Novel Hydrophobic Covalent Cross-Linking Poly(terphenyl Isatin Piperidinium) with Poly(triphenylpyridine) for Anion Exchange Membranes
Shujing Tuo, Yajie Dai, Lin Tian, Chuan Liu, Fanghui Wang, Hong Zhu
Abstract
Many properties of anion exchange membranes (AEMs) exhibit trade-off effects, among which the balance between high ion conductivity and excessive swelling rate is a typical trade off problem that needs to be balanced. A hydrophobic covalent cross-linking strategy has been proposed to balance the trade-off problem. Developing a high-performance and long-term stable PTAP–PTBINP-Q x (x = 5, 10, 15, 20) AEM with a controllable cross-linking degree is achieved by combining the advantages of poly( p -terphenylpyridine) (PTAP) and poly( p -terphenyl isatin piperidium) (PTBINP-Q x ) through covalent cross-linking. The dimensional stability of AEMs is improved while maintaining high ion conductivity. The PTAP–PTBINP-Q 5 have good tensile strength (43.15 MPa), high hydroxide conductivity (130.38 mS/cm at 80 °C), low swelling (16.73% at 80 °C), and good alkali stability (the conductivity was retained at 83.27% in 2 M NaOH at 80 °C for 1800 h). A H 2 /O 2 fuel cell based on the PTAP–PTBINP-Q 5 AEM exhibited a maximum power density of 256 mW/cm 2 at 565 mA/cm 2 . Covalent cross-linking is an effective method to enhance the size stability of membranes, which can enhance their mechanical properties and suppress swelling, while maintaining high ion conductivity.