Poly (arylpiperidine) anion exchange membrane (AEM) has been widely studied in anion exchange membrane fuel cells (AEMFCs) and alkaline electrolyzed water due to their excellent alkali resistance and stability. In this work, poly (triphenyl fluorene piperidine) (PTDP) AEM was prepared from 9,9?diphenylfluorene monomer with distorted large volume structure, and hydrophilic large volume cyclodextrin crosslinking agent (β?CD?Br7) was introduced on this basis, which can control the microphase separation structure in AEMs. The prepared qPTDP?10?CD5 AEM with 5% crosslinker content reached a high conductivity (130.2 mS/cm at 80 ℃). After the membrane was treated in 1 mol/L NaOH at 80 ℃ for 2 000 h, its conductivity retention was 94.3%, showing good stability. The H2/O2 fuel cell assembled with qPTDP?10?CD5 yielded a peak power density of 1 490 mW/cm2 at 80 ℃. In the durability test, the fuel cell assembled with qPTDP?10?CD5 showed a voltage retention rate of 89.7% after 30 h, showing good cell performance.
At present, the demand for clean energy is constantly increasing to achieve sustainable development of human society. Among numerous new energy storage and conversion devices, proton exchange membrane fuel cells (PEMFCs) can directly convert chemical energy into electrical energy. Therefore, PEMFCs have been considered to have the merits of high efficiency, safety and wide application, etc. The proton exchange membrane is the core component of PEMFCs. However, the trade?off of proton conductivity and mechanical strength has become the primary challenge to hinder the development of proton exchange membranes. Although significant progress has been made in improving the single performance, the mutual constraints of key technical properties restrict the development of proton exchange membranes. Most importantly, the road to the commercialization of fuel cells is thus tortuous. We believe that the development of flexible proton exchange membranes is a main strategy to solve this technical challenge. Based on this, this article summarizes the recent research progress on flexible proton exchange membranes,including flexible polymer materials, structural optimization, and flexible additive design, expecting to provide inspiration for breaking through the performance bottleneck of flexible proton exchange membranes.
The reduction of graphene oxide(GO), in?situ loading of SnSe and interface assembly were achieved simultaneously by microwave method, and the reduced graphene oxide(rGO)?supported the petal?shaped SnSe (SnSe/rGO) composite was successfully prepared. The SnSe/rGO was characterized by Raman spectroscopy, X?ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), and the effects of different rGO contents for SnSe/rGO composite on the electrocatalytic oxygen reduction reaction(ORR) were investigated. The results indicated that there was an interaction between SnSe and matrix rGO, and Sn-C and Sn-O-C bonds were used as bridges of charge transfer. The intimate interconnection between the petal?like SnSe and the rGO formed a robust three?dimensional mesh structure, which served to reinforce the overall structural integrity of the catalyst, preventing its collapse. Based on this, the optimized SnSe/10%rGO catalyst (10rGO means that the mass fraction of rGO is 10%) exhibited excellent ORR activity with a limiting current density of 3.79 mA/cm2, an onset voltage (vs.RHE) of 0.85 V, and an electron transfer number of 3.10. Meanwhile, the SnSe/10%rGO catalyst performed the electrocatalysis long?term stability superior that of commercial 20%Pt/C (20%Pt means that the mass fraction of Pt is 20%) with the current density remaining 81.15% of the start value after 20 000 s of reaction. The present work offers insights into the preparation of non?precious metal cathode oxygen reduction catalytic materials for fuel cells.
A series of novel anion exchange membranes (AEMs) were prepared by constructing semi?interpenetrating polymer networks (sIPN) based on imidazole functional brominated polyphenyl ether (ImF?BPPO) and quaternary ammonium polyvinyl alcohol (QPVA). The effects of different contents of QPVA on the comprehensive properties of the composite membranes were systematically studied, the structure of the series composite membranes was analyzed by 1H?NMR and FT?IR, and the morphology of composite membrane was investigated by SEM, and the ion exchange capacity, water uptake and conductivity and other properties of the composite membranes were tested. The results show that the prepared series of composite membranes have good compatibility and no obvious phase separation phenomenon. When the mass fraction of QPVA was 40%, the water uptake and swelling rate of the composite membrane were 58.2% and 24.6%, respectively. At 80 ℃, the conductivity of the composite membrane reached 67.24 mS/cm. After soaking in 6 mol/L KOH alkaline solution for 168 h, about 90% of the initial conductivity was still retained, indicating that the membrane had good conductivity and alkali resistance stability.