Sulfonated-PPS/LDH Composite Membrane With Hydrogen Bond Network for High-Performance Alkaline Water Electrolysis

Composite membranes play a pivotal role in alkaline water electrolysis for green hydrogen production. However, current membranes still suffer from low conductivity and inadequate long-term stability. Herein, we develop a sulfonated polyphenylene sulfide (sPPS) and NiFe-layered double hydroxide (LDH) composite membrane featuring a hydrogen bond network for highly efficient alkaline water electrolysis. This sPPS/LDH composite membrane is fabricated by a sulfonation-casting strategy. The resulting composite membrane exhibits excellent thermal stability, mechanical strength, hydrophilicity, high bubble point pressure, and low area resistance compared to the widely used commercial ZIRFON 500 composite membranes. Molecular dynamics simulations further reveal that more hydrogen bonds were formed due to the presence of LDH, accelerating the ion transport. When applied in an alkaline water electrolyzer, the optimized sPPS/LDH membrane enabled a current density of 936 mA cm^-2 at 1.9 V in 30 wt.% KOH at 80°C and maintained stable operation for over 500 h at 500 mA cm^-2. This work sheds light on the way to form conductive and stable membranes through forming a hydrogen bond network within the composite membranes.