Analysis of Inkjet Printed PEFC Electrodes with Varying Platinum Loading

Abstract

PEFC electrodes manufactured using inkjet printing are investigated. Cell performance, Tafel slope, reaction order and local oxygen transport resistance of electrodes with varying Pt loadings of 0.014 to 0.113 mg/cm2 are studied in order to understand the nonlinear relationship between loading and performance. The performance increase with Pt loading was substantially reduced above Pt loadings of 0.08 mg/cm2. Electrochemical active area of the electrodes decreased from 66.4 to 40.4 m2/g as the Pt loading increased from 0.026 to 0.113 mg/cm2. Below the transition voltage of 0.8 ViRfree, the Tafel slope was found to be a function of the Pt loading and oxygen partial pressure. The kinetic performance dependence on was quantified by measuring the total reaction order. Oxygen transport resistance evaluated from limiting current experiments revealed its dependence on the inlet relative humidity of the reactants. The local oxygen transport resistance was found to drop from 5.93 ± 3.16 s/cm to 3.43 ± 1.67 s/cm as the humidity increased from 50% to 90%.