A novel TiO2/CuSe based nanocomposite for high-voltage asymmetric supercapacitors
Muhammad Zia Ullah Shah, Muhammad Sufyan Javed, Muhammad Sajjad, A. F. M. Shahen Shah, Muhammad Sanaullah Shah, Shams Rahman, Arshad Mahmood, Muhammad Ashfaq Ahmad, Mohammed A. Assiri, Hongying Hou
Abstract
TiO2/CuSe nanocomposites were synthesized using a straightforward wet chemical without any sophisticated template. A variety of characterization techniques, including XRD, Raman spectra, UV-Vis spectroscopy, X-ray photoelectron spectroscopy (XPS), and SEM/EDS analysis were used to elucidate the structure, morphology, and optical properties of the TiO2/CuSe nanocomposite. In addition, CV, GCD, and EIS were used to study the supercapacitive performance of the TiO2/CuSe based electrodes in detail. Three-electrode cells made of TiO2/CuSe with 0.56 g weight ratio of CuSe content (denoted as ZT-3) exhibited a maximum specific capacitance of around 184 F g−1, low Rs and Rct values (2.99 Ω/6.21 Ω) among samples investigated, facilitating the charge transport and efficient utilization of ion diffusions during the electrochemical activities. Based on the outstanding performance of the ZT-3 electrode, we further assembled an asymmetric supercapacitor (ASC) composed of ZT-3//AC and successfully expanded a voltage window (2.2 V) for the first time, which yielded a specific capacitance of 40.5 F g−1 at 1 A g−1. More importantly, the ASC exhibited a high specific energy of 27 Wh kg−1 and maintained 11.4 Wh kg−1 at a high specific power of 7125.5 W kg−1 even at a high current density of 20 A g−1 with excellent cycling stability (90% retention) after 20,000 cycles.