CONTEXT

The microbial combustible batteries designed until now are based on the traditional configurations in two compartments separated by a membrane of exchange from ions or a separator porous. It is known that this separator constitutes an internal resistance which decreases the output of the piles significantly. The ageing of the separator or the reductions in its capacities of exchange takes part moreover in the bad behavior of the piles in time.

Ideally, one can free oneself from a separator between anode and cathode only if the electrodes are selective one of fuel, the other of the compound reduced with cathode, generally oxygen. In this case, it would be possible to plunge the two electrodes in a single medium containing at the same time fuel and oxygen. The selectivity of each catalysis would make so that only the fuel oxidizes with the anode and only oxygen is reduced to cathode.

For the moment, such a selectivity is not possible with mineral catalysts, an exchanging membrane of ions is thus necessary to avoid the contact of fuel with cathode and oxygen with the anode. The inventors propose to raise this limitation by implementing electrodes made selective by the formation of a biofilm at their surface, which can thus be used plunged in a single medium.