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1.
锂离子电池正极材料Li1+xMn2O4的合成及其性能研究 总被引:11,自引:0,他引:11
采用醋酸锰和醋酸锂作为起始反应物,在水溶液中混合均匀,通过加热蒸发形成混合均一的反应前趋体并在不同温度下焙烧可获得最终产物。在850℃下,起始反应物锂锰摩尔比例采用1.1:2可获是电化学性能较好的活性材料,利用热重分析及红外光谱对反应历程进行分析并提出了可能的反应机理。对所合成的产物进行XRD、结构形貌及电化学性能进行了测试研究,表明其颗粒细小、分布均匀、结晶性能好、为蜂窝状结构、比表面积较大,初始容量较高和循环稳定性能良好,初始容量达128mAh/g。 相似文献
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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
3.
锂离子电池正极材料LiMn2O4制备新工艺 总被引:6,自引:0,他引:6
采用球磨湿混和旋转合成相结合的新工艺来制备锂离子的电池正极材料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10.67um,首次充电容量为124mAh/g,放电容量为115mAh/g,循环次数达30次时,放电容还大于100mAh/g,循环稳定性,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.
用高温固相法制备了BaFe2O4。采用扫描电子显微镜(SEM)及X射线衍射仪(XRD)对产物的表面形态和结构进行了表征;以循环伏安、模拟电池恒电流充放电实验研究了BaFe2O4电极的电化学性能。结果表明,以BaFe2O4为正极充电起始物质,与贮氢合金电极组成二次碱性电池,在1.2V附近有一个平稳的放电平台,具有较好的电化学活性。合成时反应物的比例对产物的结构和电化学性能有明显的影响,在900℃,灼烧10h的条件下,以反应物Fe2O3与Ba(OH)2摩尔比为1:1.5时获得的产物性能较好。 相似文献
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锂离子电池正极材料LiNi1-yCoyO2的研制 总被引:2,自引:2,他引:0
在高温增加氧气压力的条件下,通过固态反应合成了锂离子电池正极材料LiNi1-yCoyO2。讨论了合成条件对产物的电化学性能的影响,得到最佳的反应条件为:反应时间(8h;10h);氧气压力0.20MPa;反应温度800℃;反应物的摩尔比Li:Ni:Co为1.2:0.9:0.1。合成出具有晶型完整、电化学性能优良的LiNi0.9Co0.1O2产品,其放电容量达189.4mAh/g。实验结果表明,增加反应过程中氧气压力,对产物的结构及电化学性能有较大的影响。 相似文献
7.
以Li2CO3、FeC2O4·2H2O、MnCO3和NH4H2PO4为原料,按5:6:4:10的摩尔比混合,采用固相反应和水热法结合的新方法制备得到LiMn0.4Fe0.6PO4。通过XRD、SEM、TEM以及循环伏安(CV)和充放电测试对材料进行结构、形貌以及电化学性能表征。结果表明,此方法合成的产物具有单一的橄榄石晶体结构,颗粒尺寸约为120 nm,且表面均匀包覆一层无定形碳。电化学测试结果表明,样品的循环伏安曲线中有两对氧化还原峰,分别对应Fe3+/Fe2+(3.5 V)和Mn3+/Mn2+(4.0 V)。LiMn0.4Fe0.6PO4/C在0.1C下的初始放电比容量为160 mAh/g,0.5C下的初始放电比容量为143 mAh/g,且具有较好的循环性能。 相似文献
8.
微波碳热还原法合成锂离子电池正极材料Li_2FeSiO_4/C 总被引:3,自引:0,他引:3
以Li2CO3、FeOOH、纳米Si O2为原料,聚乙烯醇和超导碳为碳源,采用微波碳热合成法合成了Li2FeSi O4/C材料。通过XRD、SEM和恒流充放电测试,对样品结构、形貌和电化学性能进行了表征和分析。结果表明,微波合成法可以快速制备具有正交结构的Li2FeSi O4材料;在处理温度650℃、时间12min的条件下获得了高纯度、晶粒细小均匀的产物,并具有良好的电化学性能。以C/20倍率进行充放电测试,首次放电容量为127.5mAh/g,20次循环后容量仍有124mAh/g。 相似文献
9.
利用醋酸盐合成Li1.06Mn2O4及其电化学性能的研究 总被引:1,自引:0,他引:1
由醋酸锂和醋酸锰直接合成富锂尖晶石结构Li1.06Mn2O4,并由红外光谱及热重分析探讨其反应机理。最终产物具有良好的电化学性能及循环稳定性能。 相似文献
10.
采用固相法合成锂离子正极材料尖晶石相Li1.02CoxCryMn2-x-yO4,研究元素Co、Cr不同掺杂量对产物的结构、晶胞常数、电化学性能和电池内阻的影响.分析表明,掺杂少量的Co、Cr的LiMn2O4依然保持着尖晶石结构;晶胞常数随掺杂量的增加而减小,从而使尖晶石的比表面积增大,有利于提高电池的初始容量;并有效地抑制了充放电过程中的Jahn-Teller效应和Mn^3+的歧化反应.掺杂Co、Cr后Li1.02MnO4初始容量有所下降,且随掺杂量增加而减小,但能明显改善材料的循环性能. 相似文献
11.
《International journal for numerical methods in engineering》2018,113(9):1488-1506
In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method. 相似文献
12.
Standards are the basis for production enterprises to organize production ex-factory inspection trade 《中国标准化(英文版)》2008,25(1):24-25
Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.…… 相似文献
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A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa. 相似文献
15.
On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.…… 相似文献
16.
Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß. 相似文献
17.
C. Qihong W. Zhan‐Wen J. Yi J. Yehua L. Fei F. Hanguang 《Materialwissenschaft und Werkstofftechnik》2014,45(7):582-590
In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M2(B,C), (W,Mo)2(B,C), M3(B,C), M23(B,C)6 type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm2. The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K1 mill housing of bar mill. 相似文献
18.
《中国标准化(英文版)》2014,(4)
正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from 相似文献
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《中国标准化(英文版)》2014,(5)
正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively. 相似文献
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《中国标准化(英文版)》2014,(4)
正China and Greece Sign the Standardization Cooperation Agreement Witnessed by Chinese Premier Li Keqiang and Greek Prime Minister Antonis Samaras,AQSIQ Minister Zhi Shuping and ELOT Chairman and Executive Director Angelos Tolkas signed the SAC-ELOT Standardization Cooperation Agreement.The Agreement is one of the critical cooperation documents signed during Li Keqiang’s visit in Greece,encouraging China and Greece to 相似文献