the main goal of scientists from Clarkson University, New York, who not only did it, but also used hemp for it.
During the annual meeting of the American Chemical Society, held in San Francisco, Dr David Mitlin and his team from Clarkson University, New York, presented what could only be considered as a break through discovery. Using leftover bast fibre from hemp, produced during manufacturing of clothing and building materials, the guys were able to make 100% organic material that can function in the same way as graphene in supercapacitors.
The team’s main focus of research is to find a way to convert bio waste into materials that can transform the world of energy storage. They managed to make themselves famous just a few months ago with their incredible banana-peel batteries, but it seems this was by far not the only thing they were working on.
Now, they switched from bananas to hemp, and before you ask, no, it is not the illegal hemp that they used. This one does not contain any THC, and it is widely used in various industries across Asia, North America, and Europe. In fact, they are not even interested in the hemp itself, but rather the leftover bast fibre, which usually gets dumped in landfills.
The principle is quite simple. The hemp fibre is exposed to hydrothermal synthesis, a procedure, which resembles cooking food in a pressure cooker. This dissolves the semicellulose and the lignin, and leaves behind perfectly thin carbon nanosheets that form the so-called pseudo-graphene structure. The material is highly conductive, perfectly suitable for use in supercapacitors, and it comes at a much cheaper price than graphene.
As Dr Mitlin points out, the key is not to develop a universal formula that can serve all purposes. Instead, each new energy storage device should be custom-made to fit the specific requirement of particular electronics, electric vehicles or renewable energy source. This is exactly what his team did.
Their findings appear in the journal ACS Nano.
Image (c) Reuters