Amphiphilic core-sheath structured composite fiber for comprehensively performed supercapacitor

As an important branch of fiber-shaped energy storage devices, the fiber-shaped supercapacitor has been widely studied recently. However, it remains challenging to simultaneously achieve fast electron transport and excellent ion accessibility in one single fiber electrode of the fibershaped supercapacitor. Herein, a novel family of amphiphilic core-sheath structured carbon nanotube composite fibers has been developed and applied to the fiber-shaped supercapacitor to address the above challenge. The polyaniline-modified hydrophilic sheath of the composite fiber electrode effectively enhanced the electrochemical property via advancing ion accessibility, while Au-deposited hydrophobic core demonstrated improved electrical conductivity by fast electron supply. On the basis of a synergistic effect, a remarkable specific capacitance of 324 F cm −3 at 0.5 A cm −3 and greatly enhanced rate performance were achieved, i.e., a 79% retention (256 F cm −3 ) at 50 A cm −3 . The obtained fiber-shaped supercapacitor finally displayed remarkable energy and power densities of 7.2 mW h cm −3 and 10 W cm −3 , respectively. The strategy developed herein also presents a general pathway towards novel fiber electrodes for high-performance wearable devices.