Synthesis and Characterization of SnO2-La2O3 for Electrochemical Supercapacitor Performance in Redox Additive Electrolyte

In the present work, chemical precipitation was used for preparing the SnO2-La2O3 metal oxide supercapacitor. The prepared material was characterized by XPS, FE-SEM, HR-TEM, and XRD. The enhanced conductivity and low resistance of the SnO2-La2O3 material are coupled in the presence of an optimized redox additive electrolyte, specifically 3 M KOH (KH) with 0.2 M K3[Fe(CN)6] (RE). Within a potential window of − 0.3 to 0.7 V, the suggested hybrid electrode in the three-electrode system exhibited an ultrahigh specific capacitance of 637 F g−1 at a current density of 1 A g−1. The electrode utilizing an electrolyte based on redox additives demonstrates synergistic effects and enhances capacitance performance by up to 637 F g−1. The SnO2-La2O3 electrode in KH + RE has a greater capacity for energy storage than the aqueous electrolyte of KOH. By connecting two symmetrical supercapacitors in series and activating a red light-emitting diode (which illuminated for 2 min.), the device’s practicality was further confirmed. With consistent cyclic stability for up to 10,000 cycles, the dual redox additive-based electrolyte demonstrated good cyclic performance in specific capacitance.