Ethylene-Styrene Multiblock Copolymers with Rigid Side Chains Densely Terminated by Piperidinium for High-Performance Anion Exchange Membranes

The combination of copolymerization of ethylene with styrene derivatives or isoprene and hydrosilylation reaction afforded the corresponding ethylene-styrene multiblock copolymers (Et-sPS and Et-sPS-Ph) or ethylene-isoprene multiblock copolymers (Et-IP) based anion exchange membranes (AEMs) bearing different pendent piperidinium. Compared with Et-IP membrane bearing piperidinium attached to polyisoprene structures, the Et-sPS and Et-sPS-Ph membranes bearing piperidinium attached to bulky and rigid phenyl structures possessed better mechanical properties, conductivity, thermal and alkali stability. The introduction of an alkoxy cross-linked structure to the Et-sPS-Ph membrane further improved the mechanical properties, conductivity, and alkali stability. The combination of hydrophobic polyethylene block, rigid polystyrene block, and cross-linked structure, the most desirable Et-sPS-Ph(62)-C (6) membrane with 62 mol % piperidinium and 6 mol % cross-linked structure units showed an excellent combination of desirable properties, including high conductivity, low swelling ratio, good mechanical properties, excellent alkali, and working stability. The single cell with desirable Et-sPS-Ph(62)-C (6) membrane showed open-circuit voltages and peak power density were 1.12 V and 676.2 mW cm-2, respectively.

Automated summary

The copolymerization of ethylene with styrene derivatives or isoprene and subsequent hydrosilylation reaction resulted in the synthesis of ethylene-styrene or ethylene-isoprene multiblock copolymers bearing piperidinium groups. Compared to the ethylene-isoprene membrane, the ethylene-styrene membranes displayed improved mechanical properties, conductivity, and stability due to the attachment of piperidinium groups to bulky and rigid phenyl structures. Furthermore, the introduction of an alkoxy cross-linked structure further enhanced the desired properties of the ethylene-styrene membranes.