Enhanced optical transmittance and energy‐storage performance in NaNbO₃‐modified Bi_0.5Na_0.5TiO₃ ceramics

Abstract

Dielectric ceramics with both excellent energy storage and optical transmittance have attracted much attention in recent years. However, the transparent Pb-free energy-storage ceramics were rare reported. In this work, we prepared transparent relaxor ferroelectric ceramics (1 − x)Bi 0.5 Na 0.5 TiO 3 -xNaNbO 3 (BNT-xNN) by conventional solid-state reaction method. We find the NN-doping can enhance the polarization and breakdown strength of BNT by suppressing the grain growth and restrained the reduction of Ti 4+ to Ti 3+ . As a result, a high recoverable energy-storage density of 5.14 J/cm 3 and its energy efficiency of 79.65% are achieved in BNT-0.5NN ceramic at 286 kV/cm. Furthermore, NNdoping can promote the densification to improve the optical transmittance of BNT, rising from ∼26% (x = 0.2) to ∼32% (x = 0.5) in the visible light region. These characteristics demonstrate the potential application of BNT-xNN as transparent energy-storage dielectric ceramics.

Structurally Regulated Design Strategy of Bi0.5Na0.5TiO3-Based Ceramics for High Energy-Storage Performance at a Low Electric Field

“…The comprehensive energy-storage characteristic of 0.96 (0.7BNT-0.3ST)-0.04 SZN is superior to those of the reported BNT-based ceramics ,− with an excellent energy-storage performance at a low electric field of 290 kV/cm. Figure a shows that the W rec of 0.96 (0.7BNT-0.3ST)-0.04 SZN is higher than those of the reported lead-free energy-storage ceramics under similar electric fields (280–310 kV/cm). ,,− The reported W rec values of lead-free ceramics can reach up to 7–8 J/cm 3 under an applied electric field strength of >400 kV/cm (Figure b). − However, the W rec values of 0.96 (0.7BNT-0.3ST)-0.04 SZN reach 7.43 ± 0.05 J/cm 3 under an electric field strength of 290 kV/cm. Moreover, 0.96 (0.7BNT-0.3ST)-0.04 SZN has excellent temperature and frequency energy-storage stability and good charge–discharge properties ( P D ∼ 74 ± 1 MW/cm 3 and τ 0.9 ∼ 159 ± 2 ns) (Figures S2 and S4).…”

“…(a) Comparison of W rec under similar electric fields strength (280–310 kV/cm) ,,− and (b) electric field strength required for similar W rec (7–8 J/cm 3 ) values for 0.96 (0.7BNT-0.3ST)-0.04 SZN ceramic and reported lead-free energy-storage ceramics. − …”

Achieving outstanding energy storage behaviors via combinatorial optimization design in BNT-based relaxor ferroelectric ceramics under medium–low electric fields

“…Furthermore, a comparison with recent reported work on lead-free ceramic energy storage properties is presented in Table 1. 8,23,27–37 Our work is very significant as it not only maintains higher W rec and η , but also has a leading W rec / E under a low electric field. (1 − x )BNT–BZT– x NN ceramics will shine in future energy storage components of power systems.…”

“…22 Similar features were also observed in other BNT-based ceramics modified with NaNbO 3 , CaZrO 3 , and NbTaO 3 . 23–25 It is noteworthy that the weak peaks ( T c ) appear in the high-temperature region [Fig. 4(b)–(d)], which is attributed to the contribution of the NN antiferroelectric phase.…”

Achieving High Energy Storage Performance under a Low Electric Field in KNbO3-Doped BNT-Based Ceramics

“…However, due to the harmful effects of the Pb element, researchers are seeking lead-free materials to substitute lead-containing materials. , In the lead-free energy storage ceramics, BNT-based ceramics are considered to be one of the most promising substitutes for lead-based ceramics due to their large P max (>40 μC/cm 2 ) values . However, their high P r (≈38 μC/cm 2 ) leads to high W loss , which limits their application in energy storage. − To improve its ESP, there are many effective ways, such as doping perovskite materials or oxides, adopting different sintering methods. − For example, Zhou et al found a high W rec (3.52 J/cm 3 ) in 0.8Bi 0.5 Na 0.5 TiO 3 -0.2Sr­(Zr 0.2 Sn 0.2 Hf 0.2 Ti 0.2 Nb 0.2 )­O 3 ceramic. The dielectric constant of the sample has a wide range of temperature stability and a low value of dielectric loss.…”