Probing high pseudo-capacitance behaviour in bismuth tetratitanate (BTeT) for energy storage premises: a first-principles approach and experimental analysis.

Bismuth tetratitanate Bi₂Ti₄O₁₁ (BTeT) was drawn by sintering and investigated through several characterization techniques. An analysis utilizing powder X-ray diffraction (PXRD) found that BTeT exhibits a monoclinic crystal structure and falls in the C2/c space group with a crystalline size of 42 nm. The presence of Bi–O and O–Ti–O bonds in BTeT was confirmed by vibrational analysis. Further, the synthesised BTeT exhibited a bandgap of 2.78 eV, indicating that the material was semiconducting in nature. The Energy-dispersive X-ray analysis (EDAX) spectrum and morphological studies revealed that the BTeT consists of only Bi, Ti, and O elements. The first-principles calculation was executed using density functional theory (DFT) through by Quantum ESPRESSO (QE) software package and the geometrical properties of BTeT were estimated, resulting in a total energy of − 4589.62 Ry through self-consistent field (SCF) calculation. The binding energy of BTeT was estimated as − 0.52824 Ry, and its Fermi energy was found to be 10.4308 eV. Utilizing the methods of galvanostatic charge–discharge (GCD) and cyclic voltammetry (CV), the electrochemical behavior of an electrode material developed for BTeT at 900 °C was evaluated. In a 6 M KOH aqueous electrolyte, electrochemical studies revealed a specific capacitance of 4612 Fg⁻¹ at a current density of 3 mAg⁻¹ where it achieved an energy density of 160 Wh/kg and a power density of 249 W/kg. This electrochemical study showed outstanding performance, indicating that the synthesised BTeT on nickel foam (NF) effectively facilitates rapid electron/ion diffusion pathways. Therefore, BTeT was considered an excellent choice for energy storage applications. [ABSTRACT FROM AUTHOR]