Performance evaluation and mechanistic study of a flannel-based self-pumping single-stream microfluidic fuel cell

Conventional self-pumping microfluidic fuel cells are plagued by critical drawbacks including severe fuel-oxidant cross-mixing and poor high-concentration-fuel tolerance, which substantially limit their output performance and practical deployment. To overcome these bottlenecks and optimize the structural design and operating mechanism of microscale fuel cells, a three-dimensional multi-physics model integrating capillary imbibition, mass transport and electrochemical kinetics is established for a flannel-based self-pumping single-stream microfluidic fuel cell. Grid-independence verification is performed before numerical simulation. Experimental validation reveals that the maximum relative error of the present model is below 5%, verifying its favorable reliability and calculation accuracy. Systematic parametric simulations are conducted to explore the regulatory effects of key operating and structural parameters on the cell output performance. The results show that moderate elevation of fuel concentration and channel thickness improves electrochemical reaction efficiency and alleviates activation polarization. Under the recommended parameter combination acquired from single-factor analysis, the cell achieves a peak power density of 1.71 mW/cm 2 and a limiting current density of 7.58 mA/cm 2 . The optimized cell achieves 20% higher peak power density than reported flannel-based microfluidic fuel cells. When benchmarked against other reported one-chamber or single-stream microfluidic fuel cells, the present device delivers competitive electrochemical performance.