Enhanced energy storage density and efficiency in lead-free Bi(Mg1/2Hf1/2)O3-modified BaTiO3 ceramics

Recently, the energy crisis become more and more intense and people are gradually committed to new energy storage devices to ease the pressure. Composite energy storage ceramics are extensively explored for its splendid dielectric/ferroelectric performances. In this research, it is the first time that the (1 − x)BaTiO3-xBi(Mg1/2Hf1/2)O3 (BT-BMH) lead-free ferroelectric ceramics are prepared by traditional solid-state method. By introducing BMH into BT lattice, normal ferroelectric can be induced to relaxor ferroelectric. Especially in the case of high BMH doping (x ≥ 0.05), the relaxation dispersion behaviors are more obvious. As addition BMH goes up, the hysteresis loops gradually shrink to sublinear, which is conducive to the high efficiency of energy storage performance of ceramic capacitors. Meanwhile, the recoverable energy of BT–BMH (x = 0.1) ceramics can reach 3.38 J/cm3 with efficiency of nearly 87% at a relatively low electric field of 240 kV/cm. In addition, the optimized ceramic samples possess excellent stability of variable temperatures and frequencies, showing the potential for storage application.