High-Temperature Anion Exchange Membrane Water Electrolysis

While the low-temperature (50–80 °C) anion-exchange membrane water electrolysis (AEMWE) field is blooming, the potential for cell operation above 100 °C remains unexplored. Hereafter, we show the first high-temperature AEMWE (HT-AEMWE) cell operating at 110 °C under dry cathode operations with platinum-group metal-free catalysts. Increasing temperature strongly enhances OH– conductivity (119–216 mS/cm at 50–95 °C), water diffusivity (∼6.0-fold at 30–70 °C), and oxygen and hydrogen evolution reaction kinetics (∼30- and ∼6.0-fold increases, at 10–70 °C), altogether translated into substantial cell-level performance gains. The KOHaq-fed HT-AEMWE reaches >5 A/cm2 at <2.2 V and shows negligible degradation (4 μV/h) over a 500 h test at 1.0 A/cm2. Notably, the pure water-fed HT-AEMWE operated for 400 h at 110 °C and 0.5 A/cm2 is extremely stable (6 μV/h), suggesting that the HT-AEMWE technology can eliminate the need for an alkaline liquid electrolyte. This represents a significant landmark for the AEMWE technology.