Structure, dielectric and relaxor properties in lead-free ST-NBT ceramics for high energy storage applications

Structure and dielectric properties of NBT-xBT-ST lead-free ceramics for energy storage

“…However, NBT-based ceramics have also been reported a pseudocubic phase, and the absence of R and/or T splitting indicates on possible defects arising from the A-site and oxygen sublattice of the perovskite structure. [19][20][21] In this work, the NBT-xBT-ST ceramics have a major pseudocubic phase in accordance with that reported by Cui et al 22 With the increase of x value, the diffraction peak (200) gradually shifts to lower angles, which should be related to the expanding of lattice due to the substitution of smaller cations Figure 2 shows the SEM images of the polished and thermally etched surface of NBT-xBT-ST ceramics with different x values. For pure NBT-ST ceramics, as shown in Fig.…”

Progress, Outlook, and Challenges in Lead‐Free Energy‐Storage Ferroelectrics

“…In this case, better energy storage performances can be obviously excepted by combining these two, and good dielectric and piezoelectric properties of NBT‐ST composites revealed by Parija et al have already provided theoretical basis . As shown in Figure a–f, Pu et al have prepared (1− x )SrTiO 3  x (Na 0.5 Bi 0.5 )TiO 3 ((1− x )ST‐ x NBT) system ceramic and critical component of x = 0.4 has been confirmed with ESD of 1.7 J cm −3 . Based on this, systematic work has been first set about by adding BT to form a series of (0.8‐ x )SrTiO 3 0.2Na 0.5 Bi 0.5 TiO 3 ‐ x BaTiO 3 ((0.8‐ x )ST‐0.2NBT‐ x BT) ceramics, then by B‐site substitution to form (1− x )(0.45SrTiO 3 0.2Na 0.5 Bi 0.5 TiO 3 0.35BaTiO 3 )‐ x SnO 2 (STNBTBT‐Sn x ) ceramics.…”

“…a) Temperature‐dependent permittivity and dielectric loss and b) P – E loops of 0.6ST–0.4NBT ceramic. Reproduced with permission . Copyright 2017, Elsevier.…”

“…Those solutions referred to have all been aimed at structure optimizing, and besides, phase transitions such as FE to RFE and FE to AFE have also gave rise to increasing ESD and η in ferroelectrics. Better performances of RFE and AFE than normal FE have been revealed of shrinkage of E c and stretch of P m − P r and sometimes delayed polarization saturation in P – E loops, resulting in both increasing ESD and η . In the process of development for studying energy storage dielectrics/ferroelectrics, computer simulation has played an increasing important role, especially in analyzing the effects of interface engineering.…”

Recent progress of ecofriendly perovskite-type dielectric ceramics for energy storage applications

“…[130][131][132][133][134][135][136] For example, 0.6SrTiO 3 -0.4(Na 0:5 Bi 0:5 ÞTiO 3 ceramics exhibit high W R of $ 1.7 J/cm 3 and η of $ 70% under an electric field of 210 kV/cm. 135 exhibit an ultrahigh W R of $ 9.0 J/cm 3 , but this largely depends on temperature variation and leads to a drastic decrease in W R above 100 ○ C. To minimize the reliance on temperature in energy storage performance, Mn dopant has been added into CHT matrices and W R found to be maintained at $ 9.5 J/cm 3 even with temperature up to 200 ○ C. 137 Subsequently, the oxide additive HfO 2 has been added into (Ca 0:7 Sr 0:3 ÞTiO 3 ceramics to optimize microstructure and energy storage behavior. Hf-rich intergranular grains have been shown to exhibit higher insulating properties, which is beneficial for charge transportation between grains and grain boundaries and the suppression of interfacial polarization.…”