Unveiling the influence of radiation-induced grafting methods on the properties of polyethylene-based anion-exchange membranes for alkaline fuel cells

Abstract

Anion-exchange membranes (AEM) are envisioned as the enabling materials for the widespread use of cost-effective and efficient polymeric fuel cells. Advancing the understanding of the effect of radiation-induced grafting (RIG) method on the final properties of AEMs is crucial to boost the performance of anion-exchange membrane fuel cells (AEMFCs). The present study provides a systematic investigation of the effect of RIG methods on physicochemical properties of LDPE-based AEMs with similar degree of grafting (DoG) and ion exchange capacity (IEC). Samples grafted by two methods − pre-irradiation (PIM) and simultaneous (SM) − have the same molecular structure, but distinct physicochemical properties due to markedly differences in the degree of crosslinking. Detailed characterization of AEMs showed that RIG method determines the mechanical properties, water transport, and the distribution of ionic groups, which have a direct impact on fuel cell performance and durability. The discussed results show that grafting step directly influences the internal structure and morphology. Controlling the synthesis parameters during RIG is a key feature to design AEMs with enhanced properties that lead to high AEMFC performance and stability. • Physicochemical properties of LDPE-AEMs depend on radiation grafting methodology. • More crosslinking is obtained in LDPE membranes grafted by pre-irradiation method. • Water absorption is higher for LDPE membranes synthesized by simultaneous grafting method. • Controlling AEM synthesis parameters can lead to enhanced AEMFC performance.