A parametric study of the direct formic acid fuel cell (DFAFC) performance and fuel crossover

The effect of formic acid concentration (2–20 M), operating temperature (30–70 °C), and relative humidity (RH 40–90%) on the direct formic acid fuel cell (DFAFC) performance and fuel crossover were studied. In addition, air and oxygen were used to investigate the effect of oxidant flow rate on DFAFC performance and fuel crossover by operating the DFAFC under three modes of reactant supply: passive, semi passive (oxidant supplied), and active (both oxidant and fuel supplied). Fuel crossover was determined by measuring the percentage of exhausted carbon dioxide (CO2) at the cathode using a CO2 analyzer, from which the equivalent formic acid crossover flux was calculated. The results indicate that the DFAFC performance and fuel crossover were affected by formic acid concentration, temperature, humidity, oxidant flow rate, and the mode of operation. Optimums of these operating parameters were established for obtaining high performance of the DFAFC. The relationships between these parameters and the performance and fuel crossover of the DFAFC are discussed in this paper.