Construction of Stable Wide‐Temperature‐Range Proton Exchange Membranes by Incorporating a Carbonized Metal–Organic Frame into Polybenzimidazoles and Polyacrylamide Hydrogels

• Published in: Small (Weinheim an der Bergstrasse, Germany) Vol. 17; no. 43; pp. e2103214 - n/a
• Main Authors: Yin, Bibo, Liang, Rui, Liang, Xiaoxu, Fu, Duo, Wang, Lei, Sun, Guoxing
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01.10.2021
• Subjects: branched OPBI; Carbon; Cold starts; Commercialization; Electric vehicles; Frequency stability; Hydrogels; Hygroscopicity; Membranes; Nanotechnology; PAM hydrogels; Phosphoric acid; Polyacrylamide; Polybenzimidazoles; Proton exchange membrane fuel cells; Protons; Room temperature; UiO‐66‐derived carbon; wide‐temperature‐range PEM; Zirconium dioxide; Zr(HPO 4) 2H 2O; ZrO 2
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.202103214

Proton exchange membrane fuel cells (PEMFCs) are promising devices for clean power generation in fuel cell electric vehicles applications. The further request of high‐efficiency and cost competitive technology make high‐temperature proton exchange membranes utilizing phosphoric acid‐doped polybenzimidazole be favored because they can work well up to 180 °C without extra humidifier. However, they face quick loss of phosphoric acid below 120 °C and resulting in the limits of commercialization. Herein UiO‐66 derived carbon (porous carbon–ZrO2), comprising branched poly(4,4′‐diphenylether‐5,5′‐bibenzimidazole) and polyacrylamide hydrogels self‐assembly (BHC1‐4) membranes for wide‐temperature‐range operation (80–160 °C) is presented. These two‐phase membranes contained the hygroscopicity of polyacrylamide hydrogels improve the low‐temperature proton conductivity, relatively enable the membrane to function at 80 °C. An excellent cell performance of BHC2 membrane with high peak power density of 265 and 656 mW cm−2 at both 80 and 160 °C can be achieved. Furthermore, this membrane exhibits high stability of frequency cold start‐ups (from room temperature to 80 °C) and long‐term cell test at 160 °C. The improvement of cell performance and stability of BHC2 membrane indicate a progress of breaking operated temperature limit in existing PEMFCs systems. Herein, a membrane that can operate on wide‐temperature‐range for proton exchange membrane fuel cells is prepared by self‐assembly process with UiO‐66 derived carbon (porous carbon–ZrO2), branched poly(4,4′‐diphenylether‐5,5′‐bibenzimidazole) (OPBI) and polyacrylamide hydrogels. The ZrO2 nanoparticles in porous carbon–ZrO2, immersed in phosphoric acid at 160 °C, turn into Zr(HPO4)2H2O nanoflowers. Furthermore, this membrane exhibits excellent stable cold start‐up cycles and long‐term stability.