These large potentials result in a rather unusual phenomenon for fuel cells at high current densities, once the oxygen has been depleted from the oxidant stream, proton reduction becomes the cathode reaction. The MLSPBFC operated in the alkaline anode/acidic cathode mixed-media configuration, a large OCP of 1.72 V was measured, which, in light of the known overpotentials at both the cathode and the anode, is in good agreement with the theoretical OCP of 2.95 V. The MLSPBFC can thus be run in a mixed-media configuration in which the anode can be alkaline while the cathode is acidic, or vice versa, to improve individual electrode kinetics and thermodynamics. Fuel and oxidant react at the electrodes while the two liquid streams and their common liquid-liquid interface provide the required ionic conductance to complete the fuel cell chemistries. In the previous work, we were able to show that this phenomenon can be utilized to create a membraneless micro fuel cell by merging two streams, one containing fuel (Hydrazine) and one oxidant (sodium perborate), respectively, and allowing these streams to flow over the anode and cathode electrodes placed on opposing side walls within the microfluidic channel. 2), and continue to flow laminarly in parallel without turbulent mixing, if the system is characterized by a Reynolds number, Re < ~2100. In multistream laminar flow, two or more liquid streams merge into a single microfluidic channel ( Fig.
Also, the cell was allowed to run for an hour for the flow to reach a steady state. The flow rate of each of the streams was 0.3 mL min 1 (total flow rate of 0.6 mL min 1). The fuel and oxidant solutions were pumped through the device using a syringe pump (Schiller India).