Superhydrophilic polyphenylene sulfide membrane with enhanced ion transfer for alkaline water electrolysis

Porous membranes play a crucial role in alkaline water electrolyzer, and addressing the urgent need for the development of membranes with enhanced ion-transferring properties and superior gas-retarding properties is of utmost importance. This work presents a simple and efficient method for preparing the superhydrophilic polyphenylene sulfide (PPS) membrane, which includes surface oxidation to generate photosensitive sulfone groups, then UV irradiation radical reaction to introduce amine groups as the reaction site, and finally covalently grafting chitosan oligosaccharide (COS) monomers containing hydrophilic groups onto the PPS surface via interfacial polymerization to form a superhydrophilic coating on the surface of fibers. The application of ATR-FTIR, XPS, and SEM has been employed to illustrate that the monomers utilized in the preparation procedure are chemically bonded to the membrane surface, resulting in the formation of a hydrophilic surface layer. The modified PPS membrane can fast adsorb water droplets, promote ion transfer and gas bubbles detachment in an alkaline solution. When used as a membrane in an alkaline water electrolyzer with a 30% KOH electrolyte solution, the cell voltage of 1.90 V at 80oC and 5000 A m- 2, and the hydrogen and oxygen produced with a purity of 99.88% and 99.49%, respectively, which was better than the commercial PPS membrane, and the performance was remained essentially unchanged after 120 h of operation. As a result, the superhydrophilic PPS membrane generated by this process has a wide range of applications in alkaline water electrolysis.