Analysis of Low Platinum Loading Thin Polymer Electrolyte Fuel Cell Electrodes Prepared by Inkjet Printing

作者：Shukla S; Domican K; Karan K; Bhattacharjee S^*; Secanell M

来源：Electrochimica Acta, 2015, 156: 289-300.

DOI：10.1016/j.electacta.2015.01.028

• Polymer electrolyte fuel cells
• Low platinum loading
• Electrode fabrication
• Inkjet printing
• Catalyst layer characterization

Thin, low Platinum loading polymer electrolyte fuel cell (PEFC) electrodes fabricated by inkjet printing are investigated. Catalyst coated membranes (CCMs) with Pt loading of 0.026mg(Pt)/cm(2), catalyst layer thickness between 1.5 and 2 mu m and varying Nafion loadings (NL) on the cathode electrodes of 10, 20, 30, 40 and 50 wt% are analyzed. Ex-situ scanning electron microscopy (SEM) visualization shows that the layers are porous and composed of Pt/C aggregates binded by ionomer. In-situ electrochemical testing shows that the Tafel slope of these electrodes is relatively large, i.e., 120 mV/dec. Further, at 80 degrees C and varying relative humidities, the CCMs are not sensitive to Nafion loading changes within the 20 wt% 40 wt% range. Proton transport limitations are only observed at low NL of 10 wt% while transport losses are only observed at high currents for CCM with 50 wt% NL. Comparing conventional and thin, low loading, inkjet printed electrodes, the inkjet printed electrodes show a much higher sensitivity to oxygen partial pressures. These results suggest that macro-scale oxygen and proton transport are not limiting the electrode at the 20 wt% - 40 wt% Nafion range. Pt mass activity for the inkjet CCM at ambient pressure was observed to be 196 A/mgPt (12.4kW g(Pt)(-1)), i.e., 10 times higher than a spray coated CCM, due to its reduced CL thickness and thereby reduced transport losses in the macro-scale. The Pt utilization at 2 bar gauge pressure is 47.6kW g(Pt)(-1) and represents one of the highest utilization values reported for low Pt loading electrodes.

• 出版日期2015-2-20