Al2O3包覆LiNi0.03Co0.05Mn1.92O4正极材料的制备及其电化学性能

以Al(NO3)3?9H2O为包覆原料，通过燃烧法制备得到LiNi0.03Co0.05Mn1.92O4@Al2O3正极材料。通过X射线衍射(XRD)，场发射扫描电子显微镜(FESEM)和透射电镜(TEM)等表征手段对材料的结构和形貌进行分析，并通过恒电流充放电、循环伏安(CV)、交流阻抗(EIS)等测试分析材料的电化学性能。结果表明，Al2O3包覆没有改变LiNi0.03Co0.05Mn1.92O4的尖晶石型结构，包覆层厚度约10.6nm。LiNi0.03Co0.05Mn1.92O4@Al2O3正极材料电化学性能得到了明显改善，1 C和10 C倍率下初始放电比容量分别为119.9 mAh?g-1和106.3 mAh?g-1，充放电循环500次后容量保持率分别为88.4%和78.2%，而未包覆的LiNi0.03Co0.05Mn1.92O4在1 C和10 C倍率下初始放电比容量分别为121.2 mAh?g-1和104.0 mAh?g-1，500次循环后容量保持率分别为84.1%和67.6%。LiNi0.03Co0.05Mn1.92O4@Al2O3活化能为32.92 kJ?mol-1，而未包覆材料的活化能为36.24 kJ?mol-1，包覆有效降低了材料Li+扩散所需克服的能垒，提高了材料的电化学性能。     

掺杂Pr3+的尖晶石LiPrxMn2-xO4的合成及电化学性能

采用溶胶凝胶法合成掺杂稀土镨离子的锂锰尖晶石LiPrxMn2-xO4,并对其结构和电化学性能进行初步研究.结果表明,当掺入的Pr3+含量较低(x≤0.02)时,得到的产物能保持完整的尖晶石结构,并表现出极佳的电化学性能.Pr3+的掺入使材料的循环稳定性能大幅度提高,而这种提高是源于Pr3+对尖晶石结构的稳定作用.电极材料LiPr0.02Mn1.98O4显示了最优的电化学性能,在0.2 C放电速率下,其初始放电容量为118 mAh·g-1,100次循环后仍能保持初始容量的98%.     

Li[Li0.2Ni0.15Mn0.55Co0.1-xCrx]O2-yCly富锂正极材料的合成及电化学性能研究

采用溶胶-凝胶法合成富锂正极材料,900℃煅烧12 h得到产物Li[Li0.2Ni0.15Mn0.55Co0.1-xCrx]O2-yCly。X射线衍射光谱(XRD)测试表明,材料均具有层状α-NaFeO2结构;扫描电镜(SEM)观察材料颗粒均匀,粒径达到纳米范围;充放电测试显示,Cl-、Cr3+共掺材料在2~4.8 V电压范围及0.1 C倍率下,20℃时,首次放电比容量达到239.8 mAh·g-1,首次库伦效率为81.2%;55℃时,首次放电比容量和首次库伦效率分别为308.3 mAh·g-1和92.7%。并且40个循环之后在1 C倍率下,材料在20和55℃时放电比容量仍分别达到173.5和207.7 mAh·g-1。     

锂离子电池富锂材料Li[Li0.2Ni0.2Mn0.6]O2的制备及掺杂改性

以乙酸盐为原料,采用喷雾干燥法制备层状α-NaFeO2结构的富锂正极材料Li[Li0.2Ni0.2Mn0.6]O2及掺杂Cr的Li[Li0.2Ni0.15Cr0.1Mn0.55]O2。采用X射线衍射、扫描电镜、半电池充放电和电化学阻抗谱等方法研究材料的物相、结构、形貌及电化学性能。结果表明:Cr掺杂使材料的颗粒变粗,但不改变材料的结构,而使材料的层状特征更为明显;Cr掺杂后材料的电化学性能得到明显改善,电荷转移阻抗Rct从275.0降低到105.0,循环稳定性和倍率性能均有所改善,Li[Li0.2Ni0.15Cr0.1Mn0.55]O2材料1C倍率下的放电比容量为140.0 mA.h/g,循环50次后放电比容量为133.7 mA.h/g,远高于未掺杂Cr材料的比容量,未掺杂Cr材料在1C倍率下放电比容量为107.1mA.h/g,循环50次后放电比容量为102.1 mA.h/g。     

Li1.05Ni0.05Mn1.9O4正极材料脱锂过程中的结构变化

与未掺杂的尖晶石LiMn2O4进行比较,用固相混合合成法制得的结晶良好的尖晶石Li1.05Ni0.05Mn19O4正极材料在室温和55℃下的循环性能都能得到较大改善,首次放电容量在室温和55℃分别保持理论容量的92.6%和91.5%.在常温条件下,以0.5 C充放电倍率循环50次,容量保持为首次放电容量的95.3%.采用非原位X射线衍射的方法对不同脱锂状态的Lix[Li005Ni005Mn19]O4(0.1＜x＜1)试样进行了结构分析.结果表明:Li、Ni的协同掺杂明显减小了晶格参数的变化,稳定了试样的结构及改善了电池循环性能.     

锰掺杂对锂离子电池正极材料Li3V2（PO4）3/C性能的影响（英文）

采用溶胶-凝胶法合成Li3V2-2/3xMnx(PO4)3(0≤x≤0.12)。采用XRD、SEM、XPS、恒流充放电和电化学阻抗谱(EIS)研究Mn掺杂对Li3V2(PO4)3/C结构和电化学性能的影响。XRD研究表明:掺杂少量的Mn2+不会影响材料的结构,所有样品均具有单一相态的单斜结构(P21/n空间群)。XPS分析表明:在Li3V1.94Mn0.09(PO4)3/C中,V和Mn的化合价分别为+3和+2,原料中的柠檬酸在煅烧过程中分解成C而残留在Li3V1.94Mn0.09(PO4)3/C中。电化学测试表明:掺杂Mn改善了电极材料的循环性能和倍率性能,正极材料Li3V1.94Mn0.09(PO4)3/C表现出最好的循环稳定性和倍率性能。在40mA/g的放电电流密度下,循环100次后,Li3V1.94Mn0.09(PO4)3/C的放电容量从158.8mA·h/g衰减到120.5mA·h/g,容量保持率为75.9%,而未掺杂样品的放电容量从164.2mA·h/g衰减到72.6mA·h/g,容量保持率为44.2%。当放电电流密度增加到1C时,Li3V1.94Mn0.09(PO4)3/C的初始放电容量仍能达到146.4mA·h/g,循环100次后,放电容量保持为107.5mA·h/g。EIS测试表明,掺杂适量的Mn2+减小了电荷转移阻抗,这有利于Li+的脱嵌。     

锂离子电池纳米Co3O4-PTFE复合负极材料的循环性能

采用在加温的水溶液中电沉积然后烧结方法制备锂离子电池的纳米Co3O4-PTFE复合负极材料.XRD分析表明,电沉积的物质在245℃真空热处理后转变为Co3O4-PTFE.SEM观察可以发现,Co3O4-PTFE中的Co3O4呈现蜂窝结构,其厚度为30～50nm;PTFE则形成交联的柱状体吸附在片状Co3O4两侧,其直径为50～100nm.这种纳米Co3O4-PTFE复合沉积层具有结构稳定、抗粉化的特点.充放电实验结果表明,Co3O4掺杂PTFE可明显提高负极材料的可逆比容量和循环性能,其首次放锂比容量为920.1mAh·g-1,20次循环后放锂比容量为685.6mAh·g-1;而没有掺杂PTFE的试样对应的数据分别为865.1mAh·g-1和180.4mAh·g-1.     

Ni2+替代对LiFePO4正极材料电化学性能的影响

利用炭热还原法合成了橄榄石型LiFe1-xNixPO4/C (x=0.0,0.1,0.3,0.5) 正极材料,并系统研究了Ni2+替代对材料电化学性能的影响。充放电循环、循环伏安和交流阻抗测试,结果表明Ni2+替代部分Fe2+可以显著改善LiFePO4材料的电化学性能。在0.2 C (1 C=170.0 mA·g-1)电流密度下,LiFe0.9Ni0.1PO4/C的放电比容量达到160 mAh·g-1。LiFe1-xNixPO4/C电化学性能的改善归因于材料电导率的提高和电荷传输电阻的降低。利用第一性原理对LiFe1-xNixPO4/C的电子结构进行了研究,结果表明Ni2+的铁位替代能够提高体系的电子电导性。LiFe0.875Ni0.125PO4的结构最稳定,带隙最小,导电性能最好     

LiMgxNi0.5-xMn1.5O4的制备和电化学性能

为改善LiNi0.5Mn1.5O4的电化学性能,采用流变相法合成掺镁的锂离子电池正极材料LiMgxNi0.5-xMn1.5O4(x=0,0.05,0.1)。XRD测试结果表明所得材料仍为尖晶石结构。电化学性能测试结果显示:当x取值0.1,在3.5～4.9V电压范围内进行充放电循环时,材料LiMg0.1Ni0.4Mn1.5O4具有较好的循环性能,1C充放电时,初始放电比容量可达110.22mAh/g,30次循环后容量衰减率仅为7.7%。     

化学计量比对贮氢合金电极特性的影响

研究了化学计量比对AB4.8~AB5.2贮氢合金电化学性能的影响。结果表明:在本实验研究范围内,当x=0.1时,贮氢合金电极的0.2C,1C和5C放电容量、高倍率放电特性及3C循环寿命分别达到324mAh·g-1,301mAh·g-1,263mAh·g-1,0.81和530次。此外,化学计量比对贮氢合金的活化性能和温度特性均有较大的影响,当x分别为–0.2,–0.1,0.0,0.1和0.2时,贮氢合金电极在0.2C充放电的条件下活化次数分别为3次、4次、7次、5次和6次,且随着x的增大,贮氢电极的高温(45℃,1C)和常温(25℃,1C)放电效率下降,低温(–18℃,1C)放电效率则有增大的趋势。从合金活化性能、大电流充放电特性和循环稳定性来看,x=0.1时(AB5.1),能得到具有较佳的电化学性能的贮氢材料。     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

Effect of Short-Time Aging on the Pitting Corrosion Behavior of a Novel Lean Duplex Stainless Steel 2002

The effect of short-time aging in the temperature range between 400 and 1000 °C on the pitting corrosion behavior and mechanical property of a novel lean duplex stainless steel(LDSS) 2002 was investigated through the potentiostatic critical pitting temperature(CPT) tests and the Charpy impact tests. Both the pitting corrosion resistance and the toughness of aged specimens degraded due to the precipitation of detrimental secondary phases and the most significant reduction of CPT and impact energy emerged at 650 °C concurrently. The CPT of LDSS 2002 specimen aged at 650 °C decreased by 28 °C, and the impact energy dropped from 69 to 29 J/cm~2 compared with the solution-annealed sample. Transmission electron microscopy characterization showed that the main precipitates in LDSS 2002 were Cr_2N and M_(23)C_6 along the ferrite–austenite grain boundaries.     

INTRODUCTION TO PATENTS

The invention provides a method of making a mold which can reduce SOx generation rate while preventing decrease in hardening rate in the case of using sulfuric acid for a hardener composition. The method has a mixture step in which fire-resistant particles, a hardener composition and a binder composition are mixed to obtain a composition for a mold. The hardener composition contains sulfuric acid. In the mixture step, sodium carbonate is added. A molar ratio of the sulfuric acid to the sodium carbonate is 0.5 or more and 4.0 or less.     

China Foundry Week 2014

China Foundry Week, hosted by the Foundry Institution of Chinese Mechanical Engineering Society （FICMES） each year, is a large academic event in China. It is one of the ten high-impact activities sponsored by the Chinese Mechanical Engineering Society.     

17th Conference of Hydrodynamic and Electromechanical Control Engineering Call for papers

正1.Contents In order to promote the academic exchanges and technical communication of the research in the field of fluid power transmission and control,fluid control engineering specialized committee of the Chinese Society of Theoretical and Applied Mechanics will hold the 17th Conference of Hydrodynamic and Electromechanical Control Engineering on July 27-29,2014 in Tibet,Lhasa city.     

Information for Contributors

正The Transactions of Nonferrous Metals Society of China,founded in 1991 and sponsored by The Nonferrous Metals Society of China,is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology,including mineral processing,extraction metallurgy,metallic materials and heat treatments,metal working,physical metallurgy,powder metallurgy,with the emphasis     

Preface

<正>We are pleased to present this Special Issue of Transactions of Nonferrous Metals Society of China containing selected papers from the First Asian Conference on Aluminum Alloys(ACAA-2013),held in Beijing,China,13–17 October 2013.This conference has been initiated,with approval of     

Information for Contributors

The Transactions of Nonferrous Metals Society of China, founded in 1991 and sponsored by The Nonferrous Metals Society of China, is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology, including mineral processing, extraction metallurgy, metallic materials and heat treatments, metal working, physical metallurgy, powder metallurgy, with the emphasis on fundamental science. It is the unique preeminent publication in English for scientists, engineers, under/post-graduates on the field of nonferrous metals industry. This journal is covered by many famous abstract/index systems and databases such as SCI Expanded, Ei Compendex Plus, 1NSPEC, CA, METADEX, AJ and JICST.     

Formulas of Tension of Continuous Rolling Process

The development of computer controlled continuous rolling process calls for a mathematical expression that can express the inequality condition of "constant flow". Tension is the link of the continuous rolling process. From the condition of dynamic equilibrium, a differential equation of tension is given out. On the basis of the physical rules established from the industrial practice and experimental studies, the law of volume constancy, the linear relation of forward slip and tension, the state equation of continuous rolling, the formula of dynamic tension, and the formula of static tension have been obtained. These formulae reflect the functional relations between tensions, thickness, roll velocity, and time in the continuous rolling process. It is implied that the continuous rolling process is a gradually steady, controllable, and measurable dynamic system. An assumption of predicting the thickness of a steel plate using these tension formulae is also put forward.