Work

Sulfonated Polybenzimidazole Membranes: How Sulfonation Affects Properties, Stability, and Performance in Vanadium Redox Flow Batteries

Year: 2025

Type: article

Abstract: Poly(4,4′‐diphenylether‐5,5′‐bibenzimidazole), OPBI, is sulfonated at different conditions to reach different degrees of sulfonation (DOS of 35, 54, 102, and 133%). The membrane with a DOS of 102% shows the most balanced properties. The tensile strength is 55 MPa and the elongation at break is 130%. Conductivity in 3 m sulfuric acid exceeds that of Nafion 212 (58 mS cm −1 ) and reaches 70 mS cm −1 . The resistance of a 23 µm thick membrane is 33 mΩ cm 2 , and energy efficiencies of 91.8% at 80 mA cm −2 and 90.4% at 100 mA cm −2 are achieved. OPBI showed the highest stability in contact with VO 2 + , because the ions cannot enter the membrane. Sulfonated OPBI swells more in sulfuric acid, and therefore has a lower stability. However, it is found that the stability increases with the DOS. This indicates that attack by VO 2 + occurs preferentially at positions that are activated for electrophilic aromatic substitution reactions.

Source: Advanced Energy Materials

DOI: 10.1002/aenm.202500440

Authors: Trung Tuyen Bui, Sungmin Park, Mingyu Shin, Muhammad Mara Ikhsan, Yongchai Kwon, Dirk Henkensmeier

Institutions: Korea Institute of Science and Technology, Seoul National University of Science and Technology, Korea University of Science and Technology, Korea University

Language: English

Topic: Advanced battery technologies research

Subfield: Electrical and Electronic Engineering

Field: Engineering

Domain: Physical Sciences

SDG: Affordable and clean energy

Open Access status: hybrid

Estimated APC paid: $5,790