Effect of Reactant Flow Rate and Operation modes on Direct Formic Acid Fuel Cell (DFAFC) Performance

Background/Objectives: The main focus of this research is to study the effects of reactant flow, i.e. formic acid and oxidant, and operation mode, i.e. passive, semi-passive or active conditions, on the Direct Formic Acid Fuel Cell (DFAFC) performances. Methods/Statistical Analysis: A single cell DFAFC with 5 cm² electrode is used in this study. The DFAFC is operated with 10 M of formic acid concentration under four modes of reactant supply: air breathing, air flowing(80 to 600 mL min^-1), oxygen flowing (10 to 100 mL min^-1) at the cathode, and formic acid flowing (2 to 15 mL min^-1) at the anode to investigate their effects on cell performance. Findings: It is obtained that the DFAFC performances are affected by oxidant types, i.e., air and oxygen, flow rate, and the mode of operation. In passive operation, the maximum power density is obtained at 2.95 mW cm^-2. The highest performance is achieved in semi-passive using 50 mL min^-1 of oxygen with maximum power density of 10.92 mW cm^-2. Meanwhile, for semi-passive using air flow condition at 400 ml min^-1 shows a maximum power density at which 8.89 mW cm^-2. For active operation, the highest performance is obtained using 6 mL min^-1 with a maximum power density at 8.52 mW cm^-2. Application/Improvements: The semi-passive operation with oxygen could improve the DFAFC performances, and hence the DFAFC could be used as an energy source for electric and electronic applications.