Novel crosslinked AB‐type polyphenylquinoxaline membranes for high‐temperature proton exchange membrane fuel cells

Abstract

AB-type polyphenylquinoxaline (ABPPQ) membranes exhibit great mechanical properties and thermal properties for hightemperature proton exchange membranes (PEMs). However, they dissolve in high-concentration phosphoric acid (PA) during acid doping. In order to improve the PA resistant of ABPPQ, crosslinked ABPPQ membranes were prepared using sulfuric acid. The crosslinked ABPPQ membranes showed high PA resistance. The acid content of PA-doped membranes decreased slightly with crosslinking, but the crosslinked polyphenylquinoxaline (CPPQ)-20 membrane could reach 2.5 × 10 −2 S/cm proton conductivity at 160 C. Membrane electrode assemblies were fabricated with an active area of 4 cm 2 and Pt loading of 1 mg/cm 2 . A startup and shutdown test (operated at 150 C with 0.2 A/cm 2 for 12 h and then 12 h off at room temperature) and a 30-day long-term durability test (150 C with 0.2 A/cm 2 ) were conducted. In the startup and shutdown test, the crosslinked membranes showed a low open-circuit voltage decay rate of 0.15 mV/h. In the 30-day long-term durability test, the voltage decay rate was 0.039 mV/h. In both tests, the crosslinked membranes showed a stable performance. Therefore, the crosslinked ABPPQ membranes can be regarded as a novel material for high-temperature PEM fuel cells. POLYM. ENG.

Poly(4-vinylpyridine) Based Semi-Interpenetrating Cross-Linked High Temperature Proton Exchange Membranes for Fuel Cells

“…Under elevated temperatures, the solubility of membranes in polar solvents is regarded as an effect approach to testify the formation of the cross-linked structure. , As shown from Figure , the pure PP blending membrane displayed a mass loss ratio of 57% after a 24 h solubility test. The reason for the lack of 100% dissolution may be due to the formation of a cross-linked structure between the two polymers, i.e., PVC and P4VP .…”

“…As previously reported, covalent cross-linking can effectively improve the mechanical strength of membranes. 28,40,41,57 So the Semi-IPN x%CL-PP membranes containing the macromolecular crosslinked structure exhibited a decrease in both area and volume swellings as the cross-linking degree increased, as depicted in Table 1. For example, the 15%CL-PP membrane exhibited a volume swelling of 99%, which was obviously lower than that of the 5%CL-PP membrane (around 150%).…”

“…To confirm the presence of cross-linking in membranes, the solubility of membranes in the polar organic solvent was employed as an indicator. , The samples were placed in DMAc at 80 °C until their mass reached a constant value. The chemical structure of the cross-linked x %CL-PP membrane was confirmed by Fourier transform infrared (FT-IR) spectra and X-ray photoelectron spectra (XPS).…”

SPEEK/CMABPBI Ionic and Self-Covalent Cross-Linked Composite Membrane: A Method to Comprehensively Enhance the Properties of High-Temperature Proton Exchange Membranes

“…Recent developments in clean and efficient energy have attracted much attention . Proton exchange membrane fuel cells (PEMFCs) have been intensively investigated due to their superior performance .…”