Fabrication of high power density paper-based microfluidic fuel cell using a stepped catalyst layer

Paper-based microfluidic fuel cells (PMFCs) gradually become alternative energy sources due to their advanced features, including simple structure, low cost, without requiring auxiliary equipment. However, the applications of PMFCs are limited by the poor power density and expensive cost. Therefore, a novel design of catalyst layer with stepped Pd distribution is proposed to improve the PMFC performance and reduce the cost. An experimental investigation is performed to understand the underlying influence mechanism of the catalyst layer properties, including Nafion solution content catalyst layer area, catalyst loading and catalyst distribution. We found that the proportioin choice of 4.76% Nafion solution in preparing catalyst layer achieves a shortest reaction time and a highest output performance. In addition, choosing a small catalyst layer area and high catalyst loading is beneficial to improve the current density. With the hybrid arrangement of stepped catalyst layers, the PMFC reduces the cost and presents highest current density of 44.10 mA cm−2 and peak power density of 12.87 mWcm−2. Finally, our designed PMFC stack is employed to power a thermohygrograph and a blood glucose meter for at least 5 h. These practical applications are in favor of supporting the developments of integrated device with energy generation and electrochemical detection.