Ultra-high energy storage performance under low electric fields in Na0.5Bi0.5TiO3-based relaxor ferroelectrics for pulse capacitor applications

High ambient temperature (> 150 degrees C) of pulse power capacitors raises the strict requirements for dielectric ceramics. (1-x)Na0.5Bi0.5TiO3-xLaAlO(3) ((1-x)NBT-xLA for short) dielectric ceramics with superior pulse discharge performance at high ambient temperature were designed and fabricated. With LA addition, pseudo-cubic structure and reduced tolerance factor were available, benefiting to enhance the relaxor behavior. The grain size and shape are greatly changed to submicron degree and square, respectively. The x = 0.03 sample shows typical pinched P-E loops and ultra-high P-m of 50 mu C/cm(2). The x = 0.07 sample exhibits ultra-high W-d of 3.18 J/cm(3) and eta of 60% under relative low field of 210 kV/cm mainly due to its high polarization 45 mu C/cm(2). This ceramic also shows a high power density of 20 MW/cm(3), high pulse discharge energy density(W-D) of 0.45 J/cm(3), high current density of 400 A/cm(2) and a high speed discharge duration of 80 ns at high ambient temperature (150 degrees C).