Membraneless microchannel glucose biofuel cell with improved electrical performances

Simulation and experimental data are combined to optimize the electrode geometry of a membraneless laminar flow glucose biofuel cell. The design of the cell is based on a Y-shaped microfluidic channel that exploits the laminar flow of fluids. Glucose is oxidized by the glucose oxidase enzyme at the anode whereas oxygen is reduced by the laccase enzyme at the cathode. The energy output level of the microfluidic biofuel cell is limited by the reaction-depletion boundary layer at the electrode surfaces. To optimize the electrochemical characteristics of the device, our approach involves the reduction of both electrode length and spacing between anode and cathode in the microchannel. Computational fluids dynamics and electrochemical measurements show that the current density and power density are 3 times higher by decreasing the electrode length from 10 to 0.5 mm. The device delivers a power density of 0.33 mW cm−2 for a cell voltage of 0.22 V in buffered solutions at 300 μL min−1 flow rate. Moreover, the electrical performances are increased by generating up to 0.55 mW cm−2 for a cell voltage of 0.3 V when ohmic losses in the electrolyte are decreased by reducing the distance between cathode and anode in the microchannel.