(Ba,Sr)TiO₃–Bi(Mg,Hf)O₃ Lead-Free Ceramic Capacitors with High Energy Density and Energy Efficiency

Abstract

Dielectric capacitors with high energy storage performance have been actively studied for emerging applications. In this work, a series of environmental friendly lead-free relaxor ferroelectric ceramics, (1 − x)(Ba 0.75 Sr 0.25 )TiO 3 −xBi(Mg 0.5 Hf 0.5 )O 3 with 0 ≤ x ≤ 0.5 [abbreviated as (1 − x)BST−xBMH], were synthesized by a high-temperature solid-state reaction method. The perovskite structure without any secondary phase can be obtained in samples with x ≤ 0.4. As the BMH content increases, the polarization−electric field (P−E) loop becomes slim and slanted. A large recoverable energy storage density of 4.3 J/cm 3 and high energy efficiency of 92% were achieved simultaneously in 0.6BST−0.4BMH at 390 kV/cm. The fine grain morphology with minimal porosity and the high conductivity activation energy were responsible for the enhanced breakdown strength. Of particular importance is that the 0.6BST−0.4BMH ceramic shows excellent temperature stability and cycling reliability with energy density variations below 3 and 4%, respectively. In addition, the 0.6BST−0.4BMH ceramic possesses fast discharge time (∼0.59 μs) with a high power density of 3.5 MW/cm 3 . All these merits reveal that the lead-free 0.6BST−0.4BMH relaxor ceramic is a promising candidate for high-temperature and high-power energy storage capacitor applications.

Enhanced energy storage properties of hafnium-modified (0.7Ba0.55Sr0.45–0.3Bi0.5Na0.5)TiO3-based relaxor ferroelectric ceramics via regulating polarization nonlinearity and bandgap

“…S8 (ESI †) shows the comparison of the ESPs for the x = 0.15 samples and previous reported lead-free ceramics. 8,16,31,46,51,52,56,63,64 The recently reported lead-free ceramics usually manifested temperature-stable ESPs from room temperature to high temperature, while the x = 0.15 sample exhibited excellent stability within À95 1C to 125 1C in this work. Particularly, it can maintain the stability of ESPs even at ultralow temperatures, which can be used in some extreme temperature environments.…”

“…The S3 (ESI †). [51][52][53][54][55][56][57][58][59][60][61][62] In practical application, capacitors are usually operated under part of the BDS in consideration of safety. Therefore, the x = 0.15 sample is selected to assess the reliability of ESPs due to the higher energy storage density under the same electric field below BDS compared with x = 0.20.…”

Energy storage performance of BiFeO3–SrTiO3–BaTiO3 relaxor ferroelectric ceramics

“…Figure 6 exhibits the comparison of W rec and η values between x = 0.12 in this work and some recently reported typical lead‐free dielectric ceramics, including Bi 0.5 Na 0.5 TiO 3 (BNT)‐, BaTiO 3 (BT)‐, BiFeO 3 (BF)‐, and K 0.5 Na 0.5 NbO 3 (KNN)‐based ceramics 12,13,18,23–37 . As can be seen, excellent energy storage properties have been achieved in many works, but the simultaneous enhancement of W rec (> 5 J/cm 3 ) and η (> 80%) is still a challenge.…”

“…Figure 6 exhibits the comparison of W rec and η values between x = 0.12 in this work and some recently reported typical lead-free dielectric ceramics, including Bi 0.5 Na 0.5 TiO 3 (BNT)-, BaTiO 3 (BT)-, BiFeO 3 (BF)-, and K 0.5 Na 0.5 NbO 3 (KNN)-based ceramics. 12,13,18,[23][24][25][26][27][28][29][30][31][32][33][34][35][36][37] As can be seen, excellent energy storage properties have been achieved in many works, but the simultaneous enhancement of W rec (> 5 J/cm 3 ) and η (> 80%) is still a challenge. Fortunately, the x = 0.12 ceramic explored in this work exhibits more superior comprehensive energy storage properties than most of lead-free bulk ceramics.…”

Simultaneous achievement of ultrahigh energy storage density and high efficiency in BiFeO3-based relaxor ferroelectric ceramics via a highly disordered multicomponent design

“…† Fig. 5 compares the vital parameters for dielectric energy storage between the recently reported Bi 0.5 Na 0.5 TiO 3 (BNT)-, [29][30][31][32][33] BaTiO 3 (BT)-, 6,7,[34][35][36] (K 0.5 Na 0.5 )NbO 3 (KNN)-, 12,[37][38][39][40] BiFeO 3 (BFO)based 10,[13][14][15][16][17]24,27,41,42 relaxor ferroelectric ceramics and our case. The detailed composition, as well as the values of E test /E b , W rec and h are listed in Table S3.…”