Improved performance of sulfonated poly ether ether ketone/three-dimensional hierarchical molybdenum disulfide nanoflower composite proton exchange membrane for fuel cells

As one of the most essential components of fuel cells, the commercialized Nafion-based proton exchange membranes(PEMs) suffer from several drawbacks like high cost and methanol permeability. The aim of this work is to fabricate a high performance PEM with combined low cost and methanol permeability together with high proton conductivity. Three-dimensional hierarchical molybdenum disulfide (MoS 2 ) nanoflower is synthesized via a facile one-pot hydrothermal method, and then was embedd into sulfonated poly ether ether ketone (SPEEK) matrix to prepare composite PEM. The three-dimensional hierarchical architectures of MoS 2 nanoflower can not only avoid the aggregation of MoS 2 nanosheets but also provide abundant surface area and active sites, which are of benefit to fully take advantage of the intrinsic water absorption and methanol diffusion resistance ability of MoS 2 nanosheets. The formed hydrogen bond network with water passway contributes to the improvement in proton conduction of composite membrane. As a consequence, composite membrane with 1 wt% MoS 2 nanoflower loading content achieves optimized proton conductivity (0.123 S cm −1 , 80 °C) and methanol permeability (21.5 × 10 –7 cm 2 s −1 , 70 °C), which is 59.7% higher and 79.1% lower than that of SPEEK control membrane. Owing to increased proton conductivity and decreased methanol permeability, the maximum power density of the SPEEK/MoS 2 -1 composite membrane is 82.7 mW cm −2 at 70 °C, which is nearly 64.7% higher than that of pure SPEEK membrane (only 50.2 mW cm −2 ). Furthermore, the durability test confirms that the SPEEK/MoS 2 composite membrane still possesses satisfactory stability even after continuous operation at 70 °C for 100 h. Graphical abstract