Enhanced energy storage efficiency and temperature stability of Li2CO3-assisted BST-based ceramics by optimizing B-site dopants

In this work, 5 wt‰ Li2CO3-doped 0.88Ba0.8Sr0.2TiO3-0.12BiMeO3 (BST-BMe+5‰Li2CO3, Me = Al3+, Ga3+, Ta5+, and In3+) ceramics were fabricated using solid phase sintering approach. The impacts of different B-site Me ions on the crystalline structure, permittivity stability, energy density, and energy storage efficiency of these ceramics were studied. The XRD results revealed that the mixed tetragonal (T) and pseudo cubic (pC) phase structure was obtained for all the samples. The In/5‰Li2CO3 sample exhibits the optimal energy density of Wrec = 1.04 J/cm3 and the energy efficiency of η = 96% at 170 kV/cm. Meanwhile, the sample shows outstanding temperature stability satisfying the EIA-X8R criteria, which is ascribed to the combined roles of defect dipoles and large lattice distortion. Li2CO3 plays a key role in reducing the sintering temperature, raising the breakdown strength, enhancing the relaxation characteristics, and improving the thermal stability of energy efficiency of the ceramics.