High energy storage density and power density achieved simultaneously in NaNbO_(3)-based lead-free ceramics via antiferroelectricity enhancement

High-performance lead-free dielectric ceramics with simultaneously high energy storage density and power density are in high demanded for pulse power systems.To realize excellent energy-storage characteristics,a strategy to enhance antiferroelectricity and construct a local random field simultaneously was proposed in this study.Based on the above strategy,a series of(1-x)NaNbO_(3)-xBi(Ni_(1/2)Sn_(1/2))O3[xBNS,x=0.05,0.10,0.15,0.20,and 0.22]solid solutions were designed and fabricated.An ultrahigh energy storage density(Utotal)of 7.35 J/cm^(3),and recoverable energy density(Urec)of 5.00 J/cm^(3) were achieved in the 0.10BNS ceramics.In addition,an adequate stability of energy storage properties at a range of temperatures(20e140℃),frequencies(1e100 Hz),and fatigue test durations(1e1-10^(4) cycles)were realized in 0.10BNS ceramics.0.10BNS ceramics displayed a high current density of 1005 A/cm2,an ultrahigh power density of 100.5 MW/cm^(3,)and an ultrashort discharge time of 46.5 ns?This remarkable performance not only justified our strategy but also confirmed 0.10BNS ceramics as a promising candidate for energy storage.

Enhanced thermal and frequency stability and decent fatigue endurance in lead-free NaNbO_(3) -based ceramics with high energy storage density and efficiency

Lead-free ceramic capacitors have the application prospect in the dielectric pulse power system due to the advantages of large dielectric constant,lower dielectric loss and good temperature stability.Never-theless,most reported dielectric ceramics have limitation of realizing large energy storage density(W_(rec))and high energy storage efficiency(h)simultaneously due to the low breakdown electric field(E_(b)),low maximum polarization and large remanent polarization(P_(r)).These issues above can be settled by raising the bulk resistivity of dielectric ceramics and optimizing domain structure.Therefore,we designed a new system by doping(Bi_(0.5)Na_(0.5))_(0.7)Sr_(0.3)TiO_(3) into 0.9NaNbO_(3)-0.1Bi(Ni_(0.5)Zr_(0.5))O_(3) ceramics,which simulta-neously obtained a higher bulk resistivity by decreasing the grain size and achieved a smaller P_(r) by optimizing domain structure,thus the better E_(b) of 530 kV/cm and W_(rec) of 6.43 J/cm^(3) were achieved,h was improved from 34%to 82%.Besides,the 0.4BNST ceramics show excellent temperature,frequency and fatigue stability under the conditions of 20-180℃,1-100 Hz and 104 cycles,respectively.Mean-while,superior power density(P_(D)=107 MW/cm^(3)),large current density(C_(D)=1070 A/cm^(2))and discharge speed(1.025 m s)were achieved in 0.4BNST ceramic.Finally,the charge-discharge performance displayed good temperature stability in the temperature range of 30℃-180℃.The above results indicated that the ceramics have potential practical value in the field of energy storage capacitor.