CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Tingting Tang,Hua Huang,Chaoyang Li,Jian Shen
High performance and miniaturization are becoming increasingly important for practical microwave electronics and high-density communication systems. Here, LiNb 0.6 Ti 0.5- x (Zn 1/3 Nb 2/3 ) x O 3 (LNT- x ZN, x = 0, 2, 4, 6, 8 mol%) ceramics have been successfully prepared by a solid-phase reaction. The relationship between the physical structure, microscopic morphology, Raman spectroscopy , and microwave properties is revealed. The better microwave dielectric properties of the LNT-4ZN ceramic sintered at 1075 °C are ε r ∼59.9, Q× f ∼8261 GHz, and τ f ∼-7.4 ppm/°C. Using this ceramic, a miniaturized dielectric resonant antenna (DRA) is designed and demonstrated. The return loss, radiation efficiency, and realized gain of this device at the center frequency are −43.57 dB, 78.4 %, and 8.59 dB, respectively. The antenna, in addition to the good radiation performance, has a size advantage over similar devices (#Cylindrical sample, # R 3.1 mm × h 1.6 mm, @Square substrate, @ a = b = 18 mm × h 3.1 mm). This work exemplifies the great potential of LNT-4ZN materials in communication devices and promotes the application of microwave dielectric ceramics in antenna fields.
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PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2023
·Vol. 25
·期 40
·27606-27617
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IF 3.3
Haiting Shi,Qingqing Wu,Jinxi Bao,Shuaitong Liang,Yanli Hu,Ruiqi Shao,Shuo Wang,Jie Shi,Zhiwei Xu
Fe2O3 is considered a potential electrode material owing to its high theoretical capacity, low cost, and non-toxic characteristics. However, the significant volume expansion and structural degradation during charging and discharging hinder its application in potassium ion batteries. The electrochemical properties of the electrode material are primarily influenced by the diffusion efficiency of ions and the mechanics of the object. From the construction of a one dimensional structure, a three-dimensional flower-like Fe2O3 with a high specific surface and low-dimensional spherical Fe2O3 were prepared. Considering the convenience and visualization of the research, micron-scale Fe2O3 was prepared, although the larger particle size will lose part of the capacity. Notably, compared with the spherical structure, the specific capacity of the flower structure was increased by about 100%. The von Mises stress distribution on the two structures was simulated by the finite element method, revealing the mechanism of electrode failure induced by volume expansion and confirming the vital role of the multidimensional system in relieving stress concentration and improving electrochemical performance. Furthermore, synchrotron radiation soft X-ray absorption spectrum and X-ray micro-tomography revealed the phase transformation process and reaction mechanism of Fe2O3 in potassium ion batteries. The dimensional structure construction strategy reported here can provide theoretical support for modifying transition metal oxides.
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PubMed
高影响因子
JOURNAL OF POWER SOURCES
·
2021
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IF 9.127
Shuya Wang,Xingwu Zou,Chunsong Li,Hong Zheng,Bo Li,Quanchao Zhuang
K-ion batteries (KIBs) have attracted considerable attention because of their unique advantages. Manganese-containing electrode materials have poor cycle performance due to the dissolution of manganese in the electrolyte. Here, manganese-containing KIB cathode with a yolk–shell structure is synthesised by a homogeneous precipitation method. In addition, large charge–discharge capacity and good cycle stability are obtained. Electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS) are used to understand the improvement in the electrochemical performance caused by the developed material. Due to the volume-buffering effect, the yolk–shell structure does not cause particle rupture, which helps form a stable solid–electrolyte interface (SEI) film. This reduces the number of Mn ions exposed to the electrolyte and results in long-term cycle stability. This work provides a universal route to improve the cycling performance of manganese-containing cathode for KIBs applications.
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JOURNAL OF CHEMICAL AND ENGINEERING DATA
·
2021
·
IF 2.694
Tingting Liu,Shui Wang,Yan Shi,Zhong Zhao
Doxofylline (DFL) is a theophylline derivative with poor solubility in water. In this paper, the solubility of DFL (as mole fraction) in 17 organic solvents including 4 esters (ethyl acetate, n-propyl acetate, n-butyl acetate, methyl propionate), 8 alcohols (methanol, ethanol, n-propanol, iso-propanol, n-butanol, iso-butanol, sec-butanol, n-pentanol), 3 ketones (acetone, 2-butanone, cyclohexanone), acetonitrile, and water was studied at the temperatures ranging from “T = 283.15 to 323.15 K”. The solubility of DFL in pure solvents was simulated using three semiempirical models (modified Apelblat, λh, and three-parameter Van’t Hoff) and two activity coefficient models (Wilson and NRTL). In addition, the thermodynamic mixing properties (ΔmixG, ΔmixH, ΔmixS, ln (γ1∞) and H1E,∞) were evaluated using the solubility data and the Wilson model.
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Journal of Materials Chemistry A
·
2021
·Vol. 9
·期 22
·13125-13134
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IF 12.732
Xiaogang Niu,Jiale Qu,Youran Hong,Leqing Deng,Ruiting Wang,Meiying Feng,Jiangwei Wang,Liang Zeng,Qianfan Zhang,Lin Guo,Yujie Zhu
Potassium ion batteries (KIBs) are attracting increasing research interest as a potential low-cost energy storage system. Currently, the development of KIBs is mainly hindered by the poor cycle life of cathode materials, caused by the large K-ion-induced mechanical failure during charge–discharge. Herein, taking layered K0.5V2O5 as an example, we show that reducing the long-range structural order is an effective way to boost its K-ion storage performance. The obtained nanocrystalline K0.5V2O5·0.5H2O is capable of retaining 81% of its capacity after 200 cycles, outperforming its highly crystalline counterpart which only exhibits 33.3% capacity retention after 100 cycles. Detailed spectroscopic and electrochemical characterization techniques indicate that the charge storage mechanism is changed from battery-type intercalation accompanied by phase transition in the highly crystalline K0.5V2O5 to phase transition-free pseudocapacitive K-ion intercalation in the nanocrystalline K0.5V2O5·0.5H2O. Theoretical calculations further suggest that the interlayered water plays a critical role in suppressing the phase transition which mitigates the mechanical damage of the nanocrystalline sample, leading to its enhanced cycling stability. The present work will provide new insights to improve the cycling stability of other electrode materials for KIBs.
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Nano Energy
·
2020
·
IF 16.602
Yuying Wu,Wenbin Fan,Zhangran Gao,Zheng Tang,Lin Lei,Xiaofan Sun,Yongle Li,Hong-Ling Cai,Xiaoshan Wu
The rapid development of organic-inorganic metal halides in optoelectronic devices has been considered a promising approach for light-emitting diodes. Mn-based halogen hybrids represent a class of fascinating luminescence functional materials . Up to date, studies on Mn-based metal halides remain blurry and suffer from instability and low photoluminescence quantum yield (PL QY). Here, the single crystalline of MEA(MnBr 4- x Cl x ) 2 (MEA=((CH 3 ) 4 N)((C 2 H 5 ) 4 N) 2 ·NH 4 , x = 0, 2, 3) were designed and constructed by a one-pot solution method for the first time, featuring brilliant green emissions under ultraviolet light and revealing PL QY up to 99 ± 1% with x = 3 at room temperature. The excellent luminescence is ascribed to the Mn 2+ d 5 configuration with the 4 T 1 – 6 A 1 transition. Moreover, the thermostability and anomalous photoluminescence (PL) behavior triggered by heat are modulated via varying halogen ratio Cl/Br. Particularly, MEA(MnBr 4 ) 2 has an ultrahigh melting up to 600 K, which is, as we know, the highest one among the Mn-based organic-inorganic hybrid compounds. Our findings not only present the outstanding performance of three crystals, but also highlight the potential of these compounds in optoelectronics.
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JOURNAL OF CHEMICAL AND ENGINEERING DATA
·
2020
·
IF 2.369
Xue-ping Zhang,Wei Wang,Han-zhong Zhang,Shi-hua Sang
In this paper, the stable phase equilibrium data of the ternary system CaBr2-SrBr2-H2O at T = 273, 298, and 323 K and 101.3 kPa have been determined by isothermal the dissolution equilibrium method. The phase diagrams of them at the investigated temperatures have been drawn. It is found that the isothermal phase diagrams of the CaBr2–SrBr2–H2O system at T = 273, 298, and 323 K are classified as a simple co-saturation type consisting of an invariant point and two univariant curves. The equilibrium solid phases corresponding to an invariant point of the system were detected as CaBr2·6H2O + SrBr2·6H2O at 273 and 298 K and those identified as CaBr2·4H2O + SrBr2·6H2O at 323 K. In this system, calcium bromide exhibits a strong salting-out effect on strontium bromide. Furthermore, isothermal solubilities at three temperatures were compared and discussed.
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JOURNAL OF MOLECULAR LIQUIDS
·
2020
·
IF 5.065
Kaiyu Zhao,Yafei Guo,Dan Li,Lingzong Meng,Tianlong Deng
Isopiestic molalities and water activities for the commercial absorption refrigerants LiBr and SrBr 2 at 288.15 K were accurately measured using an improved isopiestic method. And the solubilities for the absorption refrigeration systems were determined by the isothermal dissolution equilibrium method, meanwhile, the refractive indices and densities were measured. The Pitzer and HW model was used to correlate the measured water activities and solubilities, simulate the thermodynamic properties and predict the data in the phase equilibrium process for the absorption refrigeration systems, and the predicted data agreed well with the experimental solubilities. On the basis of the Pitzer ion-interaction parameters and solubility product constant ( K sp ) obtained in this work, the ion-interactions between alkali metal ions with Sr 2+ and phase equilibrium behaviors were illustrated on the molecular level, which could give an essential guide for the designing of absorption refrigeration system.
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JOURNAL OF MOLECULAR LIQUIDS
·
2020
·
IF 5.065
Kui Wu,Yajun Li
Being an important synthetic monomer , isobutyramide (IBA) is employed as an intermediate for the synthesis of organic dyes and pharmaceuticals. It is well known that investigation of the solubility behavior of drugs and intermediates has become an extensive research topic in pharmaceutical development. In this work, the solid-liquid equilibrium (SLE) data of IBA in fifteen solvents, including methanol, ethanol, n -propanol, isopropanol, n -butanol, isobutanol , acetonitrile , chloroform, acetone, ethyl formate , methyl acetate , cyclohexanone , cyclopentanone , tetrahydrofuran and 2-butanone was measured with a static gravimetric method with the temperature ranging from 273.15 to 324.75 K under atmospheric pressure. The solubility of IBA increases with the rising temperature in all selected solvents. The ranking of solubility in various solvents is not in accordance with the order of solvent physicochemical properties, namely polarity index, dipole moment , dielectric constant and solubility parameter. The modified Apelblat equation, λh equation, nonrandom two-liquid (NRTL) model and the Wilson model were used to correlate the experimental data. Maximum root-mean-square deviation ( RMSD ) and relative average deviation ( RAD ) were 7.157 × 10 −3 and 1.80%, respectively. The λh equation presented less effective correlating results compared with other three models. The dissolution properties of IBA, including Gibbs energy (△ dis G ), molar enthalpy (△ dis H ) and molar entropy (△ dis S ) were determined based on the Wilson model and the solubility data. Positive values of the dissolution enthalpy and entropy illustrated that the dissolution process of IBA in selected solvents are endothermic and entropy-driven.
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JOURNAL OF CHEMICAL AND ENGINEERING DATA
·
2021
·
IF 2.694
Qing Hao,Huan Zhou,Mengli Zhang,Si Wu,Junfang Yang
Rare-earth ore concentrate is calcined at high temperature by the alkaline method, and the associated elements fluorine and phosphorus are enriched in the form of sodium fluoride and sodium phosphate in water elution. To separate and recover fluorine and phosphorus from the aqueous solution, the solid–liquid equilibrium behaviors of the quaternary systems Na+//F–, CO32–, PO43–-H2O and their two sub-ternary systems NaF-Na3PO4-H2O and Na2CO3-Na3PO4-H2O at 313.15 K were studied via the isothermal solubility phase equilibrium method. Solubility data, liquid density and pH, two complete isothermal phase diagrams of the ternary system, and one complete isothermal phase diagram of the quaternary system were obtained. The results showed that two double salts NaF·2Na3PO4·19H2O and Na3PO4·3Na2CO3·8H2O occurred in the respective ternary systems. Five solid species of one anhydrous salt of NaF, two hydrous salts of Na2CO3·H2O and Na3PO4·12H2O, and two double salts of Na3PO4·3Na2CO3·8H2O and NaF·2Na3PO4·19H2O were found in the quaternary system. The phase diagram of the quaternary system consisted of three invariant points, five crystallization regions, and seven univariate curves. Na3PO4 easily combined with NaF to form double salt NaF·2Na3PO4·19H2O, which occupied a larger phase region in the quaternary phase diagram. The increase in Na2CO3 will lead to the decrease in the solubility of Na3PO4 and NaF in the system.
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ChemSusChem
·
2021
·Vol. 14
·期 18
·3815-3820
·
IF 8.928
Di Li,Wu Tang,Fan Tang,Jiaji Yan,Lvchuan Jing,Chuan Wang,Yichao Yan,Liang Xu,Cong Fan
Graphical One electrode fits all : The polyanionic organic compound 9,10-anthraquinone-2,6-disulfonate is used as a common cathode and metallic bismuth as a common anode to simultaneously assemble low-cost Na-ion and K-ion full cells. The Na-ion full cells deliver a peak discharge capacity of 139 mAh g −1 and the K-ion full cells can show a peak discharge capacity of 130 mAh g −1 at 0.5–3.0 V. Molecule-aggregation organic electrodes in principle have the capability for “single-molecule-energy-storage” in metal-ion rechargeable batteries, which indicates that the same organic electrode can be simultaneously applied to multiple metal-ion rechargeable batteries. In this study, the polyanionic organic compound 9,10-anthraquinone-2,6-disulfonate (Na 2 AQ26DS, 130 mAh g −1 ) is used as a common cathode and metal bismuth (Bi) as a common anode to simultaneously assemble low-cost Na-ion and K-ion full cells. The Na-ion full cells can deliver the peak discharge capacity of 139 mAh g −1 cathode at 0.5–3.0 V, and the K-ion full cells can show the peak discharge capacity of 130 mAh g −1 cathode at 0.5–3.0 V. These results are comparable to the best organic-based Na-ion and K-ion full cells reported to date.
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Polymer Chemistry
·
2021
·Vol. 12
·期 33
·4812-4821
·
IF 5.582
Yudi Feng,Ke Jin,Jia Guo,Changchun Wang
The development of the modern microelectronic industry calls for low permittivity interlayer dielectric materials with excellent thermal stabilities, robust mechanical strength and matching processability. Traditionally, it is difficult to fabricate materials with low k values, high heat endurance, high modulus and good processability simultaneously. Herein, we prepared two novel hydrocarbon precursors with dibenzocyclooctene (DBCOD) and thermo-crosslinkable benzocyclobutene (BCB) units by group transformation and cross-coupling reactions. These precursors can be cured at elevated temperatures to give crosslinked all-aliphatic/aromatic-ring structures. The low-polarizable hydrocarbon skeletons possess low dielectric constants (Dk = 2.66/2.54, respectively) and superior hydrophobicity (high water contact angle of ∼113°/125° and low water uptake of 0.10%/0.37%). Moreover, the rigid crosslinked cyclic structures render significantly high thermostability and mechanical modulus, such as very high glass transition temperatures (Tg > 380 °C/369 °C), high 5% weight loss temperatures (Td,5% = 499 °C/492 °C), low coefficient of thermal expansion of 41.7/41.8 ppm K−1, and storage modulus of 3.7/3.8 GPa, respectively. The enhanced comprehensive performances make the all-carbocycle hydrocarbon resins good candidates for next-generation interlayer dielectrics.
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