Electrospun synthesized sulfonated peek separator for power composites

The controlled sulfonation on polyetheretherketone (PEEK) is carried out withthe aim of production of electrospinning nanofibers. The produced electrospunnanofibers are used as a separator to fabricate the Li+-ion conducting polyethyleneoxide (PEO) solid electrolyte for utilization in the power composite. The presence ofthe -SO3H functional group confirms the successful sulfonation under the conditionsof 8 h and 60 °C. By electrospinning, the amount and shape of the porosity anddiameter of fibers are controlled, which led to the fabrication of a very thin layerof separator with enhanced mechanical performance, thermal stability, and ion conductivity.The optimum condition of electrospinning includes an applied voltage of16 kV, a feed rate of 3 μl/min, a distance of 10 cm, and a solution concentration of35 wt.%, in which no bead formation happened and electrospun nanofibers have betterwettability and mechanical properties. The diameter of nanofibers is measuredunder optimal conditions, ranging from 50 to 71 nm. Electrochemical ImpedanceSpectroscopy (EIS) analysis is carried out to measure the ionic conductivity of thesystem. The carbon fiber (CF) woven fabrics are employed as electrodes, and theionic conductivity of the electrolyte is enhanced by utilizing a sulfonated PEEK(SPEEK) membrane leading to obtaining a high ionic conductivity of 1.27×10−3S.cm−1 at room temperature. Dynamic mechanical analysis (DMA) is carried out,and the obtained results illustrate the better storage and loss modulus for the sulfonatedPEEK separator and offer a wide range of service temperatures due to thehigher glass transition temperature.