High energy storage density and large strain with ultra-low hysteresis in Mn-doped 0.65Bi_0.5Na_0.5TiO₃-0.35SrTiO₃ ceramics

In this study, the energy storage performance and strain behavior of MnO-doped 0.65Bi_0.5Na_0.5TiO₃-0.35SrTiO₃ (NBT-ST-xMn) lead-free ceramics were investigated. MnO was induced as a ‘hard’ dopant to promote the formation of defect dipoles and improve relative density, enhancing the difference between the maximum and remnant polarization (P_max-P_r) as well as the breakdown electric field (BDS) values. A high recoverable energy density of 1.14 J cm³ with a high energy efficiency of 83 % were achieved simultaneously under low electric field of 89 kV cm^-1 at x = 0.5 mol%. Meanwhile, a relatively high strain of 0.22 % with ultra-low hysteresis of 14 % was attained under a moderate electric field of 60 kV/cm at x = 1.0 mol%. The results illustrate that the proper selection of base composition and effective chemical modifier make the NBT-ST an outstanding candidate for actuators and energy storage devices.