Improved performance of a paper-based glucose fuel cell by capillary induced flow

This work describes the use of a capillary quasi-steady flow to improve the power and current output of a paper-based enzymatic glucose/O2 fuel cell. Anode and cathode of the fuel cell are made with screen-printed carbon electrodes properly functionalized with enzyme-based inks. The electrodes have been placed at both sides of a paper strip. The strip is connected to a paper-based microfluidic system that allows establishing capillary flow. Quasi-steady flows with different flow rates have been generated by modifying the paper materials that constitute the adsorbent pad of the system. The polarization curves of the fuel cell at physiological glucose concentration (5 mM, pH 7.4) show that convective mass transport generated by the capillary flow allows mitigating cathode current limitations and improves the overall fuel cell performance. Four different flow rates ranging from 0.22 ± 0.01 μL/s to 2.68 ± 0.30 μL/s were investigated obtaining an increase in the fuel cell power output up to 56%.