Simultaneous improved polarization and breakdown strength in Mn/W co-doped silver niobate ceramics

Dielectric ceramics have attracted ever-increasing interest in energy storage applications due to their high-power density and fast charge-discharge speed. In particular, AgNbO3-based antiferroelectric ceramics are considered potential substitutes for lead-based ceramics. AgNbO3 ceramics sintered with fine hydrothermal-synthesized powders show the advantage of high breakdown strength. However, the fine grains lead to the decreased polarization, which harms the recoverable energy density. In this work, a little amount over-stoichiometrical WO3 and MnO2 were introduced to synergistically improve the polarization and dielectric breakdown strength of obtained AgNbO3 ceramics. The dependences of structures and dielectric properties on WO3 doping were explored. A maximum polarization of 49.4 mu C/cm(2) and E-b as large as 285 kV/cm were achieved in 0.1 wt % WO3 and MnO2 co-doped AgNbO3 ceramic. The corresponding W-rec reached 2.75 J/cm(,)(3) which was 1.3 times larger than that of pristine AgNbO3 ceramics. Moreover, benign thermal stability with W-rec = 2.2-2.7 J/cm(3) over 30-150 degrees C at 240 kV cm(-1) was also achieved in 0.1 wt.% WO3 and MnO2 co-doped AgNbO3 ceramics.