Anion Exchange Membranes by Cross-Linking Poly(styrene‑b‑ethylene-co-butylene‑b‑styrene) with Poly(aryl piperidinium) Containing Rigid-Flexible Units

• Published in: ACS applied polymer materials 2024-09, Vol.6 (18), p.11291-11301
• Main Authors: Choi, Jiyong, Lee, Yerim, Lim, Haeryang, Maeng, Hyeonjun, Park, Taiho, Kim, Tae-Hyun
• Format: Article
• Language: English
• ISSN: 2637-6105; 2637-6105
• DOI: 10.1021/acsapm.4c01848

With the increasing significance of green hydrogen production, anion exchange membrane-based water electrolysis (AEMWE) is gaining prominence. AEMWE with remarkable cell performance and durability has recently been developed, especially that built on poly­(aryl piperidinium) (PAP)-based anion exchange membranes due to its high ion conductivity, remarkable chemical stability, and improved mechanical durability. In this work, we developed PAP-based cross-linked poly­[(PPBP-co-pTP)-SEBS] membranes by chemically cross-linking two polymer components: a copolymer of para-terphenyl (pTP) and bis-4,4′-(3-phenylpropyl)­biphenyl (PPBP), referred to as PPBP-pTP, and poly­(styrene-b-ethylene-co-butylene-b-styrene) (SEBS). Specifically, the structurally rigid pTP was copolymerized with PPBP, containing flexible alkyl chains, forming a unit (PPBP-pTP) similar in structure to SEBS (a polymer combining the rigidity of styrene with the elasticity of ethylene–butylene). Subsequently, cross-linking PPBP-pTP and SEBS yielded x-(PPBP-pTP)-SEBS membranes with pronounced microphase separation. Additionally, x-(PPBP-15-pTP)-SEBS, with the 15% of PPBP content, exhibited the high OH– conductivity (126.71 mS/cm at 80 °C); excellent mechanical properties (tensile strength = 24.91 MPa and elongation at break = 57.59%); exceptional alkaline stability (100% conductivity retention in 2 M KOH at 80 °C after 960 h); and an excellent AEMWE cell performance of 2.67 A/cm2 at 1.8 V, using a non-noble catalyst for Ni-based oxygen evolution reaction applications.