High performance piperidinium based anion exchange membranes with different twisted backbone structures for fuel cells

High-performance anion exchange membranes (AEMs) can be widely used in anion exchange membrane fuel cells (AEMFCs), so improving the performance of membranes is the top priority. However, achieving ideal performance for AEMs remains a significant challenge. Herein, we structurally design the polymer backbone by introducing different fused aromatic hydrocarbons (anthracene, fluorene and phenanthrene) into the backbone to synthesize a series of main chain type AEMs with different degrees of twisting. The twisted structures reduce the chain stacking and increase the free volume in the membranes, thus providing a smooth channel for the transmission of OH- . Most importantly, compared with other twisted structures, the introduction of the phenanthrene structure not only makes the polymer have good membrane forming properties, but also improves the mechanical stability of the membranes. PPTP-DMP has excellent tensile strength (TS) and elongation at break (Eb) in both dry and wet states, and can still maintain 33.9 MPa TS and 86.9 % Eb after alkaline stability test. At the same time, PPTP-DMP also shows excellent OH- conductivity (167.3 mS cm- 1 , 80 degrees C). The PPTP-DMP-based single cell shows high peak power density (996.5 mW cm- 2 , 80 degrees C) and good durability after 100 h. In addition, the PFTP-DMP membrane has excellent alkaline stability, and the conductivity retention is 95.8 % after 1200 h in a 2 M NaOH solution (80 degrees C). Therefore, the newly developed AEMs have great application prospects in AEMFCs.