Maximum Dielectric Permittivity Research Articles

Large Room-Temperature Electrocaloric Effect in Lead-Free Relaxor Ferroelectric Ceramics with Wide Operation Temperature Range.

In order to obtain large room-temperature electrocaloric effect (ECE) and wide operation temperature range simultaneously in lead-free ceramics, we proposed designing a relaxor ferroelectric with a Tm (the temperature at which the maximum dielectric permittivity is achieved) near-room temperature and glass addition. Based on this strategy, we designed and fabricated lead-free 0.76NaNbO3-0.24BaTiO3 (NN-24BT) ceramics with 1wt.% BaO-B2O3-SiO2 glass addition, which showed distinct relaxor ferroelectric characteristics with strongly diffused phase transition and a Tm near-room temperature. Based on a direct measurement method, a large ΔT (adiabatic temperature change) of 1.3 K was obtained at room temperature under a high field of 11.0 kV mm-1. Additionally, large ECE can be maintained (>0.6 K@6.1 kV mm-1) over a broad temperature range from 23 °C to 69 °C. Moreover, the ECE displayed excellent cyclic stability with a variation in ΔT below ±7% within 100 test cycles. The comprehensive ECE performance is significantly better than other lead-free ceramics. Our work provides a general and effective approach to designing lead-free, high-performance ECE ceramics, and the approach possesses the potential to be utilized to improve the ECE performance of other lead-free ferroelectric ceramic systems.

Low-frequency dynamics of 0.45PMN-0.55PSN solid solution

Lead magnoniobate-scandoniobate (PMN-PSN) solid solutions are important functional materials for transducer/actuator devices due to their extraordinary dielectric and electromechanical properties. These unique properties are related to the unusual low-frequency relaxation dynamics, which has not been sufficiently understood until now. In our paper the low-frequency relaxation dynamics of 0.45Pb(Mg1/3Nb2/3)O3–0.55Pb(Sc1/2Nb1/2)O3 single crystal is studied in frequency range 10 mHz–1 MHz at temperatures near the dielectric permittivity maximum. Four relaxation processes are identified. Low-frequency mode demonstrating the critical divergence around 306 K is revealed. However, the phase transition into ferroelectric phase at this temperature does not occur. Near 306 K, the appearance of M-type superstructure is found related to the combination of oxygen octahedral rotation and anti-parallel shifts of lead ions. The appearance of the additional order parameter suppresses the slowing down of the ferroelectric mode and the phase transition into the ferroelectric phase occurs only below 295 K. In addition, two relaxation processes, similar to reorientation and “breathing” polar nanoregion (PNR) modes reported for PMN, are found. The sharp softening of “reorientation mode” is observed on cooling from 315 to 295 K with Tf ∼288 K. The fourth relaxation process is the Debye process, and we assume that it is associated with defects relaxation. Below 295 K, all four relaxation processes still exist, but their parameters are practically temperature independent. The low-temperature phase is not exactly a “normal” ferroelectric phase, the PNRs persist in the FE phase.

Relaxor-like behavior of the dielectric response of dense ferroelectric composites

We study experimentally and theoretically the influence of size effects and structural factors on the dielectric and ferroelectric properties of the dense ferroelectric composites. The composites have the form of the tape-casted films with 28 vol% of nanosized or submicron BaTiO3 particles dispersed in the polyvinyl butyral. We measured and analyzed the temperature dependences of the capacitance and dielectric losses in the temperature range (−200 – +200)oC and frequency range (102–105) Hz. The nonmonotonic temperature dependences of dielectric permittivity of the studied composite films have a wide plateau-like maxima located between 80oС and 160oС, in contrast to the relatively sharp maximum near the Curie temperature (∼124oC) observed in the fine-grained and coarse-grained ceramics, sintered from the same nanosized or submicron BaTiO3 particles at 1250oC. The shift of the dielectric permittivity and losses maxima (in more than 40oC) and their strong frequency dispersion do not agree with the behavior expected for the systems with a weak interaction between ferroelectric particles and a polymeric matrix. In contrast, we reveal the relaxor-like behavior of the composite dielectric response. To explain the observed results, we propose the analytical model, which considers the strong dipole-dipole cross-interaction of the BaTiO3 particles in the dense nanocomposite. The analytical model is corroborated by the structural studies of the BaTiO3 nanosized and submicron particles by X-ray phase analysis and static 137Ba NMR spectra, as well as by the finite element modelling of the composite polar properties, which confirms the strong cross-interactions between the dipole moments of single-domain nanoparticles and/or between the domain walls of different submicron polydomain particles.The obtained results may be useful for development of cheap and flexible lead-free dense ferroelectric nanocomposites with relaxor-like behavior of the dielectric response, which are promising for non-volatile memory and energy-saving elements, modulators, electrical converters and piezoresistive elements.

Influence of thermal cycling rate and sintering temperature of barium titanate and barium strontium titanate ceramics on their dielectric properties

One of the negative effects of ferroelectric applications, particularly for electrocaloric effect (ECE) applications, is temperature hysteresis (ΔT Hyst). Temperature hysteresis is the difference between the temperatures corresponding to the maximum dielectric permittivity in heating and cooling modes. The value of ΔT Hyst is commensurate with the value of the ECE temperature change. The ECE is a phenomenon in which a material shows a reversible temperature change under an applied electric field. The aim of this work is to study the possibilities of temperature hysteresis reduction by varying the ceramic sintering temperature, changing the stoichiometry of BaxSr1-xTiO3 solid solutions, and changing the rate of the heating-cooling cycle.

Composition and electric field driven studies on modified NBT-based lead-free ceramics

A considerable increase in the c/a ratio, tilt angle, octahedral strain, and Ti-Ti distance with an application of electric field was observed for all the compositions in (1-x) (Na0.5Bi0.5TiO3).x(Ba0.85Ca0.15Ti0.90Zr0.10O3) ceramics. In the x = 0.09 sample, a P4bm phase (∼45 %) was observed which reduced to ∼ 15 % upon poling. The tilt angle modifies the A1 phonon mode at 784 cm−1 upon substitution and application of the electric field. Incorporating Ba0.85Ca0.15Ti0.90Zr0.10O3 increased the maximum dielectric permittivity (εm) from ∼ 2466 (x = 0) to ∼ 3231 (x = 0.09). The degree of diffuseness (γ) also increased with substitution from ∼ 1.384 (x = 0) to ∼ 1.980 (x = 0.09). With poling the value of γ was observed to decrease for each composition. The transformation from a compressive octahedral strain to a tensile one increased the piezoelectric coefficient (d33). The d33 value increased from ∼ 70 (x = 0) to ∼ 120 (x = 0.06).

Phonon mode and dielectric function dynamics of Bi0.5Na0.5TiO3-xSm2Ti2O7 ceramics during the phase transitions discovered by Raman scattering and spectroscopic ellipsometry

Recently, Bi0.5Na0.5TiO3-based ceramics have drawn widespread attention due to their excellent energy storage properties. Here, a comprehensive analysis of the composition- and temperature-driven transition processes in (1 − x)Bi0.5Na0.5TiO3-xSm2Ti2O7 (BNST-x) polycrystals have been presented using Raman scattering and spectroscopic ellipsometry. With increasing Sm2Ti2O7 content, BNST-x ceramic gradually becomes disordered and belongs to the superparaelectric state at x = 0.12 near room temperature. Moreover, the thermal evolution of the lattice kinetic behaviors shows two crucial temperatures: the depolarization temperature Td and the temperature at the maximum dielectric permittivity Tm, which suggest the transitions from nonergodic relaxor ferroelectric—ergodic relaxor (ER) ferroelectric and ER ferroelectric—superparaelectric, respectively. It is noteworthy that the series of changes is closely related to the ordering degree of the B-site ion affected by the doping and the temperature. This work gives an insight into the connection among the phonon behavior, electronic transition, and lattice structure of BNST-x ceramics, which can further understand the phase transition mechanisms under the doping and thermal field.

Ferroelectric relaxor behaviour in Bi and K/Na-substituted solid solutions of tetragonal tungsten bronze PbNb2O6

Lead metaniobate (PbNb2O6 or PNO) belongs to the tetragonal tungsten bronze (TTB) family. There are three polymorphic forms of PNO: tetragonal (stable at high temperature), rhombohedral (stable at room temperature), and the metastable orthorhombic phase, which has ferroelectric properties. The metastable orthorhombic phase is formed by quenching from the high temperature tetragonal phase due to the reconstructive/sluggish tetragonal to rhombohedral phase transition. A suitable ionic substitution can also lead to the stable ferroelectric orthorhombic phase. Stabilization of the ferroelectric orthorhombic phase by ionic substitution, and the formation of ferroelectric relaxors with increased amounts of dopants is hereby reported for the compositions Pb(1-x)Bi(x/2K(x/2)Nb2O6 and Pb(1-x)Bi(x/2)Na(x/2)Nb2O6. The solid solutions of PNO showed evidence of linked dielectric relaxation and ferroelectricity, validating the distinctive ferroelectric relaxor behaviour for the compositions Pb0.6Bi0.2K0.2Nb2O6 and Pb0.6Bi0.2Na0.2Nb2O6. As the concentrations of bismuth (Bi) and potassium/sodium (K/Na) dopants increased, the Curie temperature (Tc), or the temperature corresponding to the maximum dielectric permittivity (Tm), dropped. By using the Uchino-Nomura relation as a modification of the Curie-Weiss law, it was established that the Pb0.6Bi0.2K0.2Nb2O6 solid solution exhibit higher degree of diffuseness than Pb0.6Bi0.2Na0.2Nb2O6 at the transitions. The width of the ferroelectric hysteresis loop increased as the percentage of dopants increased, from x = 0.1 to x = 0.3. At x = 0.4, a narrow ferroelectric hysteresis loop and a frequency-dependent Tm abruptly formed, which is indicative of a ferroelectric relaxor.

Structural Refinement, Dielectric and Electromechanical Properties of (1-x)NBT-xKBT Piezoceramics in the Morphotropic Phase Boundary Region

Lead-free ferroelectric materials of sodium-potassium bismuth titanate, (1-x)NBT-xKBT systems were synthesized by a hydrothermal process. In this way, the appropriate conditions for the hydrothermal synthesis of NBT and KBT (i.e., concentrations of synthetic precursors, solution pH and temperature) are given graphically. Ceramics of (1-x)NBT-xKBT with (x(mol.%) = 0; 12; 16; 20; 30 and 100) were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The rhombohedral-tetragonal morphotropic phase boundary (MPB) was confirmed to be in the region of 0.12 ≤ x ≤ 0.20 for (1-x)NBT-xKBT at ambient temperature. Scherrer's formula and the Williamson-Hall (W-H) analysis were used to examine the average crystallite size and lattice strain. Raman spectroscopy was effectively applied to study the structural evolution of the (1-x)NBT-xKBT phase. The ceramics exhibited a high temperature of maximum dielectric permittivity at (Tmax = 343 °C at 100 kHz) along with electromechanical coupling factors (kp = 0.34, d33 = 147 pC/N). Based on the composition of all specimens, the results indicate a diffuse phase transition, probably of second order, between ferroelectric and paraelectric phases.

Intrinsic-designed polyimide dielectric materials with large energy storage density and discharge efficiency at harsh ultra-high temperatures.

Polymer dielectric materials with excellent temperature stability are urgently needed for the ever-increasing energy storage requirements under harsh high-temperature conditions. In this work, a novel diamine monomer (bis(2-cyano-4-aminophenyl)amine) was successfully synthesized to prepare a series of cyano-containing polyimides (CPI-1-3), which possessed excellent dielectric properties and high thermostability. The maximum dielectric permittivity was up to 5.5 at 102 Hz for CPI-3, being 2.5 times higher than that of commercially used BOPP. In comparison, the CPI-1 exhibited an outstanding breakdown strength of 433 MV m-1 and a high energy density of 2.5 J cm-3 even at 250 °C, which was the highest value reported under the same conditions. The synthesized CPIs through such an intrinsic approach are potential candidate materials for energy storage and even other applications under simultaneously harsh electrical and thermal conditions.

Dielectric and energy storage properties of surface-modified BaTi0.89Sn0.11O3@polydopamine nanoparticles embedded in a PVDF-HFP matrix.

In the most recent electronic and electric sectors, ceramic-polymer nanocomposites with high dielectric permittivity and energy density are gaining popularity. However, the main obstacle to improving the energy density in flexible nanocomposites, besides the size and morphology of the ceramic filler, is the low interfacial compatibility between the ceramic and the polymer. This paper presents an alternative solution to improve the dielectric permittivity and energy storage properties for electronic applications. Here, the poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) matrix is filled with surface-modified BaTi0.89Sn0.11O3/polydopamine nanoparticles (BTS11) nanoparticles, which is known for exhibiting multiphase transitions and reaching a maximum dielectric permittivity at room temperature. BTS11 nanoparticles were synthesized by a sol-gel/hydrothermal method at 180 °C and then functionalized by polydopamine (PDA). As a result, the nanocomposites exhibit dielectric permittivity (εr) of 46 and a low loss tangent (tan δ) of 0.017 at 1 kHz at a relatively low weight fraction of 20 wt% of BTS11@PDA. This is approximately 5 times higher than the pure PVDF-HFP polymer and advantageous for energy storage density in nanocomposites. The recovered energy storage for our composites reaches 134 mJ cm-3 at an electric field of 450 kV cm-1 with a high efficiency of 73%. Incorporating PDA-modified BTS11 particles into the PVDF-HFP matrix demonstrates highly piezo-active regions associated with BTS11 particles, significantly enhancing functional properties in the polymer nanocomposites.

Investigation of crystal structure and variable range hopping conduction mechanism in Gd doped Na0.5Bi0.5TiO3 ceramics

We report the crystal structure, dielectric, and conductivity properties of Gd doped Na0.5Bi0.5TiO3 i.e., [Bi(1-x)Gdx]0.5Na0.5TiO3 (x: 0.00, 0.01, 0.02, 0.03 and 0.04) ceramics prepared by solid-state reaction method. Rietveld refinement results of X-ray diffraction data suggest that all the sample exhibit rhombohedral crystal structures with the R3c space group. We have adopted the Megaw and Darlington formalism of atomic positions for the R3c space group to refine the crystal structure. The primary XRD reflection around 32° i.e., (104)/ (110) initially shifts to a higher angle up to x ≤ 0.02 and then moves towards a lower angle for a higher doping level, indicating the presence of an amphoteric nature. The deconvolution of the Raman peak was carried out using the Lorentz function and a broadening in the Raman modes with a raise in Gd percentage was observed. The temperature-dependent dielectric data show that the temperature corresponding to maximum dielectric permittivity (Tm) increases with Gd content whereas the Td declines with increasing composition. The variation of conductivity as a function of the temperature of the samples was examined by Arrhenius's equation and Mott's variable-range hopping mechanism. Above x = 0.02, activation energy values at high temperature increase in Gd content, which suggest ferroelectric hardening that resulted due to acceptor type Gd3+ doping. The parameters like hopping length (RH), the density of states (N(EF)), and hopping energies (WH) were calculated from the fitting of the model. The above results are expected to provide the fundamental importance of ferroelectric hardening and p-type conductivity in Na0.5Bi0.5TiO3-based perovskites.

Defects minimisation promoted by lead-volatility in (Pb,La)(Zr,Ti)O3 ferroelectric ceramics

La-modified PbZrTiO3 ferroelectric ceramics with Pb0.92La0.08(Zr0.686Ti0.294)O3 nominal composition were obtained via the conventional solid-state reaction method, by considering different PbO excess (5, 10 and 15 mol %). The structural properties, were investigated from X-ray diffraction (XRD) and Raman Spectroscopy techniques, both at room temperature. Results confirmed the formation of the perovskite structure with rhombohedral symmetry (R3m space-group) for all the samples. The dielectric properties were also investigated, from the temperature dependence of the dielectric response, and results revealed the characteristic response of ferroelectric materials for all the compositions. The obtained very broad peak in the maximum dielectric permittivity, around Tm (~107°C), suggests the diffuse character of the ferroelectric-paraelectric phase transition.

A comprehensive investigation of dielectric properties of epoxy composites containing conducting fillers: Fluffy carbon black and various types of reduced graphene oxide

AbstractThe dielectric properties of epoxy nanocomposites with conducting nanofillers, such as graphene based and fluffy carbon black (FCB) were investigated in the frequency range of 40 to 30 MHz using an impedance analyzer to measure the dielectric permittivity, tan δ and AC conductivity. At very low filler loadings, epoxy nanocomposites showed remarkable dielectric characteristics. Dielectric constant of the composites decreased with increasing frequency and increased with filler loading. This is related to a decrease in interfacial polarization with increasing frequency and greater interfacial polarization with increase in filler loading. Dielectric loss peaks of epoxy nanocomposites with frequency suggested that both DC conductivity and dielectric polarization processes due to inhomogeneity within the nanocomposites contribute towards dielectric loss. Rising of AC conductivity of the composites with frequency was mainly due to hopping of charge carriers. An AC conductivity of 8.33 × 10−4 S/m and 2.455 × 10−5 S/m at 30 MHz was recorded for FCB/epoxy at 5 phr composite and neat epoxy. This composite also exhibited the maximum dielectric permittivity, 3.16 at 40 Hz and 0.82 at 30 MHz. The distinctive dielectric properties of epoxy‐based nano dielectric systems are due to the significant volume fraction of interfaces in the bulk of the material and the consequent interactions between charged nanoparticle surface and epoxy chains.

Electrical Conductivity and Dielectric Relaxation in Ag1−xLixNbO3

The broadband electrical properties of Ag1−xLixNbO3 (ALNx) ceramics (x ≤ 0.1) together with AgNbO3 (AN) crystals were studied over a wide temperature interval of 20–800 K. For ALNx with x ≤ 0.05, a very diffused ferroelectric phase transition was observed. The position of the dielectric permittivity maximum in this phase transition is strongly frequency-dependent and is described well by the Vogel–Fulcher law. The freezing temperature decreases when the lithium concentration increases. Below the ferroelectric phase transition temperature, the dielectric dispersion is mainly caused by ferroelectric domain dynamics. Moreover, for ALN3 and ALN5 ceramics at very low temperatures (below 100 K), behavior typical of dipolar glasses is observed. At higher temperatures (above 650 K for ALN5), electrical conductivity effects become important. The DC conductivity increases with temperature according to the Arhenius law and the activation energy is highest in the antiferroelectric phase. Moreover, the activation energy is strongly dependent on the lithium concentration and it is greatest when x = 0.02.

Significant increase in comprehensive energy storage performance of potassium sodium niobate-based ceramics via synergistic optimization strategy

K0.5Na0.5NbO3 (KNN)-based ceramics are considered as one of the most promising lead-free dielectric ceramics owing to relatively high dielectric breakdown strength (DBS) resulted from their unique submicron grains. Unfortunately, it has been difficult to increase recoverable energy-storage density (Wrec) and energy-storage efficiency (η) simultaneously at present. Herein, we propose a synergistic optimization strategy, namely, simultaneously enhancing DBS by tailoring grain size to submicron scale and inducing the temperature range between the maximum dielectric permittivity temperature (Tmax) and the Burns temperature (TB) to room temperature, for solving the bottleneck. (1-x)K0.5Na0.5NbO3-xBi(Ni0.5Zr0.5)O3 (KNN-BNZ) ceramics were chosen as an example to illustrate the validity of this strategy. An ultrahigh Wrec of 8.09 J·cm−3 was obtained at the optimum composition of x = 0.15 under the electric field of 870 kV·cm−1, which is much higher than those of other reported KNN-based ceramics. Most importantly, this high Wrec was accompanied by a high η of 88.46%, which is superior to those of other KNN-based ceramics and very important for practical applications. The excellent comprehensive energy storage performance was resulted from the polar nanoregions, which is confirmed by high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), piezo-force microscopy (PFM) and first-order reversal curve (FORC) distributions. The work not only finds out novel KNN-based ceramics with excellent comprehensive energy storage properties, but also provides a remarkable designing strategy for exploring a series of novel lead-free dielectric ceramics with high energy storage properties for practical applications in the future.

Suppression of high-temperature dielectric loss by designed thermal annealing treatment in (Bi1/2Na1/2)TiO3 ceramics

Dielectrics for automobile applications generally require high temperature reliability. Bi1/2Na1/2TiO3-based materials are excellent high-temperature dielectric candidates with relatively large temperature-insensitive dielectric responses and a maximum dielectric permittivity temperature as high as 300 °C. However, they suffer from a high dielectric loss that increases exponentially above 200 °C due to ionic conduction from thermally activated oxygen vacancy migration. Here, we demonstrate that the impact of ionic conduction on dielectric loss can be effectively suppressed by introducing a sodium deficiency and thermal annealing An appropriate combination of both treatments elevated the temperature insensitivity of the dielectric loss up to ∼ 300 °C. A systematic investigation using impedance spectroscopy correlated with microstructure analysis revealed that the sodium deficiency and thermal annealing affected the mobile oxygen vacancy concentration differently.

Grain growth anomaly and piezoelectric properties of liquid phase sintered high TC 0.36BiScO3 - 0.64PbTiO3 ceramics with sillenite Bi12PbO19

The sintering behavior of 0.36BiScO 3 -0.64PbTiO 3 (0.36BS-0.64 PT) ceramics was studied to investigate the effect of grain growth by the sillenite Bi 12 PbO 19 (BP) phase on their piezoelectric properties for application in high-temperature piezoelectric devices. The BP phase formed during calcination at temperatures <750 °C led to a grain growth anomaly of the 0.36BS-0.64 PT ceramics sintered at 1000 °C. This phase assisted the grain growth of the 0.36BS-0.64 PT ceramics by liquid phase sintering. In particular, the 0.36BS-0.64 PT ceramic calcined at 700 °C exhibited excellent piezoelectric properties with a d 33 of 531 pC/N, g 33 of 41×10 −3 Vm/N, k p of 61.8%, and Q m of 16. In addition, the 0.36BS-0.64 PT ceramics exhibited ferroelectric relaxor-like characteristics with an extremely large relaxation coefficient ( γ ) of 1.94 along with high maximum dielectric permittivity temperature (426 °C).

Grain-size-insensitive dielectric properties of Sr0.6Ba0.4Nb2O6 relaxor ferroelectric ceramics with tetragonal tungsten bronze structure

The influence of grain size on the dielectric properties of Sr0.6Ba0.4Nb2O6 (SBN60) ceramics with a tetragonal tungsten bronze structure was examined. The conventional and two-step sintering procedures were used to fabricate dense and phase-pure SBN60 ceramics with grain sizes ranging from 2.2 μm to 17.3 μm. In the temperature dependence of the dielectric permittivity, all samples showed a relaxor-like broad dielectric peak with a maximum at around 60 °C. The maximum dielectric permittivity and dielectric maximum temperature of the SBN ceramics were found to be less dependent on the grain size. The reason for the grain-size-insensitive dielectric properties of the SBN60 ceramics is discussed based on the analysis of the dielectric properties and Raman spectra.

Optical induction in K0.5Na0.5NbO3 ferroelectric ceramic at low calcination temperature by sol-gel route

K0.5Na0.5NbO3 ceramic was synthesized at low calcination temperature by sol-gel route. Structural properties of ceramic were investigated by X-ray diffractometer, FESEM and FTIR spectrometer. Electro-optical properties of ceramic were investigated by UV-Vis and PL spectrometer. Dielectric nature of ceramic was studied at different frequencies and temperatures which disclosed that ceramic has maximum dielectric permittivity at 500 KHz. AC conductivity analysis shows negative temperature coefficient of resistance behavior. Leakage current was studied up to 180 V which shows low value of leakage current at room temperature. Ferroelectric nature was analyzed at different electric fields (5–20 kVcm−1) at 50 Hz.

Synthesis and characterization of PVDF-Er2O3 polymer nanocomposites for energy storage applications

In the present study, PVDF-Er 2 O 3 polymer nanocomposite films were synthesized at 85 °C via the solution casting method. Structural characterization of the nanocomposite films was determined from XRD, SEM and FTIR analysis. The results indicate a semicrystalline nature of the PVDF nanocomposite films. The crystal structure of Er 2 O 3 nanoparticles is cubic with an average crystallite size of 39 nm. Images from the SEM microscopy confirmed uniform dispersion of nano-Er 2 O 3 with small agglomerations. FTIR measurements revealed the characteristic bands of α, β and γ phases for PVDF in all nanocomposite films. From TGA analysis, the onset temperature of degradation decreases as Er 2 O 3 weight percentage increases in the PVDF polymer matrix. Dielectric analysis revealed the increase of real permittivity for the PVDF-Er 2 O 3 nanocomposites with increasing Er 2 O 3 content. At 3.0 wt% of Er 2 O 3 , the maximum permittivity was achieved. It is also noticed that the nanocomposite film with a concentration of 1.0 wt% gave the highest energy density. • Nanocomposites of PVDF-Er 2 O 3 prepared by a solution casting method. • XRD results indicate a semicrystalline nature of the PVDF nanocomposites. • At 3.0 wt% of Er 2 O 3 , the maximum dielectric permittivity was achieved. • The nanocomposite film doped with 1.0 wt% of Er 2 O 3 gave the highest energy density.