Dual strategy of branching and graft on poly(terphenyl piperidine) to achieve excellent proton conductivity in high-temperature proton exchange membranes

High-temperature proton exchange membrane fuel cells (HT-PEMFCs) exhibit higher catalytic efficiency and lower hydrogen purification costs. However, the conductivity and stability of high-temperature proton exchange membranes (HT-PEMs) still do not meet the requirements of commercial use. In this work, we synthesize 1,3,5-triphenylbenzene branched poly(terphenyl piperidine) and subsequently graft different ratios of long alkyl piperidine side chains, obtaining a series of novel HT-PEMs with excellent performance. The 1,3,5-triphenylbenzene improves the mechanical properties and chemical stability of membranes. The grafted side chains can increase PA uptake and optimize PA distribution, thereby improving the proton conduction capacity of the membrane. The test result shows that the b-PTP-75MPD membrane can achieve a high proton conductivity (137.7 mS cm −1 ) and high power density (742.9 mW cm −2 ). In conclusion, these strategies pave a new avenue for simple and low-cost method for developing high-performance HT-PEMs.