Enhancing Electron/Ion Transport in SnO₂ Quantum Dots Decorated Polyaniline/Graphene Hybrid Fibers for Wearable...

Fiber-based supercapacitors are the potential power sources in the field of wearable electronics and energy storage textiles due to their unique advantages of electrochemical properties and mechanical flexibility, but achieving high energy density and practical energy supply still presents some challenges. In this study, we reported an approach of microfluidic assisted wet-spinning to fabricate SnO₂ quantum dots encapsulated polyaniline/graphene hybrid fibers (SnO₂ QDs@PGF) by incorporating uniformly polyaniline into graphene fibers and covalently bridging SnO₂ quantum dots. The assembled SnO₂ QDs@PGF fiber-typed flexible supercapacitors exhibit an ultralarge specific areal capacitance of 925 mF cm^-2 in PVA/H₂SO₄, superior rate capabilities, and capacitance retention of 88% after 8000 cycles, indicating that the SnO₂ QDs@PGF possess near-ideal capacitance properties, efficient ion transfer rate, and good cycling stability. In the EMITFSI/PVDF-HFP electrolyte system, SnO₂ QDs@PGF realize a wide operating potential window of 2.5 V, a specific areal capacitance of 678.4 mF cm^-2, and an energy density of 147.2 μWh cm^-2 at 500 μW cm^-2, which can be utilized to power an alarm clock, an electronic timer, and a desk lamp with a requirement of a 3 V battery. The exceptional performance of the SnO₂ QDs@PGF can be attributed to the molecular-level homogeneous composite of granular polyaniline and graphene nanosheets and the interfacial C-O-Sn covalent coupling strategy employed between SnO₂ QDs and PGF. These avenues not only effectively prevent the undesirable restacking of graphene nanosheets but also increase the interlayer electroactive sites, ordered ion diffusion channels, and strong interfacial charge transfer.