Polyetherimide based anion exchange membranes for alkaline fuel cell: Better ion transport properties and stability

Abstract

Alkaline anion exchange membrane (AAEM) is the key component for alkaline exchange membrane fuel cells (AEMFCs). AAEMs with good ionic conductivity, excellent thermo-mechanical and alkaline stability were synthesized by chloromethylation and quaternization followed by alkalization of polyetherimide. Chloromethylation of polyetherimide, a key step in the synthesis of anion exchange membranes based on polyetherimide, frequently involves cancer-causing chemicals. Here, an approach towards the use of non-carcinogenic reagent has been implemented for the synthesis of AAEMs. Physiochemical properties of prepared membranes are tuned by varying tertiary amines. Derivatives during the membrane synthesis are characterized by proton NMR spectroscopy. FTIR spectroscopy confirms the successful quaternization of polyetherimide, and dense nature of membranes is cross-checked by SEM imaging. Synthesized anion exchange membranes show ionic conductivity in order of 2.68–3.22 × 10−2 S/cm complemented by ion exchange capacity of 1.58–2.07 meq/g. Under strong alkaline conditions 1 M KOH at 60 °C and 5 M KOH at room temperature, membranes are stable without losing their integrity. Based on preliminary studies, it is anticipated that functionalized polyetherimide may be a suitable candidate as an anion exchange membrane in fuel cell applications.