Hydrophilic Polyphenylene Sulfide/Cellulose/Polyphenylene Sulfide Composite Membrane with High Bubble Point Pressure and High Oxygen Purity for Alkaline Water Electrolysis

The advancement of ecofriendly and high-performance energy transformation systems has driven the development of advanced membrane materials for alkaline water electrolysis (AWE), which conduct hydroxide ions and block the interpenetration of hydrogen and oxygen. The wettability and inadequate gas blocking remain challenges for the AWE membrane. In this study, a hydrophilic polyphenylene sulfide/cellulose/polyphenylene sulfide (PPS/C/PPS) composite membrane with high bubble point pressure (BPP), outstanding oxygen purity, and low area resistance (AR) was fabricated. The porous PPS/C/PPS membrane exhibits a high BPP of 12.4 bar and low AR of 0.014 Ω·cm2. Notably, gas purity tests reveal that the oxygen purity is about 99.974%, which is much higher than that of commercial hydrophilic polyphenylene sulfide (C-HPPS) (98.5%). The AWE cell with the PPS/C/PPS composite membrane shows a current density (CD) of 319.2 mA·cm–2 in 30 wt % KOH solution at 80 °C at a voltage of 2 V, surpassing that of C-HPPS (208.0 mA·cm–2). Additionally, the AWE cell exhibits high stability of more than 450 h at KOH solution (30 wt %) without attenuation, emphasizing the membrane’s competitive edge and its vast application potential.