Investigation on SPEEK/PAI/SrTiO3-based nanocomposite membrane for high-temperature proton exchange membrane fuel cells

Abstract

Optimization of an alternative proton exchange membrane fuel cell (PEMFC) instead of Nafion membrane electrolyte with sulfonated poly(ether ether ketone) (SPEEK) is regarded as the most promising alternative to commercial membranes. In this work, facile composite membranes consisting of SPEEK/poly (amide imide) (PAI) and SrTiO3-based nanocomposite electrolyte are prepared by solvent casting technique. The prepared samples are characterized by FT-IR, thermo-mechanical stability, electrochemical impedance spectroscopy (EIS), water uptake capacity, swelling ratio, and ion transport capacity tests. The incorporation of PAI in the membrane structure has increased the mechanical strength, increased water uptake, and restricted swelling ratio. Incorporation of SrTiO3 nanoparticle fillers are easily bounded into the polymer membrane matrix via ionic interaction due to presence of sulfonic acid groups moieties in SPEEK. The addition of SrTiO3 filler in the blend membranes provided enhanced protonic conductivity, ion exchange capacity with restricted swelling capacity, and inhibit water loss at high temperatures. The highest proton conductivity of 10.78 × 10−3 S cm−1 at 150 °C is obtained by the SPEEK (90 wt%)/PAI (10 wt%)/SrTiO3 (06 wt%) coded membrane in electrochemical impedance spectroscopy. This study shows that nanocomposite blend membrane seems to be a promising alternative membrane for PEMFC application. The SPEEK and SPEEK/PAI/SrTiO3(06 wt%) nanocomposite membrane obtained the current density and power density values of 277 mA cm−2, 56 mW cm−2 and 379 mA cm−2, and 75 mW cm−2, respectively.