Fluorinated Poly(aryl piperidinium) Membranes for Anion Exchange Membrane Fuel Cells

Anion‐exchange‐membrane fuel cells (AEMFCs) are a cost‐effective alternative to proton‐exchange‐membrane fuel cells (PEMFCs). The development of high‐performance and durable AEMFCs requires highly conductive and robust anion‐exchange membranes (AEMs). However, AEMs generally exhibit a trade‐off between conductivity and dimensional stability. Here, a fluorination strategy to create a phase‐separated morphological structure in poly(aryl piperidinium) AEMs is reported. The highly hydrophobic perfluoroalkyl side chains augment phase separation to construct interconnected hydrophilic channels for anion transport. As a result, these fluorinated PAP (FPAP) AEMs simultaneously possess high conductivity (>150 mS cm−1 at 80 °C) and high dimensional stability (swelling ratio 80 MPa and elongation at break >40%) and chemical stability (>2000 h in 3 m KOH at 80 °C). AEMFCs with a non‐precious Co–Mn spinel cathode using the present FPAP AEMs achieve an outstanding peak power density of 1.31 W cm−2. The AEMs remain stable over 500 h of fuel cell operation at a constant current density of 0.2 A cm−2. Side‐chain fluorination leads to poly(aryl piperidinium) membranes with both high conductivity and high dimensional stability. These membranes are stable over 500 h in anion‐exchange‐membrane fuel cells (AEMFCs) with a PGM‐free (Co–Mn spinel) cathode.