Fiber resonator using negative-curvature anti-resonant fiber with temperature stability

The coupling efficiency of hollow-core fiber changes with temperature,which leads to the decrease of the finesse(F)of fiber resonator and limits the performance of the resonant fiber optic gyroscope(R-FOG)system.Negative-curvature antiresonant fiber(ARF)can maintain single-mode characteristics under the condition of large mode field diameter,achieve efficient and stable fiber coupling,and significantly improve the consistency of the F of the spatial coupling resonator in variable temperature environment.A new type of ARF with a mode field diameter(MFD)of 25μm is used to fabricate a fiber resonator with a length of 5.14 m.In the range of 25℃-75℃,the average F is 31.45.The ARF resonator is used to construct an R-FOG system that shows long-term bias stability(3600 s)of3.1°/h at room temperature,4.6°/h at 75℃.To our knowledge,this is the best reported index of hollow-core fiber resonator and R-FOG system within the temperature variation range of 50℃ test.

Effect of yttrium and manganese addition on catalytic soot combustion activity and anti-high-temperature stability of CeO_(2) catalyst

In order to analyze the influence of the addition of yttrium and manganese on the soot combustion performance and high temperature stability of CeO_(2) catalyst,a series of Y/Mn-modified CeO_(2) catalysts were prepared.The effects of structural properties,textural properties,oxygen vacancies,Ce^(3+),surface adsorbed oxygen species,reduction properties and desorption properties of oxygen species on the activity were analyzed by various characterization methods.The results of the activity test show that the addition of manganese is beneficial to enhancement of the activity,while the addition of yttrium increases the amount of reactive oxygen species,but decreases the activity.After aging at 700℃,the activity of the CeMn catalyst decreases most sharply,while the catalytic activity of the CeY catalyst can be maintained to a certain extent.Interestingly,the addition of yttrium and manganese at the same time can stabilize the activity.The fundamental reason is that yttrium and manganese move to the surface of the solid solution after aging,which increases the reduction performance of the catalyst,thus contributing to the increase of activity.Although the activity of CeYMn catalyst decreases after aging at 800℃,it is still higher than that of other catalysts aged at 700℃.

Exceptional electrostrain with minimal hysteresis and superior temperature stability under low electric field in KNN-based lead-free piezoceramics

Over the past two decades,(K_(0.5)Na_(0.5))NbO_(3)(KNN)-based lead-free piezoelectric ceramics have made significant progress.However,attaining a high electrostrain with remarkable temperature stability and minimal hysteresis under low electric fields has remained a significant challenge.To address this long-standing issue,we have employed a collaborative approach that combines defect engineering,phase engineering,and relaxation engineering.The LKNNS-6BZH ceramic,when sintered at T_(sint)=1170℃,demonstrates an impressive electrostrain with a d_(33) value of 0.276%and 1379 pm·V^(-1)under 20 kV·cm^(-1),which is comparable to or even surpasses that of other lead-free and Pb(Zr,Ti)O_(3)ceramics.Importantly,the electrostrain performance of this ceramic remains stable up to a temperature of 125℃,with the lowest hysteresis observed at 9.73%under 40 kV·cm^(-1).These excellent overall performances are attributed to the presence of defect dipoles involving V′_(A)-V∙∙_(O) and B′_(Nb)-V∙∙O,the coexistence of R-O-T multiphase,and the tuning of the trade-off between long-range ordering and local heterogeneity.This work provides a lead-free alternative for piezoelectric actuators and a paradigm for designing piezoelectric materials with outstanding comprehensive performance under low electric fields.

Enhanced capacitive energy storage and dielectric temperature stability of A-site disordered high-entropy perovskite oxides

In this work,a novel high entropy perovskite oxide(1-x)(Na_(0.2)Bi_(0.2)Ba_(0.2)Sr_(0.2)Ca_(0.2))TiO_(3-x)NaNbO_(3)(abbrevi-ated as(1-x)NBBSCT-x NN,x=0,0.05,0.1,0.15,and 0.2)was designed to improve temperature dielectric stability and energy storage performance by combining relaxor and antiferroelectric characteristics.The optimal composition of x=0.2 exhibits a high energy storage density of 3.51 J/cm^(3),together with wide temperature stable stability(■<15%,-70 to 110℃),excellent frequency stability(W rec andηvary by only±2.1%and±5.2%within the range of 1-600 Hz)and fast discharge rate(t_(0.9)=55.2 ns).This is mainly due to the enhancement of relaxation behavior and increase of E b caused by the decrease of grain size.These results offer a new strategy for designing high entropy ceramic materials of high performance in the future.

Synergy of lead vacancies and morphotropic phase boundary to promote high piezoelectricity and temperature stability of PBZTN ceramics

The flourishing development of emerging electromechanical applications has stimulated an urgent demand for ferroelectric ceramics with high piezoelectric properties and broad temperature usage range.However,it remains a challenge to simultaneously obtain good piezoelectricity and reliable temperature stability in lead zirconate titanate(PZT)-based piezoelectric ceramics.To solve this issue,a synergetic strategy was proposed to introduce lead vacancies through niobium doping and construct morphotropic phase boundary(MPB).In this work,Pb_(0.905)Ba_(0.085)(V Pb″)_(0.01)[(Zr_(x)Ti_(1-x))_(0.98)Nb_(0.02)]O_(3)(PBZTN-x)material system was designed.Good comprehensive properties(d_(33)=864 pC/N,k_(p)=84%,T_(C)=201℃)and excellent temperature stability(less than 10%variation of electrical properties from 20℃ to 160℃)were obtained in PBZTN-0.540 ceramics.Good piezoelectricity can be attributed to high extrinsic contribution(domain wall motion)induced by Pb^(2+)vacancies and the existence of nano-domains emerged at MPB,while excellent temperature stability is mainly attributed to the minimized local stress in the lattice and the stable domain structure.

Effects of Al and Co doping on the structural stability and high temperature cycling performance of LiNi_(0.5)Mn_(1.5)O_(4) spinel cathode materials

The poor structural stability and capacity retention of the high-voltage spinel-type LiNi_(0.5)Mn_(1.5)O_(4)(LNMO)limits their further application.Herein,Al and Co were doped in LNMO materials for a more stable structure and capacity.The LNMO,LiNi_(0.45)Al_(0.05)Mn_(1.5)O_(4)(LNAMO)and LiNi_(0.45)Co_(0.05)Mn_(1.5)O_(4)(LNCMO)were synthesized by calcination at 900℃ for 8 h,which was called as solid-phase method and applied universally in industry.XRD,FT-IR and CV test results showed the synthesized samples have cation disordering Fd-3m space group structures.Moreover,the incorporation of Al and Co increased the cation disordering of LNMO,thereby increasing the transfer rate of Li+.The SEM results showed that the doped samples performed more regular and ortho-octahedral.The EDS elemental analysis confirmed the uniform distribution of each metal element in the samples.Moreover,the doped samples showed better electrochemical properties than undoped LNMO.The LNAMO and LNCMO samples were discharged with specific capacities of 116.3 mA·h·g^(-1)and 122.8 mA·h·g^(-1)at 1 C charge/discharge rate with good capacity retention of 95.8% and 94.8% after 200 cycles at room temperature,respectively.The capacity fading phenomenon of the doped samples at 50℃ and 1 C rate was significantly improved.Further,cations doping also enhanced the rate performance,especially for the LNCMO,the discharge specific capacity of 117.9 mA·h·g^(-1)can be obtained at a rate of 5 C.

Simultaneously improving piezoelectric properties and temperature stability of Na_(0.5)K_(0.5)NbO_(3)(KNN)-based ceramics sintered in reducing atmosphere

It is a very difficult work to sinter K_(0.5)Na_(0.5)NbO_(3)(KNN)-based materials with good reduction resistance in strong reducing atmosphere.0.945K_(0.48)Na_(0.52)Nb_(0.96)Ta_(0.04)O_(3)-0.055BaZrO_(3)+0.03ZrO_(2)+y mol%MnO(KNNT-0.055BZ+0.03Zr+yMn)ceramics sintered in reducing atmosphere were prepared successfully by conventional solid-state reaction methods.MnO dopant increases grain size at y=5-8 due to strong lattice distortion and then decreases grain size at y=9 due to much Mn4Nb2O9 accumulated at the grain boundary.MnO dopant as an excellent sintering aid can effectively reduce volatilization of alkali metal by decreasing the sintering temperature(T_(sinter)).Reducing alkali metal volatilization can greatly reduce oxygen vacancies and improve piezoelectric properties.MnO dopant can improve the anti-reduction properties.The KNNT-0.055BZ+0.03Zr+yMn ceramics aty=6-9 show outstanding anti-fatigue of unipolar piezoelectric strain under the synergistic effect of reduced oxygen vacancies due to reduced volatilization and increased grain size.Piezoelectric properties and temperature stability of KNNT-0.055BZ+0.03Zr ceramics sintered in reducing atmosphere are improved simultaneously by MnO dopant.Optimum inverse piezoelectric coefficient(d33)of ceramics at y=8 reaches up to 480 pm/V under low driving electric field E=20 kV/cm at room temperature,and its temperature stability of d33 reaches 158℃.It will be an excellent lead-free material candidate for the preparation of multilayer piezoelectric actuators co-fired with nickel electrode.

Tetragonal (Ba, Ca) (Zr, Ti)O_(3) textured ceramics with enhanced piezoelectric response and superior temperature stability

Lead-free ceramics with both high piezoelectric response and good temperature stability are urgently demanded for electromechanical conversion devices.Unfortunately,owing to coexistence of poly-morphic phases near room temperature(RT),enhanced piezoelectric properties were usually achieved with occurrence of strong temperature dependence in modified BaTiO_(3)(BT)-based ceramics.In this work,we demonstrate that tailoring grain orientations of tetragonal BT-based ceramics can effectively produce substantially enhanced and thermally stabilized piezoelectric response.Both<001>c-and<111>c-oriented tetragonal(Ba_(0.85)Ca_(0.15))(Zr_(0.05)Ti_(0.95))O_(3)(BCZT)ceramics with texture degrees F>90%were synthesized via templated grain growth.Interestingly,the ceramics textured along the<001>c polar axis show much higher microscopic and macroscopic piezoelectric properties than those with nonpolar<111>c texture,indicating an“extender”ferroelectricity nature.Compared with randomly oriented samples,the<001>c-oriented ceramics exhibit simultaneously~1.6 times higher piezoelectric strain d_(33)^(*)(~760 pm/V),4.4 times higher piezoelectric figure of merit d_(33)×g_(33)(8.8×10^(-12) m^(2)/N),and better temperature stability(strain variation≤5%between RT and 110℃).Such thermally stabilized strain response can be mainly attributed to wide temperature range of tetragonal phase and stable domain structure.This work provides a promising route for further developing lead-free piezoceramics with high and temperature-insensitive performance,which can greatly broaden their application areas.

Enhanced piezoelectric properties and temperature stability in KNN-based textured ceramics

Considering the advantages of high Curie temperature and environment-friendly nature of KNN piezoelectric ceramics,the limitation of weak piezoelectric response and their temperature sensitivity to applications is worth exploring.Herein,the<001>textured(1-x)(K_(0.5)Na_(0.5))(Nb0.96Sb0.04)O3-x(Bi_(0.5)Na_(0.5))HfO_(3)(x=0.01-0.045)lead-free ceramics were synthesized by templated grain-growth method.The high piezoelectric performance(d33 of 474 pC/N and strain of 0.21%)and excellent temperature stability(unipolar strain maintained within 4.3%change between 30℃and 165℃)were simultaneously achieved in the textured KNNS-0.03BNH ceramics.The high piezoelectric performance can be attributed to the summation of the crystallographic anisotropy and phase structure contributions in<001>textured ceramics.The superior temperature stability of piezoelectric properties can be interpreted by the contribution of crystal anisotropy to piezoelectric properties reduces the effect of phase transition on piezoelectric properties deterioration.This study provides an effective strategy for simultaneously achieving high piezoelectric properties and superior temperature stability in KNN-based textured ceramics.

Enhanced energy-storage density and temperature stability of Pb_(0.89)La_(0.06)Sr_(0.05)(Zr_(0.95)Ti_(0.05))O_(3) anti-ferroelectric thin film capacitor

As the fundamental energy storage components in electronic systems,dielectric capacitors with high power densities were demanded.In this work,the anti-ferroelectric Pb_(0.89)La_(0.06)Sr_(0.05)(Zr_(0.95)Ti_(0.05))O_(3)(PLSZT)ceramics and thin film capacitor were successfully fabricated by a solid-state reaction route and pulsed laser deposition method,respectively.The ferroelectric,dielectric,energy-storage properties,and temperature stability of anti-ferroelectric PLSZT capacitor were investigated in detail.By compared with the PLSZT ceramic(energy storage density is 1.29 J/cm^(3) with an efficiency of 78.7%under 75 kV/cm),the anti-ferroelectric PLSZT thin film capacitors exhibited the enhanced energy storage density of 52.6 J/cm^(3) with efficiency of 67.7%under an electric field as high as 2068.9 kV/cm,and the enhanced energy-storage temperature stabilities from room temperature(RT)to more than 200℃ were demonstrated,and the oxygen defects mechanism and size effect were discussed.Moreover,the fast charging(~0.05 μs)and discharging(~0.15 μs)time were certified for the anti-ferroelectric PLSZT film capacitor.These findings broaden the horizon for PLSZT anti-ferroelectrics in high energy storage properties and show promising for manufacturing pulse power capacitor.

Structure, electrical properties and temperature stability of PIN–PZN–PT piezoelectric ceramics with morphotropic phase boundary compositions

A series of Pb(In_(1/2)Nb_(1/2))O_(3)–Pb(Zn_(1/3)Nb_(2/3))O_(3)–PbTiO_(3)(PIN–PZN–PT)ternary piezoelectric ceramics with compositions at the morphotropic phase boundary(MPB)were prepared.The phase structure,microstructure,electrical properties and temperature stability of PIN–PZN–PT ceramics were investigated systematically.The structural analysis indicated that an MPB phase consisting of rhombohedral and tetragonal phases was formed in all ceramics.For the selected compositions,dielectric measurements demonstrated that the Curie temperature TC changed from 237℃ to 295℃ and showed a strong trend of compositional depen-dence.All the samples showed good piezoelectic properties.Particularly,the 0.35PIN–0.40PZN–0.25PT sample has the optimum piezoelectric properties,the piezoelectric coefficient d_(33) is 589 pC/N,the electromechanical coupling factors kp and kt are 59%and 49%,respectively.Compared with PZN–PT and PMN–PT ferroelectric crystals,the superior limit of usage temperature of PIN–PZN–PT ceramics was achieved around 230℃ by thermal depoling method.These results make PIN–PZN–PT ceramics a promising material to meet the practical demands of higher temperature and larger electric field operating ranges.

High-temperature polymer-based nanocomposites for high energy storage performance with robust cycling stability

High-power capacitors are highly demanded in advanced electronics and power systems,where rising concerns on the operating temperatures have evoked the attention on developing highly reliable high-temperature dielectric polymers.Herein,polyetherimide(PEI)filled with highly insulating Al_(2)O_(3)(AO)nanoparticles dielectric composite films have been fabricated aiming for high thermal stability and reliability operated under high cycling electric field and elevated temperature.At room temperature,incorporating a small fraction of 0.5 vol%AO nanoparticles gives rise to a highest discharged energy density(U_(e))of 5.57 J·cm^(-3)and efficiency(η)of 90.9%at650 MV·m^(-1),and a robust cycling stability up to 10^(7) cycles at 400 MV·m^(-1).Due to the substantially reduced dielectric loss,2.0 vol%AO/PEI nanocomposite film exhibits excellent high-temperature capacitive performances,delivering U_(e)~7.33 J·cm^(-3)withη~88.8%under 700 MV·m^(-1),and cycling stability up to 10^(6) cycles under 400 MV·m^(-1)at 100℃,and U_(e)~5.57 J·cm^(-3)withη~84.7%under 620 MV·m^(-1)at 150℃.Molecular dynamic simulations are performed to understand the microscopic mechanism via revealing the polymer relaxation process in the AO/PEI composite at elevated temperatures.Our results are therefore very encouraging for high-temperature high-power capacitor application.

Investigation of High-Stability Temperature Control in Primary Gas Thermometry

We presented a relationship between the temperature control and measurement stability limit and the temperature resolution,particularly for using rhodium-iron resistance thermometers and AC resistance bridges.Based on this,temperature control was investigated and demonstrated in primary gas thermometry under various working conditions.With optimized parameters,micro-Kelvin level temperature control stability was realized in the temperature region from 5 K to 24.5 K.The temperature control stabilities are better than 8μK over 180 h with an integration time of 33.6 s in the concerned temperature range,closing to the limit that the sensors and the instruments can control and measure.These stabilities were significantly improved about(44±8)%at 24.5 K and(70±7)%at 5 K comparing with our previous work(Chen et al.,Cryogenics,2019,97:1–6).

Highly stretchable,conductive,and wide-operating temperature ionogel based wearable triboelectric nanogenerator

The rapid development of wearable electronic products brings challenges to corresponding power supplies.In this work,a thermally stable and stretchable ionogel-based triboelectric nanogenerator(SI-TENG)for biomechanical energy collection is proposed.The ionic conductivity of the ionogel increased to 0.53 S·m^(−1) through optimal regulation of the amount of aminoterminated hyperbranched polyamide(NH2-HBP),which also has high strain of 812%,excellent stretch recovery,and wide operating temperature range of−80 to 250°C.The SI-TENG with this ionogel as electrode and silicone rubber both as the triboelectric layer and encapsulation layer exhibits high temperature stability,stretchability,and washability.By adding appropriate amount of nano SiO2 to triboelectric layer,the output performance is further improved by 93%.Operating in singleelectrode mode at 1.5 Hz,the outputs of a SI-TENG with an area of 3 cm×3 cm are 247 V,11.7μA,78 nC,and 3.2 W·m^(−2),respectively.It was used as a self-charging power supply to charge a 22μF capacitor to 1.6 V in 167 s with the palm patting and then to power the electronic calculator.Furthermore,the SI-TENG can also be used as a self-powered motion sensor to detect the amplitude and frequency of finger bending,human swallowing,nodding,and shaking of the head motion changes through the analysis of the output voltage.

Temperature-insensitive KNN-based ceramics by elevating O-T phase transition temperature and crystal texture

The inferior temperature stability of piezoelectric response is the main drawback of KNN-based ceramics.Here,the Ba-doped 0.97(K0.48Na0.52)(Nb0.96Sb0.04)O3-0.03Bax(Bi0.5Ag0.5)1-xZrO3(abbreviated as KNNSBxBAZ)textured ceramics were prepared by the template grain growth(TGG)method.Excellent comprehensive properties(d33¼(406±15)pC/N,TC=274℃,strain is 0.17%)were achieved in KNNSBxBAZ textured ceramics with x=0.2.Meanwhile,its piezoelectric and strain properties also show superior temperature stability(d33 maintained within±20%change in awide temperature range from 25℃to 200℃and strain variation was less than 5%in the temperature range from room temperature to 165℃).The high O-T phase transition temperature(TO-T is 110℃)induced by incorporating Ba ions accounts for the enhanced temperature stability of piezoelectric properties.In addition,the crystal texture always maintains the contribution of piezoelectric anisotropy to the piezoelectric properties during elevated temperature,which significantly improved the temperature stability of piezoelectric properties.This work provides an effective strategy for simultaneously achieving high piezoelectric response and excellent temperature stability in KNN-based ceramics.

The electromechanical features of LiNbO_(3) crystal for potential high temperature piezoelectric applications

Lithium niobate(LiNbO_(3),LN)crystal is a multi-functional material with favorable piezoelectric,nonlinear optical and electro-optic properties.In this study,the electromechanical properties of the radial extensional(RE)and the thickness extensional(TE)modes of the congruent LN are studied and the temperature dependent behaviors are revealed.The RE mode electromechanical coupling factors(kp)for the Y-and Z-oriented discs are calculated and found to be 3.8%and 24.7%,respectively,which are nearly the same as the experimental results of 3.8%and 25.2%,respectively.The maximum RE and thickness shear(TS)modes electromechanical coupling factors are obtained to be 47.6%and 68.5%for the Yx/25
and Yx/167
crystal cuts,respectively.The LN crystal possesses good temperature stability of the electromechanical coupling factors(RE and TE modes)from 20℃ to 500℃,where the variations of kp and kt for the Y-oriented discs are<8.0%and<1.8%,respectively.

Effects of core/shell volumetric ratio on the dielectric-temperature behavior of BaTiO_(3)

Two sets of(Mg,Y)-doped BaTiO_(3)samples were prepared to investigate the effects of the core/shell volumetric ratio on the dielectric-temperature behavior of BaTiO3:one set with samples of the same grain size but different core sizes and the other with samples of the same core size but different shell thicknesses.The microstructural variation of the samples was characterized and their dielectric properties were measured.For both sets of samples,the temperature stability of the dielectric properties was generally improved with a reduction of the volumetric shell ratio regardless of the grain and core sizes.There existed,however,a limit of the reduction;for the studied range,shell thickness of one third of the core radius appeared to be an optimum thickness for the given amounts of dopants.It was concluded that the volumetric shell ratio should be optimized so as not to exceed a specific limit,for our case two thirds of the grain volume,to secure temperature stability of the dielectric properties of BaTiO_(3).

Tailoring depolarization temperature by phase transition causing properties evolution in Bi_(0.5)(Na_(1-x)K_(x))_(0.5)TiO_(3)ceramics

(Bi_(0.5)Na_(0.5))TiO_(3)-based materials have attracted widespread attention due to large electro-strain,large remnant polarization(P r)and high Curie temperature(T C),but the existence of inherent depolarization temperature(T d)limits the temperature stability and application temperature range.In this work,we find that K/Na ratio can regulate T d(from 90℃to 246℃)of the ceramics,which confirms that the increase of K substitution can effectively improve the temperature stability of the material.The phase structure and electrical properties of Bi_(0.5)(Na_(1-x)K_(x))_(0.5)TiO_(3)(BNKT x)ceramics can be well modulated by changing K/Na.In addition,BNKT x system exhibits excellent piezoelectric response at morphotropic phase boundary(MPB)of 20%BKT content(d_(33)=180 pC/N),where rhombohedral(R 3 c)phase and tetragonal(P 4 bm)phase coexist in MPB.With K further substitution,BNKT x ceramics transform into tetragonal phase,and the domain size grows due to the structural transition from short-range-correlated P 4 bm to long-range-correlated P 4 mm.The deferment of T d is also tightly related to the increase of P 4 mm/P 4 bm ratio.This work can provide an effective way to tailor depolarization temperature and electrical properties of BNT-based ceramics.

Temperature-stable dielectric properties from 100 to 375℃ in system (K0.495Na0.495La0.01)(Nb0.997Cu0.0075)O3-Bi(Mg0.5Zr0.5)O3

(1-x)(K(0.495)Na(0.495)La(0.01))(Nb(0.997)Cu(0.0075))O3-xBi(Mg(0.5)Zr(0.5))O3(abbreviated as KNLNC-xBMZ) ceramics were designed and prepared.The phase transition,microstructure and electrical properties of the ceramics were investigated.The phase structures of the ceramics transform from orthorhombic to pseudocubic phases and the grain sizes decrease gradually with BMZ content(x) increasing.Additionally,BMZ additions can significantly enhance the dielectric temperature stability and decrease the dielectric loss of ceramics over a relatively broad temperature range.KNLNC-0.02 BMZ ceramics exhibit high dielectric permittivity(εr=1542) and small variation(Δεr/ε(r150℃)≤±15%)in dielectric permittivity from 100 to 375℃,and low dielectric loss(tanδ≤2%) in the temperature range of 100-350℃,which suggests that this ceramic is a candidate for high-temperature capacitor application.

NaNbO_(3) modified BiScO_(3)-BaTiO_(3) dielectrics for high-temperature energy storage applications

Among the lead-free compositions identified as potential capacitor materials, BiScO_(3)-BaTiO_(3) (BS-BT)relaxor dielectrics exhibit good energy storage performance. In this research, 0.4BS-0.6BT is consideredas the parent composition, with NaNbO_(3) (NN) addition intended to substitute the A and B site cations.The NN modified BS-BT ceramics exhibit excellent temperature stability in terms of their dielectricproperties, with the room-temperature dielectric constant on the order of 500e1 000 and variation lessthan 10% up to 400 C. In addition, NN has a high band-gap energy leading to increased breakdownstrength and energy storage properties in modified compositions. The highest breakdown strength wasachieved for 0.4BS-0.55BT-0.05NN, being on the order of 430 kV/cm, and a high energy density of 4.6 J/cm3 with high energy efficiency of 90% was simultaneously achieved. Of particular importance is that thevariation of the energy density was below 5% due to the temperature-insensitive dielectric constant,while ~90% energy efficiency was retained over the temperature range of 25e160 C. The improvedtemperature stability with NN addition makes this composition promising for high temperaturecapacitor and dielectric energy storage applications.