Amorphous MoSx nanoparticles grown on cobalt-iron-based needle-like array for high-performance flexible asymmetric supercapacitor

Although flexible supercapacitors have important applications, the development of high-performance flexible supercapacitors still remains a critical challenge owing to the low ion diffusion rate, poor electro-conductivity, and limited active defect sites. Herein, we report the first amorphous MoSx nanoparticles grown on crystalline FeCo-based nanoneedles (FC@MS-EG) via an ethylene glycol-induced strategy. The FC@MS-EG electrode presents an unprecedented specific capacitance of 1956 F g(-1) at 1 A g(-1) and over 91.1% of capacitance retention even after 6000 cycles because of the unique morphology, the rich defect sites, the high carrier concentration. The FC@MS-EG//AC asymmetric supercapacitor delivers an ultrahigh specific capacitance of 282 F g(-1) at 1 A g(-1) and an excellent energy density of 88.09 Wh kg(-1) along with a power density of 750 W kg(-1). And the self-assembled flexible all-solid-state supercapacitor device can be easily bent and twisted with negligible electrochemical properties attenuation.