导电剂形貌对富锂正极材料性能发挥的影响

研究了纳米颗粒状的Super P、气相生长的碳纤维(VGCF)、片状的KS6和石墨烯四种不同的导电剂对富锂正极材料Li_(1.2)Mn_(0.54)Ni_(0.13)Co_(0.13)O_2(LR-MNC)的电化学性能发挥的影响。研究结果表明,当导电剂的添加量为10%(质量分数),以Super或VGCF的导电剂在活性材料的表面形成了完整的导电通路,电极的表面电阻最小,从而有利于电子的传输,因此,正极活性物质表现出优异的倍率放电性能和循环性能。其中,以Super P为导电剂的电极性能最优,3 C放电比容量为164.4 mAh/g,1 C循环100周,容量保持率为82.3%。而以片状的KS6或石墨烯单独作为导电剂,在电极中没有形成完整的导电通路,不利于正极活性物质的大倍率放电性能的发挥。     

Photoluminescent properties of tunable green-emitting oxynitride (Ba3-xSrx)Si6O12N2:Eu2+phosphor and its application in white LEDs

Green emitting Eu2+-doped (Ba3?xSrx)Si6O12N2 solid solutions were synthesized through solid state reaction at 1350 oC for 10 h under a N2/H2 atmosphere. The XRD patterns revealed that the solid solutio...     

High temperature stability of Eu2＋-activated nitride red phosphors

The novel nitride-based luminescent materials have received much attention since the end of the last century. In this paper, the commercial Eu2＋-activated nitride red phosphors, Sr1.95Si5N8：Eu0.05, Sr1.85Si5N8：Eu0.15 and Ca0.99AlSiN3：Eu0.01 phosphors were an-nealed at different temperatures （beyond 300 oC） to investigate the dependence of their luminescence performance and structure vari-ability on the temperature. By photoluminescence spectra, X-ray diffraction （XRD） and thermogravimetry-differential scanning calo-rimetry （TG-DSC） analysis, the high temperature stability of the hosts and activator of the three samples were disclosed. With the an-nealing temperature increasing, the activator Eu2＋ions were firstly oxidized and then host in Sr1.95Si5N8：Eu0.05 and Sr1.85Si5N8：Eu0.15, but for Ca0.99AlSiN3：Eu0.01, only the oxidation of the host could be observed, which would lead to the luminescence degradation and even failure of these phosphors. The activator Eu2＋ions were much more stable in CaAlSiN3：Eu than Sr2Si5N8：Eu due to their crystal surroundings, and its concentration also influenced the temperature stability of Sr2Si5N8：Eu.     

Structure and permanent magnetic properties of SmFex （x=3-8） melt spun ribbons during heat treatment

Compounds with the composition SmFex（x=3–8） were prepared by melt spun method at a velocity of 40 m/s and subsequent annealing at temperature between 600–1000 ℃. The crystal structures of the as-quenched and as annealed powders were investigated by XRD methods with following Rietveld analysis. The glass forming ability could be enhanced by the increase of Sm content to x≤5.Metastable Sm5Fe17-type structure existed when 3≤x≤5 and temperature was lower than 800 ℃. SmFe2-type structure could be stable up to 1000 ℃ when x〉3 and temperature was under 800 ℃. The content of SmFe2-type decreased with the increase of x value and increased with temperature lower than 800 ℃, from which SmFe2-type started to bring the transition to SmFe3-type. As for Sm5Fe17-type compounds with x=3.4, the highest coercivity of 33.6 kOe could be obtained under a velocity of 30 m/s and heat treated under 700 ℃×1h.     

氢氧化物前驱体制备LiNi_(0.5)Co_(0.2)Mn_(0.3)O_2的机理

用共沉淀法制备前驱体Ni0.5Co0.2Mn0.3(OH)2,焙烧前驱体与Li2CO3制备Li Ni0.5Co0.2Mn0.3O2。用XRD、SEM和DSCTGA分析焙烧中间产物的结构、形貌及变化,探索制备Li Ni0.5Co0.2Mn0.3O2的机理。随着焙烧温度的升高,前驱体分解成(Ni0.5Co0.2Mn0.3)3O4,随后Li2CO3参与反应,形成Li Ni0.5Co0.2Mn0.3O2。Li Ni0.5Co0.2Mn0.3O2的生成在650℃时结束,但层状结构在900℃时才趋于完美。     

Thermodynamic Analysis of Burning Resistivity of Ti-Cr-V-Mo Alloys

ＴｈｅｒｍｏｄｙｎａｍｉｃＡｎａｌｙｓｉｓｏｆＢｕｒｎｉｎｇＲｅｓｉｓｔｉｖｉｔｙｏｆＴｉＣｒＶＭｏＡｌｏｙｓ①ＬｉｕＹｕｑｉｎ，ＺｈｕａｎｇＷｅｉｄｏｎｇ，ＢａｉＫｅｗｕ，ＳｈｅｎＪｉａｎｙｕｎ②ａｎｄＺｈａｎｇＺｈｕ（刘玉芹）（庄卫东）（白...     

YCl_3－AECl_2（AE＝Mg，Ca，Sr，Ba）二元相图的研究

用差热分析法测定了ＹＣｌ_３一ＳｒＣｌ_２体系二元相图，并用Ｘ时线衍射法验证了该二元体系中新相的生成。使用ＣＡＬＰＨＡＤ技术评估和优化了ＹＣｌ_３一ＡＥＣｌ_２（ＡＥ＝Ｍｇ，Ｃａ，Ｓｒ，Ｂａ）系列四个二元相图和热力学性质，取得了热力学性质和相图自相一致的结果。     

副产醋酸水溶液回收利用工艺研究进展

化工生产副产大量的醋酸水溶液,将其中的醋酸分离并回收利用,是涉及化工资源利用和环境保护的重要课题。醋酸水溶液分离方法包括精馏、萃取、吸附法、膜分离等物理方法和直接酯化、反应精馏等化学方法,在对已见报道的分离方法进行综述的基础上,提出利用烯烃水合反应脱水将醋酸提浓的新思路,并简要介绍初步研究结果。     

陶瓷金卤灯用封接材料膨胀系数的研究

为了制造性能良好的陶瓷金卤灯，保证陶瓷放电管和金属电极引线之间形成牢固的气密性封接是一个关键，和石英管不同，陶瓷管无法在加热软化后通过挤压与金属电极引线粘合在一起，为了完成放电管和电极的密封，必须采用合适的封接材料将它们封接起来，因此对陶瓷金卤灯的关键材料Al2O3-Dy2O3-SiO2系封接材料膨胀系数进行了研究。     

Luminescence Properties of Eu~(2 ) and Mn~(2 ) Co-Doped Ca_8Mg(SiO_4)_4Cl_2

The green phosphor for white LED, Ca8Mg(SiO4)4Cl2∶Eu2+, Mn2+, was synthesized by high temperature solid state reaction under reducing atmosphere. During the process of the phosphor prepared, the excess CaCl2 can improve the intensity of emission. The experimental results indicate that there is an effective energy transfer from Eu2+ to Mn2+in Ca8Mg(SiO4)4Cl2 host. This kind of energy transfer may be due to resonance transfer, and this energy transfer is limited.