Performance of passive direct formate fuel cells using chitosan as an anode binder

In this study, passive anion-exchange membrane (AEM) direct formate fuel cells (DFFCs) were developed and tested. Passive DFFCs consist of a fuel reservoir attached to a Pd-loaded anode, a commercially available AEM, and an air-breathing Pt-loaded cathode. Nafion or chitosan content of 22, 15, 10, or 5 wt% was blended with the anode catalyst ink as electrode binders. The polarization curves of the cells and Cyclic Voltammetry (CV) curves of the anodes were measured under different analyte compositions by mixing HCOOK and KOH with the molarity ranging from 1 M to 7 M at room temperature. The results showed that the ECSA values of the anode increased with the decrease in the binder content regardless of the binder type. The 15 wt% Nafion-based and 5 wt% chitosan-based passive AEM DFFCs fed with fuel containing 3 M HCOOK in 3 M KOH produced the highest maximum power density of 24.9 mW/cm2 and 27.5 mW/cm2, respectively. Finally, the current output of discharging of the 5 wt% chitosan-based passive AEM DFFCs at 0.4 V for 10 hr showed that providing the cell with more concentrated fuel produced more stable current as the concentrations of HCOOK and KOH are identical.