Hydrophilic modified polyphenylene sulfide fabric separator for efficient alkaline water electrolysis

Abstract

The separator plays a crucial role in alkaline water electrolysis (AWE) by conducting hydroxide ions and separating gases. Therefore, developing a high-performance AWE separator is of significant importance. This study proposes a method for preparing a hydrophilic polyphenylene sulfide (PPS) fabric separator. Firstly, PPS fabric separator undergoes a chloromethylation reaction to graft chloromethyl groups onto its surface, increasing its reactivity. Subsequently, chemical grafting introduces imidazole groups and quaternary ammonium groups to improve hydrophilicity. The modified PPS separator can rapidly conduct hydroxide ions and facilitate gas separation in alkaline solutions. Experimental results show that the modified PPS separator exhibits an area resistance of 0.219 Ω cm² in 30 wt % KOH solution at 80 °C, which is a 74.86 % reduction compared to the unmodified separator. Additionally, the bubble point pressure is enhanced by 2.46 %. During alkaline electrolysis experiments in a custom zero-gap electrolyzer, the modified separator demonstrates a current density of 493 mA cm⁻² at a voltage of 2 V and maintains the stable performance after 500 h of operation, indicating the excellent electrolytic stability. This study provides a feasible reference for the industrial production of low-resistance, high gas-tightness AWE hydrogen production separators.