Engineering capacitance in silver niobate nanoparticles through lanthanum doping for high-performance asymmetric supercapacitors

This study investigates the potential of perovskite oxides for supercapacitor applications, focusing on AgNbO₃ synthesized via the solid-state route and doped with Lanthanum (La) at concentrations of 0 %, 5 %, and 9 %. The doped nanomaterials were characterized using XRD, FESEM, HRTEM, XPS, FTIR, Raman, and UV-Vis spectroscopy to confirm the crystal structure, morphology and the optical properties of the synthesized materials. Electrochemical analysis demonstrated that La doping significantly enhances the capacitance of the perovskite material, with the areal capacitance increasing from 4.8 mF/cm² at 0 % La to 22.5 mF/cm² at 9 % La at a scan rate of 5 mV/s. Moreover, an asymmetric supercapacitor device was fabricated using the activated carbon (AC) as the anode and La-doped AgNbO₃ as the cathode. This device demonstrated remarkable electrochemical performance, maintaining robust cyclic stability over an extensive 4000 charge-discharge cycles at 5 mA/cm². This study underscores the viability of La doping is a feasible approach for optimizing the energy storage properties of AgNbO₃ and also paves the way for further investigation and improvement of perovskite-based materials in high-performance energy systems.