Micro-supercapacitors based on ultra-fine PEDOT: PSS fibers prepared via wet-spinning

The development of continuous ultra-fine conducting polymer fibers is essential for fiber-based devices because of their outstanding electrical conductivities and excellent flexibilities, promising to fabricate miniaturized wearable electronics with good performances. Among them, poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT: PSS) fibers have been considered as a promising candidate. However, it is difficult to obtain continuously nano-scaled PEDOT: PSS fibers. In this work, a new coagulation bath with a suitable solvent system for preparing ultra-fine PEDOT: PSS nanofiber via wet-spinning has been successfully developed. To the best of our knowledge, the continuous single PEDOT: PSS nanofiber is approached for the first time. The resultant fiber reveals a diameter of 865 nm with a conductivity of 4128 ± 297 S/cm. The micro-supercapacitor based on the resultant PEDOT: PSS fibers exhibit an excellent electrochemical activity and cycle stability, which can provide a volume capacitance of 188.5 F/cm3 and a power density of 3.58 × 105 mW/cm3. Meanwhile, it can maintain a high capacitance retention of 80 % even after 1.9 million cycles at an ultra-high current density of 1000 A/cm3. Moreover, the ultra-fine PEDOT: PSS fiber derived micro-supercapacitor indicates superior performance, which can generate a high output voltage of 134.9 V in a small area of 4.5 cm2. Therefore, a novel approach to prepare a continuous nanosized PEDOT: PSS fiber via wet-spinning has been demonstrated, which opens a new way for manufacturing such fine fibers, broadening their practical applications.