Microfluidic Construction of Polypyrrole-Coated Core–Sheath Polyaniline/Graphene Hybrid Fibers with Excellent Properties for Wearable Supercapacitors

Flexible supercapacitors assembled by graphene fibers are emerging energy storage equipment for wearable electric products, and realizations of their high energy densities and actual applications are necessary yet challenging. In this paper, polypyrroles anchored on core–sheath polyaniline/graphene composite fibers (PPy@PANI/GF) are fabricated by a construction approach of microfluidic technology combined with wet-spinning. The as-designed core–sheath microstructures and synergistic effects among polypyrrole, polyaniline, and graphene nanosheets can provide more electroactive sites, high energy densities, and good practical energy supply applications. The wearable fiber-shaped supercapacitors assembled by different lengths of PPy@PANI/GF covered with PVA/H₂SO₄ or ionic liquid gel electrolytes exhibit a high specific capacitance of 612.4 mF cm^–2 at 0.08 mA cm^–2 and an outstanding energy density of 95.1 μW h cm^–2 even at a power density of 799.9 μW cm^–2. The as-constructed supercapacitors can power miniaturized traffic lights for 20 min. This research finding reveals an avenue for the preparation of flexible electrodes and may facilitate the exploitation of wearable energy storage equipment in next-generation portable electronic devices.