Ultra-thin quaternized polybenzimidazole anion exchange membranes with throughout OH− conducive highway networks for high-performance fuel cells. Issue 12 (25th February 2021)

• Record Type: Journal Article
• Authors: Wang, Xiaozhou; Chen, Wanting; Li, Tiantian; Yan, Xiaoming; Zhang, Yang; Zhang, Fan; Wu, Xuemei; Pang, Bo; Li, Jiannan; He, Gaohong
• Is Part Of: Journal of materials chemistry. Volume 9:Issue 12(2021)
• Page Start: 7522
• Page End: 7530
• Publication Date: 2021-02-25
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/d0ta11717j
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : Throughout ion conducive highway networks in AEMs is proposed to overcome the OH − conduction barrier in a hydrophobic matrix. Abstract : A hydrophilic–hydrophobic microphase separation structure is essential for anion exchange membranes (AEMs) to balance ion conduction and mechanical strength. However, continuous hydrophobic microphase will inevitably become a barrier for ion conduction between dispersed hydrophilic ionic clusters. In this study, throughout ion conductive highway networks are constructed in quaternized polybenzimidazole (PBI) AEMs, in which OH − could break through the hydrophobic polymer backbone by forming dense hydrogen bond networks with pyridine nitrogen (–N) in PBI repeating units, and a tri-cationic/non-cationic ether pendant side chain is proposed to greatly improve ionic aggregation that was still difficult to achieve in reported quaternized PBI membranes. The molecular dynamics simulation indicates comparable OH − coordination through ionic bonds in hydrophilic microphase and hydrogen bonds in the hydrophobic microphase. The as-prepared membranes exhibit excellent toughness to fabricate ultrathin self-supporting AEMs (10 μm) with low ohmic resistance. H2 /O2 fuel cells achieves a high peak power density of about 1162.3 mW cm −2 at a large current density of 2749.5 mA cm −2, which is the highest value among recently reported PBI-based AEMs and multi-cation side-chain type AEMs. The design of throughout conductive highway network makes the highly stable commercial PBI material one of the best candidates for AEMFCs.