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

Abstract 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 nickel-plated 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.