High performance bismuth oxide embedded sulfonated poly ether sulfone composite membranes for fuel cell applications

Abstract

Organic-inorganic sulfonated poly(ether sulfone) (SPES)-bismuth oxide (Bi₂O₃) composite membranes were prepared by the facile solution casting method. Poly(ether sulfone) (PES) polymer was sulfonated using concentrated sulfuric acid as a sulfonating agent and the degree of sulfonation was found to be 42.6%. Structural analysis of prepared samples was characterized using FT-IR, proton NMR, XRD, GPC, SEM and XPS. Physicochemical properties like water uptake, ion exchange capability, thermal properties and proton conductivity of pristine and composite membranes were analyzed. The ion-exchange capacity of the prepared electrolyte membranes was found in the range between 1.5 and 2.4 meq g⁻¹. SPES composite membrane loaded with 6 wt.% Bi₂O₃ displayed the highest ionic conductivity of 0.045 S cm⁻¹ than the pristine membrane (0.023 S cm⁻¹). The overall results validate that the impregnation of Bi₂O₃ into SPES polymer exhibits good performance over the neat membrane. This research demonstrates that SPES/Bi₂O₃ composite membranes are viable electrolytes for fuel cell practice.

Graphical Abstract

Keywords:

• Bismuth oxide
• polymer membrane
• SPES
• conductivity
• fuel cell

Acknowledgments

The authors wish to acknowledge Department of Chemistry, SRM Institute of Science and Technology (SRMIST) for providing gel permeation chromatography measurements. The authors also wish to thank Nanotechnology Research Centre (NRC), SRMIST for providing XPS facility to investigate the surface characteristics of electrolyte membrane.

Disclosure statement

No potential conflict of interest was reported by the author(s).