Durability and Performance Limitations in Currently Available Alkaline Exchange Membrane Electrolysis Materials and the Relationship to Total System Cost

Abstract

Anion exchange membrane (AEM) electrolyzers have the potential to reduce the cost of hydrogen generated via. electrolysis through reducing the cost of stack materials, improved electrochemical kinetics, and exhibiting a higher tolerance range for water purity (e.g. brackish and saltwater electrolysis). These potential benefits have resulted in a large amount of research funding, and as a result several commercial AEMs are now available. Additionally, several commercial, AEM specific catalysts are also available.With the increasing maturity of AEM electrolysis (still in the very early stages), there is a growing need for benchmark performance and durability using only membrane electrode assembly (MEA) materials that are commercially available. Several materials, both polymers and catalysts, will be discussed for both performance and durability under differential pressure. The incumbent technology, proton exchange electrolyzers, typically operate up to 435 psig differential H2 pressure accomplished through a combination of electrolysis and electrochemical compression. To provide a more direct comparison to the current technology, durability will be measured under differential H2 pressure. Additionally, test will be performed to identify presence of electronic shorting or cross-cell leaks, both cell failures that will result in apparent improved performance due to the lower operating voltage.For industry to adopt AEMs, there must be demonstrated device reliability and projected system cost savings. A techno-economic analysis will be performed to compare AEM and PEM electrolysis in several different scenarios to better understand the state of the technology.