Ultrahigh energy-storage performance in lead-free BZT thin-films by tuning relaxor behavior

Relaxor ferroelectric thin films show excellent energy-storage performance for pulse-power applications. In this study, La-doped Ba1-xLax(Zr0.25Ti0.75)O3 (BLZT, x = 0–8%) thin films were grown on LaNiO3 buffered Ca2Nb3O10-nanosheet/Si substrates. BLZT thin films indicate prominently increasing relaxor behavior with increasing La-doping concentration, which is conducive to obtaining a very slim polarization hysteresis loop with a low remanent polarization and a high breakdown strength. As a result, BLZT thin films with 5 mol.% La-doping simultaneously exhibit a great 72.2 J/cm3 recoverable energy-storage density and a large 78.6% energy-storage efficiency under a high 3.8 MV/cm breakdown strength. These results present a promising environmentally friendly candidate for the next generation of advanced energy-storage capacitor applications.