Reduced graphene oxide/MnO2 composite films as the electrodes for high-performance supercapacitors produced by successive ionic adsorption and reaction (SILAR) method

Abstract

In this work, rGO/MnO₂ (SL-GMN X) composites films on stainless steel (SS) substrate for three different number of cycles (X= 10, 15, and 20) has been prepared using the successive ionic adsorption and reaction (SILAR) method. This synthesis method provides a binder-free route. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) were used to study the structure and composition of MnO₂ and SL-GMN X composite films. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) are used to assess the morphology of materials. Surface area and porosity measurements are analyze using Brunauer-Emmett-Teller analysis (BET). According to electrochemical investigations, when using a 1M Na₂SO₄ aqueous electrolyte in a three electrode configuration, the SL-GMN 15 composite film exhibits an exceptional specific capacitance of 424 F g^-1. At a charging current of 1 mA, the SL-GMN 15 composite symmetric supercapacitor has a high specific capacitance of 117 F g^-1 and a maximum energy density of 16.3 Wh kg^-1. Additionally, with a charging current of 3 mA, after 5000 cycles of testing, the composite has a long cycle life and retains a 99.5% specific capacitance. These findings pave the door for advancement of rGO/MnO₂ composite electrodes for supercapacitors and other energy storage applications.