High performance flexible supercapacitor based on metal-organic-framework derived CoSe2 nanosheets on carbon nanotube film

Abstract The manufacture of high-performance wearable supercapacitors (SCs) requires a new class of flexible electrodes with both high conductivity and high mechanical stability. Herein, we report a simple and efficient strategy to design novel CoSe2 two-dimensional nanosheets on carbon nanotube (CNT) films derived from Co-based Metal-Organic Frameworks (MOFs) via an in situ approach. The density functional theory (DFT) simulations show the higher conductivity of the CoSe2/CNT electrode than the Co3O4/CNT electrode. Due to the synergistic properties of self-supported two-dimensional CoSe2 nanosheets and the high pathway of one-dimensional (1D) CNTs, the nanocomposite electrode provides efficient transmission and short paths for electron/ion diffusion. A flexible asymmetric SC (ASC) assembled from the CoSe2 nanosheet positive electrode and FeSe2 nanorod negative electrode delivers high areal energy density of 0.25 mW h cm−2, superior mechanical stability and long lifespan. In addition, the flexible ASC device can power the CoSe2//CNT-based photodetector to generate fast and stable responses to light irradiation with different wavelengths, indicating the excellent practical application performance of flexible ASCs.