Enzymatic fuel cell with membrane bound redox enzyme

#The present invention relates to fuel cells, including re-chargeable fuel cells, for use in powering electrical devices.

#Fuel cells are useful for the direct conversion of chemical energy into electrical energy. Fuel cells are typically made up of two chambers separated by two porous electrodes and an intervening electrolyte. A fuel chamber serves to introduce a fuel, typically hydrogen gas, which can be generated in situ by “reforming” hydrocarbons such as methane with steam, so that the hydrogen contacts H2O at the first electrode, where, when a circuit is formed between the electrodes, a reaction producing electrons and hydronium (H3O+) ions is catalyzed. 1

#The electrolyte acts to convey hydrogen ions from the first electrode to the second electrode. The second electrode provides an interface with a recipient molecule, typically oxygen, found in the second chamber. The recipient molecule receives the electrons conveyed by the circuit. 2

#FIGS. 1 and 2 schematically illustrate fuel cells.

#FIG. 3A illustrates a proton-conductive divider between an anode and a cathode chamber.

#FIG. 3B shows an expanded, schematic view of a proton conductive divider, while FIG. 3C shows such a divider in the context of a cell housing. The schematic of FIG. 3D is more realistic as to the structure of the biocompatible membrane, while that of FIG. 3E shows another placement of the electrodes.

#FIG. 1 illustrates features of an exemplary fuel cell 10. The fuel cell 10 has a first (anode) chamber 1 containing an electron carrier, with the textured background fill of the first chamber 1 illustrating that the solution can be retained within a porous matrix (including a porous polymeric membrane). Second (intermediate) chamber or porous polymeric membrane 2 (“anode/cathode barrier”) similarly contains an electrolyte (which can be the same material as found in the first chamber) in a space, which space can also be filled with a retaining matrix, intervening between porous first electrode 4 and porous second electrode 5. A face of second electrode 5 contacts the space of third (cathode) chamber 3, into which an electron acceptor molecule, such as oxygen or a peroxide, is introduced. First electrical contact 6 and second electrical contact 7 allow a circuit to be formed between the two electrodes.

#The reaction, typically catalyzed by redox enzymes, that occurs at the first (anode) electrode can be exemplified with NADH as follows: 3

#This reaction can be fed by the following reactions: 4