Polymer electrolyte membrane water electrolyser with Aquivion® short side chain perfluorosulfonic acid ionomer binder in catalyst layers

The Aquivion® short-side-chain (SSC) perfluorosulfonic acid (PFSA) ionomer was adopted in catalyst layers (CL) of polymer electrolyte membrane water electrolysers (PEMWE) instead of long-side-chain (LSC) Nafion® ionomer. The effects of SSC ionomer content in CL for oxygen evolution reaction were studied in half cell with cyclic voltammetry and steady state linear sweep. In a single cell test the MEA with SSC-PFSA Aquivion® ionomer exhibited better thermal stability than the one with LSC-PFSA Nafion® ionomer at 90 °C. The cell voltage at a current density of 1 A cm−2 was 1.63 V at 90 °C using the SSC-PFSA Aquivion® ionomer binder, Nafion® 117 membrane, and without back pressurizing. In a continuous operation the cell voltage degradation rate of the MEA using Aquivion® ionomer binder was only about 0.82 mV h−1.