Effect of Lu doping on the structure, electrical properties and energy storage performance of AgNbO_3 antiferroelectric ceramics

摘要

Recently, AgNbO_3 antiferroelectric ceramics have attracted great attention by virtue of their characters of high energy storage density and environmental friendliness. To further optimize the electrical properties, in this work, Lu_2O_3 modified AgNbO_3 ceramics were prepared via conventional solid state method. Crystal structure and element analysis indicated the Lu~(3+) ion preferred to enter the A-site when Lu_2O_3 content was lower than 2 mol%, otherwise, it was more likely to form LuNbO_4 or Lu_3NbO_7-based solid solutions. Remarkably improved stability of antiferroelectric phase was observed once Lu~(3+) ions enter into the A-site, on account of the decrease of cell volume and tolerance factor. As a consequence, an enhanced recoverable energy storage density (W_(rec)) of 3.5 J/cm~3 was achieved in 1 mol% Lu_2O_3 modified AgNbO_3 ceramics at 210 kV/cm, which is superior to the other lead-free ceramics under moderate electric field (＜ 220 kV/cm). It is believed our study will provide a good reference for the development of AgNbO_3-based dielectric capacitors.