Influence of Contact Pressure on Performance and Crossover in Zero‐Gap Alkaline Water Electrolysis

ABSTRACT

Performance and product gas purity in alkaline water electrolysis are influenced by the mechanical contact pressure between electrodes and diaphragm in zero‐gap cells. This relation is addressed here using a self‐designed contact pressure cell, which allows us to adjust the contact pressure directly during cell operation. It is found that the performance in non‐welded lab cells can depend significantly on contact pressures. This mainly depends on varying contact resistances, but also on the deformation of the electrodes and diaphragm. The latter leads to increased crossover, which is also visible in a reduced bubble point pressure. Welding the electrode to the flow field reduces the impact of the contact pressure on performance, but not on the crossover. Optimizing and controlling contact pressure impacts in zero‐gap cells is essential, and the presented cell simplifies future studies in this field.