Polyoxometalate-polymer nanocomposites with multiplex proton transport channels for high-performance proton exchange membranes

Multiplex ion channels play a critical role in life processes and are highly desired for advanced electrolytes due to the synergistic effect on ion transport. However, it is a challenge to integrate different types of proton transport channels in the same membrane system while keeping their intrinsic structural stability. Here, we report a facile strategy for the preparation of nanostructured polymer composite membranes with multiplex proton transport channels based on the supramolecular co-assembly of sulfonated poly(ether-ether-ketone) (SPEEK), poly(ether-ether-ketone)-grafted-poly(vinyl pyrrolidone) (PGP) and polyoxometalate H3PW12O40 (PW). The spherical ionic domains from SPEEK and the bicontinuous ionic domains from the electrostatically assembled PGP/PW components were fabricated in the membranes simultaneously, which co-construct the multiplex channels for proton conduction. The optimized membranes exhibit a high proton conductivity of similar to 130 mS/cm and a high modulus of similar to 4.3 GPa, which are similar to 2.2 and similar to 1.3 times higher than the pristine SPEEK, respectively. Furthermore, the direct methanol fuel cell performance based on these membranes is enhanced by 50.4% compared to SPEEK. This approach can provide a paradigm to design advanced polymer electrolyte membranes with highly efficient ion-conducting channels for energy applications.

Automated summary

This study presents a facile strategy to prepare nanostructured polymer composite membranes with multiplex proton transport channels. These membranes exhibit high proton conductivity and modulus, and enhance the performance of direct methanol fuel cells.