Understanding of role of Li in high-performance Pb-free Li-doped (Ba0.85Ca0.15)(Ti0.9 Zr0.1)O3 piezoceramics from theory and experiments

The role of Li in the Li-doped (Ba0.85Ca0.15)(Ti0.9Zr0.1)O-3 (BCTZL-x) perovskite ceramic are investigated through the measurements of electrical, structural and ferroelectric properties, whose analysis is assisted by the first-principles atomic calculations. The results show that Li is expected to be located normally at A-site, but the excess of Li promotes the formation of B-site Li in the Li-rich condition, which are evidenced by (i) the increase of lattice constants and phase transition by Li-addition and (ii) the increase in the activation energy of the ionic conductivity, which is consistent with the strong interaction between B-site Li and O-V that is supported by the formation enthalpies and electronic structures of the various Li-driven states.