Enhanced Energy-Storage Properties of Lanthanum-Doped Bi0.5Na0.5TiO3-Based Lead-Free Ceramics

A series of Bi(0.5-x)Lax(Na0.82K0.18)(0.5)Ti0.96Zr0.02Sn0.02O3 (BNKTZS-xL) (x=0-0.18) lead-free ceramics were designed and fabricated by using a conventional solid-state sintering method. The effects of the La3+ content on the properties of the BNKTZS-xL ceramics were systematically investigated. Temperature-dependent dielectric constant curves displayed two depressed anomalies, which resulted in significantly improved dielectric temperature stability. The polarization-electric field hysteresis loops illustrated that the addition of La3+ markedly enhanced the breakdown strength, energy-storage density, and energy-storage efficiency. A maximum energy-storage density of 1.95 Jcm(-3) was obtained for the material with x = 0.10, and the energy-storage efficiency significantly improved from 28 to 85% upon increasing the value of x from 0 to 0.18. These properties indicate that the BNKTZS-xL ceramics may be promising lead-free materials for high energy-storage capacitor applications.