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 W_rec. Increasing the polarization and enhancing the voltage endurance are efficient ways to reach higher W_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 (E_b) and energy storage efficiency (η) always increase, while at the same time, the maximum polarization (P_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 − x)Ba_0.15Ca_0.85Zr_0.1Ti_0.9O₃–xBi(Zn_2/3Ta_1/3)O₃ (BCZT–xBZT) 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 E_b. A W_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.