Quaternized chitosan/polyvinyl alcohol anion exchange membrane enhanced by functionalized attapulgite clay with an ionic "chain-ball" surface structure.

ABSTRACT

Biomass chitosan has garnered considerable interest for alkaline anion exchange membranes (AEMs) due to its eco-friendly and sustainable characteristics, low reactant permeability and easily modifiable nature, but it still faces the trade-off between high hydroxide conductivity and sufficient mechanical properties. Herein, a novel functionalized attapulgite clay (f-ATP) with a unique ionic "chain-ball" surface structure was prepared and incorporated with quaternized chitosan (QCS)/polyvinyl alcohol (PVA) matrix to fabricate high-performance composite AEMs. Due to the strengthened interfacial bonding between f-ATP nanofillers and the QCS/PVA matrix, composite membranes are synergistically reinforced and toughened, achieving peak tensile strength and elongation at break of 24.62 MPa and 33.8 %. Meanwhile, abundant ion pairs on f-ATP surface facilitate ion transport in the composite AEMs, with the maximum OH- conductivity of 46 mS cm-1 at 80 °C and the highest residual IEC of 83 % after alkaline treatment for 120 h. Moreover, the assembled alkaline direct methanol fuel cell exhibits a remarkable power density of 49.3 mW cm-2 at 80 °C. This work provides a new strategy for fabricating high-performance anion exchange membranes.