Synthesis of poly N-aryl piperidinium membrane and ionomer for anion exchange membrane fuel cell applications

Ether free backbones have recently attracted widespread attention in anion exchange membrane fuel cells (AEMFCs). Here we report the synthesis of two poly N-aryl piperidinium (PNAP) membranes from their monomers by the polycondensation method using trifluoromethanesulfonic acid as a catalyst. Density functional theory identifies the chemical reaction, and the radial distribution function represents the interactions between a water molecule and a functional group of PNAP membranes. The performance of the anion exchange membrane can be enhanced by varying the monomer ratios of PNAP. An optimized PNAP-2 membrane exhibits a hydroxide conductivity of 183 mS cm⁻¹ at 90 °C and PNAP-2 ionomers with Pt/C catalysts display a greater half-wave potential (E_1/2) of 0.81 V and a lower Tafel value of 65 mV dec⁻¹. In fuel cell tests, a PNAP-2 ionomer alongside a 60% platinum-on-carbon (Pt/C) membrane electrode assembly achieved a peak power density of 2.07 W cm⁻². The PNAP-2 remained stable for more than 230 h at a constant current density of 0.3 A cm⁻². PNAP-2 also displays exceptional resistance to alkaline conditions, lasting for more than 1000 h in both 1 M and 5 M NaOH solutions at 60 °C.