Anion exchange membrane (AEM) water electrolysis has emerged as a leading pathway for next-generation green hydrogen production. However, most current AEM systems still depend on alkaline supporting electrolytes such as potassium hydroxide. While these additives improve ionic conductivity, they also introduce issues including bipolar plate corrosion, shunt currents and accelerated membrane degradation.

The long-term goal for AEM technology is stable operation using pure water feed, but challenges persist. Key barriers include the instability of the membrane-electrode three-phase interface, limited achievable current densities and poor overall durability during extended operation.

A research team led by Prof. Shao Zhigang and Prof. Zhao Yun at the Dalian Institute of Chemical Physics (DICP), Chinese Academy of Sciences, has reported a major advancement toward overcoming these limitations. In a study published in Advanced Energy Materials, the team demonstrated a pure water-fed AEM system capable of operating continuously for over 2,400 hours, enabled through targeted membrane–electrode interface engineering.

Improved bonding strength 

To address durability issues, the researchers developed a new AEM composite membrane using poly(ether-ether-ketone) (PEEK) as the base material due to its strong mechanical properties. They incorporated quaternised polystyrene (QPS), a resin with a low glass transition temperature, as a secondary structural component.

During hot-pressing and subsequent cell operation, the QPS transitioned from a glassy to a highly elastic state. This behaviour allowed it to act like a “glue,” strengthening the membrane-electrode interface while promoting efficient hydroxide ion (OH-) transport.

Experimental results showed that the interfacial bonding strength between the composite membrane and electrode was two orders of magnitude higher than that of conventional poly(aryl piperidine) membranes, which have a glass transition temperature above 200°C. The improved structure enhanced OH- mobility, enabling the pure water-fed system to achieve 1,200 mA cm⁻² at 80°C and 1.8 V.

The optimised system sustained 2,464 hours of continuous operation at 500 mA cm⁻². Additionally, a 160 cm² large-area cell operated steadily for 160 hours at 200 mA cm⁻², demonstrating scalability and industrial potential.

Source:

https://www.eurekalert.org/news-releases/1106413