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

Abstract

As highlighted by the recent roadmaps from the European Union and the United States, water electrolysis is the most valuable high‐intensity technology for producing green hydrogen. Currently, two commercial low‐temperature water electrolyzer technologies exist: alkaline water electrolyzer (A‐WE) and proton‐exchange membrane water electrolyzer (PEM‐WE). However, both have major drawbacks. A‐WE shows low productivity and efficiency, while PEM‐WE uses a significant amount of critical raw materials. Lately, the use of anion‐exchange membrane water electrolyzers (AEM‐WE) has been proposed to overcome the limitations of the current commercial systems. AEM‐WE could become the cornerstone to achieve an intense, safe, and resilient green hydrogen production to fulfill the hydrogen targets to achieve the 2050 decarbonization goals. Here, the status of AEM‐WE development is discussed, with a focus on the most critical aspects for research and highlighting the potential routes for overcoming the remaining issues. The Review closes with the future perspective on the AEM‐WE research indicating the targets to be achieved.

A Step Forward: Hydrogen Production on Cobalt Molybdenum Sulfide Electrocatalyst in Anion Exchange Membrane Water Electrolyzer

“…Under conditions that are the same as ours (50 °C and Ir as anode), current densities of 0.5 and 1 A cm –2 at 2 V were obtained with NiMo/C and NiCu MMO/C cathodes, respectively. , Interestingly, both cells were also tested with a higher electrolytic concentration (1 M KOH), which led to the best performance. Although the increase of electrolyte concentration boosts cell performance, it brings technological disadvantages, and therefore, the goal is, in fact, to reduce it until the technology reaches maturity as verified for proton exchange membrane water electrolyzers (PEMWEs), which are only fed with water . So far, most studies in AEMWE operate with 1 M KOH feeding, making the result reported herein even more relevant since an excellent cell performance was obtained with a KOH concentration 10-fold lower than those commonly reported.…”

“…Water electrolysis emerges as the most promising process for this purpose once it demands energy, which can be derived from renewable sources, e.g., wind and solar, to split water toward high purity hydrogen and oxygen in the cathode and anode compartments, respectively. ,, Water electrolyzers may exist in several configurations. Specifically, the one known as the anion exchange membrane water electrolyzer (AEMWE), though still in research stages, has the potential to operate at high current densities; in addition, it avoids the use of platinum-group metal (PGM) catalysts . These are both very relevant features.…”

Improving poly(arylene piperidinium) anion exchange membranes by monomer design

“…[1][2][3][4] In parallel, the anion exchange membrane water electrolyzer (AEMWE) is developed to efficiently produce green hydrogen under alkaline conditions in a low-cost and sustainable way. [5][6][7] Consequently, considerable research efforts are currently devoted to the development of durable and functional anion exchange membranes (AEMs) for AEMFCs and AEMWEs. [8][9][10][11][12][13] AEMs should possess high ion conductivity at a limited ionic content to avoid excessive water uptake and swelling that will compromise the mechanical strength.…”

Valorization of the inedible pistachio shells into nanoscale transition metal and nitrogen codoped carbon-based electrocatalysts for hydrogen evolution reaction and oxygen reduction reaction

“…Doping of transition metal over a carbonaceous backbone generates electrochemically active sites while the defect-rich carbon framework ensures a conducive platform for catalytic performance [12,15]. In the past, interesting scientific exertions have been made for metal-carrying carbon electrocatalysts which verify the employment of iron primarily important for ORR electrocatalysis [16][17][18][19][20] while nickel emerges as a suitable option for HER [6,[21][22][23][24][25]. Moreover, in a comparison with other non-PGMs, iron and nickel not only safeguard the cost practicality due to their higher relative abundance, but their utilization in the electrocatalysts is also congruous with the biomimicry of hydrogenases involving iron and/ or nickel-based active sites for electrocatalysis [26].…”