Modification of electrodes using Al2O3 to reduce phosphoric acid loss and increase the performance of high-temperature proton exchange membrane fuel cells

Abstract

The addition of a small amount of Al₂O₃ (6 wt%) to the catalyst layer of high temperature-polymer electrolyte membrane fuel cells (HT-PEMFCs) using phosphoric acid-doped membranes was proved to be an effective way to increase durability and performance. It was confirmed from the XRD study that Al₂O₃ reacts with phosphoric acid diffusing from the membrane to the electrode and produces aluminum dihydrophosphate (Al(H₂PO₄)₃), which has proton conductivity. As a result, the formation of Al(H₂PO₄)₃ not only reduces the loss of phosphoric acid and the resistance in fuel cells but also enhances the electrochemical surface area of catalysts.