The performance of an alkaline electrolyzer diaphragm depends on several factors

 The performance of an alkaline electrolyzer diaphragm depends on several factors, including:

Porosity

A diaphragm with a higher porosity can improve alkaline water electrolysis performance. For example, a PEEK/PPS diaphragm with 20% polymer content and a porosity of 38.9% showed the best performance. 

Thickness

A thinner diaphragm can improve performance. For example, a 0.1 mm diaphragm can achieve a nominal current density of 1.8 A cm−2 at 100 °C. 

Electrolyte solution

A highly concentrated electrolyte solution is required to maintain high ionic conductivity. 

Gas crossover

Gas crossover can limit the ability to operate at low loads. To enable a low minimum load, the operating pressure should be kept below 8 bara. 

Other factors that affect the performance of an alkaline electrolyzer include: 

Temperature: The operating temperature is typically in the range 60–80 °C.

Pressure: Higher pressure can reduce the efficiency and purity of the gas, but it requires less energy for production of compressed hydrogen.

A diaphragm is a critical component of an alkaline water electrolyzer because it: Ensures ionic contact between the electrodes and Prevents the product gases from mixing.