Effects of (Mg1/3Sb2/3)4+ substitution on the structure and microwave dielectric properties of Ce2Zr3(MoO4)9 ceramics

Ce2[Zr1−x(Mg1/3Sb2/3)x]3(MoO4)9 (0.02 ⩽ x ⩽ 0.10) ceramics were prepared by the traditional solid-state method. A single phase, belonging to the space group of $$R⩈erline 3 c$$ R 3 ¯ c , was detected by using X-ray diffraction at the sintering temperatures ranging from 700 to 850 °C. The microstructures of samples were examined by applying scanning electron microscopy (SEM). The crystal structure refinement of these samples was investigated in detail by performing the Rietveld refinement method. The intrinsic properties were calculated and explored via far-infrared reflectivity spectroscopy. The correlations between the chemical bond parameters and microwave dielectric properties were calculated and analyzed by Phillips-van Vechten-Levine (P-V-L) theory. Ce2[Zr0.94(Mg1/3Sb2/3)0.06]3(MoO4)9 ceramics with excellent dielectric properties were sintered at 725 °C for 6 h (εr = 10.37, Q×f = 71,748 GHz, and τf = −13.6 ppm/°C, εr is the dielectric constant, Q×f is the quality factor, and τf is the temperature coefficient of resonant frequency).

Effects of (Mg1/3Sb2/3)4+ substitution on the structure and microwave dielectric properties of Ce2Zr3(Mg1/3Sb2/3)3-3(MoO4)9 ceramics

Ce 2 [Zr 1-x (Mg 1/3 Sb 2/3 ) x ] 3 (MoO 4 ) 9 (0.02≤x≤0.10) ceramics were prepared well through the traditional solid-state method. A single phase, belonging to the space group of R-3c, was detected by using X-ray diffraction at sintering temperatures ranging from 700 to 850 °C. The crystallization micro-structural of specimens was examined by applying Scanning electron microscopy. The structural refinement of these samples was investigated in detail by performing the Rietveld refinement method. The intrinsic properties were calculated and explored via far-infrared reflectivity spectroscopy. The correlations between the chemical bonds parameters and microwave dielectric properties were calculated and analyzed by P-V-L theory. Ce 2 [Zr 0.94 (Mg 1/3 Sb 2/3 ) 0.06 ] 3 (MoO 4 ) 9 ceramics with excellent dielectric properties: ε r = 10.37, Q×f = 71748 GHz and τ f = −13.6 ppm/°C sintered at 725 °C for 6 hours.

Effects of (Mg1/3Sb2/3)4+ Substitution on the Structure and Microwave Dielectric Properties of Ce2Zr3x(Mg1/3Sb2/3)3-3x(MoO4)9 Ceramics

Ce2[Zr1-x(Mg1/3Sb2/3)x]3(MoO4)9 (0.02≤x≤0.10) ceramics were prepared well through the traditional solid-state method. A single phase, belonging to the space group of R-3c, was detected by using X-ray diffraction at sintering temperatures ranging from 700 to 850 °C. The crystallization micro-structural of specimens was examined by applying Scanning electron microscopy. The structural refinement of these samples was investigated in detail by performing the Rietveld refinement method. The intrinsic properties were calculated and explored via far-infrared reflectivity spectroscopy. The correlations between the chemical bonds parameters and microwave dielectric properties were calculated and analyzed by P-V-L theory. Ce2[Zr0.94(Mg1/3Sb2/3)0.06]3(MoO4)9 ceramics with excellent dielectric properties: εr = 10.37, Q×f = 71748 GHz and τf = −13.6 ppm/°C sintered at 725 °C for 6 hours.

Synthesis and luminescence properties of CaLaMgNbO6:Mn4+ red phosphor for UV-based w-LEDs

A series of [Formula: see text] ([Formula: see text] = 0.0005, 0.001, 0.003, 0.005, 0.007, 0.009) phosphors were prepared by traditional solid-state method at high temperature. The structure and morphology of the samples were analyzed. The results showed that the prepared [Formula: see text] [Formula: see text] phosphors were uniformly dispersed and the particle size was less than 5 [Formula: see text]m. [Formula: see text] phosphors have the strongest excitation peak at 351 nm, which is caused by the [Formula: see text] transition of [Formula: see text] ions. The strongest emission peak is at 697 nm, which is due to the [Formula: see text] level transition of [Formula: see text]. The optimum doping concentration is 0.5 mol.% and the mechanism of concentration quenching is the dipole–dipole interaction between [Formula: see text] ions. Importantly, [Formula: see text] sample has good thermal stability ([Formula: see text]/[Formula: see text] = 48.3%). In addition, the color coordinates of all samples were concentrated in the far-red region (0.733, 0.267). The above results indicate that [Formula: see text] sample has potential application value in the field of white light-emitting diodes ([Formula: see text]-LEDs).

Effect of MgB2 additives on structure, electrical and thermal properties of Eu1Ba2Cu3O7

The effect of MgB2 addition on the Eu1Ba2Cu3O7 (EBCO) ceramics was systematically studied. Series of Eu1Ba2Cu3O7 + x(MgB2) samples (x = 0 wt.%, 0.05 wt.%, 0.1 wt.%, 1 wt.%, 3 wt.%) were prepared using traditional solid state method. X-ray powder diffraction measurements were used for phase identification. The lattice parameters and orthorombicity decreased with MgB2 addition. A standard four point measurement method was used to determine transition temperatures Tc of superconducting samples. Tc values of the samples were decreasing with MgB2 concentration. TGA results indicate thermal stability of doped samples.

Hydrothermal Synthesis and Electrochemical Performance of LiNi0.5Mn0.5O2 as Lithium-Ion Battery Cathode

Hydrothermal method was successfully employed to synthesize LiNi0.5Mn0.5O2 and the crystallinity of the resultant product was further improved by an annealing process. The structural information of the final product was analyzed by X-ray diffraction (XRD) and Rietveld refinement. The results showed that the Li/Ni exchange rate of hydrothermal samples was lower than traditional solid state method. Because of the improvement of the crystallinity the capacity of the annealed product was much better than that of the as prepared hydrothermal product. The capacity of annealed sample maintained 100mAh/g after 100 charge/discharge cycles. ICP-OES element analysis show that both hydrothermal and annealed samples are non-stoichiometric due to the existence of high valence Ni3+ and Mn4+ ions in LiNi0.5Mn0.5O2 samples which might be largely responsible for the lower electrochemical capacity. Our work demonstrated that stoichiometric LiNi0.5Mn0.5O2 with lower Li/Ni exchange could be synthesized by hydrothermal method when suitable oxidants were selected.

Synthesis and Electrochemical Performance of K-Doped Li4Ti5O12 as Anode Material for Lithium-Ion Batteries

Spinel Li4-xKxTi5O12(x=0, 0.03) were successfully synthesized by a traditional solid-state method and systematically investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and the charge-discharge test, respectively. The results demonstrated that Li3.97K0.03Ti5O12exhibited much better rate performance in comparsion with Li4Ti5O12. At 0.2 C and 10 C, it delivered a discharge capacity of 173 mAh g-1and 124 mAh g-1respectively, and after 100 cycles at 10 C, 96.1% of its initial capacity was retained.

Physical and Electrochemical Properties of Li2-xFeSiO4/C Cathode Material for Li-Ion Batteries

Li2-xFeSiO4/C (x=0.01, 0.05, 0.1) were successfully synthesized by a traditional solid-state method and systematically investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and the charge-discharge test, respectively. The results demonstrated that Li2-xFeSiO4exhibited the best electrochemical performance among the three as-synthsied samples. it delivered a specific discharge capacity of 142 mAh g-1, 112 mAh g-1at 0.2 C and 2 C, respectively. After 100 cycles at the rate of 1 C, the discharge capacity remained 95.1% of its initial value.

Small hysteresis and high energy storage power of antiferroelectric ceramics

In this paper, modified Pb ( Zr , Ti ) O 3( PZT ) antiferroelectric (AFE) ceramics system was investigated by traditional solid state method. It was observed that the effect of different contents of Zr / Sn , Zr / Ti on modified PZT antiferroelectrics. With increasing Zr / Sn content, the E AFE (electric field of AFE phase to ferroelectric (FE) phase) value was enlarged. The phase switch field was reduced from FE to AFE (E FA ). The hysteresis loops were changed from "slanted" to "square"-types. With increasing Zr / Ti concentrate, the E AFE value, and also the E FA was enlarged, while the hysteresis switch ΔE was reduced. The hysteresis loops was from "square" to "slanted"-types. The samples with square hysteresis loops are suitable for energy storage capacitor applications, the composition of ceramics was Pb 0.97 La 0.02( Zr 0.90 Sn 0.05 Ti 0.05) O 3, which have the largest energy storage density ~ 4.426J/cm3 at 227 kV/cm, and ΔE was ~80 kV/cm, energy efficient η was about 0.612.