Microchannel Modification in Membraneless Microfluidic Fuel Cell to Control the Concentration Boundary Layer

Abstract

The concentration boundary layer thickness is one of the most important parameters used to characterize the performance of membraneless microfluidic fuel cells. Low concentration boundary layer thickness leads to a high electrochemical reaction over the electrodes, improving the performance of the fuel cell. For this purpose, this paper proposes a modified microchannel which directs the fuel and the oxidant to the electrode surfaces. According to the results obtained, the amount of concentration on the cathode electrode surface and therefore the amount of current density increased with the modified microchannel. At the same point of the cathode electrode surface, the oxidant concentration in the conventional microchannel was 0.055 mol/m3, while it was 0.19 mol/m3 in the modified microchannel. Since the concentration overpotential reduced, the limiting current density was 0.372 mA/cm2 in the conventional microchannel and 0.741 mA/cm2 in the modified microchannel. Thus, the limiting current density value increased by 91.5%.