Ni-Co selenide nanowires supported on conductive wearable textile as cathode for flexible battery-supercapacitor hybrid devices

In recent years, with the rapid development of flexible electronic devices, flexible energy storage devices have attracted more and more attention. In numerous energy storage devices, battery-supercapacitor hybrid (BSH) devices have been widely studied due to their high power density and energy density. Apart from high electrochemical performance for battery-supercapacitor hybrid devices, mechanical flexibility of which is getting more and more attention nowadays. In this work, we designed and fabricated a novel cathode based on nickelplated cotton cloth (NPCC), which is coated with Ni-Co selenide nanowires for flexible energy storage devices. This Ni4.5Co4.5-selenide nanowires/NPCC cathode shows ultrahigh specific capacity of 1333.0 C g(-1) and excellent charge-discharge stability. After 10,000 cycles, the specific capacitance increases to 120% steadily. Moreover, a flexible high-performance BSH device was designed based on the Ni4.5Co4.5-selenide nanowires/ NPCC cathode, a silk fabric separator and Fe3C/carbon fiber anode. This BSH device shows a large energy density of 47.4 Wh kg(-1) at the power density of 1.5 kW kg(-1). Besides, it has excellent cycling stability and retains 80.0% of capacitance after 4,000 cycles. This work demonstrates a facile and effective method of fabricating the wearable and high-performance BSH devices.