Realizing ultra-high energy storage density of lead-free 0.76Bi0.5Na0.5TiO3-0.24SrTiO3-Bi(Ni2/3Nb1/3)O3 ceramics under low electric fields

The electrical and electronic devices become more and more integrated and miniaturized. It is necessary to develop high performance lead-free energy storage ceramics. In this work, new relaxor ferroelectric (1-x)(0.76Bi0.5Na0.5TiO3-0.24SrTiO3)-xBi(Ni2/3Nb1/3)O3 ceramics were prepared by the traditional solid-state reaction method. Particularly, the 0.90(BNT-ST)-0.10BNN ceramic exhibits the excellent recoverable energy storage density (Wrec = 4.1 J/cm3) and efficiency (η = 83.15%) under a low electric field (250 kV/cm). The 0.90(BNT-ST)-0.10BNN ceramic has excellent stability between 25 °C and 120 °C. In addition, an ultrahigh power density of 49.8 WM/cm3 and a fast charge-discharge rate (t0.9 = 62.4 ns) can be obtained simultaneously. These properties indubitably reflect that the (1-x)(BNT-ST)-xBNN ceramics have a great potential for the applications of high energy storage capacitors.