Supporting data for “BOOSTING PERFORMANCE OF MEMBRANELESS MICROFLUIDIC FUEL CELLS VIA CELL ARCHITECTURE OPTIMIZATION AND FLOW MANAGEMENT”

This research focuses on developing high-performance membraneless microfluidic fuel cells (MFCs) via cell architecture designs and flow management. Both self-pumping and pump-assisted MFCs were designed with innovative architectures. Both single-electrolyte and dual-electrolyte MFCs were developed. For each design, the MFC was tested with architecture-sensitive fuel.

• Fuel-tolerated cathode material was synthesized for the single-electrolyte MFC. HCOOK was dissolved in water to serve as an efficient and safe liquid fuel.
• To enhance the voltage of a MFC, acid-alkaline dual-electrolyte configuration was adopted. A low-cost hydrogel was sandwiched between the two electrodes and two paper flow channels to restrain the mixing and electrolyte neutralization. The improvement of the gel-aided architecture was proven with H₂O₂ as both the fuel and oxidant.
• For pump-assisted MFCs, fuel utilization was frequently sacrificed to achieve high electrochemical performance. To enhance fuel utilization while maintaining high electrochemical performance, the density and viscosity of the co-flow were increased via the addition of suitable polymer additives. The influence of the polymer additives in the electrolytes was investigated with methanol fuel.

All the MFCs were optimized through a parametric study. The optimal fuel and electrolyte concentrations were decided. For self-pumping MFCs, their durability and reactivation ability were investigated. For pump-assisted MFCs, optimal and minimum feasible flow rates were explored, and the influence of the flow rate on the fuel

The self-synthesized electrode materials were characterized by XRD, XPS, and Raman spectra, and the electrolytes were studied via FT-IR tests. The morphology of the electrodes was studied by SEM and TEM microscopy. The EPR was employed to assist in the study of the electrochemical disproportionate reactions of H₂O₂ on each electrode.

The overall performances of the MFCs were significantly improved through the innovative designs and flow management in this study. Higher power output is usually provided by pump-assisted MFCs while self-pumping MFCs exhibit better portability and flexibility. The selection of the MFCs is based on the requirements of the applications including the power demands, the dimension restrictions, and operation conditions. In summary, the designs in this study broaden the MFCs' practical applications and pave the way for their future development.