Phase Inversion-Induced Porous Polybenzimidazole Fuel Cell Membranes: An Efficient Architecture for High-Temperature Water-Free Proton Transport

• Published in: Polymers Vol. 12; no. 7; p. 1604
• Main Authors: Lee, Sangrae, Nam, Ki-Ho, Seo, Kwangwon, Kim, Gunhwi, Han, Haksoo
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 19-07-2020; MDPI
• Subjects: Acids; Alternative energy sources; Boiling points; Carbon monoxide; Cell membranes; Crosslinking; Electrodes; Electrolytes; Electrolytic cells; Energy resources; Fourier transforms; Fuel cells; Heat treatment; High temperature; high-temperature polymer electrolyte membrane fuel cells; Low concentrations; Membranes; Methods; Morphology; Phase inversion; Phase shift; Phosphoric acid; polybenzimidazole; Polybenzimidazoles; Polymers; porous membrane; Proton exchange membrane fuel cells; proton transport; Protons; Researchers; Scanning electron microscopy; Swelling; thermal cross-linking; United States > US; Japan
• ISSN: 2073-4360; 2073-4360
• DOI: 10.3390/polym12071604

To cope with the demand for cleaner alternative energy, polymer electrolyte membrane fuel cells (PEMFCs) have received significant research attention owing to their high-power density, high fuel efficiency, and low polluting by-product. However, the water requirement of these cells has necessitated research on systems that do not require water and/or use other mediums with higher boiling points. In this work, a highly porous meta-polybenzimidazole (m-PBI) membrane was fabricated through the non-solvent induced phase inversion technique and thermal cross-linking for high-temperature PEMFC (HT-PEMFC) applications. Standard non-thermally treated porous membranes are susceptible to phosphoric acid (PA) even at low concentrations and are unsuitable as polymer electrolyte membranes (PEMs). With the porous structure of m-PBI membranes, higher PA uptake and minimal swelling, which is controlled via cross-linking, was achieved. In addition, the membranes exhibited partial asymmetrical morphology and are directly applicable to fuel cell systems without any further modifications. Membranes with insufficient cross-linking resulted in an unstable performance in HT-PEMFC environments. By optimizing thermal treatment, a high-performance membrane with limited swelling and improved proton conductivity was achieved. Finally, the m-PBI membrane exhibited enhanced acid retention, proton conductivity, and fuel cell performance.