Enhanced Energy-Storage Density by Reversible Domain Switching in Acceptor-Doped Ferroelectrics

By doping and aging in a ferroelectric, we realize a ``reversible domain switching'' that produces the desirable double hysteresis loop typical of an antiferroelectric with a small remnant polarization and consequently large storage densities. We use Ginzburg-Landau modeling to demonstrate our concept theoretically, and then our predictions are experimentally validated in ${\mathrm{Ba}\mathrm{Ti}\mathrm{O}}_{3}$-based single crystals (${\mathrm{K}}^{+}$ doped) and ceramics (${\mathrm{Nb}}^{5+}$ and ${\mathrm{Mn}}^{3+}$ doped), where we measure the enhancement of energy storage due to aging. Based on our experimental results, we estimate that our proposed strategy of doping and aging will result in storage energy density increases of 5 to 35% depending on the ferroelectric system. Thus, our proposed concept can be widely employed across the range of ferroelectric systems. Moreover, as energy dissipation and output efficiency are useful in energy-storage applications, we show how our hybrid doping with acceptor and donor is an efficient way to decrease dissipation and increase output efficiency. In terms of fatigue, we show that even after ${10}^{6}$ cycles, the double hysteresis loop of the aged acceptor-doped ferroelectric material yields an energy-storage density and efficiency that is quite robust.