Excellent energy storage performance of lead-based antiferroelectric ceramics via enhancing dielectric breakdown mechanism

Lead-based antiferroelectric (AFE) material with high power density has received extensive attention for potential applications in the energy storage devices. Nevertheless, the presence of a secondary phase reduces the band gap and concentrates a significant localized electric field at the center of the tips of both secondary phases, leads to a poor breakdown electric strength (Eb). Hence, we designed high Eb of (Pb1-1.5xSmx)(Zr0.995Ti0.005)O3 ceramics with high energy performance via enhancing dielectric breakdown mechanism by restraining secondary phase. Density functional theory calculations reveal that the valence and conduction bands of secondary phase are in close proximity to the Fermi level, indicating the smaller band gap of secondary phase is unable to withstand the concentration of local electric fields in this samples, thus leading to obtain a poor Eb. UV–vis absorption spectra experiments demonstrate that the overall band gap increases due to the A-site Sm modification strategy, effectively reducing the secondary phase and resulting in elevated levels of Eb. As a consequence, Eb is remarkably improved from 350 kV/cm into 540 kV/cm with increasing Sm3+ content. A record-high Eb of 520 kV/cm and high recoverable energy storage density of 12.9 J/cm3 (energy efficiency of 77.1 %) are achieved in (Pb0.91Sm0.06)(Zr0.995Ti0.005)O3 (PS6ZT) ceramics by tape-casting method. Concerning the performance of pulse charge–discharge, ultrahigh discharge energy density of 8.5 J/cm3 and excellent power density of 188.53 MW/cm3 are achieved in PS6ZT ceramics. Moreover, outstanding stability behavior with a broad frequency range of 1∼140 Hz and a broad temperature range of 20–120 ℃ are obtained. These results show that enhancing Eb mechanism will be provided a potential option to enhanced energy density for PbZrO3-based AFE ceramics.