MnO2/Ni–Cu-Plated Polyester Fabric as a Free-Standing Electrode in Supercapacitor Applications

The main objective of this research is to investigate the electrochemical characteristics of Ni–Cu-plated polyester when MnO₂ is deposited on it and serves as a flexible electrode. For this purpose, the Ni–Cu-plated polyester electrode fabrics prepared in this way were deposited with MnO₂ over different immersion times. The conductive polyester electrode that was prepared underwent immersion in an aqueous solution of KMnO₄ (0.1 M) for durations of 5, 10, and 30 min. The electrical resistance of the prepared samples was measured using a two-point probe technique. Additionally, the electrochemical properties of the Ni–Cu-plated polyester with MnO₂ deposition were examined using a three-electrode cell setup under ambient conditions. The surface structure and elemental composition of the sample electrodes were examined with a scanning electron microscope (SEM). In this research, the asymmetric supercapacitor cell (ASC) consisting of a Ni–Cu/MnO₂-deposited textile as the cathode electrode and active carbon-coated activated carbon cloth as the anode electrode was assembled. Also, the symmetric supercapacitor cell (SSC) using Ni–Cu/MnO₂ deposited polyester as both the anode and cathode was assembled. Cyclic voltammetry (CV), galvanostatic charging–discharging (GCD), and electrochemical impedance spectroscopy (EIS) measurements were utilized to assess and compare the electrochemical performance. The areal specific capacitances of the ASC at current densities of 2, 4, 8, and 16 mA cm^–2 were calculated to be 558.6, 481.9, 435.5, and 330 mF cm^–2, respectively. In comparison, the achieved storage results related to ASC are far higher than those of SSC. The results are discussed in the text in detail.