These prototypes were producing milliwatts of power over a day or two. That's tiny! Notice how the construction depends on an anode, a cathode and an electrolyte? Notice how the construction includes nickel and manganese, typical components of a battery?
Like all these so-called "energy breakthroughs" where the owners do not permit serious scientific investigation, there's nothing going on beyond regular chemical energy.
If the developers really had what they claim, they would allow someone to test it for long enough to rule out chemical energy as the source.