Paper-based microfluidic fuel cell with innovative dual-zone pore structure, a numerical investigation

Paper-based microfluidic fuel cell (PMFC) is well known for its low cost, simple structure and high renewability, which is especially suitable for powering biosensors, lateral-flow test arrays, smart packages, etc. Recent research on the PMFC primarily focuses on its reactant selection, electrolyte composition and macroscopic structural modification, while few attentions have been paid to the micropore structure of its paper substrate, which can significantly affect the electrolyte capillary flow and reactant mass transfer inside. To address this research gap, the present study establishes a three-dimensional PMFC numerical model to comprehensively investigate the influence of key pore parameters, including porosity, pore size and tortuosity, on the PMFC performance, while the underlying mechanisms of fluidic dynamics and mass transport are also revealed in depth. Furthermore, a novel dual-zone pore structure is proposed for the first time, enabling independent optimization of the anode and cathode performance. Modeling results demonstrate that a paper substrate with porosity of 0.4, pore size of 11 μm and tortuosity of 1.5 achieves the most efficient mass transport and electrochemical process. By dividing the paper substrate into two zones and selectively reducing the cathode-side porosity from 0.8 to 0.2, the cell performance can be further improved by 36.4% compared with the one with uniform paper porosity of 0.8.