Fabrication of high-performance asymmetric supercapacitor using hybrid niobium (V) oxide anchored La2O3 nanocomposite for high energy density performance

Abstract

The strong worldwide economic expansion and rapid industrial advancement have led to a pressing energy dilemma. Interestingly, there has been a transition from conventional renewable energy sources to innovative and environmentally friendly alternatives. Supercapacitors are widely acknowledged as a cost-efficient and exceptionally efficient technique for storing energy. The search for an ideal approach to improve energy storage and expand the potential operating range has resulted in the recognition of a mutually beneficial impact on binary metal oxide nanocomposites (NCs). In this context, a hydrothermal approach was used to manufacture a nanocomposite of Nb₂O₅-La₂O₃ which was then ultrasonically characterized to achieve a precise particle structure. Moreover, the vibrational characteristics, crystallographic structure, particle morphology, and size were examined via FT-IR, XRD, FE-SEM, and HR-TEM analysis. The electrochemical analysis demonstrated that the Nb₂O₅-La₂O₃ NCs displayed an impressive specific capacitance of 825 Fg^-1 when subjected to a current density of 1 Ag^-1. In addition, the Trasatti and Dunns plot analysis found that the electrochemical behavior of the Nb₂O₅-La₂O₃ NCs was mostly characterized by 91.9% capacitance and 8.1% diffusion percentages. Notably, the built Nb₂O₅-La₂O₃//AC ASC displayed energy density (53.75 Wh/kg) and a noteworthy power density of 900 W/kg. Evaluating capacitance retention and coulombic efficiency over 10,000 continuous cycles indicated a significant performance with retention rates of 74.7% and 69.6%, respectively. Overall, the binary Nb₂O₅-La₂O₃ NCs are interesting supercapacitor electrodes due to their electrochemical properties.