Enhanced gas removal and cell performance of a microfluidic fuel cell by a paper separator embedded in the microchannel

The generated gas bubbles in microfluidic fuel cells (MFCs) cover the active surface area of the electrode and greatly limit the cell performance. In this study, a feasible approach is proposed to effectively accelerate bubbles removal and enhance cell performance by embedding a paper separator in the middle of the microchannel. Visualization of bubble behaviors and the corresponding electrochemical measurements are performed to investigate the effect of bubbles on the cell performance. Periodical process of the bubble growth and removal leads to the fluctuation in the current density of the MFC. The rapid gas removal and the low ohmic resistance are observed after embedding a layer of filter paper in the microchannel, causing improved fuel transfer and smaller ohmic loss. Although the current density fluctuates more frequently, the fluctuation amplitude decreases and the cell performance is enhanced. Compared with the MFC without paper separator, the maximum power density and the limiting current density of the MFC with paper separator is increased by 25.2% and 130%, respectively. Moreover, the cell performance is improved with increasing the flow rate of reactant solution and the peak power density achieves 25.9 mW cm(-2) under flow rate of 1500 mu L min(-1). (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

By embedding a paper separator in microfluidic fuel cells, the rapid gas removal and low ohmic resistance lead to improved fuel transfer and reduced ohmic loss, enhancing cell performance. Although there is frequent fluctuation in current density due to periodic bubble growth and removal, the fluctuation amplitude decreases with the paper separator present, resulting in better cell performance.