Highly Stretchable Fiber-Shaped Supercapacitors Based on Ultrathin Gold Nanowires with Double-Helix Winding Design

The ability of developing highly durable fiber-shaped electronic devices is crucial for next-generation smart textile electronics. Past several years have witnessed encouraging progress made in stretchable fiber-shaped supercapacitors using carbon materials, transition metal oxides, and conducting polymers. Here, we report a dry-spun strategy to produce scalable ultrathin gold nanowire-based fibers, which can lead to highly stretchable fiber-based supercapacitors using a double-helix winding design. Hildebrand's and Hansen's solubility parameters of gold nanowire-binding oleylamine ligands match those of styrene-ethylene/butylene-styrene and tetrahydrofuran, enabling the formation of high-quality dry-spun fibers. In conjunction with conductivity enhancement by electroless plating and pseudocapacitance by polyaniline, we obtained fiber-shaped supercapacitors stretchable up to 360% with a capacitance of 16.80 mF cm-2. The capacitance retention is about 85% after 2000 cycles of 0-200-0% stretching/releasing. Our fiber capacitors can be woven into an everyday glove, with negligible capacitance changes for normal finger movements.