Enhanced electrochemical properties of hierarchically sheath-core aligned carbon nanofibers coated carbon fiber yarn electrode-based supercapacitor via polyaniline nanowire array modification

Scalable manufacturing of yarn-based supercapacitors with high energy density is highly desired for powering wearable electronics and smart textiles. In this paper, we report a novel type of sheath-core polyaniline nanowire array grown on aligned carbon nanofibers/carbon fiber yarn electrode (CFY@CNFs@PANI NWA) based supercapacitors. The carbon fiber yarn can maintain the yarn electrode with high electrical conductivity and mechanical properties. The introduced PANI NWA can further enlarge the specific surface area of the electrode and introduce pseudo-capacitance. The assembled solid-state supercapacitors show high areal specific capacitance of 234 mF/cm2 at a current density of 0.1 mA/cm2, and corresponded energy density of 21.4 μW h/cm2 at power density of 0.52 mW/cm2 in EMIMBF4/PVDF/DMF gel electrolyte. The supercapacitors also exhibit ultrahigh rate capability (68%) and excellent cycle stability (90% after 8000 cycles). We also demonstrated that a 20-cm long supercapacitor can be readily to power up 36 pieces of red LEDs with a logo of “DHU”. The scalable strategy paves a way towards mass production of wearable energy storage devices for smart textiles.