Interesting! I have to wonder how this discovery affects the theory that metabolisim comes out of hydrothermic vents where there's a proton differential across a thin layer of mineral that's been deposited. (FWIW, all living cells work this way, using 'proticity' to manage energy). Researchers have managed to make that reaction work in the lab (including driving some of the reactions in the Krebbs cycle), but the assumption has been that the oceans before life happened had no oxygen - or for that matter, before cyanobacteria developed the ability to split water using photons.
Is it possible that the deposition of these 'batteries' could only happen because there was oxygen in the upper layers of the ocean? I'm thinking about the layers of ferric oxide in sedimentary rock layers that were precipitated out of the ocean after the 'great oxygenation event'.