High‐Performance Sulfonated Polyphenyl Sulfone Electrospun Proton Exchange Membranes: Synthesis, Characterization, and Electrochemical Properties

Electricity generation from sustainable and renewable energy sources has become one of the key research priorities recently. The increasing investments in wind and solar power generation have highlighted the necessity of developing efficient energy storage technologies for smart grid systems and electric vehicle infrastructures. In this context, the need for more durable, environmentally friendly, and technically advanced energy storage systems has become increasingly important. Vanadium redox flow batteries (VRFBs) represent one of the most promising large‐scale energy storage technologies, attributed to their high efficiency, extended cycle life, and design versatility. A crucial element of VRFBs is the proton exchange membrane (PEM), which facilitates proton transfer and directly affects the overall system performance. The elevated expense and restricted chemical stability of commercial membranes like Nafion have necessitated the search for alternative, cost‐effective, and resilient materials. In this study, a novel membrane with high proton conductivity, mechanical strength, and cost efficiency was developed as an alternative to Nafion. Polyphenyl sulfone (PPSU), a thermally and chemically stable engineering polymer, was chemically sulfonated and fabricated into fibrous membranes using the electrospinning technique. The synthesized sulfonated PPSU (sPPSU) membranes demonstrated an ion exchange capacity (IEC) of 2.1 meq g −1 and a proton conductivity of 1.68 × 10 −2 S cm −1 . These results indicate that the developed sPPSU‐based membranes provide a promising, durable, and cost‐effective alternative as PEMs for fuel cells and all redox flow battery applications.