Fabrication of Dual-Functional Bacterial-Cellulose-Based Composite Anion Exchange Membranes with High Dimensional Stability and Ionic Conductivity

Anion exchange membranes (AEMs) are increasingly becoming a popular research area due to their ability to function with nonprecious metals in electrochemical devices. Nevertheless, there is a challenge to simultaneously optimize the dimensional stability and ionic conductivity of AEMs due to the "trade-off" effect. Herein, we adopted a novel strategy of combining filling and cross-linking using functionalized bacterial cellulose (PBC) as a dual-functional porous support and brominated poly(phenylene oxide) (Br-PPO) as the cross-linking agent and filler. The PBC nanofiber framework together with cross-linking can provide a reliable mechanical support for the subsequent filled polymer, thus improving the mechanical properties and effectively limiting the size change of the final quaternized-PPO (QPPO)-filled PBC composite membrane. The composite membrane showed a very low swelling ratio of only 10.35%, even at a high water uptake (81.83% at 20 °C). Moreover, the existence of multiple -NR