Solid-phase Reaction Method Research Articles

Effects of Ta5+ substitution on mechanical and microwave dielectric properties of R(Nb1-xTax)2O6 ceramics

Microwave dielectric ceramics (MWDCs) are prone to mechanical failure, and improving the mechanical properties of MWDCs is of significance for their application under extreme conditions. Novel high-entropy R(Nb1-xTax)2O6 (R = Mg0.2Mn0.2Co0.2Ni0.2Zn0.2) ceramics were prepared by the solid-phase reaction method. The single-phase and composite solid solutions of the R(Nb1-xTax)2O6 series were successfully prepared, as evidenced by XRD, Raman spectra, and combined with EDS energy spectrum analysis. The average grain size was found to increase with the Ta5+ content, while the grain dispersion exhibited a trend of increasing and then decreasing, resulting in a trend of increasing and then decreasing Q×f. The replacement of Nb5+ by Ta5+ has been demonstrated to improve τf and enhance the mechanical properties. An increase in Ta5+ content from 0.5 to 0.75 results in a significant enhancement in εr and mechanical properties, which is primarily attributed to the generation of the RTa2O6 phase. When x = 1, the R(Nb1-xTax)2O6 ceramics exhibit excellent microwave dielectric properties (εr = 31.28, Q×f = 20,722, τf = 48.36) and the most favorable mechanical properties (Hv = 7.99 GPa, σ = 882 MPa, TRS = 237.7 MPa). This study provides a new idea to improve the mechanical properties of MWDCs.

Harnessing visible light for sustainable biodiesel production with Ni/Si/MgO photocatalyst

Sustainable energy sources frequently demonstrate greater reliability and resilience in comparison to conventional energy sources. Biodiesel, with its markedly reduced carbon footprint when compared to petroleum-based diesel fuel, owes this advantage to its production from renewable resources. Heterojunction photocatalysts have gained significant interest due to their immense promise in tackling environmental challenges. In this study, a highly efficient photocatalyst, Ni/Si/MgO, for biodiesel production under visible light irradiation was synthesized using a solid-phase reaction method with silica as the silicon source, along with Ni and MgO. The surface functionality of Ni/Si/MgO was crucial for achieving high efficiency of photocatalytic systems, as evident from XPS. The transesterification reaction on the Ni/Si/MgO photocatalyst proceeds by the formation of SiH and SiOH bonds over the catalyst. The photocatalytic activities of Ni/Si/MgO photocatalysts were higher than those of the Si/MgO nanoparticle when exposed to light. Achieving an optimal yield of 98 %, the biodiesel production was carried out under the following reaction conditions: A catalyst dosage of 2 % by weight was utilized, along with a methanol-to-oil molar ratio of 12:1, and the entire procedure was executed within a duration of 3.5 h. Plasmonic near-fields are speculated to be responsible for the increased transesterification activity along the Ni/Si/MgO interface. In order to carry out the transesterification reaction, electron-hole pairs are generated along the Ni/Si/MgO interface, where plasmonic near-fields are highly concentrated. This study contributes a significant perspective on mechanisms governing the process of efficient plasmonic photocatalysis responsive to visible light. These findings hold the potential to offer valuable guidance in the formulation and design of next-generation, high-performance photocatalysts.

Formation and mechanical properties of Y-substituted (Ce0.2Zr0.2La0.2Sm0.2Nd0.2)O2-δ high-entropy fluorite oxide

In this paper, in order to improve the mechanical properties of high-entropy fluorite oxides (HEFOs), five equimolar multicomponent oxides were synthesized by solid-phase reaction method by using element Y replacing one of the five cations in (Ce0.2Zr0.2La0.2Sm0.2Nd0.2)O2-δ. The substitution of La, Sm or Nd in (Ce0.2Zr0.2La0.2Sm0.2Nd0.2)O2-δ with Y element are able to form single-phase HEFOs at 1600 °C, while Ce4+ and Zr4+ replaced by Y3+ contains a large number of secondary phase. The former three components are almost dense and smooth, and all the elements are uniformly distributed with no obvious segregation and agglomeration. The Ce3+ concentration of Y-substituted Sm HEFOs is calculated to be 13.7%, yielding a nominal composition of (Ce0.2Zr0.2Y0.2Sm0.2Nd0.2)O1.6863. In addition, the HEFOs have the best mechanical properties with Vickers hardnesses, flexural strengths and fracture toughnesses of 15.12 GPa, 101.1 MPa and 7.88 MPa-mm1/2, respectively, which have potential applications in high-performance structural materials.

Changes of magnetic configurations in MnCo2O4 caused by synthesis temperature

The synthesis temperature of the sample is a key parameter that not only affects the occupancy of cations, but also has a significant impact on the magnetic configuration. In this study, we synthesized pure phase MnCo2O4 powder using a solid-phase reaction method and studied the change of its magnetic configuration with synthesis temperature. Due to the Jahn-Teller distortion caused by octahedral Co2+ and Mn3+ ions, magnetic interactions between octahedral cations dominate in all the samples. When the synthesis temperature is low, some octahedral Co3+ is reduced to Co2+. The appearance of antiferromagnetic interaction between octahedral Co2+ makes the antiferromagnetic characteristics in the sample more prominent. The magnetic configuration in the MnCo2O4 powders synthesized at low temperature undergoes a transition from collinear to non-collinear as the test temperature decreases. As the synthesis temperature increases, a stable collinear magnetic structure is formed, and the ferromagnetic phase gradually becomes dominant. The defined saturation magnetization reaches its maximum at a synthesis temperature of 700°C, with the Neel temperature of the sample close to the ideal value.

Effects of phase transition on the structure and microwave dielectric properties of (1-x)CeO2-0.5xSm2O3 (x=0-0.9) ceramics

(1-x)CeO2-0.5xSm2O3 (x=0-0.9) microwave dielectric ceramics are synthesized by the conventional solid-phase reaction method, with the effects of phase transition on structure and microwave dielectric properties being investigated in detail. The phase transition process is analyzed using the ionicity and lattice energy of (1-x)CeO2-0.5xSm2O3 ceramics, which is related to the coordination number and effective valence electron charge. With the increase of Sm3+ content, there are three phase regions: the cubic fluorite phase (0 ≤ x ≤ 0.4), the rare-earth C-type phase (0.4 <x ≤ 0.8) and the mixed phase (0.8 <x < 1.0). With the phase transition, the microstructures of (1-x)CeO2-0.5xSm2O3 (x=0-0.9) ceramics show a quasi-periodic change, where x=0.4 and x=0.8 are the critical points with similar grain size and distribution. When the phase transition occurs, the polarization, Q׃ values and the resonant frequency temperature coefficients (τƒ) of (1-x)CeO2-0.5xSm2O3 (x=0-0.8) ceramics are all mutated, which is due to the change of bond ionicity and effective valence electron charge caused by the phase transition. The microwave dielectric properties in each pure phase region vary regularly with bond ionicity and valence. Compared with the cubic fluorite phase (0 ≤ x ≤ 0.4), (1-x)CeO2-0.5xSm2O3 ceramics with rare-earth C-type phase (0.4 <x ≤ 0.8) have lower dielectric constant, with better Q׃ values and τƒ values.

Effect of A/B sites co-doping on the structure, electric and dielectric properties of CaTiSiO5 ceramics

Dielectrics with high permittivity and temperature stability are important for the development of high-temperature multilayer ceramic capacitors (MLCCs). In this study, Ca[Formula: see text]NaxTi[Formula: see text]NbxSiO5 (abbreviated as CTS[Formula: see text]NN) ceramics were prepared by solid-phase reaction method. The introduction of NN weakens the long-range ordered displacement of Ti, leading to a significant increase in the dielectric temperature stability. The CTS−2%NN samples exhibit high permittivity (53) and TCC [Formula: see text] ppm/∘C in the range of [Formula: see text]C to 300∘C. The CTS-based ceramics behave high dielectric temperature stability. In addition, the bandgap of the CTS-based ceramics increased significantly, which is favorable for improving the breakdown strength of the material. For [Formula: see text]% samples, the breakdown strength reaches 621[Formula: see text]kV/cm. Thus, the designed CTS-based dielectrics are promising for high-temperature capacitors.

Effect of chemical bonding and relative density on microwave dielectric properties of LiInW2O8 ceramics

To meet the demands of the growing field of electronic communications, LiInW2O8 ceramics with low dielectric loss (high Q×f) and low dielectric constant (εr) are prepared by a solid phase reaction method. X-ray diffractometry reveals a scheelite single-phase structure for the prepared ceramics. Compared with the standard LiInW2O8, the as-prepared LiInW2O8 has a higher relative diffraction intensity for the (200) crystal plane, indicating an anisotropic growth phenomenon in the present case. Raman spectroscopy and calculations of the P-V-L complex chemical bonding theory show that W-O bonding is a key factor affecting the dielectric properties of LiInW2O8 ceramics. Furthermore, excellent microwave dielectric properties with εr ≈ 14.2, Q×f ≈ 63000 GHz, and τf ≈ −28 ppm/℃ are obtained by sintering the ceramic at 1025°C.

Cu(I) and Cu(II) in mixed bismuth tantalate pyrochlores according to XPS and NEXAFS spectroscopy

Mixed copper-containing pyrochlores Bi2Co1/2Cu1/2Ta2O9+Δ, Bi2Ni1/2Cu1/2Ta2O9+Δ, Bi2Co1/3Cu1/3Ni1/3Ta2O9+Δ (sp.gr. Fd-3 m) were synthesized by the solid-phase reaction method. The surface composition and chemical state of transition element atoms in pyrochlores were characterized by XPS, NEXAFS spectroscopy. According to the XPS spectra, bismuth and tantalum cations have an effective charge of + 3 and +(5-δ). The NEXAFS Cu2p spectra of pyrochlores are shown to represent a superposition with the CuO and Cu2O spectra in terms of the main spectral characteristics. This indicates a variable Cu ion content in oxide pyrochlores in the form of Cu(I,II) ions.

Corrosion performance of (ZrYTaAlCr)O ceramic coating materials for heated surface tubes

The comprehensive advantages of waste incineration power generation are evident, gradually replacing composting, landfill, and other treatment methods. However, the presence of chlorine, sulfur, heavy metals, and a variety of hazardous elements in the flue gas has led to severe corrosion of the heated surface tubes of the waste incineration boilers and an increase in the failure rate of the boilers, thus restricting the wider application of waste incineration power generation technology. In this study, (ZrYTaAlCr)O high-entropy ceramic materials were synthesized via the solid-phase reaction method and subjected to exposure in a standard corrosive mixture (SCM) simulating the molten salts environment of waste incineration boilers, consisting of NaCl (25 mol%), KCl (25 mol%), Na2SO4 (25 mol%), and K2SO4 (25 mol%). The corrosion behavior of (ZrYTaAlCr)O ceramics with different proportions was studied through visual detection, corrosion kinetics, XRD, and SEM/EDS analysis. The results show that (Zr0.5Y0.125Ta0.125Al0.125Cr0.125)O forms a NaTaO3 tantalate protective layer in the early stages of corrosion, with fewer types of corrosion products. Compared with other compositions, (Zr0.5Y0.125Ta0.125Al0.125Cr0.125)O has good corrosion resistance and is suitable as a corrosion protection material for the heating surface tubes of waste incineration boilers.

Luminescence performance, temperature sensing characteristics and Judd-Ofelt theory analysis of Y2MoO6:Er3+/Yb3+/Li+ upconversion phosphors

A series of Y2MoO6:0.01Er3+/0.09 Yb3+ upconversion phosphors doped with different concentrations of Li + ions (0.05, 0.10, 0.15, 0.20, 0.25, and 0.30 mol) were prepared by the high temperature solid phase reaction method, and their physical phase structures and upconversion luminescence were analyzed. At the excitation wavelength of 980 nm, the addition of Li+ sharply increased the upconversion luminescence intensity. With the increase of Li+ ion content, the luminescence intensity first increases and then decreases. When the doping amount reaches 0.25 mol, the luminescence intensity reaches the maximum, and the sample emits green light in the two-photon process. Y2MoO6:0.01Er3+/0.09 Yb3+/0.25Li + exhibits excellent temperature sensing properties. Its absolute sensitivity Sa reaches up to 0.012 K-1, the relative sensitivity Sr is 0.017 K-1 and the measurement error δT is less than 0.3 K at room temperature. Its temperature sensing performance is far superior to similar materials. In addition, Judd-Ofelt theory calculations revealed that in comparison with Y2MoO6:0.01Er3+/0.09 Yb3+, its Ω2 increased from 0.56 × 10−20 cm2 to 3.68 × 10−20 cm2, and the spectroscopic quality factor Ω4/Ω6 ratio reached 4.09, which is much higher than that of the other fluorescent materials. The main reason is that Li + replaces the Y3+ ion lattice site, causing lattice distortion and reducing the lattice symmetry around the active ion. The increase in asymmetry increases the possibility of spontaneous radiative transitions. It is shown that the prepared upconversion luminescent materials have potential applications in the field of solid-state lasers and optical sensing.

Local electronic structure modulation via S substitution enables fast-discharging capability for Li-rich Mn-based oxides cathodes

Anionic and cationic redox reaction contribute to the ultrahigh specific capacities of Li-rich Mn-based oxides cathodes (LMNC). However, the irreversible oxygen evolution and sluggish kinetics result in the continuous capacity decay and poor rate performance, which limited its application as cathode material in lithium-ion batteries. Herein, the local electronic structure of LMNC is appropriately modulated via S2− doping to alleviate oxygen release, stabilize the crystal structure stability, and facilitate Li+ diffusion via facile surface defect engineering. The effect of S2− doping site on the systematically energy is investigated by DFT. Under the guidance of this result, LNMC-S is prepared by co-precipitation and high-temperature solid-phase reaction method. The effect of doping concentration on electrochemical property of LMNC was systematically investigated. The results exhibit that S2− doping can effectively suppress the electronic insulation of Li2MnO3, enhance the transport dynamics of lithium ion and inhibit the phase transition of LMNC sample during charge-discharge process. Thereby, the modified sample exhibits superior electrochemical property, such as the 200th discharge capacity is 184.3 mAh·g−1 under 1C, with a capacity retention rate of 87.6 %. This paper is beneficial for enriching the existing theoretical findings and discoveries, providing theoretical guidance for the preparation of high-performance material.

Sol–gel derived Bi2NiNb2O9 pyrochlore: Synthesis, characterization and dielectric properties

The Pechini method was used for the first time to synthesize the phase-pure nickel-containing cubic pyrochlore Bi2NiNb2O9 (space group Fd-3m, a = 10.5371(5) Å), while the solid-phase reaction method provided no possibility to obtain impurities-free pyrochlore. At a synthesis temperature of 950°С, low-porosity ceramics with indistinct grain boundaries were formed. The results of elemental mapping indicated a uniform distribution of metal atoms on the surface of the sample. The X-ray energy dispersive analysis showed that the chemical composition of the synthesized sample corresponded to the predetermined theoretical composition. The calcination of the sample synthesized by the Pechini method was studied by the thermal analysis up to 1100°С. The functional composition of intermediate synthesis products was analyzed by vibrational spectroscopy (FTIR). In the FTIR spectrum of pyrochlore (4000–400 cm−1), absorption bands were identified at 829, 540, 654, and 490 cm−1. The dielectric properties of the pyrochlore were studied using an impedance spectroscopy. Pyrochlore Bi2NiNb2O9 has the high relative dielectric permittivity of 145 and low dielectric losses of 0.001 (at 24°С, 1 MHz), which make it a promising for dielectric in multilayer ceramic capacitors.

High-entropy processed high quality and low-temperature cofired LiMgPO4-based dielectric ceramics for low-loss packaged millimeter-wave filters

In this work, we successfully integrated the high-entropy concept into LiMgPO4-based ceramics by strategically substituting Mg2+ with various divalent ions. Through a low-temperature solid-phase reaction method, a series of high-entropy LiMg0.9R0.1PO4 (R = Ni, NiCo, NiCoZn, NiCoZnCu, NiCoZnCuMn) ceramics were prepared successfully, and their MW dielectric properties were found to be heavily influenced by the ionic character, lattice energy, bond energy, entropy, ion radius disorder, and electronegativity of chemical bonds. Remarkably, LiMg0.9(Ni0.2Co0.2Zn0.2Cu0.2Mn0.2)0.1PO4 (LM5RP) ceramics exhibited exceptional MW dielectric properties (εr = 7.43, τf = − 27.6 ppm/°C, and Q × f = 83,216 GHz@13 GHz and 105,889 GHz@28 GHz) when sintered at an extraordinarily low temperature of 900 °C for 2 h. To demonstrate the real-world applicability of the LM5RP high-entropy ceramic, we designed and fabricated a state-of-the-art millimeter-wave (mmWave) filter, operating at 28 GHz, using low-temperature co-fired ceramic (LTCC) packaging technology. The filter exhibited unparalleled performance, featuring a low insertion loss (0.9 dB) and wide stopband suppression (> 17 dB @ 2.14 f0). These groundbreaking findings underscore the immense potential of high-entropy ceramics in revolutionizing advanced MW applications, particularly in the domain of B5G/6 G mmWave communication systems.

A novel Cr3+-doped MgGaBO4 phosphor: Expanding the horizons in plant illumination

Near-infrared (NIR) spectroscopy technology has demonstrated unparalleled efficacy in night vision, iris authentication, plant illumination, food inspection, and various other domains. Nonetheless, the quest for novel phosphors exhibiting superior luminescent efficiency and enduring thermal stability persists as a formidable obstacle. In this study, phosphors MgGaBO4: Cr3+, Al3+ were successfully synthesized by high-temperature solid-phase reaction method. Firstly, starting from MgGaBO4: Cr3+, the crystal field environment around Cr3+ ions was modulated by replacing Ga3+ with Al3+ to further improve the luminescence performance of the phosphor. The emission peak wavelength of MgGaBO4: 0.0075Cr3+,0.005Al3+ phosphor was about 756 nm, the full width at half-maximum (FWHM) was about 174 nm under the blue light excitation of 440 nm. In addition, the luminescence intensity at 100 °C remains at 77.41 % of that at room temperature. Finally, the excellent moisture resistance of this phosphor was demonstrated. This work not only introduces a novel broadband NIR phosphor with promising application potential in advanced agricultural lighting but also proposes a synergistic enhancement strategy for effectively improving the performance of broadband NIR phosphor-converted LED light sources.

Luminescent color modulation of Zn/BaAl2O4:0.2%Eu phosphors for LED application

Spinel-type aluminate (ZnAl2O4) doped with europium (Eu) ions has garnered considerable attention in the field of luminescence. This study explores a series of Zn/BaAl2O4:0.2%Eu phosphors (x = 0∼0.25, x is for the mole fraction of BaAl2O4), fabricated through a high temperature solid-phase reaction method in air or reduction environment. In the case of phosphors synthesized in air, the photoluminescence emission (PL) spectra show a series of sharp emission peaks at 570 nm, 589 nm, 620 nm, 660 nm, and 710 nm, which are generated by the 5D0-7FJ (J = 0, 1, 2, 3, 4) level transitions in Eu3+. Time-resolved photoluminescence and X-ray photoelectron spectroscopy (XPS) characteristics also validate the presence of Eu3+ in samples synthesized in air. An intriguing observation is the abnormally strong emission peak at 570 nm under 346 nm excitation, originating from the Eu3+5D0-7F0 level transition. For x = 0.15, the corresponding CIE color coordinate is (0.3246, 0.3449), suggesting its potential application as a mono-doped and uni-matrix white phosphor. On the other hand, phosphors synthesized in reduction environment exhibit PL spectra with a wide emission band spanning from 400 nm to 550 nm, resulting from the electric-dipole-allowed transition of f-d state of Eu2+. The partial substitution of Zn2+ with Ba2+ significantly enhances the Eu2+ luminescence intensity. Moreover, an elevation of the mole fraction of Zn/BaAl2O4:0.2%Eu leads to a notable redshift (450 nm→500 nm) in the emission peaks of Eu2+ caused by lattice expansion, providing the adjustability of emitting color.

Mechanisms affecting microwave dielectric properties of Li2Mg2TiO5 ceramics based on lithium excess

Herein, the feasibility was assessed through first principles, and the effect of lithium excess on both the structure and dielectric properties of Li(1+x)2Mg2TiO5 (0.000 ≤ x ≤ 0.200) ceramics was investigated by solid-phase reaction method. An appropriate excess of lithium can moderately inhibit the volatilization of lithium and reduce the production of the secondary phase MgTi2O4, though it cannot completely inhibit its production. Li(1+0.050)2Mg2TiO5 exhibits the best dielectric properties with εr =14.55, Q × f =127,393 GHz (@9.6 GHz), and τf = −19.91 ppm/°C. The influence of non-inherent factors on the dielectric properties is dominant, with the increase in relative density to 93.53 % and the growth in average grain size to 28.67 μm contributing to the reduction of dielectric loss. The decrease in εr is due to the decrease in secondary phase content. Results from bond ionicity and Raman wavenumber variations in the intrinsic factors show that the intrinsic factors have little effect on the εr. Whereas, the increase in lattice energy as well as the decrease in FWHM contribute to the decrease in dielectric loss. In addition, a proper excess of lithium helps to increase the bonding energy thereby optimizing the temperature stability. The optimized Li(1+0.050)2Mg2TiO5 has great potential for application in microwave communications.

Enhanced high-temperature performance of selected high-entropy rare earth disilicates

First-principles calculations were utilized to evaluate the synthesis feasibility of (Yb0.2Y0.2Lu0.2Ho0.2Er0.2)2Si2O7, (Yb0.2Tm0.2Lu0.2Sc0.2Er0.2)2Si2O7, (Yb0.2Tm0.2Lu0.2Sc0.2Gd0.2)2Si2O7, and (Yb0.2Y0.2Lu0.2Sc0.2Gd0.2)2Si2O7, followed by their fabrication using the solid-phase reaction method. This study investigates the thermal properties of four novel high-entropy rare earth disilicates and compares them with Yb2Si2O7, a material known for its high-temperature stability. The aim was to explore the influence of high configurational entropy and small grain size on enhancing material properties that are critical in high-temperature applications. Key findings demonstrated that these high-entropy materials exhibit lower thermal conductivity, higher specific heat capacity, an0d reduced coefficient of thermal expansion compared to Yb2Si2O7. Among them, (Yb0.2Tm0.2Lu0.2Sc0.2Er0.2)2Si2O7 and (Yb0.2Y0.2Lu0.2Ho0.2Er0.2)2Si2O7 have the lowest thermal conductivity and suitable CTE, making them the best choices for advanced thermal/environmental barrier coatings in high-temperature applications. Furthermore, the in-depth discussion in this study provides guidance for designing high-entropy rare earth disilicate materials with ideal CTE and thermal insulation properties.

Effect of SiO2-Li2O3-CuO additive on piezoelectric properties of PMS-PZT ceramics at low sintering temperature

Lead zirconate titanate (PZT) based piezoelectric ceramics are applied in ultrasonic transducers and multilayer actuators fields universally. Excellent piezoelectric properties of PZT-based ceramics of low sintering temperature are crucial for the applications of high-power motors and multilayer piezo-actuators due to the reduction of cost and energy consumption. In this paper, a ternary solid-solution ceramic system 0.05Pb(Mn1/3Sb2/3)O3-0.47PbZrO3-0.48PbTiO3 (PMS-PZT) was studied. A new complex additive composed of SiO2-Li2O3-CuO was doped into the PMS-PZT ceramics. The doping of CuO and Li2O3 was discovered to be able to lower the sintering temperature and remain electric properties efficiently, while the doping of SiO2 can decrease the grain size and increase the density. All ceramic samples were fabricated by solid-phase reaction method and sintered in the low temperature range from 800 °C to 1000 °C. The phase structure, morphology of natural surface and electrical properties of ceramics doped by 0.5 wt% additive were characterized. The 0.5 wt% additive doped PMS-PZT ceramics exhibit remarkable comprehensive piezoelectric properties sintered at 900 °C (d33 = 343 pC/N, Qm = 1016, Tc = 328 °C, tanδ = 0.4 % (at 25 °C), εr = 1344, d33* = 490 pm/V). The sintering temperature 900 °C is significantly below the melting point of Ag (961.9 °C) and Cu (1083.4 °C), so the more cost-effective Cu internal electrodes and Ag rich Ag/Pd electrodes can be used to substitute the expensive Pd rich Ag/Pd internal electrodes in the production of devices composed of multilayer ceramic. The research of this work provides an important candidate additive for the applications of high-performance transducers and multilayer actuators with low cost.

Enhancing Energy Storage Performance of 0.85Bi0.5Na0.5TiO3-0.15LaFeO3 Lead-Free Ferroelectric Ceramics via Buried Sintering.

Bismuth sodium titanate (Bi0.5Na0.5TiO3, BNT) ceramics are expected to replace traditional lead-based materials because of their excellent ferroelectric and piezoelectric characteristics, and they are widely used in the industrial, military, and medical fields. However, BNT ceramics have a low breakdown field strength, which leads to unsatisfactory energy storage performance. In this work, 0.85Bi0.5Na0.5TiO3-0.15LaFeO3 ceramics are prepared by the traditional high-temperature solid-phase reaction method, and their energy storage performance is greatly enhanced by improving the process of buried sintering. The results show that the buried sintering method can inhibit the formation of oxygen vacancy, reduce the volatilization of Bi2O3, and greatly improve the breakdown field strength of the ceramics so that the energy storage performance can be significantly enhanced. The breakdown field strength increases from 210 kV/cm to 310 kV/cm, and the energy storage density increases from 1.759 J/cm3 to 4.923 J/cm3. In addition, the energy storage density and energy storage efficiency of these ceramics have good frequency stability and temperature stability. In this study, the excellent energy storage performance of the ceramics prepared by the buried sintering method provides an effective idea for the design of lead-free ferroelectric ceramics with high energy storage performance and greatly expands its application field.

Unleashing the potential of sulfur-incorporated polymer framework composite for enhanced performance and stability of lithium-organosulfur batteries

Sulfur-containing polymer have emerged as a promising cathode material due to their high theoretical capacity, energy density and low cost. However, their commercial development is hindered by the shuttle effect and slow lithium-ion transport efficiency. Here, a novel sulfur-containing polymer framework material (1,4-NDC@S@PAA) was synthesized by using a solid-phase reaction method. The carbon skeleton of polyacrylic acid (PAA) is functionalized with both 1,4-naphthalenedicarboxylic acid (1,4-NDC) and sulfur molecular clusters. By incorporating small molecules into the carbon skeleton, the lithium-ion transport channels within the electrode material are increased, resulting in improved performance. Compared to traditional vulcanized sulfur chain-type polymers, employing PAA as the main chain enhances stability during charge/discharge process. After 500 cycles at 1.0 C, the material demonstrates a modest average decay rate of 0.091% per cycle. Additionally, the introduction of 1,4-NDC constructs a molecular framework that facilitates rapid Li+ ions diffusion, leading to a two-order of magnitude increase of Li+ ions diffusion coefficient as high as 3.58×10−8 cm2 s−1 and excellent rate performance with a 721 mAh g−1 specific capacity at 5.0 C. This high-performance sulfur-containing polymer framework material holds great promise for advancing lithium-sulfur battery technology and addressing the limitations faced by traditional lithium-ion batteries.