From Quaternized Polysulfones to Terphenyl-Based Polymers: Next-Generation Anion Exchange Membranes for Durable AEM Water Electrolysis

Anion exchange membrane water electrolysis (AEMWE) is rapidly emerging as a disruptive technology for sustainable hydrogen production, offering a compelling alternative to conventional alkaline and proton exchange membrane (PEM) systems. By operating in alkaline environments and enabling the use of earth-abundant, non-noble metal catalysts, AEMWE significantly lowers system costs and complexity. Early development efforts focused on quaternized polysulfone (qPS) membranes, appreciated for their ease of synthesis and promising initial conductivity. [1] However, their poor chemical resilience under highly alkaline and hightemperature conditions has proven to be a critical bottleneck, resulting in rapid conductivity loss, mechanical degradation, and ultimately limited device lifetime. To overcome these inherent limitations, research has shifted toward the design of advanced polymer backbones with enhanced chemical robustness. This study traces the transition from first-generation qPS membranes to a new class of terphenyl-based anion exchange membranes, which exhibit markedly improved alkaline stability and mechanical integrity. A comparative analysis of the physico-chemical, electrochemical, advanced ion transport studies (by NMR spectroscopy) and durability characteristics of qPS and terphenyl-based AEMs reveals key structure–property relationships that govern performance. These insights not only mark a significant leap in AEM design but also lay the foundation for the development of durable, scalable, and economically viable AEMWE technologies for next-generation hydrogen production.