Thin film surface modifications of thin/tunable liquid/gas diffusion layers for high-efficiency proton exchange membrane electrolyzer cells

A proton exchange membrane electrolyzer cell (PEMEC) is one of the most promising devices for high-efficiency and low-cost energy storage and ultrahigh purity hydrogen production. As one of the critical components in PEMECs, the titanium thin/tunable LGDL (TT-LGDL) with its advantages of small thickness, planar surface, straight-through pores, and well-controlled pore morphologies, achieved superior multifunctional performance for hydrogen and oxygen production from water splitting even at low temperature. Different thin film surface treatments on the novel TT-LGDLs for enhancing the interfacial contacts and PEMEC performance were investigated both in-situ and ex-situ for the first time. Surface modified TT-LGDLs with about 180 nm thick Au thin film yielded performance improvement (voltage reduction), from 1.6849 V with untreated TT-LGDLs to only 1.6328 V with treated TT-LGDLs at 2.0 A/cm2 and 80 °C. Furthermore, the hydrogen/oxygen production rate was increased by about 28.2% at 1.60 V and 80 °C. The durability test demonstrated that the surface treated TT-LGDL has good stability as well. The gold electroplating surface treatment is a promising method for the PEMEC performance enhancement and titanium material protection even in harsh environment.