A review of alkaline solid polymer membrane in the application of AEM electrolyzer: Materials and characterization

Abstract

Summary Electrochemical water splitting is one of the practical systems for green hydrogen production. This hydrogen processing is sustainable by the use of a water electrolysis cell known as an electrolyzer. In recent decades, the alkaline electrolyzer and the proton exchange membrane electrolyzer have entered the advanced commercial level for the hydrogen processing industry. Unfortunately, both techniques have many crucial issues, such as the handling of hydrogen, large structure, and expensive materials needed during the construction of the cell. Anion exchange membrane (AEM) electrolyzers have been recommended to address the worst of previous electrolyzer types due to the ability to use non‐platinum and non‐Nafion membrane materials, high hydrogen storage density, and the ability to build compact micro‐cells on a large cell scale. A solid polymer alkaline membrane is a key component that influences the efficiency of the AEM electrolyzer, which reacts as an anion exchange membrane (AEM membrane). AEM membrane serves as an anode and cathode separator, ion transfer pathway, and electron flow barriers. This review paper explores polymeric materials and the characterization of an alkaline solid polymeric membrane used in an AEM electrolyzer. Several polymeric membranes that have been investigated by researchers for this application have been discussed. Critical characterizations such as ion exchange capability, ionic conductivity, chemical and mechanical stability, and cell performance durability are comprehensively addressed to guide future research and development in an alkaline solid polymeric membrane for application in an AEM electrolyzer. Highlights An overview of materials and characterization assessment of alkaline solid polymeric membrane in AEM electrolyzer is discussed. The progress of polymeric materials for alkaline solid polymeric membrane modification in the AEM electrolyzer is presented. Critical characterization of the alkaline solid polymeric membrane is described, including the ion exchange capacity, ionic conductivity, chemical and mechanical stability, and durability of cell performance.

What is Next in Anion‐Exchange Membrane Water Electrolyzers? Bottlenecks, Benefits, and Future

“…Hence, AEMs must be: (i) ionically conductive; (ii) thermally stable; (iii) mechanically stable; (iv) chemically stable; (v) electrochemically stable, and to make them more attractive, they also need to be low cost, easy to process, and produced by sustainable processes. [54,55] Unfortunately, to some extent, a compromise between their mechanical strength and ionic conductivity has to be made. While an increase in the loading of the AEM's functional groups might be advantageous for the hydroxide conductivity, this increases the water uptake, which tends to lower the mechanical stability.…”

“…Differently than A‐WE, where a non‐conducting diaphragm is used, AEMs physically separate the two compartments and avoid crossover of reagents and products. Hence, AEMs must be: (i) ionically conductive; (ii) thermally stable; (iii) mechanically stable; (iv) chemically stable; (v) electrochemically stable, and to make them more attractive, they also need to be low cost, easy to process, and produced by sustainable processes [54,55] . Unfortunately, to some extent, a compromise between their mechanical strength and ionic conductivity has to be made.…”

“…[10][11][12][13][14][15][16][17] The recent development of AEM and anion-exchange ionomers for AEM-WE or AEM fuel cell application was reviewed in Refs. [18][19][20][21][22]. Particularly, AEMs developed for AEM-WE application were summarized in Refs.…”

“…Particularly, AEMs developed for AEM-WE application were summarized in Refs. [18,19]. Lim et al recently presented a Review related to radiation-grafted AEMs for fuel cells and electrolyzers.…”

Recent Advances in Alkaline Exchange Membrane Water Electrolysis and Electrode Manufacturing

“…The numerous advantages mentioned have led other authors to focus their attention on this technology in recent years. Nevertheless, these studies have mainly focused on comparing the critical anion exchange membrane cell components and efficiencies [6,10,11,24,25]. On the other hand, in this review, a particular attention is paid to the catalyst preparation methods since they are critical for the yield optimization and the setting of optimum working conditions for these cells, which has not been previously studied.…”