Effective strategy for achieving superior energy storage performance in lead-free BaTiO3–Bi(Zn2/3(Nb0.85Ta0.15)1/3)O3 ferroelectric ceramics

Abstract

Material with low remnant polarizations with slim hysteresis loops are favorable for energy conversion efficiencies and have been receiving immense interest as energy storage materials with high recoverable energy densities. This study proposes a noble barium-based dielectric ceramic ((1-x)BaTiO3-xBi[Zn2/3(Nb0.85Ta0.15)1/3]O3) (BT-BZNT), with x ranging from 0.05 to 0.25 manufactured using solid-state reaction method. All the samples exhibited dual crystal symmetry revealing the coexistence of tetragonal (p4mm) and rhombohedral (R3c) phases with dense microstructures. The activation energy for conduction increased (0.37–0.61 eV) with BZNT substitution which might be attributed to a decrease in the density of states N(EF) from 3.91 × 1018 to 1.28 × 1018 eV−1 cm−3. This implies that oxygen vacancies and defects are reduced in samples with greater BZNT substitution, validating the elemental composition and oxidation states, which significantly enhance the energy storage capacity. At a lower applied field of 180 kV/cm, the BT-BZNT3 ceramic displayed a remarkably high recoverable energy density of 2.06 J/cm3 with an energy efficiency of 78 %. In the same applied field, an improvement in energy efficiency up to 96 % is achieved for higher BZNT substituted samples. These results have implications for the development of high-performance BT-BZNT ceramics for their use in future energy storage applications.