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, AgNbO 3 -based antiferroelectric ceramics are considered potential substitutes for lead-based ceramics. AgNbO 3 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 WO 3 and MnO 2 were introduced to synergistically improve the polarization and dielectric breakdown strength of obtained AgNbO 3 ceramics. The dependences of structures and dielectric properties on WO 3 doping were explored. A maximum polarization of 49.4 μC/cm 2 and E b as large as 285 kV/cm were achieved in 0.1 wt % WO 3 and MnO 2 co-doped AgNbO 3 ceramic. The corresponding W rec reached 2.75 J/cm 3 , which was 1.3 times larger than that of pristine AgNbO 3 ceramics. Moreover, benign thermal stability with W rec  = 2.2–2.7 J/cm 3 over 30–150 °C at 240 kV cm −1 was also achieved in 0.1 wt.% WO 3 and MnO 2 co-doped AgNbO 3 ceramics.