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1.
LiNi0.8Co0.2O2是很有希望取代LiCoO2的新一代锤离子电池正极材料.采用控制结晶法合成球形 α-Ni0.8Co0.2(OH)2为前驱体,与 LiOH·H2O混合,在700℃通O2热处理4h合成锂离子电池正极材料LiNi0.8Co02O2粉末.X光衍射分析表明合成的LiNi0.8Co0.2O2粉末结晶良好,具有规整的α-NaFeO2层状结构.扫描电镜分析表明粉末颗粒呈球形,粒径约8μm.粉末的流动性好,堆积密度高.充放电测试表明,合成的 LiNi0.8Co0.2O2正极材料具有优良的电化学性能:首次充电比容量为197mAh·g-1,放电比容量为174mAh·g-1,10次充放电循环后保持初始放电比容量的96.6%.  相似文献   

2.
以Mn_3O_4为前驱体的LiMn_2O_4及其电化学性能   总被引:3,自引:0,他引:3  
对传统的固相反应进行了改进,以控制结晶法合成出来的Mn3O4为前驱体,和LiOH混合煅烧,制备出锂离子电池正极活性材料尖晶石LiMn2O4。对由此方法得到的尖晶石LiMn2O4的结构和电化学性能进行了研究.通过X光衍射和扫描电镜分析表明,该材料为纯相尖晶石LiMn2O4,不含其它杂质相,而且晶粒大小比较均匀;通过电化学性能测试表明,该尖晶石LiMn2O4具有良好的电化学性能:其首次放电比容量为128mAh/g,经过10次充放电循环后,其放电比容量仍有 124mAh/g.  相似文献   

3.
采用球磨湿混和旋转合成相结合的新工艺来制备锂离子电池正极材料LiMn2O4,并对制备的材料进行了粒度、化学成分以及电化学性能测试.制备的LiMn2O4为正尖晶石结构,而且物质纯净.同一批次制备的材料化学成分均匀,粉末粒度分布范围窄,中粒径为10.67μm,首次充电容量为124mAh/g,放电容量为115mAh/g.循环次数达30次时,放电容量还大于100mAh/g,循环稳定性良好.球磨湿混工艺能将原料混合均匀,并能有效地使原料粒度细化而且粒度均匀.旋转合成工艺能使反应物和反应产物的温度均匀、粒度均匀、晶型结构与成分均匀.球磨湿混和旋转合成相结合的固相合成新工艺能制备出电化学性能性能良好的LiMn2O4  相似文献   

4.
锂离子电池正极材料LiV3O8的低温合成研究   总被引:5,自引:0,他引:5  
以LiNO和NHVO为原料,通过溶胶-凝胶法制备了层状锂钒氧化物LiV锂离子电池正极材料,通过TG-DTG、XRD等考察了合成条件对产物首次放电比容量的影响.实验结果表明,在450℃左右热分解20h可得到单一相产物LiV,其层状结构较为完整,电化学性能好,首次放电比容量可达350mAh·g-1,作为高能锂离子电池正极材料较为理想.  相似文献   

5.
彭正顺  马洁 《功能材料》1999,30(4):379-381
溶胶-凝胶-酯化方法是通过金属离子与多元有机酯的均一的螯合物。在较低的温度(〈250℃)下形成尖晶石型LiMN2O4正极材料。雇轩的LiMn2O4具有很好的电化学活性。Li=LiMn2O4二次电池首次充放电容量超过130mAh/g,循环10次以后容量仍然保持在120mAh/g的较高水平。  相似文献   

6.
纳米级LiMn2O4尖晶石合成及电化学性能研究   总被引:13,自引:0,他引:13  
以Li2CO3和Mn(NO3)2为原料,以聚丙烯酰胺为高分子网络剂制得前驱体后,用微波加热技术敢纳米晶尖晶石LiMn2O4粉体后,通过循环伏安及充放电技术对其进行电化学性能测试表明,该材料的电化学比容量为120mAh/g,循环50次后衰减率为4.7%;通过SEM及XRD分析蓁同观形貌表明,材料不仅相纯度高,粒度返于纳米级,有利于Li^+的嵌入/脱嵌,本文所的微波-高分子网络技术不仅惧有优良性能的锂  相似文献   

7.
纳米级LiMn2O4尖晶石合成及电化学性能研究   总被引:4,自引:0,他引:4  
以LiCO和Mn(NO为原料,以聚丙烯酰胺为高分子网络剂制得前驱体后,用微波加热技术合成了纳米晶尖晶石LiMn粉体,通过循环伏安及充放电技术对其进行电化学性能测试表明,该材料的电化学比容量为 120mAh/g;循环 50次后衰减率为 4.7%;通过 SEM及XRD分析其微观形貌表明,该材料不仅相纯度高,而且颗粒粒度近于纳米级,有利于Li的嵌入/脱嵌.本文所提供的微波一高分子网络技术不仅为合成具有优良性能的锂锰尖晶石氧化物材料提供了一个新方法,而且为合成其他类型高性能氧化物陶瓷材料提供了一条新思路.  相似文献   

8.
阐述了新型嵌锂材料锌锑合金的嵌锂特性及其嵌锂机理。将Zn4 Sb3 球磨后得到ZnSb 与ZnO复合相。用此复合相单独作电极得到272m Ah/g 的容量,加入铜粉后可得到462m Ah/g 的容量,可逆性提高。加入Li2O不能提高可逆性。  相似文献   

9.
新型低压WO3基压敏电阻掺杂及制备条件研究   总被引:10,自引:0,他引:10  
扎卡利亚  王豫 《功能材料》1999,30(3):299-301
研究了Co2O3掺杂剂工艺及条件等对低压WO3基压敏电阻性能的影响,在保持MnO2及Na2CO3含量不变的前提下,我们发现,对于WO3-MnO2-Na2CO3系列,掺入Al2O3可以明显改善其电化学稳定,但同时也失去了非线性,而Co2O3的掺入可以明显提高非线性,以1%(摩尔分数)的Co2O3含量为最好,其α值约为5.5(从U1mA到U0.mA)击穿场强小于10V/mm。最高烧结温度应不低于110  相似文献   

10.
锂掺杂MoO3薄膜的制备及电色性能的研究   总被引:3,自引:0,他引:3  
采用过氧化氢溶胶-凝胶法成功地在室温下制备了纯的MoO3和锂掺杂的MoO3薄膜,通过TG-DTA热分析、FTIR红外光谱分析、循环伏安和光学特性的测试,研究了薄膜成膜过程中的结构墨迹过程和薄膜的电化学性能及电变色性能,结果表明通过Li^+掺杂,MoO3溶胶的稳定性和MoO3薄膜的电化学循环稳定性都有了较大的提高,且掺杂锂的MoO3薄膜仍具有良好的变色性能。  相似文献   

11.
A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.  相似文献   

12.
Permeable crystalline materialcan permeate into pores and cracks of concrete and catalyze the reaction between Ca(OH) 2and unhydrated cement to generate a great quantity needle non-soluble crystals, which can stop up the pores and cracks of concrete, and increase the impermeability of concrete. This paper reported the results of a study conducted to evaluate steel reinforcement corrosion of concrete specimens uncoated and coated with permeable crystalline material as well as mixed with the permeable crystalline material. The properties evaluated for corrosion test were water impermeability, water absorption, compressive strength and potential. The results of water impermeability, water absorption, compressive strength clearly showed that the permeable crystalline material could prohibit water, any soluble salts and moisture from penetrating the concrete to cause corrosion, leaking, and other problems, and it did increase the compressive strength, which was favorable for protection of corrosion of reinforcing steel. Moreover, it was concluded from the potential-time curve that the steel reinforcement of uncoated specimen was in the state of activation whereas that of other specimens coated and mixed with the permeable crystalline material was in the state of inactivation. Above all, it was indicated that the permeable crystalline materialis very effective to protect the steel reinforcement of concrete from corrosion.  相似文献   

13.
In this paper, the principle of spurting take off lacquer were introduced; and with orthogonal method the unsaturate polyester was prepared ;it was easy to peel airplane paint layer off with this material and equipment.  相似文献   

14.
Quality Study of Honeycomb Core Shaping Without Wax Stabilization   总被引:1,自引:0,他引:1  
Sandwich panels utilizing honeycomb cores result in lightweight, high-strength units that are very rigid. Indeed, they give honeycomb panels the best strength-to-weight ratio of any construction type available. Conventionally, the wax is poured into the cell of the core to strengthen the structure and prevent the core from being crushed during milling. Much time and labor is required to wax, mill, and clean the cores. In this study, the process of pouring wax into the core was skipped. In other words, the cutter directly milled the core. Experiments showed that the compressive strength of the core produced without wax stabilization was only 3% lower than that of cores produced using the traditional method. In addition, the drum peel strengths of cores produced without wax stabilization were 38.4% higher than cores produced using the traditional method, in which residual wax seriously polluted the adhesive. It was also found that eliminating the wax process can reduce costs.  相似文献   

15.
The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……  相似文献   

16.
Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.  相似文献   

17.
We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.  相似文献   

18.
Polylactic acid (PLA) is one of the most widely used open source fused filament fabrication materials due to its ease of extrusion, biodegradability, and mechanical strength. The mechanical strength of PLA largely depends on the proper growth of its semi-crystalline structure, which can be severely impaired by a low rate of crystallization, particularly in open source printers. This can be further aggravated by the non-uniform thermal distribution of heat that causes improper curing among the extruded beads of the printing material. As a result, PLA printed on open source printers does not achieve the best mechanical properties. This research, for the first time, proposes an additive-free solution implemented through a detailed set of experimentation to improve the curing rate through in-process temperature variations to cure the joints among the beads. Scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy is used to confirm the improvements in the bead joints. This work is conducted in two phases of experiments. In the first phase, a full factorial ANOVA is used to investigate various process parameters and the important variables are used in the second phase to print test specimens in four different sets.  相似文献   

19.
Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.  相似文献   

20.
ABSTRACT

The production of iron in Biscay (Basque Country, Spain) has been a hallmark of this territory of the North of the Iberian Peninsula throughout its history. The Archaeology team of the Basque Country Mining Museum has spent 13 years, so far, studying the origins of this activity through the evidences left at the old pre-hydraulic iron production workshops known as mountainside ironworks (ferrerías de monte) or haizeolak. It has catalogued 170 archaeometallurgical sites of this type in Biscay, and the archeological excavation of some of them has led to the knowledge of the different stages of the production process that took place in these workshops. The team has also experimentally reproduced the work carried out in a mountainside ironworks from the High Middle Ages, and it has currently started the characterization process of this type of activity through the study of the collected materials.  相似文献   

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