Effect of LMT doping on microstructure and electrical properties of BCZT ceramics

In this study, (1-x)Ba_0.85Ca_0.15Zr_0.1Ti_0.9O₃-xLa(Mg_0.5Ti_0.5)O₃ ((1-x)BCZT-xLMT) (x = 0 %, 1 %, 3 %, 7 %) ceramics were prepared by solid-state method, and the effects of LMT contents on the structure and electrical properties for BCZT lead-free ceramics were explored. XRD results indicate that the prepared ceramics show a uniform perovskite structure with no impurities, which suggests that LMT is completely soluble in BCZT ceramics, forming a solid solution. SEM results show that the grain size of the prepared ceramics undergoes the initial increase and subsequent decrease with the increasing LMT content. Additionally, the addition of LMT results in a decrease in the Curie temperature, widening of the dielectric peak, and occurrence of dispersion phase transition. The hysteresis loop of the samples transformed from ferroelectric into relaxor ferroelectric, which results in a slimmer hysteresis loop, leading to the significant reduction in energy storage loss and the improvement in energy storage efficiency. When the doping amount is 3 %, the prepared ceramic shows the energy storage density of 0.67 J/cm³ and the energy storage efficiency of 83.1 % under the electric field of 90 kV/cm. Based on the experimental results, it can be seen that the formation of solid solution could greatly help to improve the energy storage performance, which provides a new idea for the lead-free ceramics.