Enhanced energy storage efficiency by modulating field-induced strain in BaTiO3-Bi(Ni2/3Ta1/3)O3 lead-free ceramics

Nowadays, more attention has been paid to nontoxic lead-free ferroelectric (FE) materials as the substitution of lead-based energy storage materials, due to the increasing environmental awareness. BaTiO3 (BT) has good comprehensive properties, however, its low breakdown electric field leads to the low energy storage density, which is the main challenge in BT-based ceramics. In this work, BT was modified by introducing the Bi(Ni2/3Ta1/3)O-3 (BNT) component in order to reduce the field-induced strain and further enhance the breakdown strength. Effects of BNT component on the microstructures, relaxor characteristics, energy storage efficiency and fieldinduced strain were investigated systematically. The results indicate that the long-range ordered ferroelectric domains of BT ceramics are destroyed by the incorporation of the BNT component, resulting in the distortion of the polar regions. As a result, the BT-BNT ceramics possess slim P-E hysteresis and extremely low remnant polarization, owing to the phase transition from the normal ferroelectrics to relaxor ferroelectrics. The reduced strain promotes to the increase of the breakdown field strength. Ultimately, the energy storage efficiency of BTBNT ceramics can reach 87.15%, revealing a promising application in energy storage device.