Suppression of interfacial polarization via enhancement of entropy, grain resistance and optical band-gap strategies in perovskite ceramics
Amira A. Kamal, Asmaa Al‐Rasheedi, K.A. Aly, Abd El-razek Mahmoud
Abstract
The development of dielectric ceramics for energy storage applications requires suppression of interfacial polarization (IFPs) and elevation of grain resistance to obtain high energy storage density and foster breakdown strength. The present study illustrates a strategy for reducing IFPs via increasing configurational entropy (ΔS) and optical band-gap (E g ) engineering of (Ba 0.95−x Nd x Bi 0.05 )(Ti 0.9 Zr 0.1 )O 3 (0.0 < Nd < 0.1) (abbreviated BBZTNx) ceramics. The disrupted ferroelectricity long-range order of BBZT can be fostered by increasing ΔS via Nd addition into the A-site of the lattice. Increasing ΔS from 0.5R to 0.9R can induce a stable perovskite structure and decrease the polarity of material at the highest content of Nd ions. The optical properties revealed that E g increased from 3.2 to 3.35 eV as Nd increased from 0.0 to 0.1. The augmented difference between ionic radius at A-sites as Nd increases leads to a reduction in the grain size and an increase in the resistance of grain (R g ). These cascade influences result in the suppression of IFPs and bolster the breakdown strength (E b ). The E b increased from 200 kV/cm to 300 kV/cm as Nd increased from 0.0 to 0.1, which is about five times higher than pure BT. The best energy storage properties can be achieved at 0.05 of Nd with 2.75 J/cm 3 of W rec and 93% of ƞ at moderate E = 200 kV/cm. The present study illustrates a strategy for comprehensive suppression of IFPs and enhancement of E b of perovskite structure ceramics.