Giant dielectric permittivity and high energy storage in cerium doped barium titanate

Cerium-doped Barium Titanate (Ba1−xCexTiO₃) ceramics with 0 ≤ x ≤ 0.09 were synthesized via the solid-state route. Cerium oxide (CeO₂) was employed as the dopant to tailor the dielectric response. X-ray diffraction confirmed monophasic perovskite structures without detectable secondary phases. A structural transition from tetragonal symmetry (x ≤ 0.03) to cubic symmetry (x ≥ 0.05) was identified. Scanning electron microscopy revealed a non-monotonic grain size evolution, with grain refinement at low doping levels (x ≤ 0.01) and grain coarsening at higher concentrations (x ≥ 0.03). Dielectric measurements indicated that Ba0.95Ce0.05TiO3 exhibits the highest relative permittivity of 8204.38 at 27 °C, corresponding to giant dielectric behavior. In this work, the presence of mixed-valence Ce dopants, particularly the incorporation of Ce⁴⁺ ions at Ti⁴⁺ sites, plays a significant role in enhancing dielectric constant and relative permittivity. The Ce⁴⁺ species act as effective donor dopants, modifying defect chemistry and promoting space-charge polarization, which contributes to the observed giant dielectric response. This highlights the novelty of the manuscript, demonstrating how Ce⁴⁺ incorporation alongside Ce³⁺ substitution at Ba-sites drives both structural evolution and dielectric enhancement. The combined structural and microstructural modifications induced by Ce doping are shown to enhance dielectric performance, highlighting the potential of Ba1−xCexTiO₃) for high energy storage applications.