High-temperature energy storage performances in (1-x)(Na0.50Bi0.50TiO3)-xBaZrO3 lead-free relaxor ceramics

In this study, in order to obtain superior energy storage performances over a wide temperature range in lead-free dielectric ceramics, we develop and prepare (1-x)(Na0.50Bi0.50TiO3)-xBaZrO(3) ((1-x)NBT-xBZ) relaxor ferroelectric ceramics by introducing BaZrO3 into Na0.50Bi0.50TiO3. BZ possesses small remnant polarization (P-r) and slim polarization-electric field (P-E) loops attributed to its room-temperature paraelectric phase structure characteristic. Thus, when it is added into NBT, the P-E loops of (1-x)NBT-xBZ ceramics are slimmer, and the P-r decreases. Besides, due to the donor doping effect resulting from the replacement of Ba2+ with higher valence for the Na+, with the increase of the BZ content, the grain sizes of the ceramics gradually decrease, resulting in the enhancement of the breakdown strength (E-b). All above these are in favour of improving energy storage properties, and as a result, by adjusting the BZ content reasonably, a large recoverable energy density (W-re) of 1.56 J/cm(3) and high energy efficiency (eta) of 80.56% are concurrently achieved in the 0.75NBT-0.25BZ ceramic. More interestingly, the ceramic exhibits excellent high-temperature energy storage capacity, which is superior to those of recently reported dielectric ceramics, and good fatigue properties. All these indicates that 0.75Na(0.)(50)Bi(0.)(50)TiO(3)-0.25BaZrO(3) lead-free relaxor ferroelectric ceramic is a good candidate for preparing dielectric capacitors applicable in various environmental conditions.