Overview:

Water elec­tro­lysis is a key tech­no­logy for split­ting water into hydrogen and oxygen using rene­wable ener­gies. Green hydrogen is considered a promi­sing energy carrier for a sustainable future and is produced by elec­tro­lysis using rene­wable energies.

In the CF04_4 project, the inno­va­tive approach of using anion exch­ange membranes for water elec­tro­lysis (AEM-WE) is being pursued, whereby the advan­tages of proton exch­ange membrane elec­tro­ly­zers (PEM-WE) and alka­line elec­tro­ly­zers (AEL) can be combined. On the one hand, expen­sive precious metals are no longer required to prevent corro­sion and, on the other, no concen­trated elec­tro­lyte is needed as the ion exch­ange takes place via a polymer-based anion exch­ange membrane.

The heart of an AEM-WE is the elec­tro­lysis cell based on a membrane elec­trode assembly (MEA). High-entropy alloys (HEA) are suitable as a new, precious metal-free mate­rial class for the cata­lysts. HEAs are alloys that consist of at least five homo­ge­neously distri­buted metallic elements. This results in new proper­ties that can be used in parti­cular for elec­tro­ca­ta­lytic acti­vity. This high acti­vity in the hydrogen evolu­tion reac­tion under alka­line condi­tions provides the precious metal-free cata­lysts with new, highly scalable manu­fac­tu­ring processes that can be used in industry.

Using atmo­spheric pres­sure plasma spraying, the porous nickel-based Raney cathode is deve­loped. The cathode is then deco­rated with HEA particles, which are depo­sited from the homo­ge­neously spark plasma sintered targets by magnetron sput­te­ring. The overall aim of the CF04_4 project is to develop a func­tional model of a low-cost, high-perfor­mance, precious metal-free MEA for alka­line water electrolysis.

Design and func­tional prin­ciple of a membrane elec­trode unit with struc­tured, porous trans­port layers (PTL) on the cathode side.