Giant electric-field-induced strain of 0.70%, corresponding to a d33 * value of 1400 pm V(-1) , is observed in a lead-free (Bi1/2 Na1/2 )TiO3 -based polycrystalline ceramic. This is comparable to the properties of single crystals. An in situ transmission electron microscopy study indicates that the excellent performance originates from phase transitions under the applied electric fields.

Isotropic polycrystalline ferroelectric ceramics have to be electrically poled to develop a net macroscopic polarization and hence piezoelectricity. It is well accepted that a sufficient poling can only be realized under an electric field that is much higher than the coercive field. In this study, we observed in (Bi1/2Na1/2)TiO3-BaTiO3 ceramics that large piezoelectricity can develop at poling fields far below the measured coercive field. Using in situ transmission electron microscopy, such an unusual behavior, is interpreted with the polarization alignment of polar nanodomains in the non-ergodic relaxor phase.

Neutron and electron spectroscopy reveal diffusion behavior of individual ions in lithium garnets, paving the way towards high-performance aqueous lithium batteries.