Impact of pore-forming by PSF in the anode on power generation and mass transport characteristics of direct formic acid fuel cell

Abstract

Controlling the mass transport in the anode plays a crucial role in the higher performance of direct formic acid fuel cells (DFAFCs) due to the two-phase flow of the liquid fuel reactant with the CO2 gaseous product. A pore-designed anode catalyst layer using polystyrene fiber (PSF) as a pore former is fabricated to investigate the relationship between the pore properties of the DFAFC and power generation/mass transport characteristics by controlling the diameters and amounts of the PSF. PSFs with various average diameters are prepared by the electrospinning. The anode catalyst containing the PSFs is coated by spraying method on the membrane. The PSFs in the anode catalyst layer are removed by soaking in ethyl acetate, resulting the pore forming in the catalyst layer. DFAFC using 3 μm-0.5 PSF as pore former shows the highest crossover flux at the operating temperatures of 30 °C and 60 °C, which results in 25% and 5% increases of the maximum power density respectively, as compared to without-PSF. This indicates that the appropriate PSF properties, i.e., diameter and amount, can contribute to enhancing the liquid saturation in the catalyst layer by increasing the fuel transport and CO2 removal, resulting in a performance improvement.