Technology Landscape of Anion Exchange Membrane Water Electrolyzers: Where Are We Today?
Yoon Jun Son, Gholamreza Mirshekari, Stefan J. Raaijman, Paul J. Corbett
Abstract
T he production cost of green hydrogen using mature technologies, such as alkaline water electrolyzers (AWEs) and proton exchange membrane water electrolyzers (PEMWEs), is higher than gray and blue hydrogen, making green hydrogen less competitive. 1Among emerging electrolyzer technologies, anion exchange membrane water electrolyzers (AEMWEs) have gained attention due to their lower operational expenditures (OPEX) compared to AWEs and reduced capital expenditures (CAPEX) relative to PEMWEs. [2][3]3][4] Despite rapid advancements from 2016 to 2024 (Figure S1), AEMWEs still face challenges in performance, stability, and scalability compared to AWEs and PEMWEs.To advance AEMWE technology toward commercial viability, it is crucial to understand its status and identify efficient directions.This involves not only monitoring key performance indicators (KPIs) across various reports, but also identifying key parameters driving developmental trends, understanding their relationships with performance and stability, and recognizing the gap between current status and commercial deployment.However, various combinations of cell and operating parameters in AEMWE make it difficult to decouple their effects on performance and stability, complicating fair evaluation and direct comparison of results in AEMWE reports.Additionally, as the field is advancing rapidly, even the same cell component or operating condition can yield different results depending on its combination with new parameters introduced by recent innovations.Consequently, statistical analysis of extensive AEMWE data often results in statistically insignificant correlation between key parameters and KPIs. 5 Despite these challenges, this Viewpoint analyzes the impact of cell and operating parameters on AEMWE performance and stability.This is achieved by focusing on promising results (i.e., potential) of parameters that meet U.S. Department of Energy (DOE)'s target KPIs: current density >2 A/cm 2 at 1.8 V for performance and voltage degradation rate (dE/dt) < 4 μV/h for stability. 6We identify distinct characteristics of highperformance and high-stability systems, compare the status of academia and industry, reveal gaps in AEMWE development, and propose research directions to bridge these gaps (Figure S2).We collected data that demonstrated promising performance or stability comparable to the DOE targets (Table S1).For