A novel high-performance all-solid-state asymmetric supercapacitor based on CuSe nanoflakes wrapped on vertically aligned TiO2 nanoplates nanocomposite synthesized via a wet-chemical method

Abstract

The advancement of electrode-active materials opens up new possibilities for future energy storage systems. Compositing is a possible technique for making high-performance supercapacitors that can enhance the disadvantages of one electrode material over another. This paper reports a novel nanocomposite based on CuSe-TiO2 for supercapacitors, thoroughly characterized for its morphological, structural, and spectroscopic techniques to ensure an in-depth understanding of the electrode material. The phase purity and crystal structure were confirmed from XRD, which shows the pure phase of the samples, while the SEM/TEM reflects the nanoflakes/vertical sheets morphology of CuSe and TiO2 in the composite. The oxidation states and surface chemistry were confirmed from the XPS spectrum, confirming Cu, Se, Ti, and O in the composite and supporting the XRD results. The electrochemical performance of CuSe-TiO2 and CuSe are examined in detail, exhibiting a capacitance of (370 F g−1/225 at 1.5 A g−1) with extraordinary rate performance in 1 M Na2SO4 aqueous solution. Furthermore, an all-solid-state asymmetric supercapacitor is produced to show 70 F g−1, at 31.5 Wh kg−1 and 4500 W kg−1 energy, and power density coupled with robust cycling stability of 10,000 cycles. More importantly, the single asymmetric supercapacitor device had enough energy to light up a LED for 50 s, showing its practical applicability.