CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Junpeng Jiang,Liwen Yan,Jiangtao Li,Yunjia Xue,Chensi Zhang,Xiaoxia Hu,Anran Guo,Haiyan Du,Jiachen Liu
Owing to tunable dielectric properties, light weight and high porosity, polymer-derived SiBCN ceramic aerogels possess significant application prospects in electromagnetic wave (EMW) absorption and thermal insulation. However, due to inadequate oxidation resistance, the structural collapse and performance deterioration of SiBCN aerogels will easily occur in high-temperature aerobic environments, limiting their application. Herein, to address this issue, a novel and straightforward strategy based on typical polymer-derived-ceramic (PDC) aerogel method and impregnation with boehmite sol was proposed for synthesizing SiBCN/Al 2 O 3 composite ceramic aerogels. The microstructure, phase composition, thermal insulation, oxidation resistance and EMW absorption properties of SiBCN/Al 2 O 3 ceramic aerogels were investigated. The resulting SiBCN/Al 2 O 3 composite aerogel demonstrates superior high-temperature structural stability, exhibiting an ultra-low linear shrinkage of only 6.5 % following heat treatment at 1200 °C for 2 h in air. Additionally, the composite aerogel shows a low thermal conductivity of 0.039 W/mK and a low density of 0.112 g/cm 3 . The SiBCN/Al 2 O 3 composite aerogel, composed of dielectric SiBCN, conductive free carbon, and insulating alumina, demonstrates outstanding EMW absorption properties with a minimum reflection loss of −48.6 dB and an effective bandwidth of 5.8 GHz. The enhanced microwave absorption performance is mainly attributed to the improved impedance matching, multiple reflection, and enhanced interfacial polarization resulting from the introduction of Al 2 O 3 . Given prominent oxidation resistance, thermal insulation and EMW absorption properties, the SiBCN/Al 2 O 3 composite aerogel paves the way for developing microwave absorption and thermal insulation integrated material in high-speed vehicles.
研究领域:
材料科学
·
航空航天工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Xinlei Jia,Zihan Zhou,Donghui Guo,Baolu Shi,Ning Zhou,Baosheng Xu
Polymer-derived ceramic aerogels are promising materials for thermal insulation and microwave absorption in harsh environments because their microstructures can be controlled at the molecular level. Silicon oxycarbide (SiOC) aerogels are considered as potential high-temperature electromagnetic wave (EMW) absorbers, but their application range is limited by complex preparation process and unsatisfactory microwave-absorption performance. This paper reports a new SiC nanowire/SiOC composite aerogel (SCA) synthesized through the sol–gel process, environmental pressure drying, and high-temperature treatment. The SCA performance is adjusted by controlling the ratio of SiC nanowires, obtaining low thermal conductivities (0.04–0.042 W m −1 K −1 ) and excellent mechanical properties (4.37–5.45 MPa). Increasing the SiC nanowire content gradually increases the EMW absorption capacity of SCA. The optimal reflection loss is −53.64 dB and the effective absorption bandwidth is 3.88 GHz, substantially higher than that of SiOC aerogels . This high performance is mainly attributable to the appropriate impedance matching characteristics and strong polarization loss ability. Moreover, the performance of the composite aerogels was retained after long-term treatment in an air environment at 800 °C. SCA also exhibits excellent high-temperature insulation and flame retardancy. Owing to its light weight, strong microwave-absorption ability, good thermal insulation performance, and oxidation resistance , SCA is a highly promising alternative material for use in extreme environments.
研究领域:
材料科学
·
复合材料
·
热能工程
·
电磁学
✓ 已验证
产品关联
DOI
高影响因子
Small
·
2017
·Vol. 14
·期 6
·1703454
·
IF 8.643
Jian Pan,Houpu Li,Hao Sun,Ye Zhang,Lie Wang,Meng Liao,Xuemei Sun,Huisheng Peng
Driven by the increasing requirements for energy supply in both modern life and the automobile industry, the lithium–air battery serves as a promising candidate due to its high energy density. However, organic solvents in electrolytes are likely to rapidly vaporize and form flammable gases under increasing temperatures. In this case, serious safety problems may occur and cause great harm to people. Therefore, a kind of lithium–air that can work stably under high temperature is desirable. Herein, through the use of an ionic liquid and aligned carbon nanotubes, and a fiber shaped design, a new type of lithium–air battery that can effectively work at high temperatures up to 140 °C is developed. Ionic liquids can offer wide electrochemical windows and low vapor pressures, as well as provide high thermal stability for lithium–air batteries. The aligned carbon nanotubes have good electric and heat conductivity. Meanwhile, the fiber format can offer both flexibility and weavability, and realize rapid heat conduction and uniform heat distribution of the battery. In addition, the high temperature has also largely improved the specific powers by increasing the ionic conductivity and catalytic activity of the cathode. Consequently, the lithium–air battery can work stably at 140 °C with a high specific current of 10 A g -1 for 380 cycles, indicating high stability and good rate performance at high temperatures. This work may provide an effective paradigm for the development of high-performance energy storage devices.
研究领域:
材料科学
·
能源技术
✓ 已验证
DOI
高影响因子
MATERIALS LETTERS
·
2021
·
IF 3.423
Antuo Wang,Xianglong Li,Teng Hou,Yishen Lu,Jing Zhou,Xianggui Zhang,Bin Yang
In order to solve the problem of air pollution, especially in high temperature environment, an ultrafine poly(tetrafluoroethylene) (PTFE) porous fibrous membrane (UPPFM) was created by electro-centrifugal spinning, sintering calcination and impregnation technology in this paper. The pores distribution on the surface of the fibers could be simply controlled by adjusting PVP/PTFE ratios, and prompted the porosity of obtained membrane up to 94.1%. The obtained membrane presented an ultralow air resistance to 89.9 Pa with filtration efficiency higher than 99.72%. Moreover, UPPFM showed excellent heat stability and reusability, and therefore exhibited a great potential application in the high temperature air filtration.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2020
·
IF 3.83
Jingwei Chen,Xinqiang Wang
Three kinds of Gd 2 Zr 2 O 7 /ZrO 2 (GZC) composite fibers with different proportions of Gd 2 Zr 2 O 7 were prepared by electrospinning method through changing the amount of Gd 3+ in precursor solutions. The thermal decomposition, crystallization process , high temperature stability and heat-conducting properties of GZC fibers were fully characterized. The results showed that there were three crystalline phases, tetragonal phase ZrO 2 , cubic phase ZrO 2 and defect fluorite phase Gd 2 Zr 2 O 7 in all the GZC fibers. The content of Gd 2 Zr 2 O 7 increased gradually with the increase of Gd 3+ in precursor solutions which led to the gradual slowing down of grain growth rate, the decrease of thermal conductivity and the increase of high temperature stability of the obtained composite fibers. The thermal conductivities of all the GZC fiber sheets were lower than that of 7YSZ fiber sheet. The sheets of all the GZC fibers could keep the high temperature stability up to 1300 °C.
研究领域:
材料科学
·
无机化学
✓ 已验证
产品关联
DOI
高影响因子
ACS Sustainable Chemistry & Engineering
·
2018
·
IF 6.14
Qingguo Chi,Zhiyou Gao,Tiandong Zhang,Changhai Zhang,Yue Zhang,Qingguo Chen,Xuan Wang,Qingquan Lei
In recent years, polymer-based dielectric capacitors have attracted much more attention due to the advantages of excellent flexibility, light weight, and high power density. However, most studies focus on energy storage performances of polymer-based dielectrics at room temperature, and there have been relatively fewer investigations on polymer-based dielectrics working under high-temperature conditions, which is much closer to the practical applications. Besides, dielectric capacitors operating in a high-temperature environment require excellent temperature stability of structure and performance. In this paper, high-temperature-resistant polyimide (PI) is selected as the matrix material, and 0.5Ba(Zr0.2Ti0.8)O3–0.5(Ba0.7Ca0.3)TiO3 (BZT–BCT) nanofibers are used as the filling phase. By analyzing the energy storage behaviors of BZT–BCT/PI composites at different temperatures, it can be found that when the doping content of BZT–BCT nanofibers is more than 1 vol % the dielectric strength of the composites drops sharply when the temperature increases from 25 to 150 °C, resulting in serious deterioration of energy storage properties. On the basis of this, a composite film with a sandwich structure has been designed, where BZT–BCT/PI with different volume fractions is the intermediate layer and hexagonal boron nitride (h-BN) with good thermal and insulating properties is introduced in the top and bottom layers with a content of 5 vol %. Consequently, the results have shown that the energy storage properties of the constructed sandwiched dielectric composite films exhibit excellent temperature stability. The maximum field strength of the composite film with a BZT–BCT content of 1 vol % in the intermediate layer is 360 and 350 kV/mm under temperatures of 25 and 150 °C, and the storage density is 2.3 and 1.83 J/cm3 respectively.
研究领域:
材料科学
·
能源存储
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2020
·
IF 6.182
Yulin He,Ying Li,Yaochun Liu,Nianchun Yao,Jiamei Li,Yang Liu
Inspired by the WO 3 transition metal semiconductor, a simple liquid phase WO 3 coating strategy is introduced to improve the surface stability of LiNi 0.5 Co 0.2 Mn 0.3 O 2 . The electrochemical performance of WO 3 -coated LiNi 0.5 Co 0.2 Mn 0.3 O 2 is improved at both a high cut-off voltage (4.5 V) and high temperature (50 °C). With the WO 3 (0.6 wt%) coating amount optimized, the material capacity retention is maintained at 138 mAh g −1 and 170.9 mAh g −1 at 25 °C and 50 °C after 200 cycles compared with 107.8 mAh g −1 and 143.9 mAh g −1 , respectively, for pristine NCM523. The WO 3 -coated sample also exhibits a better rate capability, maintaining 126 mAh g −1 at 25 °C in the voltage range of 3–4.5 V at the current density of 5 C. The enhanced properties of the WO 3 -coated LiNi 0.5 Co 0.2 Mn 0.3 O 2 due to the WO 3 coating layer result from the interface that prevents immediate contact between the electrolyte and the active material as well as the lower polarization and electrochemical resistance of the battery. SEM, TEM, XPS and EIS further reveal these improved electrochemical performances, which indicate the success of the approach for regenerating NCM523.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
CRYSTENGCOMM
·
2023
·Vol. 25
·期 39
·5533-5540
·
IF 3.1
Xu Zhang,Shenghui Han,Gang Lian,Deliang Cui,Qilong Wang
Matrix- and metal-free phosphorescence materials with long room-temperature lifetime and high-temperature phosphorescence properties have attracted tremendous attention but seldom reported. Herein, a universal fluorination strategy was proposed to obtain a series of matrix-free fluorinated boron nitride dots (F-BNDs) with markedly extended lifetime by constructing rigid F-induced hydrogen-bond networks. Miraculously, when the F-BNDs(e) were heated to 150 °C, the afterglow was temperature-controlled and still maintained with a lifetime as long as 0.25 s. In terms of their interesting phosphorescence properties, this work actually provides a guiding strategy to realize F-BND phosphorescence materials with time-resolved and temperature-controlled lifetime encoding characteristics. Widespread applications in higher-level information encryption, time-resolved information displaying, dynamic multidimensional anti-counterfeiting and colorless security ink were demonstrated.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Yong Zhang,Yuchang Qing,Junjie Yang,Chuanyang Jiang
SiC, with outstanding oxidation stability and tunable dielectric property, has been regarded as a promising microwave absorption material for high-temperature applications. However, the application of pristine SiC is restricted by its inadequate dielectric response and weak loss capability. Herein, a novel strategy is proposed to construct Cr-Si-C conductive shell on SiC surface via molten salt method is proposed to introduce heterogeneous interfaces and enhance dielectric loss. The optimal SiC@Cr-Si-C core-shell sample achieves a minimum reflection loss (RL m ᵢ n ) of −36.7 dB at a matching thickness of 1.4 mm. Meanwhile, it exhibits an effective absorption bandwidth (EAB) of 2.41 GHz. Notably, even after heat treatment at 600 °C in air for 5 h, the core-shell absorber maintains an intact core-shell structure and its RL m ᵢ n remains as high as −34.4 dB, demonstrating superior high-temperature stability. This work provides an effective method for high-performance microwave absorption materials targeted at high-temperature applications.
研究领域:
材料科学
·
电磁功能材料
·
介电材料
·
高温材料
·
复合材料
✓ 已验证
产品关联
DOI
高影响因子
MOLECULES
·
2022
·Vol. 27
·期 16
·5326
·
IF 4.927
Xianwen Song,Gang Lu,Jingxing Wang,Jun Zheng,Shanying Sui,Qiang Li,Yi Zhang
Polyacrylamide has promising applications in a wide variety of fields. However, conventional polyacrylamide is prone to hydrolysis and thermal degradation under high temperature conditions, resulting in a decrease in solution viscosity with increasing temperature, which limits its practical effect. Herein, combining molecular dynamics and practical experiments, we explored a facile and fast mixing strategy to enhance the thermal stability of polyacrylamide by adding common poloxamers to form the interpenetrating network hydrogel. The blending model of three synthetic polyacrylamides (cationic, anionic, and nonionic) and poloxamers was first established, and then the interaction process between them was simulated by all-atom molecular dynamics. In the results, it was found that the hydrogen bonding between the amide groups on all polymers and the oxygen-containing groups (ether and hydroxyl groups) on poloxamers is very strong, which may be the key to improve the high temperature resistance of the hydrogel. Subsequent rheological tests also showed that poloxamers can indeed significantly improve the stability and viscosity of nonionic polyacrylamide containing only amide groups at high temperatures and can maintain a high viscosity of 3550 mPa·S at 80 °C. Transmission electron microscopy further showed that the nonionic polyacrylamide/poloxamer mixture further formed an interpenetrating network structure. In addition, the Fourier transform infrared test also proved the existence of strong hydrogen bonding between the two polymers. This work provides a useful idea for improving the properties of polyacrylamide, especially for the design of high temperature materials for physical blending.
研究领域:
材料科学
·
分子动力学
·
高分子化学
✓ 已验证
DOI
高影响因子
Processes
·
2022
·Vol. 10
·期 6
·1165
·
IF 3.352
Erdong Yao,Bojun Li
This paper presents a low-cost, high-temperature-resistant and high-strength polyacrylamide gel system formed by secondary cross-linking. The gel system (named JM186) used phenolic resin and organic zirconium as cross-linking agents, and the performance of the gel system was systematically evaluated under high temperature. The gel properties studied include: gel formation time, gel strength, thermal stability, sand-filled pipe sealing efficiency, and its microstructure. The concentration of polyacrylamide in JM186 gel system was as low as 0.3%, which can control the gelling time in a range of 1–9 h by adjusting the ratio of two cross-linking agents. It can resist temperature up to 120 °C without dehydration, and its highest gel strength can reach H grade. The modulus of elasticity (G’) and viscosity (G”) can reach 32.33 Pa and 3.25 Pa, respectively. DSC (differential scanning calorimetry) test indicated that the temperature of structural failure for this composite gel is 310.5 °C. The average sealing efficiency of the gel is 96.03% in sand-filled pipes. Finally, the gel microstructure was observed by cryo-scanning electron microscopy (Cryo-SEM). It was found that the gel system by secondary cross-linking has a dense and thickened network structure compared with the single cross-linker gel system. The gel is cross-linked by both the coordination bond and covalent bond, and the two cross-linking agents have a synergistic effect. This is the reason why the secondary cross-link gel system is better than the single-cross-linker gel system.
研究领域:
材料科学
·
石油工程
·
化学工程
✓ 已验证
DOI
高影响因子
Food Bioengineering
·
2024
·Vol. 3
·期 3
·323-336
·
IF 0
Simin Feng,Yitong Tian,Jialu Sheng,Jiahao Yu,Yang Lin,Kseniya Hileuskaya,Aliaksandr Kraskouski,Huiliang Li,Zhihong Lin,Ping Shao
In this research, nanostructured lipid carriers (NLCs) loaded with limonene were developed using various solid lipids. The impact of high temperatures on the characteristics of NLCs was investigated. NLCs exhibited zeta potential values exceeding |30| mV, indicating excellent homogeneity and stability. Increasing the carbon chain length of monoglycerides from C15 to C21 resulted in a corresponding increase in particle size of NLCs from 219.1 ± 1.1 to 243.3 ± 0.9 nm. However, the particle size remained relatively constant with an increase in the number of solid lipid carbon chains. Encapsulation efficiency of limonene increased from 66.0 ± 0.7% to 86.2 ± 0.8% with an increase in the number of solid lipid carbon chains. The result showed that more ester bonds facilitated the dissolution of the target and enhanced the interaction forces between solid lipids and the target. X-ray diffraction, Fourier transform-infra-red spectroscopy and differential scanning calorimetry analyses confirmed effective encapsulation of limonene in NLCs, resulting in good stability. NLCs prepared from various solid lipids exhibited varying properties. Glycerol triglyceride demonstrated superior stability and homogeneity of nanoparticles under high-temperature conditions compared to other solid lipids. This study provides enhancing the thermal stability of limonene-loaded NLCs and proposes a novel approach for their practical application.
研究领域:
药剂学
·
材料科学
·
食品化学
✓ 已验证
DOI
危险品化学品经营许可证（带存储）