YANG Tianhao ¹, YAN Bo ¹, LI Chengyu ¹, MAO Xun ¹, HOU Yuwei ², CHEN Kepi ¹
(1. School of Energy, Power and Mechanical Engineering, North China Electric Power University, Beijing 100026, China; 2. School of Economics and Management, North China Electric Power University, Beijing 100026, China)

Abstract:(1−x)(K_1/2Na_1/2)NbO₃-xBi(Mg_1/3Zn_1/3Nb_1/3)O₃(KNN-BMZN) lead-free perovskite relaxor ferroelectric ceramics are synthesized through the conventional solid-state reaction. The effects of BMZN on phase composition, phase transition temperature and electrical properties of the KNN-based ceramics are studied systematically. All samples exhibit single perovskite phase. With increasing content of BMZN, the KNN ceramics gradually transformed from orthorhombic to pseudocubic phase. The addition of BMZN leads to a gradual decrease in Curie temperature of the KNN ceramics and an increase in the relaxation characteristics. Specifically, 0.875KNN-0.125BMZN exhibited a high recoverable energy-storage density (W_rec) of 1.63 J·cm⁻³, with an efficiency (η) of 81.5%. The energy-storage displayed an excellent temperature stability. Hence, our KNN-BMZN ceramics could be used as dielectric energy storage ceramics at low electric fields.
Key words: dielectric energy storage; lead-free ceramics; potassium sodium niobate; relaxor ferroelectrics