共查询到18条相似文献,搜索用时 67 毫秒
1.
2.
低热固相反应法制备纳米LiCoO2的研究(Ⅰ) 总被引:2,自引:0,他引:2
LiCoO2是目前商品锂离子电池的正极材料.虽然其价格昂贵,但与LiNiO2或LiMn2O4等相比,LiCoO2较易合成且生产工艺较成熟,因此其性能改进仍受到普遍关注.目前LiCoO2的合成方法主要是高温固相法[1~4],一般在700~900℃范围内烧结得到HT-LiCoO2;此外还可用低热法得到LT-LiCoO2[5~7];或通过CoOOH/LiOH·H2O/H2O混合物经H+/Li+离子交换得到LiCoO2[8]. 相似文献
3.
以草酸、硝酸铁、硝酸钴为原料, 加入不同聚合度的PEG, 采用低热固相反应法制备出草酸铁和草酸钴的混合前驱物. 在不同的温度(25, 60, 70, 75 ℃), 混合前驱物分别恒温反应2 h, 然后经450 ℃灼烧. 对获得的粉体用XRD, SEM, 激光粒度仪表征后证明: 加入PEG400在75 ℃反应获得了长径比约为6~15范围, 具有立方晶系尖晶石结构的棒状CoFe2O4铁氧体粉末. 经测试电磁学性质发现, 与粒状的CoFe2O4相比, 棒状的CoFe2O4磁导率虚部在高频15~20 GHz范围增加了近1倍, 各向异性常数Ku则增加了近5倍. 预示一维棒状结构的CoFe2O4作为吸波材料具有良好应用前景. 相似文献
4.
5.
6.
7.
The cold-melting mechanism and the cold-dissolving-melting mechanism were further studied by TG/DTA and in situ micro-photographs techniques with the mixture of dimethylglyoxime and Ni(Ac)2·4H2O, and the mixture of dimethylglyoxime and anhydrous Ni(Ac)2 as the modeled reactive examples. The endothermic peaks on the DTA curves at about 38 ℃ revealed the formation process of the cold-melting layer and cold-dissolving-melting layer on the surface of reactant particles. Further, the cold-melting state and the cold-dissolving-melting state were observed by the micrographs. These results provided the direct evidences for the theories of cold-melting mechanism and the cold-dissolving-melting mechanism. 相似文献
8.
室温和低热固相反应在合成化学中的应用 总被引:16,自引:0,他引:16
介绍了室温和低热固相反应的监测手段和影响因素。总结了它在金属原子簇化合物、多酸、简单配位化合物、亚稳态化合物合成以及材料化学和生产实际中的应用。 相似文献
9.
室温固相反应制备Keggin结构杂多酸铵盐纳米粒子 总被引:19,自引:1,他引:18
纳米材料由于其量子尺寸效应及表面效应而在磁、光、电等方面显示出许多常规粒子所不具有的特性[1] .纳米材料成功应用的实例及潜在应用前景推动了各种纳米粉末的合成及合成方法的发展 [2~ 4 ] .利用低温固相反应制备纳米粒子尚不多见 ,但已有报道 [5,6] .多金属氧酸盐因其独特的结构而具有较高的催化活性、导电性、磁性、光电致变色性以及抗病毒活性 ,因而有着广阔的应用前景 ,这些方面的研究已越来越引起人们的兴趣 [7~ 10 ] .本文采用室温固相反应首次制备了多金属氧酸盐纳米粒子 (NH4 ) 3PMo12 O4 0 · 9H2 O(1 )和 (NH4 ) 3PW12… 相似文献
10.
室温和低热温度固-固相反应合成化学 总被引:23,自引:0,他引:23
概要地综述了室温和低热温度固相反应在配合物合成中的应用,包括新的原子簇化合物、多酸化合物,以及简单配合物、混配化合物、长链配合物、固配化合物、中间化合物等的合成。 相似文献
11.
12.
13.
14.
The layered nanocrystalline sodium manganese phosphate was synthesized by low‐heating solid state reaction using MnSO4·H2O and Na3PO4·12H2O as raw materials. The resulting sodium manganese phosphate and its calcined products were characterized using element analysis, thermogravimetry and differential thermal analyses (TG/DTA), Fourier transform IR (FT‐IR), X‐ray powder diffraction (XRD), scanning electron microscopy (SEM), ultraviolet‐visible (UV‐Vis) absorption spectroscopy, and magnetic susceptibility. The results showed that the product obtained at 70°C for 3 h, NaMnPO4·3H2O, was a layered compound, and its crystallite size and interlayer distance were 27 nm and 1.124 nm, respectively. The thermal process of NaMnPO4·3H2O between room temperature and 700°C experienced three steps, the dehydration of the one adsorption water at first, and then dehydration of the two crystal waters, at last crystallization of NaMnPO4. Magnetic susceptibility measurements of NaMnPO4· 3H2O from room temperature to 2.5 K point to ferrimagnetic ordering at TN‐35 K. 相似文献
15.
The crystal structure of a solid electrolyte, beta-Al2O3, was investigated by XRD analysis and demonstrated by Diamond software. Its chemical formula was verified by the Ag ion molten salt exchange method and X-ray fluorescence analysis(XRF). The chemical formula of β-Al2O3 is Na2O·8.52Al2O3, and its crystal is of hexagonal, space group P63/mmc, with a = 5.5941 and c = 22.5300 . The chemical formula of β'-Al2 O is Na2O·6.03Al2O3, and its crystal is of trigonal, space group R 3 m, with a = 5.6017 and c = 33.6219 . The maximum span in the sodion migration of β'-phase(2.4283 ) is only about a third of that for the β'-phase(6.9037 ), so the β'-phase has higher ionic conductivity than the β-phase. 相似文献
16.
Ammonium cerium phosphate was prepared with (NH4)3PO4·3H2O and Ce(SO4)2·4H2O as raw materials and PEG‐400 as surfactant via a solid state reaction at low‐heating temperature. The characterization result of XRD indicates that the molecular formula of the product was (NH4)2Ce(PO4)2·H2O. The synthesis of benzyl acetate was carried out with H2SO4/ammonium cerium phosphate as catalyst, and uniform experimental design as well as data mining technology was applied to the experiments, in which the effect of the reaction time, the molar ratio of acid to alcohol and the amount of catalyst on the conversion yield of acetic acid were studied. When benzalcohol was 0.10 mol, under the optimal reaction conditions, i.e. reaction time of 174 min, 2.02 of molar ratio of acid to alcohol and 0.5 g of catalyst, the esterification rate of acetic acid was 97.9%. The ammonium cerium phosphate had potential for industry application since it not only was feasible and simple in synthesis technics, but also had good catalysis activity for the synthesis of benzyl acetate. 相似文献
17.
18.
三核钼-硫簇合物的低热固相合成及其晶体结构 总被引:1,自引:0,他引:1
三核钼-硫配合物Mo_3S_7(dtc)_3I·S_8·2CH_2Cl_2(dtc=C_4H_8NCS_2~-)是由低热固相合成得到的。晶体属单斜晶系,M_r=1500.19,空间群P2_1/n,a=11.881(3),b=15.559(4),c=26.197(7),β=98.53(2)°,V=4789A~3,Z=4,D_c=2.08g/cm~3,F(000)=2920,μ(MoKα)=25.24cm~(-1),对于2397个I≥3σ(I)的独立衍射点,最终偏离因子R=0.060,R=0.066。该配合物的基本骨架是[Mo_3S_7(dtc)_3]~+,其簇芯为[Mo_3S_7]~(4+)单元,3中Mo原子组成正三角形平面,Mo-Mo的平均键长力2.723,Mo原子平面上的硫原子形成盖帽的μ_3-S,其Mo-S平均键长为2.383A,3个S_2基团分别位于三角形3个棱的外侧,并分别与邻近的两个Mo原子结合形成12中Mo-S键。与μ_3-S相对而位于平面另一侧的Ⅰ原子与3个μ_2-S连结,平均距离为3.257A,成键作用较弱。 相似文献