According to the video it has a capacity of 500mAh, not bad at all for a capacitor of that size and shape, but still can't compete with lithium batteries in therms or energy density (maybe it could in terms of energy per kg though), the only thing it makes them so good is they could be charged in seconds or minutes and have a much longer lifespan than the lithium batteries.
Everytime I'm hyped for something like this it turns to be a hoax, let's just hope…