Effect of Ionomer Loading in Inket Printed Catalyst Coated Membranes on PEFC Performance

The effect of ionomer loading on ultra-thin polymer electrolyte membrane fuel cell (PEMFC) electrodes fabricated using an inkjet printer is studied under a variety of temperatures and relative humidity conditions. Catalyst layer inks with varying amounts of Nafion were prepared and loaded in inkjet cartridges. The inks were then jetted on a Nafion membrane using an inkjet printer in order to produce fuel cell electrodes with low loadings. The Pt loading for the fabricated electrodes was estimated to be in the range of 0.009–0.01 mg/cm2 per printer pass. SEM imaging shows that the thickness of a catalyst layer fabricated using 10 passes is approximately 3 microns and the catalyst layer agglomerates are about 200nm in radius. In order to determine the optimal Nafion content for this fabrication method, the electrochemical active area and steady state performance for the fabricated catalyst coated membranes (CCMs) was measured and also compared to a conventional CCM fabricated using spray deposition. Results show that optimal performance is achieved with a 40wt% Nafion loading under the operating conditions tested. The improved performance can be attributed to decrease in cell resistance and increase in proton conductivity.