Hydrophilic tailoring of s-PEEK polyelectrolyte with CeMnOx bimetal oxide to sustain oxidative dilemma and improve PEMFC performance

Abstract

Herein, we propose a strategy to overcome the oxidative durability dilemma and conductivity associated setbacks in pristine sulfonated poly (ether ether ketone) (s-PEEK) polyelectrolyte via. electrostatic and physicochemical synergy induced self-assembly performing solution-phase intercalation of hydrophilic ceria-manganese bimetal oxide (CeMnOx) nanocomposite. The CeMnOx was synthesised adopting facile alkali assisted decomposition precipitation method with hydroxyl abundant surface and successive influence of CeMnOx on CeMnOx@s-PEEK over s-PEEK was studied. Studies shows that, at higher CeMnOx loads the oxidative stability improves dramatically attributed to radical oxidative specie scavenging at bimetal oxide nanoreactor centre. Furthermore, the SPM-x exhibits high proton conductivities in range up to ⁓4.0 × 10−2 S cm−1 at 90 °C in contrast to s-PEEK (⁓3.2 × 10−2 S cm−1). The Arrhenius studies revealed lowering of activation energy barrier (Ea) for H+ conduction by ∼30% for SPM-2.0 membranes with 2.0 wt% loads. During PEMFC evaluation, the optimized SPM-2.0 and SPM-4.0 exhibited peak power density of ⁓88.0 mW cm−2 and ⁓60.0 mW cm−2 at a limiting current density of 146.5 mA cm−2 and ⁓121.0 mA cm−2, respectively which are ⁓33.0% better than pristine s-PEEK. These paradigms shows that, ceria-manganese bi-metal oxide intercalated s-PEEK are promising nanocomposite polyelectrolyte to impart mechano-oxidative reinforcement and domain concentration attributes for improving overall performance of polyelectrolytes in proton exchange membrane fuel cell (PEMFC).