A polarization double-enhancement strategy to achieve super low energy consumption with ultra-high energy storage capacity in BCZT-based relaxor ferroelectrics

Abstract

Due to dielectric capacitors' already-obtained fast charge-discharge speed, research has been focused on improving their <i>W</i>_rec. Increasing the polarization and enhancing the voltage endurance are efficient ways to reach higher <i>W</i>_rec, however simultaneous modification still seems a paradox. For example, in the ferroelectric-to-relaxor ferroelectric (FE-to-RFE) phase transition strategy, which has been widely used in the latest decade, electric breakdown strength (<i>E</i>_b) and energy storage efficiency (<i>η</i>) always increase, while at the same time, the maximum polarization (<i>P</i>_max) inevitably decreases. The solution to this problem can be obtained from another degree of freedom, like defect engineering. By incorporating Bi(Zn_2/3Ta_1/3)O₃ (BZT) into the Ba_0.15Ca_0.85Zr_0.1Ti_0.9O₃ (BCZT) lattice to form (1 - <i>x</i>)Ba_0.15Ca_0.85Zr_0.1Ti_0.9O₃-<i>x</i>Bi(Zn_2/3Ta_1/3)O₃ (BCZT-<i>x</i>BZT) solid-solution ceramics, in this work, ultrahigh ferroelectric polarization was achieved in BCZT-0.15BZT, which is caused by the polarization double-enhancement, comprising the contribution of interfacial and dipole polarization. In addition, due to the electron compensation, a Schottky contact formed at the interface between the electrode and the ceramic, which in the meantime, enhanced its <i>E</i>_b. A <i>W</i>_rec of 8.03 J cm^-3, which is the highest among the BCZT-based ceramics reported so far, with an extremely low energy consumption, was finally achieved. BCZT-0.15BZT also has relatively good polarization fatigue after long-term use, good energy storage frequency stability and thermal stability, as well as excellent discharge properties.