JOURNAL OF THE AMERICAN CERAMIC SOCIETY
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2021
·Vol. 104
·期 9
·4782-4787
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IF 3.784
Lilian Yang,Youling Hou,Guishang Pei,Yuntao Xin,Xuewei Lv
Sodium-ion batteries (NaIBs) have attracted extraordinary attentions as a promising scalable energy storage alternative to current lithium-ion batteries (LIBs), owing to their natural abundance and low costs. Sodium trititanate (Na 2 Ti 3 O 7 ) is a promising material as the material of NaIBs with low potential and high theoretical capacitance. In order to better understand their service performance when utilized in rechargeable NaIBs, studies on thermodynamic properties of Na 2 Ti 3 O 7 are indispensable. However, an extensive literature review revealed that the heat capacity of Na 2 Ti 3 O 7 is established with divergences, especially for high-temperature region. Therefore, the 99.5% purity of Na 2 Ti 3 O 7 powder was first Synthesized through solid-state reaction with sodium carbonate (Na 2 CO 3 ) and titanium dioxide (TiO 2 ) as raw materials. The as-prepared samples were used to measure the heat capacity from 573 to 1323 K which was carried out with multihigh temperature calorimeter (MHTC) 96 line. The temperature dependence of heat capacity was modeled as a function: Cp =255.51073 + 0.06059 T − 3.86912 × 106 T −2 (J mol −1 K −1 ) (298.15 - 1403 K), and then used for computing changes in enthalpy, entropy, and Gibbs free energy. Heat capacity of Na 2 Ti 3 O 7 from 0 to 1403 K was given for future application of Na 2 Ti 3 O 7 in rechargeable batteries.
研究领域:
材料科学
·
热力学
✓ 已验证
产品关联
DOI
高影响因子
Open Ceramics
·
2021
·
IF 0
Milad Kermani,Danyang Zhu,Jiang Li,Jinghua Wu,Yong Lin,Zhiquan Dai,Chunfeng Hu,Salvatore Grasso
Pressure-less consolidation of transparent alumina requires several hours dwelling at high temperature (1600 °C) under a strongly reducing atmosphere (hydrogen). Here, we report on the ultrafast consolidation of translucent alumina ceramics at 1360 °C. Transparency was promoted by synergistic effects of high initial green density (62.7%) and rapid sintering using Ultra-fast High-temperature Sintering (UHS) technique. The proposed approach, using a heating rate of 430 °C/min and dwelling time of 15 min, resulted in ultra-fine-grained translucent alumina ceramics with a grain size of 0.39 μm, and an in-line transmittance of 28.7% at a wavelength of 700 nm. For comparison, conventionally fired counterparts were opaque due to their incomplete densification and pore coalescence.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
DOI
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2022
·
IF 6.364
Qiang Gao,Cheng Han,Xiaozhou Wang,Yingde Wang
Polymeric precursors with refractory metal in the main chain while still possess meltable/soluble characteristics are highly desired for ultra-high temperature ceramics (UHTCs). Herein, we proposed a stepwise synthesis of polyzirconosilane (PZCS) with Zr-C-Si-N polymeric chain. The reaction mechanism was discussed based on the frontier molecular orbital theory and atom transfer radical polymerization , which was initiated and propagated by a low oxidation state active specie of Cp 2 Zr(II). The PZCS precursor has excellent soluble and meltable properties with a softening point of 80.8 ~ 89.2 o C, which could be spun into green fibers by melt spinning technique. The ceramization process of PZCS was studied, and the resulted SiZrNC multinary ceramics were composed of ZrC/SiC nanocrystals embedded by graphitized carbon phase. The excellent mouldable properties, oxygen-free compositions and high Zr content of PZCS make it an ideal precursor for the preparation of UHTCs matrixes and fibers.
研究领域:
材料科学
·
化学
✓ 已验证
DOI
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
·
2023
·
IF 7.4
Hang Zhang,Miaomiao Hu,Pengpeng Li,Ming Liu,Yongjin Yu,Xiujian Xia,Huiting Liu,Jintang Guo
The organic/inorganic hybrid fluid loss additive PANI C S H was synthesized to adapt for high salinity cementing at ultrahigh temperatures (UHT, 200–240 °C). Unlike common physical blending, the PANI-C-SH was synthesized by grafting calcium silicate hydrate (C S H) from polycarboxylate copolymer PANI [P(AMPS-NNDMA-IA)] via “peptide coupling” and “sol–gel” reactions. When added into the UHT cement slurry, the hybrid PANI C S H exhibited more pronounced saturated saline cement slurry fluid loss control ability (31 mL at 240 °C) than that of PANI copolymer (68 mL). The three-dimensional spatial morphology of PANI C S H hybrid was able to plug and fill in the micro voids of the filter cake and resulted in effective refinements of the micro-pore structure, which compensated the deteriorated fluid loss control capacity caused by the weakened adsorption of copolymer PANI in saturated saline cement slurry.
研究领域:
材料科学
·
石油工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Na Zhang,Hang Zhao,Chuying Zhang,Haotong Guo,Zhi-Min Dang,Jinbo Bai
Polymer dielectrics are crucial for electrostatic energy storage and offer broad application prospects in advanced high-power electrical systems, but their energy storage performance declines considerably due to increased conductivity at elevated temperatures. This work presents a structurally-simple high-temperature composite dielectric by incorporating positively charged ultrafine UIO-66 nanoparticles into polyetherimide (PEI) matrix. Be distinguished from traditional sub-micron MOF structures that usually reported in very recently, the newly-found nanoscale effect endows the ultrafine UIO-66 (∼12.9 nm) with largely-increased active sites, surface charge density and electron affinity. These ultrafine UIO-66 nanoparticles can capture free charge through strong electrostatic interactions and introduce deeper traps in composite dielectrics, reducing conduction loss and improving energy storage property significantly at elevated temperatures. Specifically, filling only as tiny as 0.5 wt% ultrafine UIO-66 endows the PEI-based composite with ultra-high energy densities of 5.9J cm −3 and 3.7 J cm −3 accompanied by high charge–discharge efficiencies of 91.4 % and 84.1 % at 150 ℃ and 200 ℃, respectively. These obtained performance in this work surpasses those of most previously reported mono-layered composite counterparts. This study provides a straightforward and effective strategy for designing high-temperature polymer dielectrics in advanced electrical and electronic systems, offering a new route for future applications and developments.
研究领域:
材料科学
·
电气工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF LOSS PREVENTION IN THE PROCESS INDUSTRIES
·
2021
·
IF 3.66
Qiang Chen,Yuqing Ni,Jun Liang,Lei Ni,Juncheng Jiang,Yong Pan,Qingsheng Wang
Esterification reactions between anhydrides and alcohols catalyzed by sulfuric acid have broad applications in the food, cosmetic, and pharmaceutical industries. However, the exothermic behavior cannot be well explained, especially in semibatch reactors with different feeding procedures. In this study, a series of esterification processes in semibatch systems were conducted with a wide range of feeding rates with two different substrates. The structures of initial catalytic substrates were characterized using in situ Fourier Transform Infrared (FTIR) spectroscopy. A total of 11 reaction pathways, including those for the initial activation of substrates and the subsequent reactions of the feeding process, were calculated by the density functional theory (DFT) method. Three possible catalytic cycles of the esterification with specific acid catalysis, protonated intermediate, and protonated intermediate and H 2 O, were established for the semibatch esterification reaction based on calculated results and experimental evidence. Thermal safety parameters such as reaction enthalpy ( Δ H r ), adiabatic temperature rise ( Δ T r , a d ), and maximum temperature of the synthetic reaction (MTSR) were determined based on Wilson equation used to calibrate mixing heat. The results reveal that mixing heat was 2.5 kJ/mol with same mole ratio of n -butanol ( n B) and propionic anhydride (PA). The reactions started by PA are dominant, no matter whether the substrate is n B or PA. The initial reaction rate is restricted by the low concentration of catalyst and active reactant when n B is used as substrate, which lead to significant reactant accumulation with high MTSR of approximately 160 °C. Furthermore, feeding n B into PA allows a controllable increase in the Δ T r , a d realized by changing the feeding rate and limiting the accumulation of reactant.
研究领域:
化学工程
·
物理化学
·
过程安全
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）