Clamping of ferroelectric PVDF to enhance the electromechanical performance of a 1–3 PMN-PT/PVDF piezoelectric composite

A group of 1–3 type piezoelectric Pb (Mg_1/3Nb_2/3)O₃-PbTiO₃/polyvinylidene fluoride (PMN-PT/PVDF) composite sheets are prepared using a complex two-step hot-pressing method. Then the molecular structure model of piezoelectric materials and an inverse piezoelectric simulation of the composites are performed to express the horizontal compression, indicating the clamping activity of ferroelectric PVDF on PMN-PT. As such, this composite sheet possesses a high dielectric permittivity (ε_r) of 560 at 100 Hz for its compacted connecting of two phases. After polarization, a very large piezoelectric coefficient (d₃₃) of 1125 pC/N and a considerable electromechanical coupling factor (k_t) of 0.43 is obtained in PMN-PT/PVDF sheet with a proper aspect ratio of 1.4 and a thickness of 2.1 mm, further indicating that promoting effect of PVDF matrix on the strain in Z-direction of PMN-PT. The result shows that ferroelectric PVDF serving as polymer matrix favors the electromechanical coupling effect, and may provide a prospect of the potential application of PMN-PT/PVDF composite in sensor or transistor for matrix ultrasonic probes.     

Effect of particle grading on the properties of photosensitive slurry and BaTiO3 piezoelectric ceramic via digital light processing 3D printing

To improve the density and piezoelectric constant of BaTiO₃ ceramics prepared by Digital Light Processing 3D printing, the properties of photosensitive slurry were investigated from the perspective of particle grading, and the nitrogen-air two-step debinding and sintering process on the relative density and electrical properties were explored. It was found that as the mass ratio of coarse particles increased, the viscosity, shear stress and cure depth of the slurry decreased. When the mass ratio of fine and coarse particles was 2:8 and sintered at 1350 °C, the ceramic had better performance, with relative density reaching 95.39 ± 0.63 %. The piezoelectric constant d₃₃ was 215 ± 13 pC/N, 29.52 % higher than the single-peak powder. The relative permittivity (ε_r) and polarization (P_r) were 978 and 16.656 μC/cm². Finally, BaTiO₃ ceramics with Triply Periodic Minimal Surface structures were prepared as piezoelectric sensors, which had the highest output voltage at the same displacement when the mass ratio was 2:8.     

SnO2 modified PNN-PZT ceramics with ultra-high piezoelectric and dielectric properties

In this work, a two-step solid-state reaction method is used to prepare the 0.55 Pb(Ni_1/3Nb_2/3)O₃-0.135PbZrO₃-0.315PbTiO₃/xSnO₂ (PNN-PZT/xSnO₂) ceramics. The influences of SnO₂ on the crystalline structure, electromechanical properties, and temperature stability of PNN-PZT ceramics were studied in detail. The results demonstrate that the Sn⁴⁺ ions are successfully introduced into the PNN-PZT crystalline lattice and substitute B-site Ni²⁺ and Zr⁴⁺. The x = 0.0025 ceramic with the coexistence of rhombohedral, tetragonal, and pseudocubic phases exhibits the optimized comprehensive properties: the quasi-static piezoelectric constant d₃₃, large-signal d₃₃*, electromechanical coupling coefficients k_p and k_t, free dielectric constant ε_r, and mechanical quality factor Q_m are 1123 pC/N, 1250 p.m./V, 0.63, 0.54, 9529, and 57, respectively. Meanwhile, the Curie temperature for this composition is 103 °C, almost maintaining the same level as the PNN-PZT matrix. After annealing at 75 °C, the retained d₃₃ of x = 0.0025 ceramic is as high as 975 pC/N, superior to the PNN-PZT matrix (retained d₃₃ ≈ 873 pC/N). Our results provide a promising piezoelectric material for board bandwidth, high sensitivity, and miniaturized medical ultrasonic transducers applications.     

Improved ferroelectric,piezoelectric, and dielectric properties in pure KNN translucent ceramics by optimizing the normal sintering method

In this study, it is reported that various properties can be selectively derived in a pure (K_0.5Na_0.5)NbO₃, KNN ceramics through optimizing the sintering temperature by the conventional sintering method. High piezoelectric, ferroelectric, and dielectric properties such as d₃₃ = 127 pC/N, P_r = 31 μC/cm², and ε_r = 767 are obtained at the sintering temperature of 1100 °C. On the contrary, the specimen sintered at 1130 °C does not show high piezoelectric and ferroelectric properties, but it is translucent with a transmittance of 22% and 57% at the wavelength of 800 and 1600 nm respectively and shows a very high dielectric constant ε_r of 881. The origin of the high piezoelectric constant owes to large remanent polarization and dielectric constant, and dense microstructure with uniform distribution of large grains with the conjunction of relatively large crystal anisotropy. On the other hand, dense microstructure with almost no porosity, highly compacted grain boundaries, uniform distribution of grains, and relatively low crystalline anisotropy are responsible for the translucency and large dielectric constant of the ceramic specimens. This study demonstrates that the lead-free KNN ceramic has the potential to show multiple noteworthy properties such as piezoelectric, ferroelectric, dielectric, and transparent properties. This work provides a pure KNN ceramic simultaneously with high piezoelectric and transparent characteristics prepared only by using the conventional sintering method at a moderate sintering temperature for the first time in the literature.     

Phase-formation,microstructure, and piezoelectric/dielectric properties of BiYO3-doped Pb(Zr0.53Ti0.47)O3 for piezoelectric energy harvesting devices

This paper proposes a method for the composition and synthesis of lead zirconate titanate (PZT) piezoelectric ceramic for use in energy harvesting systems. The proposed material consists of (1?x)Pb(Zr_0.53Ti_0.47)O₃–xBiYO₃ [PZT–BY(x)] (x=0, 0.01, 0.02, 0.03, 0.04, and 0.05 mol) ceramics near the morphotropic phase boundary (MPB) region, prepared by a solid-state mixed-oxide method. The optimum sintering temperature was found to be 1160 °C, which produced high relative density for all specimens (96% of the theoretical density). Second phases were found to precipitate in the composition containing x≥0.01 mol of BY. It is shown that the addition of BY inhibits grain growth, and exhibits a denser and finer microstructure than those in the un-doped state. Fracture surface observation revealed predominant intergranular fracture for x=0 and x=0.01, while a mixed mode of transgranular and intergranular fracture appeared for x≥0.02. The optimal doping level was found to be x=0.01, for which a dielectric constant (K₃₃^T) of 750, a Curie temperature (T_C) of 373 °C, a remnant polarization (P_r) of 50 µC/cm², a piezoelectric constant (d₃₃) of 350 pC/N, and an electro-mechanical coupling factor (k_p) of 65% were obtained. In addition, the piezoelectric voltage constant (g₃₃), and transduction coefficient (d₃₃×g₃₃) of PZT–BY(x) ceramics have been calculated. The ceramic PZT–BY(0.01) shows a considerably lower K₃₃^T value, but higher d₃₃ and k_p. Therefore, the maximum transduction coefficient (d₃₃×g₃₃) of 18,549×10^?15 m²/N was obtained for PZT–BY(0.01). The large (d₃₃×g₃₃) indicates that the PZT–BY(0.01) ceramic is a good candidate material for energy harvesting devices.     

Synthesis of (K,Na) (Nb,Ta)O3 lead-free piezoelectric ceramic powders by high temperature mixing method under hydrothermal conditions

A facile hydrothermal route via high temperature mixing method was used to synthesize (K, Na) (Nb, Ta)O₃ lead-free piezoelectric ceramic powders. The influence of Ta doping and K⁺/(K⁺ + Na⁺) molar ratios in the starting solution on the resultant powders were investigated by X-ray diffraction, scanning electron microscope, transmission electron microscopy, and selected area electron diffraction. The Ta element was successfully doped into the alkaline niobate structure to form crystalline (K, Na) (Nb, Ta)O₃ lead-free piezoelectric ceramics powder. The microstructure, piezoelectric, ferroelectric, and dielectric properties of the sintered (K, Na) (Nb, Ta)O₃ ceramics from the obtained powders were investigated. The piezoelectric coefficient (d₃₃), electromechanical coupling coefficient (k_p), dielectric constant (?_r), and remnant polarization (P_r) of the sample sintered at 1180 °C show optimal values of 210 pC/N, 34.0%, 2302, and 19.01 μC/cm², respectively.     

Enhanced piezoelectric performance of donor La3+-doped BiFeO3–BaTiO3 lead-free piezoceramics

Lead-free 0.70Bi_1.03FeO₃-0.30Ba_(1-x)La_xTiO₃ piezoelectric ceramics (with x = 0.000, 0.005, 0.010, 0.015 and 0.035 abbreviated as 0.0BaLa, 0.5BaLa, 1.0BaLa, 1.5BaLa and 3.5BaLa) were prepared through the conventional solid-state reaction route followed by water quenching process. The X-ray diffraction profile shows that the substitution of Ba²⁺ = 1.61 Å with a donor ion, La³⁺ = 1.36 Å, has a profound impact on the crystal symmetry as results the crystal structure transform from dominant rhombohedral (R) to tetragonal (T) phase. A large remnant polarization (P_r = 30.3 μC/cm²) and an enhanced direct piezoelectric coefficient, (d₃₃ = 297 pC/N) together with a high Curie temperature (T_C = 530 °C) was obtained near to the morphotropic phase boundary (MPB) of the R and T phases. A maximum strain of (S_max = 0.188%) with corresponding converse piezoelectric coefficient (d₃₃* = 340 pm/V) and low strain hysteresis (≈20%) was found for 1.5BaLa ceramic. Additionally, the water quenching effect was more prominent for 1.0BaLa ceramic as observed from the high thermal hysteresis in heating/cooling results of the dielectric constant (ε_r), leading to the enhancement of ferroelectric switching behavior. Hence, a small amount of La³⁺-substitution for Ba²⁺-site is more effective for the enhancement of ferroelectric and piezoelectric properties, similarly to the donor La³⁺-doped Pb(Zr,Ti)O₃ ceramic.     

Effect of repeated composite sol infiltrations on the dielectric and piezoelectric properties of a Bi0.5(Na0.82K0.18)0.5TiO3 lead free thick film

Bi_0.5(Na_0.82K_0.18)_0.5TiO₃ lead free thick films have been produced using a combination of screen printing and subsequent infiltration of corresponding composite sol. Their structure, dielectric, ferroelectric and piezoelectric properties were investigated with variation in the number of composite sol infiltrations and the nanopowder loading in composite sol. Dielectric constant, remanent polarization, and piezoelectric coefficient have been shown to increase with increasing numbers of composite sol infiltration. Dielectric and ferroelectric properties of the thick films are found to be strongly dependent on the powder concentration of composite sols. The resulting 40 μm thick films infiltrated with 1.5 g/ml composite sols have maximum relative permittivity of 569 (at 10 kHz), remanent polarization of 21.3 μC/cm², coercive field of 80 kV/cm, and longitudinal effective piezoelectric coefficient d_33eff of 109 pm/V. The performance of these lead free piezoelectric thick films is comparable to the corresponding bulk ceramics.     

Synchronous improvement of piezoelectric property and temperature stability in PSN-PMN-PT ceramics by forming composites with ZnO

Relaxor ferroelectric materials with high piezoelectric properties always suffer from low phase transition temperature, making them difficult to satisfy the demands for high-temperature environment applications. In this work, we proposed a composite approach to improve the piezoelectricity and temperature stability of PSN-PMN-PT ceramics at the same time. The ZnO nanoparticles as a second phase were introduced into the PSN-PMN-PT matrix to form composite ceramics. When the ZnO content reaches 5 mol%, the piezoelectric constant d₃₃ increases from 529 pC/N for pure PSN-PMN-PT ceramic to 590 pC/N. Meanwhile, the retained d₃₃ after annealing at 200 °C keeps 92% of the value before annealing, indicating the thermal depolarization behavior is suppressed by the composite method. The synchronous improvement of the d₃₃ and thermal depolarization behavior for PSN-PMN-PT/ZnO composite ceramics is related to the local electric field and stress field caused by the addition of ZnO particles. Our results pave a simple and effective way to develop next-generation PT-based relaxor ferroelectric ceramics.     

Enhanced Piezoelectric Properties of Praseodymium‐Modified Lead‐Free (Ba0.85Ca0.15)(Ti0.90Zr0.10)O3 Ceramics

The role of Pr₆O₁₁ addition on the structure, microstructure, electrical, and electromechanical properties of lead‐free (Ba_0.85Ca_0.15)(Ti_0.90Zr_0.10)O₃ piezoelectric ceramics has been systemically investigated. Addition of praseodymium (Pr) results in improved ferroelectric and piezoelectric properties. XRD analysis revealed the co‐existence of rhombohedral (R) and tetragonal (T) phases at room temperature. High remanent polarization values (2P_r ~17 μC/cm²) and loop squareness of nearly 0.87 were obtained for the BCZT‐0.04 wt%Pr ceramic, along with high piezoelectric coefficient (d₃₃ = 435 pC/N) and transduction coefficient [(d₃₃·g₃₃) = 11589 × 10^?15 m²/N]. Results are correlated with the crystal structure and microstructure that significantly influence the ferroelectric and piezoelectric properties near the R–T phase transition point. This material seems to be especially suitable for energy harvesting applications, exhibiting outstanding figure of merit.     

Enhanced piezoelectric activity with good thermal stability and improved electrical resistivity in Ta–Mn co-doped CaBi4Ti4O15 high-temperature piezoceramics

Aurivillius phase CaBi₄Ti_4-x (Ta_2/3Mn_1/3)_xO₁₅ (x = 0–0.1) high-temperature piezoelectric ceramics were fabricated using the conventional solid-state reaction process. The effects of the Ta–Mn co-doping level on the structure, piezoelectric properties and electrical conduction behaviours of the as-prepared CBT (CaBi₄Ti₄O₁₅) ceramics were explored in detail. It was revealed that the Ta–Mn co-doping efficaciously enhanced the electrical performances of the CaBi₄Ti₄O₁₅ ceramic, which may be due to optimisation of the crystal structure and a reduction in the oxygen vacancy concentration. The composition with x = 0.04 presented superior electrical properties with an outstanding piezoelectric constant (d₃₃) of 24 pC/N accompanied by a high Curie temperature (T_C) of 793 °C, an optimised dielectric loss (tanδ) of 1.5%, and an improved resistivity (ρ) of 4.96 × 10⁸ Ω cm at 400 °C. Moreover, the ceramic exhibited impressive thermal stability with the d₃₃ value maintaining 91.7% of its initial value at room temperature (25 °C) after being annealed at 600 °C for 2 h. The improved performance indicates that the Ta–Mn co-doped CaBi₄Ti₄O₁₅ ceramic might be a promising candidate for piezoelectric device applications at elevated temperatures.     

The effect of high-energy ball milling on the electromechanical strain properties of Bi-based lead-free relaxor matrix ferroelectric composite ceramics

The crystal structure, ferroelectric, and electric-field-induced strain (EFIS) properties of Bi-based lead-free ferroelectric/relaxor composite materials are investigated. Bi_1/2(Na_0.82K_0.18)_1/2TiO₃ as a ferroelectric material and 0.98Bi_1/2(Na_0.78K_0.22)_1/2TiO₃‒0.02LaFeO₃ as a relaxor were synthesized via conventional ceramic processing routes while the relaxor (matrix phase) was prepared via high-energy ball milling (HEBM) after calcination. The average particle size was decreased via HEBM treatment. As a result, a high d₃₃^* value of over 600 pm/V was obtained at 4 kV/mm for 30-min HEBM-treated composites. This demonstrates that HEBM treatment is effective in enhancing the strain properties of lead‒free piezoelectric composite materials.     

High performance lead-free Na0.5K0.5NbO3 piezoelectric ceramics obtained via oscillatory hot-pressing

Lead-free Na_0.5K_0.5NbO₃ (KNN) piezoelectric ceramics is regarded as a potential candidate for PZT material, while high performance is difficult to be obtained due to its poor sinterability and non-stoichiometric component. In this work, oscillatory pressure-assisted hot pressing (OPAHP) is utilized to fabricate KNN ceramics with high density. The KNN ceramics sintered at 860 °C exhibits superior performance with piezoelectric parameter (d₃₃) of 142 pC/N, electromechanical coupling factors (k_p) of 0.41, and relative permittivity (ε^T₃₃/ε₀) of 472–620. Additionally, hardness and flexural strength are measured as 3.55 GPa and 99.13 MPa, respectively. This work indicates that OPAHP technique is effective for fabricating KNN piezoelectric ceramics with high performance.     

Piezoelectric and dielectric properties of (K0.44Na0.52Li0.04)(Nb0.86Ta0.10Sb0.04)O3–PVDF composites

(Li, Ta, Sb) modified sodium potassium niobate/poly(vinylidene fluoride) [(K_0.44Na_0.52Li_0.04)(Nb_0.86Ta_0.10Sb_0.04)O₃–PVDF] 0-3 composites were prepared by a cold press technique, and their piezoelectric and dielectric properties were characterized. All composites exhibited good dispersion of ceramic particles in the polymer matrix. The piezoelectric and dielectric constants were found to be enhanced as the concentration of sodium potassium niobate increases. Even though the process is simple, the composite prepared in this study showed better piezoelectric and dielectric properties than PZT–polymer composites. At room temperature, a (K_0.44Na_0.52Li_0.04)(Nb_0.86Ta_0.10Sb_0.04)O₃–PVDF (7:3) composite revealed a relative dielectric constant, ?_r = 166, piezoelectric constant, d₃₃ = 33 pC/N and coercive field, E_c = 5 kV/cm.     

Novel 1–3 (K,Na)NbO3-based ceramic/epoxy composites with large thickness-mode electromechanical coupling coefficient and good temperature stability

The 1–3 piezoelectric composites are an important type of artificial functional materials for ultrasonic transducers. Currently, there are increasingly strong demands to replace the lead-containing materials. Excellent 1–3 0.96(K_0.48Na_0.52) (Nb_0.96Sb_0.04)O₃?0.03BaZrO₃?0.01(Bi_0.50Na_0.50)ZrO₃ ceramic/epoxy (abbreviated hereafter as KNNS-0.03BZ-0.01BNZ/epoxy) piezoelectric composites were prepared by a modified dice-and-fill technique. Compared to the monolithic KNNS-0.03BZ-0.01BNZ ceramic, the developed composites possess much larger electromechanical coupling coefficient k_t of 0.54–0.67 and piezoelectric voltage coefficient g₃₃ of 64–91 × 10^?3 Vm/N. In addition, these composites also possess other favorable properties such as low values of acoustic impedance Z of 6.9–13.4 Mrayl, dielectric coefficient ε₃₃ of 130–400 and mechanical quality factor Q_m of 1.3–4. More importantly, k_t is weakly temperature-dependence in the common usage temperature range between ?30 °C and 100 °C. The result indicates that the 1–3 KNNS-0.03BZ-0.01BNZ/epoxy piezoelectric composites have a great potential for high-frequency ultrasonic transducers.     

Structural and piezoelectric properties of <001> textured PZT‐PZNN piezoelectric ceramics

Rhombohedral 0.69Pb(Zr_0.47Ti_0.53)‐0.31Pb(Zn_0.6Ni_0.4)NbO₃ (PZT‐PZNN) ceramics were textured using 10.0 vol. % BaTiO₃ (BT) platelets along the <001> direction at 950°C with a high Lotgering factor of 95.3%. BT platelets did not react with the PZT‐PZNN ceramics, and the textured PZT‐PZNN ceramic had a tetragonal structure. The PZT‐PZNN ceramics exhibited a strain of 0.174% with a piezoelectric strain constant (d*₃₃) of 580 pC/N at 3.0 kV/mm. The textured PZT‐PZNN ceramic showed an increased strain of 0.276% and d*₃₃ of 920 pC/N at 3.0 kV/mm, which can be explained by the domain rotation. However, the d₃₃ values of the textured specimens are smaller than those of the untextured specimens because of the small remanent polarization and relative dielectric constant of BT platelets. The textured PZT‐PZNN ceramic synthesized in this work can be used for piezoelectric multilayer actuators because of its large strain and low sintering temperature.     

Design and properties 1–3 multi-element piezoelectric composite with low crosstalk effects

Piezoelectric composites are gaining increasingly importance in ultrasonic fields due to their superior properties. Here novel 1–3 multi-element piezoelectric composites were developed by using piezoelectric ceramic as functional phase, epoxy resin as matrix phase, and silica gel and polyurethane as decoupling materials. The effects of decoupling materials and composite thickness on dielectric, piezoelectric and electromechanical coupling properties of the composites were investigated. The coupling response among various elements of the composites was discussed by setting up an ultrasonic testing platform. The results show that the multi-element piezoelectric composites have larger piezoelectric voltage factor than piezoelectric ceramic, however, less relative permittivity and piezoelectric strain factor. With decreasing the composite thickness, the thickness resonant peaks of the piezoelectric composite shift toward high frequency direction, and no obvious high-order and coupling resonant peaks appear. The multi-element piezoelectric composites have larger thickness electromechanical coupling coefficient k_t and less mechanical quality factor Q_m than piezoelectric ceramic. When composite thickness is 5 mm, the epoxy/silica piezoelectric composite has a maximum k_t value of 70.41%, and a minimum Q_m value of 11.29. The coupling response testing results show that epoxy/silica piezoelectric composite shows less crosstalk effect than epoxy/epoxy and epoxy/polyurethane piezoelectric composites.     

CNT loaded PVDF-KNN nanocomposite films with enhanced piezoelectric properties

The emerging smart PVDF-based composites can compensate for the intrinsic property deficiencies in either of their components. The properties of the composite are determined by the properties of the constituents and its fabrication method. In this research, a lead-free piezoelectric ceramic, potassium sodium niobate (KNN), was used as the primary reinforcement, and MWCNTs were added to improve the electrical properties. Solution casting was used to prepare PVDF-KNN-CNT composite films. After phase and structure identification of composites using SEM, XRD, FTIR, and TGA methods, the dielectric, piezoelectric and ferroelectric properties of the products were investigated. The obtained results indicated a strong dependency of dielectric, piezoelectric, and ferroelectric properties of composites on KNN content. Samples with the highest KNN content rendered ε_r, d₃₃ and g₃₃ values of 156, 28 pC/N, and 20.32 mV m/N, respectively. Introducing a small amount of conductive CNT to primary PVDF-KNN composites can drastically affect the electrical properties by severely interfering in the charge distribution within the sample. While the dielectric constant was enhanced by increasing CNT content, both piezoelectric and ferroelectric properties showed their best behavior at a critical CNT loading. Beyond this limit, a percolation path formed, which is responsible for power consumption. At the optimum CNT amount, d₃₃ and g₃₃ reached 50 pC/N and 31.93 mV m/N, respectively. The presence of conducting CNTs gave rise to the formation of more round polarization curves with higher remnant polarization. The present findings give a prospective understanding of smart piezoelectric polymer-based composites that can be used as sensors and energy harvesters.     

Effect of high energy milling process on microstructure and piezoelectric/dielectric properties of K0.475Na0.475Li0.05NbO3 solid solution

K_0.475Na_0.475Li_0.05NbO₃ (abbreviated as NKLN) ceramic of near the morphotropic phase boundary (MPB) composition was synthesized by two different processes. The first one is the high energy milling [sometimes abbreviated as HEM hereafter] process, which involves mixing the starting materials and milling the calcined powder using a high energy nano-mill, in order to obtain nano-sized particles. The second one is a conventional mixed oxide method. The HEM process of the starting materials lowered the calcination temperature to the extent of 200 °C as compared with conventionally fabricated NKLN. The particle size of the powder, exposed to the HEM process, reduced to 40 nm, whereas the conventionally ball-milled powder had a larger size of 420 nm after the mixing process. Furthermore, the HEM process improved the reaction activity and homogeneity of the materials used throughout the process, accompanying the enhancement of the sintering density, grain uniformity, and the decrease of grain size. In order to investigate the effects of the HEM process on the electric properties of NKLN ceramics, the dielectric and piezoelectric properties of sintered specimens fabricated by two different processes were evaluated. It was found that the properties of the nano-sized NKLN ceramic near the MPB composition were increased by the modified method, showing the maximum values of d₃₃=179 pC/N, k_p=34% and K₃₃^T=440 compared with 132 pC/N, 29%, and 400, respectively in the conventional process. Further evidence for the grain size effect was investigated by the polarization–electric field curve at room temperature. The remnant polarization for the nano-sized NKLN specimen had a higher value of 24.3 μC/cm² compared with that of 13.7 μC/cm² for conventional NKLN, whereas the coercive field had a similar value. The modified mixing and milling method was considered to be a new and promising process for lead-free piezoelectric ceramics owing to their excellent piezoelectric/dielectric properties.     

High‐temperature piezoelectric properties of 0‐3 type CaBi4Ti4O15:x wt%BiFeO3 composites

The 0‐3 type CaBi₄Ti₄O₁₅:30 wt%BiFeO₃ composite shows much better high‐temperature piezoelectric properties than the single‐phase CaBi₄Ti₄O₁₅ or BiFeO₃ ceramics. The composite with 0‐3 type connectivity exhibits a high density of 7.01 g/cm³, a saturated polarization of 21.5 μC/cm² and an enhanced piezoelectric d₃₃ of 25 pC/N. After the poled composite was annealed at 600°C, its d₃₃ is 21 pC/N at room temperature. Resistance of the composite decreases slowly from 10⁹ ohm at 20°C to ~10⁵ ohm at 500°C. Furthermore, the poled composite shows strong radial and thickness dielectric resonances at 20°C‐500°C.