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 fiber-shaped 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.