Fabrication of Zinc Metal Organic Framework-Embedded Electrolyte Membranes Comprising Sulfonated Poly(ether ether sulfone) and Polyimide for Fuel Cells

This work focuses on the design and development of membranes with constructive physicochemical and electrochemical properties for fuel cell applications. Herein, novel electrolytes are prepared by blending sulfonated poly(1,4-phenylene ether ether sulfone) (sPEES) with polyimide (PI). To improve the ion-conducting properties, a zinc metal organic framework (Zn-MOF) is synthesized via solvothermal and sonochemical methods. From the XRD data, the average crystallite size of the prepared MOF is found to be ∼27.8 nm. For the preparation of composites, Zn-MOF is embedded in the blend matrix, and various synthesis parameters, such as reaction temperature, filler loading, and casting time, were optimized. Among the composites, the 3 wt % Zn-MOF-sPEES/PI membrane displays an ion-exchange capacity value of 1.31 mEq/g, an ionic conductivity of 0.0811 S/cm at 80 °C, and a maximum peak power density of 437 mW/cm2 with a cell voltage of 0.72 V. In summary, the experimental results affirm that the synthesized electrolytes are well-suited for applications in hydrogen–oxygen fuel cells.