Development of High Durability Bi-functional Oxygen Electrode for Unitized Regenerative Fuel Cell (URFC)

Abstract

The performance of different PtIr catalysts with varying Ir contents was optimized under fuel cell and in electrolyzer mode in unitized regenerative fuel cell (URFC). Overall conversion efficiency of 49% was obtained with 85Pt:15Ir catalyst composition. The long term stability of the URFC was improved using gold coated Ti bipolar plates. The characteristics of gold coated Ti bipolar plates were studied using x-ray diffraction (XRD), cyclic voltammetry (CV), and linear sweep voltammetry (LSV). An attempt was made to prepare high stability microporous layer (MPL) using corrosion resistant graphitized carbon. In addition, the hydrophobic characteristics of the bifunctional oxygen electrode (BOE) catalyst were modified by the incorporation of 5 wt.% PTFE binder in the catalyst layer.