Large electric-field-induced strain and energy storage properties in Bi0.5Na0.5TiO3-(0.5Ba0.7Ca0.3TiO3-0.5BaTi0.8Zr0.2O3) lead-free relaxor ferroelectric ceramics

•BNT-(BCT-BZT) ceramics with large strain and without negative strain were prepared•A large field-induced strain of 0.42% and large d33* of 547 pm/V are obtained•Large strain is mainly due to the crossover of relaxor nonpolar state to ferroelectric polar state Piezoelectric ceramics with high strain can convert electrical energy and mechanical energy into each other for a wide range of applications. (1-x)Bi0.5Na0.5TiO3-x(0.5Ba0.7Ca0.3TiO3-0.5BaTi0.8Zr0.2O3) (BNT-x(BCT-BZT)) lead-free piezoelectric ceramics were prepared through solid-state reaction methods. The structural, dielectric, field-induced strain and energy storage properties of the ceramics were investigated systematically by various characterization techniques. A large field-induced strain of 0.42% with negligible negative strain and large reverse piezoelectric coefficient of 547 pm/V are obtained in BNT-9(BCT-BZT) ceramics. A large recoverable energy storage of 3.49 J/cm3 under 360 kV/cm and high energy storage efficiency of 64.9% are achieved in the BNT-10(BCT-BZT) ceramics. It believes that the large strain with negligible negative strain is mainly due to the crossover of relaxor nonpolar state to ferroelectric polar state. We believe that the BNT-x(BCT-BZT) ceramics are favorable for the practical applications in the mobile electronic devices.