Enhanced energy storage performance in Sn doped Sr0.6(Na0.5Bi0.5)0.4TiO3 lead-free relaxor ferroelectric ceramics

SnO 2 doped Sr 0.6 (Na 0.5 Bi 0.5 ) 0.4 TiO 3 (NBT-ST) ceramics were prepared by a conventional solid-state reaction method. Their phase structures, microstructures and electrical properties were characterized in details. It is found that SnO 2 doping could increase the lattice parameters , density and average grain size. A suitable amount of SnO 2 can improve dielectric properties , and affect the relaxor behavior of the NBT-ST matrix, thereby it can effectively reduce the energy loss and optimize the energy storage performance. Furthermore, the energy storage properties are improved with SnO 2 doping. Especially, the 1 at. % SnO 2 doped NBT-ST achieves a high recoverable energy density of 2.35 J/cm 3 , which is mainly attributed to large maximum polarization of 43.2 μC/cm 2 , small remnant polarization of 5.83 μC/cm 2 and high breakdown strength of 180 kV/cm. Also, relatively good temperature stability for dielectric performance and excellent fatigue resistance are observed in this composition. These properties are attractive for lead-free energy storage applications.