Energy production using novel enzyme fuel cells

A three-dimensional interconnected electrode architecture that supplies fuel and the oxidant via a gas phase was used to develop a novel EFC configuration with power densities of up to 9.4 W/m2 or 2.9 kW/m3. A hydrophilic, porous, carbon felt was used as electrode material with a buffered enzyme solution as a surface film to create a gas-continuous EFC. The high gas-liquid interfacial area allows efficient oxygen supply for proton reduction at the cathode, making the system limited by the enzyme catalyst. The ability to use methanol and ethanol as vapors in gas phase in addition to use of hydrogen fuel was also shown, demonstrating potential to use such devices for cleaning biorefinery gaseous effluent streams with simultaneous electricity production. Implementation of electrodes with higher micro and nano-porosity can improve enzyme loading to allow further improvement in EFC power densities. Additionally, improvements in enzyme stability can bring enzyme fuel cells closer to commercial feasibility.