Electrodeposition of SnO2/MnO2 Nanocomposite Films on Ultrathin Stainless Steel Foils for High-Performance Supercapacitor Electrodes

Through a simple electrodeposition technique, SnO2/MnO2 nanocomposite films were directly deposited onto ultrathin stainless-steel (SS) foils for use in electrochemical supercapacitors. The materials were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). Electrochemical experiment revealed that the SnO2/MnO2 electrodes exhibited a high gravimetric capacitance of 876 F/g at a current density of 1 A/g. Furthermore, an asymmetric supercapacitor was fabricated using the SnO2/MnO2 nanocomposite as the positive electrode and activated carbon as the negative electrode. This asymmetric device demonstrated a capacitance of 72.2 F/g at 1 A/g and retained approximately 87.5% of its initial capacitance after 28,000 cycles, highlighting its excellent cycling stability and practical application potential. The combination of high capacitance and robust stability makes this SnO2/MnO2 nanocomposite a promising candidate for high-performance supercapacitor electrodes.