A few days ago, I stumbled onto a string of videos by RMS. They covered a wide variety of subjects, but the main theme over the last five years has been a slow steady march to documenting how to make super capacitors in your garage, in a safe, easy, and cheap manner.
He now has a company, First Working Generation, FWG. The lofty goals are many in nature.
Do not use exotic elements, or expensive elements (cobalt, for instance). Non-hazardous for easy and safe disposal if damaged by using common trash collection. Find a way to easily and cheaply make graphene, and use it in a way that dramatically increases the capacity of DIY super capacitors. For instance, one video shows how to make a cheap ball-mill and attach it to a drill press (to make a fine powder from carbon).
Another video shows how to make conductive ink that is doped with DIY graphene and can be applied to paper as the matrix by a common office printer. How to make unusually thin foil that has graphene impregnated for conductivity (graphoil?), as the collectors, since increasing the plate surface area per volume is the key to high capacity.
This is not perfect lab-grade single-layer nano-graphene (see: https://www.youtube.com/watch?v=7bTwAi2UtO0
). At best it averages 3-layers (per his claim), but...it's damn good and dirt cheap once the very affordable equipment is built. This has yet to be publicly tested by a recognized expert 3rd party, but...he has built a 20S pack of 1.5V cells for 36V, and he has been riding a scooter with it. There is no chemical reaction, it is only a capacitor collector plate pair that is unusually thin, and has many hundreds of super-thin layers squeezed into cells, using graphene to increase the surface area on the plates (on a microscopic scale).
As a capacitor, it can be charged at an unusually fast rate, and can also provide an unusually high C-rate of discharge. It can operate in extreme cold at a level that would be difficult for a chemical battery, and also extreme heat. He "claims" he has achieved an energy capacity (range) equal to current lithium-ion batteries, but there is nobody disputing that these super capacitors should last a lifetime, instead of wearing out in a few years.
In the early videos, he chose a tiny quadcopter motor with 3-bladed propeller as the common load for all the cell testing. The tiny load was because he was going to be testing hundreds of super capacitor prototypes, so he wanted the initial SC's to be small (roughly one centimeter square, close to one-half inch). After years, he settled on four main SC combinations, and then began making larger SC prototypes. The recent scooter super-capacitor (if that's what it really is) looks like a standard 48V 20-Ah lithium battery-pack in size.
Is this real? There seems to be dozens of videos covering every aspect of the material selection and assembly, and there doesn't seem to be any "secret sauce". I hope it is real. Either way, I feel this would be of interest to many of the builders here, so...here's a few links to get you started. There are quite a few places where he began calling the super-capacitors "batteries", and near the end, he calls the final style Electrical Energy Storage Device/ EESD.