Synergistic Effect of Polydopamine-Modified CaZrO3 Perovskite and Hydroxylated SPEEK on Acid-Base Cation Exchange Membrane Fuel Cells

Polydopamine-coated calcium zirconate (DCZT) nanoparticles are synthesized and dispersed in the hydroxylated sulfonated poly(ether ether ketone) (SPEEK-OH) to prepare a nanohybrid combination (SPEEK-DCZT). SPEEK-OH is prepared via the reduction process and verified by the NMR study. The formation of DCZT through condensation reaction is confirmed by FTIR, XPS, and FE-SEM analysis. The polydopamine in DCZT provides good dispersion and creates acid-base bridges (-S-O-center dot center dot center dot H+-HN-) at the filler and polymer interfaces via ionic interaction, improving the compatibility of the SPEEK-OH matrixes. Moreover, the acid-acid interaction that also exists between the SPEEK- OH matrixes via sulfonic and hydroxyl groups (-S-O-center dot center dot center dot+HO) enhances the transport (Grotthuss) and thermomechanical property. At 6 wt % DCZT, SPEEK-OH shows a superior Young's modulus (662 MPa) and transition temperature (98 degrees C) and also shows the highest water uptake and lowest swelling ratio (47.3 and 26.2% at 80 degrees C). This membrane exhibits the highest conductivity of 70.9 mS cm(-1) and a power density of 155 mW cm(-2) at 80 degrees C with 75%RH, which are higher than those of SPEEK (9.53 mS cm(-1) and 59 mW cm(-2)) and Nafion 117 (63.2 mS cm(-1) and 142 mW cm(-2)).

Automated summary

By synthesizing polydopamine-coated calcium zirconate nanoparticles and dispersing them in a hydroxylated sulfonated poly(ether ether ketone) matrix, a nanohybrid combination (SPEEK-DCZT) was successfully prepared. This nanocomposite membrane showed improved dispersion and enhanced compatibility in the polymer matrix, leading to superior conductivity and thermomechanical properties.