Dr. Hui Xu, CTO, Green Hydrogen and Head, H2 Center of Excellence at Envision Energy

Water electrolysis has become one of the most viable technologies to produce green hydrogen towards the goal of global decarbonization, particularly when integrated with renewable solar and wind energy. However, this technology still faces some grand challenges including high cost and insufficient lifetime, which make it less competitive against methane reforming that however releases large quantity of CO₂ while producing hydrogen.

There are two major commercialized water electrolysis technologies including alkaline water electrolysis (AWE) and proton encage membrane water electrolysis (PEMWE).  Alkaline water electrolysis (AWE) has been successfully commercialized for decades; however, its drawbacks include low operating current density, high shunt current, difficult in integration with renewable energy. The advent proton exchange membrane water electrolysis (PEMWE) leads to small footprint, high current density, and fast dynamics.  The combination of AWE and PEMWE enables anion exchange membrane water electrolysis (AEMWE). Currently, AEMWE faces some challenges like instability of membrane/ionomer, non-optimal electrode design and poor interfacial contact between the electrode and the membrane.

The improvements of water electrolyzers needs deep understanding of some key factors like interface, corrosion, catalyst stability, particularly under renewable intermittency. Advanced research in materials like catalysts and membranes can partially help to address these challenges.  In addition, some effective probes and analytical approaches must be developed to fully elucidate these important phenomena before we can transform the performance of water electrolyzers.   Finally, the scale-up of water electrolysis via mass manufacturing and automation will be addressed to meet ever-increasing demands for green hydrogen.  A strong collaboration between industry and research institutions becomes highly crucial for transitioning water electrolysis from mW to MW towards global decarbonization.