> <i>"Aerogel from fruit biowaste produces ultracapacitors with high energy density and stability" (2020) <a href="https://www.sciencedirect.com/science/article/pii/S2352152X19309077" rel="nofollow">https://www.sciencedirect.com/science/article/pii/S2352152X1...</a> </i><p>Years ago, I remember reading about supercapacitor electrodes made from what would be waste hemp bast fiber. They used graphene as a control. And IIRC, the natural branching structure in hemp (the strongest natural fiber) was considered ideal for an electrode.<p>"Hemp Carbon Makes Supercapacitors Superfast" <a href="https://www.asme.org/topics-resources/content/hemp-carbon-makes-supercapacitors-superfast" rel="nofollow">https://www.asme.org/topics-resources/content/hemp-carbon-ma...</a><p>How do the costs and performance compare? Graphene, hemp, durian, jackfruit<p>While graphene production costs have fallen due to lots of recent research, IIUC all graphene production is hazardous due to graphene's ability to cross the lungs and the blood-brain barrier?