Design of a Zero‐Gap Laboratory‐Scale Polymer Electrolyte Membrane Alkaline Water Electrolysis Stack

Abstract

The development of a zero-gap alkaline water electrolysis stack based on a heterogeneous anion-selective polymer electrolyte membrane is reported. A bipolar electrode arrangement was selected as the most appropriate one. The design was targeted to verify the suitability of the membrane electrode assembly design and the functionality of the gas separator system developed together with the purity of the gases produced. The influence of various operational regimes on the purity of the gases was investigated. Last, but not least, a validation of the mathematical model to be used for scale-up of the cell, foreseen for the next step of the project, was performed.

Green hydrogen from anion exchange membrane water electrolysis: a review of recent developments in critical materials and operating conditions

“…In PEM water electrolysis, Ti or platinized Ti is the common choice. 106 In alkaline water electrolysis cheaper materials like stainless steel, 107,108 nickel 109,110 or graphite 111,112 have been employed. Despite this potential advantage many studies of AEM systems still utilize Ti materials even if working in alkaline media.…”

“…This can result in simplication of the liquid electrolyte circulation and even in simplication of the gas separation and processing due to the possibility to achieve higher purity of the produced gasses. 110 In the literature, electrolyte owing through both compartments represents the state-of-the-art. 101,103,120,121,126 Leng et al 132 tested different feeding methods in 2012, observing that the best cell stability was achieved with the cathode compartment lled with water and water circulated through the anode side (stable cell voltage for more than 500 h).…”

“…Thus, environment pH in the anode compartment will be close to neutral and thus, it will not satisfy the condition of pH higher than 9 to ensure stability of the Ni-based anode. 110 Therefore, this option does not ensure the corrosion stability of the cell.…”

“…In this case, H 2 , which is generally considered as the main product, can be obtained with higher purity. 110 Such conguration of the cell also allows easier utilisation of the cell as an electrochemical compressor. 143 Nature of the electrode reactions taking place ensures stable pH at both electrodes.…”

Recent Advances in Alkaline Exchange Membrane Water Electrolysis and Electrode Manufacturing

“…The bipolar plates should be corrosion-resistant and have high electrical conductivity. Typical materials for the bipolar plates immersed in the cell alkaline environment are titanium [26,27], nickel [28,29], or graphite [30,31], although nickel is particularly recommended [32]. A fluidic circuit is engraved in the plates to guarantee an even liquid electrolyte flow through the electrodes.…”