BaTiO3 Ceramics Research Articles

Ultrahigh Energy-Storage Density of BaTiO3-Based Ceramics via the Interfacial Polarization Strategy.

Lead-free dielectric capacitors are excellent candidates for pulsed power devices. However, their low breakdown strength (Eb) strongly limits their energy-storage performance. In this study, Sr0.7Bi0.2TiO3 (SBT) and Bi(Mg0.5Hf0.5)O3 (BMH) were introduced into BaTiO3 (BT) ceramics to suppress interfacial polarization and modulate the microstructure. The results show that the introduction of SBT and BMH increases the band gap width, reduces the domain size, and, most importantly, successfully attenuates the interfacial polarization. Significantly enhanced Eb values were obtained in (1 - x)(0.65BaTiO3-0.35Sr0.7Bi0.2TiO3)-xBi(Mg0.5Hf0.5)O3 (BSBT-xBMH) ceramics. Meanwhile, the interfacial polarization was reduced to near zero in the sample with x = 0.10, achieving an ultrahigh Eb (64 kV/mm) and a very large recoverable energy-storage density (Wrec ≈ 9.13 J/cm3). In addition, the sample has excellent thermal stability (in line with EIA-X7R standards) and frequency stability. These properties indicate that the BSBT-0.10BMH ceramic holds promising potential for the application of pulsed power devices.

Effect of Bi(Zn1/2Nb2/5)O3 addition on phase transition and energy storage properties of BaTiO3 ceramics

Bi(Zn1/2Nb2/5)O3-modified BaTiO3 ceramics were designed with formula (1‒x)BaTiO3‒xBi(Zn1/2Nb2/5)O3 (0 ≤ x ≤ 0.15) and fabricated using conventional solid-state route. With increasing Bi(Zn1/2Nb2/5)O3 concentration, grain volume increased and phase structure was transformed from tetragonal to pseudo-cubic. Dielectric properties changed from temperature-dependent to temperature-insensitive and curves were flattened. Additionally, higher pseudo-cubic phase content induced slim P-E loop and low Pr. Therefore, 0.94BaTiO3‒0.06Bi(Zn1/2Nb2/5)O3 ceramic achieved energy storage density of 1.85 J/cm3 and high energy efficiency of 91.2% under electric field of 230 kV/cm. This energy storage density was 5 times higher than that of pure BT ceramic. Meanwhile, energy storage properties of this ceramic exhibited excellent thermal stability in the range of 30–120 °C and good frequency stability over 10–100 Hz. This work provides promising alternative option in energy storage materials.

Electronic, electrical and thermoelectric properties of Ba0.95Ca0.05Ti0.95Y0.05O2.975 compound: Experimental study and DFT-mBJ calculation

This article explores the impact of co-doping BaTiO3 ceramics with Ca2+ and Y3+ using solid-state reactions to improve its dielectric constant and decrease losses. The oxide BCTYO (Ba0.95Ca0.05Ti0.95Y0.05O2.975) exhibits a tetragonal crystal structure, characterized by a space group of P4mm. By examining the behavior of the doped BaTiO3 sample and performing simulations, researchers can better understand the underlying mechanisms and optimize material properties for specific applications. DFT study shows a semiconductor behavior with an indirect gap (Eg = 2.5 eV). The partial DOS proves that the hybridization between the orbitals Ti 3d, Y 3d, and O 2p is responsible for the band gap and the hopping processes. The analysis of conductivity curves provides evidence for the semiconductor characteristics of the material under investigation. By determining the activation energy (Ea) through analyzing Ln(fmax) and conductivity as a function of 1000/T, the interconnection between conduction and relaxation phenomena is demonstrated. The study of the real part of the dielectric permittivity (ε′) shows a transition at Tc = 380 K. The obtained results are promising and indicate that the studied material has the potential for various electronic applications (energy storage and diode fabrication …). Moreover, the thermal, electrical, and thermoelectric characteristics were examined utilizing the semi-classical Boltzmann theory. The findings revealed an intriguing result, suggesting that Ba0.95Ca0.05Ti0.95Y0.05O2.975 holds promise as a potential candidate for application in thermoelectric devices.

Achieving Excellent Dielectric and Energy Storage Performance in Core-Double-Shell-Structured Polyetherimide Nanocomposites.

The development of pulse power systems and electric power transmission systems urgently require the innovation of dielectric materials possessing high-temperature durability, high energy storage density, and efficient charge-discharge performance. This study introduces a core-double-shell-structured iron(II,III) oxide@barium titanate@silicon dioxide/polyetherimide (Fe3O4@BaTiO3@SiO2/PEI) nanocomposite, where the highly conductive Fe3O4 core provides the foundation for the formation of microcapacitor structures within the material. The inclusion of the ferroelectric ceramic BaTiO3 shell enhances the composite's polarization and interfacial polarization strength while impeding free charge transfer. The outer insulating SiO2 shell contributes excellent interface compatibility and charge isolation effects. With a filler content of 9 wt%, the Fe3O4@BaTiO3@SiO2/PEI nanocomposite achieves a dielectric constant of 10.6, a dielectric loss of 0.017, a high energy density of 5.82 J cm-3, and a charge-discharge efficiency (η) of 72%. The innovative aspect of this research is the design of nanoparticles with a core-double-shell structure and their PEI-based nanocomposites, effectively enhancing the dielectric and energy storage performance. This study provides new insights and experimental evidence for the design and development of high-performance dielectric materials, offering significant implications for the fields of electronic devices and energy storage.

Phase structure and electrical properties of BiFeO3–BaTiO3 ceramics near the morphotropic phase boundary

As a promising lead-free high-temperature piezoelectric material, BiFeO3–BaTiO3 (BF-BT) is still under debate on its crystal structure, especially for the compositions in the morphotropic phase boundary (MPB). Herein, the crystal structure of (1-x)BF-xBT ceramics near the MPB with x = 0.20–0.33 was analyzed by X-ray diffraction and Raman spectroscopy. With the addition of BT, the phase transition from distorted rhombohedral to pseudo-cubic structure was determined by Rietveld refinement. Raman analysis showed the weakening interactions between the A-site cations and BO6 octahedron, as well as the degenerated distortions of BO6 octahedron. Intriguingly, the results of X-ray photoelectron spectroscopy suggested the inhibition of Fe3+ reduction and decrease in oxygen vacancy concentration by the incorporation of BT. In terms of the electrical properties, the significant decline in Curie temperature, improvement in permittivity, and reduction in high-temperature dielectric loss can be observed with the increase of BT content. The increased remnant polarization, enhanced dielectric response and decreased coercive field were helpful for the piezoelectric performance. The maximum room-temperature piezoelectric coefficient of ∼160 pC/N and high-temperature piezoelectric coefficient of ∼324 pC/N were acquired in the x = 0.30 ceramics. This work provides a clear scope for further research on the structural transformation and high-temperature piezoelectric applications of BF-BT system.

Microstructure and composition driven ferroelectric properties of Er3+ doped lead-free multifunctional 0.94Bi0.5Na0.5TiO3-0.06BaTiO3 ceramics

The x mol Er3+ doped 0.94Bi0.5Na0.5TiO3-0.06BaTiO3 (BNT-BT:xEr3+) ceramics were prepared and their microstructure, electric and luminescent properties were systematically investigated. The microstructure, electric and photoluminescent properties of BNT-BT:xEr3+ ceramics are strongly dependent on the Er3+ composition. The crystal parameters and grain sizes of BNT-BT ceramics strongly depend on Er3+ composition due to the different replacement positions of Er3+ with the increase of Er3+ composition. The ferroelectric and dielectric properties are firstly enhanced due to the decrease of crystal defects, and then suppressed because of the decrease of grain size and the phase transition from R3c to P4bm phase with the increase of Er3+ composition. The discharge energy storage density is improved with a relative change of 67.58% for BNT-BT:1.0%Er3+ ceramics. Furthermore, the depolarization temperature Td and the relaxor antiferroelectric temperature TRE are decreased with the increase of Er3+ composition. But the Curie temperature Tm is enhanced for x< 0.6% as the A-site doping limits the transition from ferroelectric to paraelectric phase. The BNT-BT:xEr3+ ceramics exhibit a strong green emission at 548 nm under the excitation of 487 nm light. The investigation provides a new opportunity in exploring electro-optical coupling materials.

Research Trends on the Influence of Oxygen Vacancies in Post BaTiO3 (BT) Ceramics for Next-Generation MLCCs

In line with the trend towards electrification in mobility, there is a demand for the development of next-generation Multilayer Ceramic Capacitors(MLCCs) with superior properties compared to those using the conventional BaTiO&lt;sub&gt;3&lt;/sub&gt; (BT) ceramics. For this, various high-performing ferroelectric ceramics have been proposed as post-BT materials, and numerous studies have been conducted on the role of oxygen vacancies within these materials. It has been confirmed that oxygen vacancies in the ceramic material have a significant impact on various properties such as oxygen ionic conduction, IR degradation, microstructure, aging degradation, and hardening effect, and by controlling the concentration and mobility of oxygen vacancies, it is possible to adjust these properties. We hope that research on the role of oxygen vacancies in various high-performing ferroelectric ceramics will be utilized as a foundation of knowledge for the development of next-generation MLCCs in the future.

Phase transformation of cold-sintered doped barium titanate ceramics during the post-annealing process

The cold sintering technique has been developed to densify electroceramics at significantly low temperatures to tackle high energy consumption as well as compatibility of electroceramic components in modern electronics. However, obstacles still exist since, to obtain desired electrical properties, a post-annealing procedure at elevated temperatures must follow to trigger compulsory phase formation and/or grain growth. This work investigates the BaTiO3 and (Ba,Sr)TiO3 ceramics via both the cold and conventional sintering routes, and then compares their phase transformation behaviors during the post-annealing process. Results suggest that, given similar particle and grain sizes, the cold-sintered ceramics tend to retain a substantial part of the pristine tetragonal phase at annealing temperatures of <800 °C, while the cubic phase tends to dominate when annealed at >800 °C. This indicates a process-stimulated phase transformation that may guide or limit the selection of annealing temperature in practice.

High-Temperature Piezoelectric Response and Thermal Stability of BiGaO3 Modified BiFeO3–BaTiO3 Lead-Free Piezoelectric Ceramics

BiGaO3 doped BiFeO3–BaTiO3 ceramics were prepared by the traditional solid-phase synthesis process. The phase analysis, microstructure, piezoelectric, ferroelectric, dielectric properties, and thermal stability of 0.7BiFeO3-(0.3 − x)BaTiO3-xBiGaO3 (Abbreviated as BF–BT-xBG) were investigated. The results show that the ceramics have rhombohedral (R) and tetragonal (T) structures. Particle dimensions gradually get bigger with the increase of BiGaO3 concentration, and dense ceramic grains were observed through SEM. Electrical properties of BF–BT-xBG are improved after adding a small amount of BiGaO3: piezoelectric constants d33 = 141 pC/N, electromechanical coupling coefficient kp = 0.314, mechanical Quality Factor Qm = 56.813, dielectric loss tanδ = 0.048, residual polarization intensity Pr = 18.3 µC/cm2, Curie temperature Tc = 485.2 °C, depolarization temperature Td = 465 °C for x = 0.003. The “temperature-piezoelectric performance” curve under in situ d33 indicates that piezoelectric properties d33 increase rapidly with increasing temperature. Remarkably, the piezoelectric response d33 reaches a maximum of 466 pC/N at a temperature T = 340 °C, and afterward, reduces gradually to zero with increasing temperature until 450 °C.

Tailoring energy storage in Nb2O5-added 0.7BiFeO3–0.3BaTiO3 ceramics via A-site Gd3+ substitution

Perovskite BiFeO3-based capacitors have demonstrated potential for static electric energy storing applications with superb polarizations and rapid charge-discharge response. This report demonstrates a binary design with high storage energy densities using the lead-free 0.5 mol% Nb2O5–added 0.7(Bi1-xGdx)FeO3-0.3BaTiO3 ceramics (x = 0–0.40) tailored by the A-site gadolinium (Gd3+) substitution from ferroelectric to relaxor-ferroelectric state. An excellent recoverable energy density Wrec∼6.5 J/cm3 (at 260 kV/cm) and a storing efficiency η ∼75% (at 280 kV/cm) were respectively attained at x = 0.15 and x = 0.30. The breakdown electric field (Eb) rises from ∼120 to ∼260–280 kV/cm with increasing Gd3+ from x = 0 to x = 0.4 owing to the improved interatomic bonding, including the B-O bonds and the BO6 oxygen octahedron. The high recoverable energy densities can be correlated to the evolution of multi-phase lattice distortions, nanoscale domains, and polar nanoregions. This study signifies that the Gd3+-modified BF-BT ceramics can be candidates for electric energy-storing capacitors.

Large remnant polarization and improved dielectric, magnetic properties of Te-modified 0.7BiFeO3–0.3BaTiO3 ceramics

BiFeO3–BaTiO3 (BF–BT) ceramics, as a kind of binary ferroelectric material with excellent properties, have a wide range of applications. A novel Te-doped 0.7BiFe1−xTexO3–0.3BaTiO3 (x = 0–0.07) ceramics with enhanced ferroelectric properties were designed and synthesized via a solid-phase reaction. Results of X-ray diffraction and Rietveld refinement revealed a phase transition from the rhombohedra and tetragonal phases to a single tetragonal phase with increasing Te content, indicating the formation of a morphotropic phase boundary (MPB) in samples with x = 0–0.03. The fitting results of the X-ray photoelectron spectra showed that the Te introduction reduced the Fe2+ concentration and improved the insulating performance. Due to the Te-induced structure distortion of the rhombohedral phase and tetragonal phase, a large remnant polarization of 51 μC/cm2 is obtained at x = 0.01, which is superior to those reported in many studies on BF–BT bulk materials. The dielectric properties revealed that Te addition effectively adjusted the relaxation degree of the ceramics, showing an ideal relaxor ferroelectric behavior in samples with x = 0.05 and 0.07. Additionally, Te substitution reduced the Fe–O–Fe bond angle and the grain size, achieving enhanced ferromagnetism and affording the largest remnant magnetization in the case of x = 0.03, which is around six times that of the pure BF–BT ceramic.

Dielectric Spectroscopy Studies and Modelling of Piezoelectric Properties of Multiferroic Ceramics

Compounds and solid solutions of bismuth ferrite (BiFeO3)—barium titanate (BaTiO3) system are of great scientific and engineering interest as multiferroic and potential high-temperature lead-free piezoelectric materials. In the present paper, the results of research on the synthesis and characterisation of 0.67Bi1.02FeO3–0.33BaTiO3 (67BFBT) ceramics in terms of crystal structure and dielectric and piezoelectric properties are reported. It was found that the produced 67BFBT ceramics were characterised by a tetragonal crystal structure described by the P4mm space group, an average crystallite size &lt;D&gt; ≈ 80 nm, and an average strain &lt;ε&gt; = 0.01%. Broad-band dielectric spectroscopy (BBDS) was employed to characterise the dielectric response of polycrystalline ceramics. The frequency range from ν = 10−1 Hz to ν = 105 Hz was used to characterise the influence of the electric field strength on dielectric response of the ceramic sample at room temperature. The dielectric spectra were checked for consistency with the Kramers–Kronig test, and the high quality of the measurements were confirmed. The electric equivalent circuit method was used to fit the dielectric spectra within the frequency range that corresponded to the occurrence of the resonant spectra of the radial mode for thin disk sample, i.e., from ν = 105 Hz to ν = 107 Hz and the temperature range from T = −20 °C to T = 50 °C. The electric equivalent circuit [RsCPE1([L1R1C1]C0)] was used, and good fitting quality was reached. The relevant calculations were performed, and it was found that the piezoelectric charge coefficient exhibited a value of d31 = 35 pC/N and the planar coupling factor was kp = 31% at room temperature. Analysis of impedance spectra performed in terms of circumferential magnetic field made it possible to establish an influence of magnetic field on piezoelectric parameters of 67BFBT multiferroic ceramics. Additionally, the “magnetic” tunability of the modulus of the complex dielectric permittivity makes 67BFBT a sensing material with vast potential.

Effect of manganese doping on structural, optical, morphological, and dielectric properties of Ba(Ti1-xMnx)O3 lead-free ceramics for energy storage in supercapacitors.

A supercapacitor (SC) is considered to be one of the best energy storage devices due to its high-power density, long lifespan, fast charge storage capability, and eco-friendliness. Ceramics with low-cost, nontoxic, high efficiency, and stability are the suitable and promising materials for performed supercapacitors at room temperature. As proposal, we synthesized by sol-gel method the ceramics Ba(Ti1-xMnx)O3 (where x = 0, 1, 2, or 3%) to study the effect a low rate of manganese doping on their morphological, structural, dielectric, and optical properties. The microstructure of the sintered ceramics was examined using scanning electron microscope (SEM), and the results reveal that the average grain size (AGS) of the ceramics (0.663-1.018μm) increases with increasing Mn doping content. The optical behavior was studied by UV-visible spectroscopy, and the results indicate that Mn doping reduces the band gap (Eg) from 3.27 to 2.79eV thus, the possibility of using these materials in photocatalyze applications. The dielectric properties of all studied samples were investigated at the temperature range 30-400°C and frequency range 103-106Hz. Significant modification in dielectric permittivity and an appreciable decrease in dielectric losses were observed when adding Mn2+ ions to BaTiO3 ceramics. Variations in dielectric properties and AC conductivity, as a function of frequency, reveal a relaxation mechanism related to the Maxwell-Wagner interfacial polarization. The obtained results suggest the use of prepared ceramics in capacitor and actuator applications at room temperature (RT).

Simultaneous enhancement of dielectric properties and temperature stability in BaTiO3‐based ceramics enabling X8R multilayer ceramic capacitor

AbstractModified BaTiO3 ceramics that possess high dielectric permittivity and acceptable temperature stability have been widely utilized as multilayer ceramic capacitors (MLCCs) for high‐frequency bypass and power filtering in automotive applications. However, since the increasing demand for high‐capacity and small‐size, high‐permittivity materials that can serve as dielectric layers in MLCCs are urgently required. In this work, we design and fabricate a special BaTiO3‐0.03Mg‐0.02Y‐0.02CaZrO3 ceramic with a high dielectric permittivity of 3000 and the dielectric variation below ±13% in the temperature range of ‐55–150°C, fulfilling the requirements of X8R capacitors. To achieve these results, we employed grain size engineering and cation doping, using BaTiO3 precursors with a particle size of 240 nm to prepare the BaTiO3‐based ceramics with fine grains, while Mg and Y co‐doping was used for improving the temperature stability due to dielectric dispersion. Utilizing these high‐permittivity BaTiO3‐based materials, we fabricated MLCCs that satisfy the X8R criterion, possessing a high dielectric constant of 2950 and a high breakdown field (410 kV/cm).

Analysis of local vs. macroscopic properties of porous BaTiO3 ceramics based on 3D reconstructed ceramic microstructures

In the present work, ferroelectric BaTiO3 ceramics with variable porosity level (96%, 89%, 81%, and 74% relative densities) and anisotropy derived from the deformation of sacrificial soft polymeric additives during the pressing step, are investigated by an experimental-numerical approach. 3D micro X-ray computed tomography experimental data with specific numerical procedures are firstly used to reconstruct the 3D microstructures of the porous ceramics and to extract geometrical information concerning the samples. These 3D microstructures are then employed as input in FEM models, in order to determine the local electric field and potential distributions inside the ceramic, with the final aim of evaluating low field effective dielectric permittivity and high field ferroelectric switching P(E) features as a function of porosity and field direction. The dielectric and ferroelectric properties derived by using this procedure are discussed in comparison with experimentally determined ones. The paper demonstrates the usefulness of analyzes and simulations of properties at different lenghtscales based on real 3D microstructures, in such ceramic systems, in completing the understanding of the complex relationship between composition – microstructure – local/macroscopic properties.

Improved energy storage performance of lead-free BaTi0.96Li0.04O2.94 ceramics via domain structure engineering

BaTiO3 (BT) ceramics with excellent energy storage performance (ESP) are in great demand in the power electronics industry due to their high power density. However, the traditional BT-based ceramics cannot simultaneously achieve high breakdown strength and high maximum polarization. Here, we bring forth ideas of design strategy to promote the ESP of the BaTi0.96Li0.04O2.94 ceramics by domain structure engineering to construct the special crossover region between ferroelectric and relaxor ferroelectric state, which possesses ferroelectric domains of different scales. The Bi(Mg2/3Ta1/3)O3-doped ceramic shows high energy storage density of 3.28 J/cm3 with slim hysteresis loop at large BDS of 380 kV/cm, and accompany with high efficiency of 88.52%. The ESP are less than 3% at the temperature range of 20∼200 °C, and the ceramic exhibits outstanding temperature stability. Our work demonstrates that the crossover region in BT ceramics is conducive to obtaining excellent ESPs, providing a reference for the structural optimization of high-performance BaTiO3 ceramics.

Structural, piezoelectric and ferroelectric analysis of 0.96Bi0.5Na0.5TiO3-0.06BaTiO3: xwt%MnO2 ceramics for high-tech applications

With the rapid growth to design and engineer the smart and efficient electronic devices like piezoelectric sensors, the surge for the materials with multifunctional properties have risen tremendously. Herein, a morphotropic phase boundary (MPB) existent 0.94(Bi0.5Na0.5TiO3)-0.06BaTiO3 (BNBT) ceramics have been fabricated and the influence of additive MnO2 (0–0.20 wt%) has been examined, via structural, morphological, ferroelectric and dielectric analysis. Keeping the MPB region stable, BNBT:0.15Mn ceramic has shown the much improved results with remnant polarization (Pr) of 38.72 μC/cm2, piezoelectric coefficient (d33) of 211 pC/N, and dielectric constant (ϵr) of 4502, sample has maintained its stable d33 value (198 pC/N) till 200 °C. Moreover, the dielectric constant dependence on temperature analysis has been observed to analyze the Curie temperature (TC) of the samples, where BNBT:0.15Mn ceramic has exhibited the TC of ∼335 °C, which is the main reason of achieving the stable piezoelectric effect till 200 °C. Present study not only provides the new direction for the material engineering but also demonstrates the potential of the reported material for high-temperature piezoelectric sensors.

Tetragonal-structural changes influenced the magnetic and ferroelectric properties of (Y, Fe)-codoped BaTiO3 ceramics

We present a detailed study on the structural characterization, electronic structure, and magnetic/electric-polarization properties of Ba1-xYxTi1-xFexO3 (BYxTFxO, x = 0–0.1) ceramic samples. These samples mainly crystalized in a tetragonal structure, and a small amount of a YFeO3-related secondary phase constituted as x ≥ 0.08. With increasing x, the lattice constant a increases while c decreases. Such structural changes reduce rapidly the intensity of characteristic Raman modes. Magnetization data have proved all BYxTFxO samples exhibiting ferromagnetism at room temperature. Both the saturation magnetization and coercivity tend to increase with increasing x. This is ascribed to an enhanced exchange interaction between Fe3+ ions, and the YFeO3-phase formation. Herein, the Fe3+ presence has been confirmed upon analyzing X-ray absorption spectra. Though all the samples exhibit ferroelectricity, the electric-polarization slightly decreases with increasing x. This is associated with an increased symmetry due to the changes in the lattice parameters towards the cubic structure.

Enhanced piezoelectric properties in coarse-grained 0.7Bi(Fe0.9985Mn0.0015)O3-0.3BaTiO3 ceramics

The lead-free BiFeO3-BaTiO3 (BF-BT) based ceramics with large piezoelectric coefficient (d33) have been desired for promising applications in high-temperature fields. Herein, the 0.7Bi(Fe0.9985Mn0.0015)O3-0.3BaTiO3 ceramics with different grain sizes are intentionally prepared by solid-state method, and a large d33 (232 pC/N) and high Curie temperature Tc (501 °C) are simultaneously achieved in the case of large grain size (>9 µm). X-ray diffraction and Rietveld refinement analyses indicate that these coarse-grained samples possess stronger rhombohedral distortion and enlarged lattice parameter compared to fine-grained samples, which make domain switching easier and give rise to the increase in strain. As a result, the piezoelectric and ferroelectric properties of such samples are significantly improved with increasing grain size from 3.05 µm to 9.07 µm. In addition, electric domain configuration and field-induced strain further prove that the strong piezoelectric response in coarse-grained samples is attributed mainly to enhanced non-180° domain mobility. This study reveals the origin of large piezoelectric response in coarse-grained BF-BT ceramics, and proposes an effective approach to improve the piezoelectric properties of BF-BT ceramics.

Defect evolution and effect on structure and electric properties of A/B site Sm doped BaTiO3 sintered in different atmospheres

BaTiO3 ceramics doped with different contents of Sm (0.5-7 mol%) are prepared by a homogeneous precipitation method and sintered in air (A-xSm) and reducing (R-xSm) atmosphere respectively. With the increase of doping amount, the phase structure of Sm-doped BaTiO3 ceramics gradually changes from tetragonal phase to cubic phase, and the cubic phase is stronger in R-xSm. In the air atmosphere, Sm ions preferentially replace Ba sites as donors at low doping concentration, which is easy to convert Ti4+ ions into Ti3+ ions, resulting high dielectric constant (>104) and semiconductor like properties. As the doping amount increases, Sm ions start to replace Ti sites as acceptors to generate oxygen vacancies, which capture the electrons generated by donor doping, thus decreasing the percentage of Ti3+ ions. As a result, the dielectric loss and permittivity are decreased, and the electrical insulation properties of A-xSm ceramics are gradually improved. However, in the reducing atmosphere, oxygen atoms in the lattice are easy to escape, resulting in many oxygen vacancies and free electrons. The increase of oxygen vacancy inhibits the substitution of Sm ion to Ti site, and the free electron leads to the increase the percentage of Ti3+ ions and R-xSm ceramics exhibit semiconductor like properties. Thermally stimulated depolarization currents (TSDC) testing verified that oxygen vacancies of A-xSm ceramics mainly capture space charges, and a small part of oxygen vacancies form defective dipoles [2SmTi&#x02032;−VO..]. The complex impedance test shows that the change of resistivity of A-xSm ceramics is mainly closed to the influence of Sm doping on the grain not grain boundary of BaTiO3 ceramic.