It has been shown that hydrogen, which can be used for energy storage, can be produced efficiently by the membrane based Hybrid Sulfur (HyS) process. During the HyS electrolysis step, SO₂ and H₂O are converted to H₂ and H₂SO₄. The proton exchange membrane (PEM) used for this process should have both a high proton conductivity and acid stability. Since the widely used perfluorosulfonic type materials are restricted by their humidification requirements, materials such as polybenzimidazole (PBI) has been found to be promising in blends with partially fluorinated polyaromatic polymers at operating temperatures of 80 and 95 °C within the SO₂ electrolyser. Operation at higher temperatures (>100 °C) however holds many advantages such as improved reaction kinetics and simplified water management. For this study a cross-linked partially fluorinated polyaromatic PBI blended membrane was evaluated at 120 °C. Humidified SO₂ was supplied to the anode to produce sulfuric acid while hydrogen was formed at the cathode. The SO₂:H₂O feed was managed at the applied current densities until a constant voltage was obtained, and there after increased accordingly with increasing current density. Polarisation curves (Figure 1) recorded for the blended PBI membrane were comparable with reported s-PBI in literature values in the lower current density region (< 0.5 A/cm²). A maximum current density of 1.1 A/cm² was reached in comparison to the 0.5 A/cm² for s-PBI at a temperature of 110 °C. Voltage stability was monitored at a current density of 0.3 and 0.6 A/cm² for a duration of 6 hours or until the maximum voltage had been reached. The lower current density (0.3 A/cm²) was more constant over the course of the measurement, with a standard deviation of 3 mV, when compared to the higher applied current density. These results are promising for further testing and optimization of the blended PBI membranes for higher temperature SO₂ electrolysis.