Water is put into a reservoir where it meets a catalyst (an unkown compound in the diagram), where it is split into Hydrogen and oxygen (not shown in the diagram). The pure hydrogen is then fed to the anode (like the negative side of a battery), to which the phone, or any other device, is plugged in to. From there the hydrogen loses an electron (the e- ball-like object, which travels to the cathode, producing a charge). The hydrogen ion produced from this travels through the electrolyte solution and bonds with oxygen from the atmostphere to produce water.

Its really fairly simple, but I imagine the catalyst will have to be replaced every once and a while, so its not completely self sufficient.

they’re probably harnessing the energy of something other than plain water. no catalyst can facilitate a reaction uphill. assuming, of course, that this isn’t a joke. i’d love to see this thing work.