Advanced catalyst layers for PEM fuel cell produced by inkjet printing: Catalyst layer optimisation and comparison with ultrasonic-spray-coated one

• Inkjet printing generates continuous uniform catalyst layers. • Deposition occurred directly onto membrane surface. • Industrial inkjet printhead enables deposition over large membrane areas. • Inkjet catalyst layers have high activity and enable decrease of Pt loading. • Crack formation in layer depends on ink, print resolution and distance to printhead. Industrial inkjet printing (IJP) emerges as a progressive technology for scalable and precise deposition of catalyst layers (CLs) in proton exchange membrane fuel cells (PEMFCs). In this study, an industrial piezo-IJP head was used for deposition of the CLs directly onto a Nafion™ 212 membrane. Several strategies to mitigate cracks in CLs were considered: addition of ethylene glycol to the inkjet ink, adjusting distance between the printhead and the membrane, and reducing printing resolution in combination with specific algorithms of the drops order. The optimised printing parameters were used to fabricate crack free homogenous catalyst coated membranes (CCMs) with Pt loadings on the cathode varying from 0.1 to 0.3 mg Pt cm −2 . During operation in a PEMFC, IJP layers showed superior performance to CCMs produced by ultrasonic spray coating (USC). The USC CCMs reached a peak power density of 1.12 W cm −2 with 0.3 mg Pt cm −2 on the cathode, while the IJP reached a peak power density of 1.13 W cm −2 already with 0.1 mg Pt cm −2 on the cathode. This enhancement was attributed to the reduced ohmic resistance and increased Pt utilisation, achieved through optimisation of the catalyst layer transport properties. These findings highlight the potential of IJP for high-capacity production of low loaded CLs with improved performance.