Polyaniline Decorated Ultra-Thick CNT Fiber for Practical Wearable Supercapacitor with Outstanding Length Capacitance

Abstract

Fiber-shaped supercapacitors supercapacitors (FSSCs) composed of carbon-based fibers are considered as a excellent candidate for wearable devices. However, only few cases have been reported of achieving both high specific capacitance and length capacitance with a single strand of fiber required for real-world FSSCs’ implementation. Here, we introduce a single ultra-thick carbon nanotube fiber (UCNTF) with high linear density that can be operated as a practical electrode material in FSSCs. A series of sonochemical treatments is adopted to modify the internal structure and physical properties of pristine UCNTFs and further incoporate polyaniline as a pseudocapacitive material into the pretreated UCNTFs. The prepared PANI-incorporated UCNTF exhibited a noteworthy specific capacitance of 331 F g−1 (1 A g−1, total electrode weight) and an outstanding length capacitance of 96.5 mF cm−1 when assembled into a symmetric FSSC, without additional fibers being added. In addition, the FSSCs exhibit high flexibility (98.4% at a bending angle of 90°) and stability (80.1% after 20,000 bending cycles). We believe that the first report of FSSCs made of industrial scale single CNTF furnish a new opportunity for commercializing wearable energy storage.