And it looks like this has been known since at least 2013. https://www.asme.org/topics-resources/content/hemp-carbon-makes-supercapacitors-superfast
It can be produced at a fraction of the cost of lithium batteries and is far superior from a length of charge perspective. Apparently, even Henry Ford used a form of hemp as a fuel base in one of his Model T iterations. I can't get then info to come up on that though to learn more.