Molecular Engineering of Ion-Conducting Polymer Membranes: Synthesis, Properties, and Applications*

Ion-conducting polymers (e.g., proton and hydroxide) are used as polymer electrolyte membranes, and they are a key component of electrochemical energy conversion and storage technologies such as fuel cells, electrolyzers, and flow batteries. For example, hydrogen fuel cell and water electrolyzer industry also heavily relies on Nafion for a proton-conducting membrane for decades, though it is not ideal proton-conducting membrane material for those applications.

Perfluoroalkyl substrates (PFASs), which include Nafion, have recently received significant pressure from government and environmental activist groups due to their environmental and health hazard of PFAS. Thus, the development of alternative ion-conducting polymers based on hydrocarbon polymers (mostly made of C and H) has attracted new attention within polymer society. Compared to perfluorosulfonated Nafion, hydrocarbon ion-conducting polymers can offer advantages of flexible synthetic tunability, lower gas permeability, and importantly lower production cost. However, their systematic polymer chemistry–morphology structure–property relationships are poorly understood until now.

In this presentation, we describe an overview of recent progress in the development of advanced ion-conducting (H⁺ and OH^–) polymers, key membrane properties, and their state-of-the-art performance in in real world applications of hydrogen fuel cells and water electrolyzers.