How to develop novel electrodes for advanced alkaline water electrolysis

Water electrolysis is the electrochemical reaction by which water is converted into oxygen and hydrogen, employing an electrical current at the cathode and anode - the electrodes - of an electrochemical cell. This electrochemical process holds immense potential as water electrolysis to produce green hydrogen is regarded as one of the many solutions to execute the energy transition and move away from fossil fuels as energy vectors and carriers in the hard-to-abate sectors.

Although first developed more than a century ago, alkaline water electrolysis has been constantly evolving. Scientists at De Nora are at the frontline of creating innovative solutions to lower costs and enhance the sustainable outlook and energy efficiency of the green hydrogen production process. In this sense, research in the context of alkaline water electrolysis is directed towards creating novel and performing electrodes.

A typical electrode for lab scale demonstrations (100 cm2) is made of a substrate, and an electrocatalytic coating is applied on top of this substrate. The role of the metal substrate is to shuttle electrons, whereas the electrocatalytic coating catalyzes the hydrogen or oxygen evolution reactions at the cathode and anode of the electrochemical cells, respectively.

To construct these electrodes, scientists prepare a solution of the electrocatalytic coating that one wants to apply on the metal substrate. Then, this electrocatalytic coating solution is applied on the surface of the substrate, and finally thermally treated to obtain the final electrode.

Firstly, one of the most critical aspects of creating new solutions to apply as electrocatalytic coating is the solubilization of the metal components into the solvent. Secondly, it is essential that these solutions of electrocatalytic coating tether to the metal substrate, and different strategies can be used to ensure the binding.

Finally, the concentration of these solutions also plays a key role in determining the final loading of electrocatalysts.

An array of proprietary protocols are carried out to evaluate the properties of the new electrodes, capable to predict coating behaviour under different wearing factors considering industrial plant operation.
One of the most prominent analyses is the SEP (single electrode potential), which involves measuring the electrochemical potential.
Another essential test called ALT (accelerated lifetime) is performed, and it’s a measure of the robustness as well as durability of the electrode.

⁠This set of tests is important because not only is the evaluation of the electrochemical potential of the new electrode essential, but its long-term durability also plays a crucial role in developing novel and improved electrodes for alkaline water electrolysis.

Developing novel electrodes for De Nora's advanced alkaline water electrolysis is a challenge; however, De Nora is committed to shaping a new and sustainable world through the production of green hydrogen, and studies like these demonstrate the effort that current research is making toward achieving this goal.