Progress and perspectives in dielectric energy storage ceramics

Dielectric ceramic capacitors,with the advantages of high power density,fast chargedischarge capability,excellent fatigue endurance,and good high temperature stability,have been acknowledged to be promising candidates for solid-state pulse power systems.This review investigates the energy storage performances of linear dielectric,relaxor ferroelectric,and antiferroelectric from the viewpoint of chemical modification,macro/microstructural design,and electrical property optimization.Research progress of ceramic bulks and films for Pb-based and/or Pb-free systems is summarized.Finally,we propose the perspectives on the development of energy storage ceramics for pulse power capacitors in the future.

P-E hysteresis loop going slim in Ba0.3Sr0.7TiO3-modified Bi0.5Na0.5TiO3 ceramics for energy storage applications

(Ba0.3Sr0.7)x(Bi0.5Na0.5)1-xTiO3(BSxBNT,x=0.3–V0.8)ceramics were prepared to investigate their structure,dielectric and ferroelectric properties.BSxBNT ceramics possess pure perovskite structure accompanied from a tetragonal symmetry to pseudo-cubic one with the increase of x value,being confirmed by X-ray diffraction(XRD)and Raman results.The Tm corresponding to a temperature in the vicinity of maximum dielectric constant gradually decreases from 110℃(x=0.3)to-45℃(x=0.8),across Tm=36℃(x=0.5)with a maximum dielectric constant(ɛr=5920@1 kHz)around room temperature.The saturated polarization Ps gradually while the remnant polarization Pr sharply decreases with the increase of x value,making the P-E hysteresis loop of BSxBNT ceramics goes slim.A maximum difference between Ps and Pr(Ps-Pr)is obtained for BSxBNT ceramics with x=0.5,at which a high recoverable energy density(Wrec=1.04 J/cm3)is achieved under an applied electric field of 100 kV/cm with an efficiency ofη=77%.Meanwhile,the varied temperature P-E loops,fatigue measurements,and electric breakdown characteristics for the sample with x=0.5 indicate that it is promising for pulsed power energy storage capacitor candidate materials.

Remarkably enhanced dielectric stability and energy storage properties in BNT–BST relaxor ceramics by A-site defect engineering for pulsed power applications

Lead-free bulk ceramics for advanced pulsed power capacitors show relatively low recoverable energy storage density(Wrec)especially at low electric field condition.To address this challenge,we propose an A-site defect engineering to optimize the electric polarization behavior by disrupting the orderly arrangement of A-site ions,in which Ba_(0.105)Na_(0.325)Sr_(0.245−1.5x)□_(0.5x)Bi_(0.325)+xTiO_(3)(BNS_(0.245−1.5x)□_(0.5x)B_(0.325+x)T,x=0,0.02,0.04,0.06,and 0.08)lead-free ceramics are selected as the representative.The BNS_(0.245−1.5x)□_(0.5x)B_(0.325+x)T ceramics are prepared by using pressureless solid-state sintering and achieve large W_(rec)(1.8 J/cm^(3))at a low electric field(@110 kV/cm)when x=0.06.The value of 1.8 J/cm3 is super high as compared to all other W_(rec) in lead-free bulk ceramics under a relatively low electric field(<160 kV/cm).Furthermore,a high dielectric constant of 2930 within 15%fluctuation in a wide temperature range of 40–350℃is also obtained in BNS_(0.245−1.5x)□_(0.5x)B_(0.325+x)T(x=0.06)ceramics.The excellent performances can be attributed to the A-site defect engineering,which can reduce remnant polarization(P_(r))and improve the thermal evolution of polar nanoregions(PNRs).This work confirms that the BNS_(0.245−1.5x)□_(0.5x)B_(0.325+x)T(x=0.06)ceramics are desirable for advanced pulsed power capacitors,and will push the development of a series of Bi0.5Na0.5TiO3(BNT)-based ceramics with high W_(rec) and high-temperature stability.

Enhanced antiferroelectric-like relaxor ferroelectric characteristic boosting energy storage performance of(Bi_(0.5)Na_(0.5))TiO_(3)-based ceramics via defect engineering

3Lead-free(BiasNaus)TiO_(3)(BNT)-based relaxor ferroelectric(RFE)ceramics have attracted a lot of atten-tion due to their high power density and rapid charge-discharge apabilities,as well as their potential application in pulse power capacitors.However,because of the desire for smaller electronic devices,their energy storage performance(ESP)should be enhanced even further.We describe a defect engineering strategy for enhancing the antiferroelectric-like RFE feature of BNT-based ceramics by unequal substi-tution of rare-earth La^(3+)in this paper.The ESP of La^(3+)-doped samples is raised by 25%with the same synthetic procedure and thidkness,due to an inrease in the critical electric field(E-field)and saturated E-field during polarization response,which is induced by a modifiation in the energy barrier between the lattice torsion.More impressively,an ultrahigh recoverable energy storage density Wrec of 8.58J/cm^(3)and a high energy storage efficiengyηof 945%are simultaneously attained in 3 at.%La^(3+)-substituted 0.6(Bi_(0.5)Na_(0.4)K_(0.1))_(1-1.5x)La_(x)TiO_(3)-0.4[2/3SrTiO_(3)-1/3Bi(Mg_(2/3)Ni_(1/3))O_(3)]RFE ceamics with good temperatue stability(W_(rec)=4.6±0.2 J/cm^(3)and higher n of 290%from 30℃to 120℃),frequency stability,and fatigue resistance.The significant inrease in ESP achieved through defect engineering not only proves the effectiveness of our strategy,but also presents a novel dielectric material with potential applications in pulse power apacitors.