Characterisation of a polyaromatic PBI blend membrane for SO2 electrolysis

• Evaluation of a polyaromatic SFS001 and F6PBI blend membrane for SO2 electrolysis.
• Various MEA manufacturing methods investigated.
• Long term operation over 140 h conducted at 0.1 A cm−1.
• TGA-MS analysis used for MEA characterisation before and after long term operation.

The application of a polyaromatic acid–base blend membrane from partially fluorinated and sulfonated aromatic polyether and the polybenzimidazole F6PBI has been investigated for hydrogen production using SO2 electrolysis. Several membrane electrode assembly (MEA) pre-doping strategies have been investigated using polarisation curves. Membrane thickness variation, voltage cycling and long term operation at constant current (0.1 A cm−2) was also performed. Scanning electron microscopy (SEM) and TGA-MS was used to evaluate MEA stability before and after long term operation. It was found that doping the MEA after hot pressing performs the best reaching a current density of 0.3 A cm−2. The performance could also be improved by cycling the voltage 16 times to reach 0.33 A cm−2. Long term operation showed stable voltage at 0.1 A cm−2 staying below 0.8 V. SEM images showed that no significant sulfur deposition was present while TGA-MA analysis confirmed some degradation after the 140 h of operation.