High‐Performance,Stretchable, Wire‐Shaped Supercapacitors

A general approach toward extremely stretchable and highly conductive electrodes was developed. The method involves wrapping a continuous carbon nanotube (CNT) thin film around pre‐stretched elastic wires, from which high‐performance, stretchable wire‐shaped supercapacitors were fabricated. The supercapacitors were made by twisting two such CNT‐wrapped elastic wires, pre‐coated with poly(vinyl alcohol)/H₃PO₄ hydrogel, as the electrolyte and separator. The resultant wire‐shaped supercapacitors exhibited an extremely high elasticity of up to 350 % strain with a high device capacitance up to 30.7 F g⁻¹, which is two times that of the state‐of‐the‐art stretchable supercapacitor under only 100 % strain. The wire‐shaped structure facilitated the integration of multiple supercapacitors into a single wire device to meet specific energy and power needs for various potential applications. These supercapacitors can be repeatedly stretched from 0 to 200 % strain for hundreds of cycles with no change in performance, thus outperforming all the reported state‐of‐the‐art stretchable electronics.