Development of Nb-Doped Bismuth Titanate as High-Performance Supercapacitor Electrode

Niobium (Nb)-doped bismuth titanate (Bi₄Ti_2.5Nb_0.5O₁₂) was developed using a sustainable solid-state method and demonstrated its potential as a high-efficiency electrode material for supercapacitor applications. Nb substitution effectively tailors the structural, morphological, and electrical characteristics of bismuth titanate, leading to enhanced electrical conductivity, optimized grain morphology, and accelerated charge transfer and ion diffusion kinetics at the electrode-electrolyte interface. The optimized Nb-doped sample delivers a high specific capacitance of 630.33 F g^-1 at a current density of 3 A g^-1, along with an electrical conductivity of 0.65 Ω^-1 m^-1. The material further exhibits optimal cyclic stability, a high energy density of 1983.1 Wh kg^-1, and a power density of 7139.1 W kg^-1, outperforming the undoped counterpart. The synergistic role of Nb doping in enhancing both the electrochemical and surface properties of bismuth titanate optimized the Bi₄Ti_2.5Nb_0.5O₁₂ as a promising electrode material for high-performance, next-generation supercapacitors.