Effects of electrolyte temperature and voltage input on the hydrogen production rate of a polymer electrolyte membrane electrolyzer

This paper analyses the limiting effects of temperature and voltage on the hydrogen production rate and Faraday efficiency of a single-cell Proton Exchange Membrane (PEM) electrolyzer that operates without an active membrane humidity control. The analysis is based on the problem of identifying the optimal operating conditions for the system setup mainly due to membrane dehydration that leads to ohmic losses. The experiments are conducted under controlled laboratory conditions for distilled water temperature variations (25 to 50°C) and input voltage variations (1.8V to 3.6V). The key outputs are hydrogen production rate and Faraday efficiency. The results indicate that the MEA humidity is normal up to 45oC, but the hydrogen production kinetics loss is 14% at 50oC due to membrane dehydration. The potential loss due to membrane humidity at the manufacturer limit of 60oC is estimated at 16% through data regression approach. However, operating the electrolyzer at room temperature gives a strong performance relative to voltage variation where the Faraday efficiency is between 84 to 95%. The evaluation indicates that the PEM electrolyzer operation is optimally balanced for hydrogen output, energy input and system safety operations between 25 to 40oC and a voltage between 2.4 to 3.0V.