Anion exchange membranes: The effect of reinforcement in water and electrolyte

• Published in: Journal of membrane science 2023-11, Vol.685 (C), p.121945, Article 121945
• Main Authors: Luo, Xiaoyan, Kushner, Douglas, Kusoglu, Ahmet
• Format: Article
• Language: English
• Subjects: anion exchange; Anion-exchange membrane; capital costs; carbon dioxide; Conductivity; durability; electrochemistry; electrolysis; Electrolytes; energy conversion; platinum; polymers; Reinforcement; renewable energy sources; Structure-property; systems engineering; thermal stability
• ISSN: 0376-7388; 1873-3123
• DOI: 10.1016/j.memsci.2023.121945

Alkaline anion-conducting polymer-based CO2 electrolysis and water electrolysis are among two emerging renewable energy conversion technologies. Their system design and integration offer promise of lower capital cost due to utilization of non-noble catalysts, in contrast to platinum group metal catalysts required for cation-conducting polymer-based devices. However, a critical component, the polymer electrolyte membrane, remains an obstacle hampering system performance and durability. In this study, commercially-available Sustainion® membranes with and without PTFE-reinforcement were investigated to understand previously unreported origins of improved device performance when compared to alternative membrane chemistries. We report critical membrane properties, such as morphology, thermal stability, as well as temperature-, hydration-, and counter-ion dependent ion conductivity. Moveover, the changes in uptake and conductivity of membranes in supporting electrolytes of K2CO3 and KOH investigated as a function of their concentration. Presence of reinforcement and supporting electrolyte type alter the membrane's transport functionality, which could help guide device design for improved performance. The obtained results not only show how Sustainion® properties change with operating environment for CO2 and water electrolysis applications, but also provide understanding for internal and external factors controlling anion-exhcnage membrane functionality in electrochemical devices. [Display omitted] •Structure and properties of Sustainion-based Anion-Exchange Membranes (AEMs) with and without reinforcement were investigated in controlled external environments.•Key membrane properties, such as hydration and conductivity are reported as a function of temperature, hydration, and counter-anion forms.•The changes in electrolyte uptake and conductivity of membranes in supporting electrolytes of K2CO3 and KOH are investigated as a function of their concentration to elucidate the interrelated roles of internal (reinforcement) and external (electrolyte) factors.•Reinforcement layer alters the concentration-dependent electrolyte uptake and conductivity differently, which empower these internal-external factors as a promising design strategy for controlling selectivity and cell performance in electrolyte-based devices.