Phase transition and energy storage properties of BaTiO₃-modified Bi_0.5(Na_0.8K_0.2)_0.5TiO₃ ceramics

Abstract

Electrical energy storage systems (EESSs) with high energy density and power density are essential for the effective miniaturization of future electronic devices. Among different EESSs available in the market, dielectric capacitors relying on swift electronic and ionic polarization-based mechanisms to store and deliver energy already demonstrate high power densities. However, different intrinsic and extrinsic contributions to energy dissipations prevent ceramic-based dielectric capacitors from reaching high recoverable energy density levels. Interestingly, relaxor ferroelectric-based dielectric capacitors, because of their low remnant polarization, show relatively high energy density and thus display great potential for applications requiring high energy density properties. Here, some of the main strategies to improve the energy density properties of perovskite lead-free relaxor systems are reviewed. This includes (i) chemical modification at different crystallographic sites, (ii) chemical additives that do not target lattice sites and (iii) novel processing approaches dedicated to bulk ceramics, thick and thin films, respectively. Recent advancements are summarized concerning the search for relaxor materials with superior energy density properties and the appropriate choice of both composition and processing route to match various needs in the application. Finally, future trends in computationally-aided materials design are presented.

Significantly Enhanced Energy Storage Density and Efficiency at Low Electric Fields in Lead-Free Bi0.5Na0.25K0.25TiO3–K0.5Na0.5NbO3 Piezoceramics

“…Furthermore, to synthesize piezoceramic composites for obtaining MPB (morphotropic phase boundary) with relaxor-ferroelectric behavior, a wide range of additional perovskites may be easily diffused into this compound. According to the previous study on Bi–Na–K–TiO 3 , the dielectric constant ε = ∼3750 at temperature T m , P max = ∼30 μC/cm 2 , W rec = ∼110 mJ/cm, and η% = ∼20% at a biasing field of 50 kV/cm . Schader et al suggested the confinement of the coexistence of ergodic and non-ergodic relaxor (NR-ER) sections of the BNT–BT materials near the MPB during the phase transition from the ferroelectric to the relaxor ferroelectric .…”

“…According to the previous study on Bi−Na−K−TiO 3 , the dielectric constant ε = ∼3750 at temperature T m , P max = ∼30 μC/cm 2 , W rec = ∼110 mJ/cm, and η% = ∼20% at a biasing field of 50 kV/cm. 7 Schader et al suggested the confinement of the coexistence of ergodic and non-ergodic relaxor (NR-ER) sections of the BNT−BT materials near the MPB during the phase transition from the ferroelectric to the relaxor ferroelectric. 8 Thus, bismuth (Bi)-based perovskite structure piezoceramics such as Bi−Na−K−TiO 3 , Bi−Na−TiO 3 , BiFeO 3 , and so forth have generated a great interest in the scientific community for research on them for piezoelectric applications.…”

Re‐entrant ferroelectric relaxor phenomena in the (1 − x)[Bi1/2(Na1/2K1/2)1/2TiO3]‐xPbZrO3 system

“…One study reported on the co‐doping of the A and B‐site in the BNKT system and performed a comparative analysis of the structure‐property relationships 6 . In other studies, additives such as BaTiO 3 , 7 KNN, 8 BZT, 9 and BiAlO 3 10 were added to the BNKT system. These ternary systems have shown improved electrical performance and are easier to pole relative to the unmodified BNKT system.…”