Li-Sb-Mn复合氧化物在水溶液介质中的脱Li~+/吸Li~+性能(英文)

由固相法合成了不同Sb/Mn摩尔比的系列Li-Sb-Mn复合氧化物,利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)和原子吸收分光光度计(AAS)分别表征了其结构、形貌和锂离子脱出/吸附性能。XRD和SEM分析表明,Li-Sb-Mn复合氧化物随着Sb/Mn摩尔比从0.05提高到1.00,晶型由尖晶石型转变为正交相。Li+脱出/吸附实验表明,不同Sb/Mn配比的复合氧化物都可以作为锂无机吸附剂。其中,酸浸改型后的尖晶石锂锑锰复合氧化物(n(Sb)/n(Mn)=0.05)在含锂溶液中具有较高的锂离子吸附容量,达到33.23mg/g。Sb/Mn摩尔比是决定该复合氧化物的结构和脱Li+/吸Li+性能的主要因素。     

Sol-Gel合成LiMn2O4及其锂离子脱嵌／嵌入性能与结构的研究

采用溶胶-凝胶前驱体法合成了正尖晶石结构的LiMn2O4,研究了产物的结构、性能以及最佳的制备条件.结果表明,原料的配比和干胶的焙烧温度对产物的组成、结构以及颗粒形态有重要的影响.进一步的研究表明,LiMn2O4在1.0 mol·L-1HCl中酸浸120 h可得高纯度的λ-MnO2,λ-MnO2浸锂后得到Li+与LiMn2O4所形成的固溶体Li1.01Mn2O4,其锂离子脱嵌/嵌入在结构上是可逆的.固溶体Li1.01Mn2O4的形成可提高材料的锂离子筛分性能.     

MnO2·0.5H2O的固相法制备及其对Li+的吸附动力学

采用两步固相法制备锂离子筛MnO2.0.5H2O,采用X射线衍射仪和相关动力学模型研究MnO2.0.5H2O的结构及其吸附性能,探讨离子筛对盐湖卤水中各主要金属离子的分离特性及循环吸附性能。结果表明:溶液pH值的升高有利于离子筛对Li+的吸附,但在较强的碱性溶液中离子筛的溶损相应增加;吸附数据对伪二级动力学方程和Langmuir吸附等温方程拟合较好,相关系数分别达0.998和0.993以上;动边界模型中各控制步骤方程的线性拟合都不够理想;离子筛对Li+具有较好的选择性和较优的循环吸附性能。这表明:吸附过程为化学吸附过程,且为单层吸附;吸附过程是一个复杂过程,是多个控制步骤共同作用的结果。     

富锂尖晶石Li1+xMn2-xO4的合成与性能

将MnO2和Li2CO3通过固相反应法合成了化学计量比的LiMn2O4和富锂型Li1 xMn2-xO4(x=0.02,0.04,0.06,0.08,0.1).研究表明,所合成的样品均具有尖晶石结构,无杂相存在,样品的晶格常数随x值的增大而减小.用SEM分析了样品的表面形貌,发现掺锂可明显改善LiMn2O4一次颗粒表面的结构,抑制表面裂纹的产生.电化学性能测试表明,随着掺锂量的提高,电极的循环性能变好.通过研究发现,Li1.04Mn1.96O4具有较高的初始容量和良好的循环性能,因而,Li1.04Mn1.96O4是一种比较理想的锂离子电池正极材料.     

尖晶石锰酸锂卤水提锂热力学

针对高Mg和Li质量比盐湖卤水提锂难的问题,提出利用尖晶石LiMn2O4对盐湖卤水进行选择性提锂,并在热力学计算的基础上绘制了298.15 K时Me(Li,Na,K,Mg)-Mn-H2O体系的φ—pH图,讨论尖晶石LiMn2O4脱Li+后所形成的λ-MnO2对盐湖中Na+、K+、Mg2+与Li+的选择性提取问题。结果表明:当离子浓度为1 mmol/L,体系阴极极化电位降至0.79 V(vs SHE)时,λ-MnO2中Mn4+被还原为Mn3+,同时溶液中Li+由于"记忆效应"而嵌入λ-MnO2晶格生成LiMn2O4;而极化电位需降至0.61、0.55和0.48 V时,才分别有Mg0.5Mn2O4、KMn2O4和NaMn2O4生成,说明所选材料对Li+的选择性优于对Na+、K+和Mg2+的选择性。此外,根据西台吉乃尔盐湖卤水中主要组成阳离子浓度([Li]=30 mmol/L,[Na]=5 mol/L,[K]=0.2 mol/L,[Mg]=0.5 mol/L)绘制Me(Li,Na,K,Mg)-Mn-H2O系叠加φ—pH图。热力学研究表明:只需在卤水原始pH条件下将体系的阴极极化电位调至0.70 V<φ<0.87 V,λ-MnO2即可实现对Li+与大量Na+、Mg2+、K+的有效分离;将嵌Li+后的LiMn2O4通过调节电位极化至φ>0.87 V,可实现Li+的脱附和富集。     

室温固相反应法制备Ni0.66Mn2.34-xCoxO4(x=0.15,0.30,0.45,0.60)负温度系数热敏电阻

以Mn(CH3COO)2·4H2O,Ni(CH3COO)2·4H2O,Co(CH3COO)2·4H2O和H2C2O4·2H2O为原料,采用室温固相反应法制备出镍锰钴草酸盐前驱体,将该前驱体在850℃煅烧2 h得到尖晶石相Ni0 66Mn2.34xCoxO4(x=0.15,0.30,0.45,0.60)超细粉体.用XRD,TGA,SEM,沉降式粒度分析仪和热膨胀仪对镍锰钴草酸盐前驱体与Ni0.66Mn2.34-xCoxO4(x=0.15,0.30,0.45,0.60)超细粉体进行了表征.结果表明,由室温固相反应法得到的草酸盐前驱体是单相的镍锰钴复合草酸盐在850℃煅烧2 h得到镍锰钴氧化物为纯尖晶石相,粉体颗粒为球形,团聚较少,粒径均匀,平均粒径约为0.2μm,有较好的烧结活性,是制备热敏陶瓷材料的理想粉体.     

Li2MnO3的电化学活性及脱嵌锂机理研究进展

富锂固溶体正极材料xLizMnO3·（1-x）LiMO2（M--Co,Ni,Mn…）,首次不可逆容量很大程度上与组分中的LizMnO3电化学过程有关。富锂固溶体正极材料4．5V区域充电平台是组分中Li2MnO3电化学活化过程;Li2MnO3首次循环不可逆容量较大,约在50～100mAhg-1,4．5V电位脱出Li＋同时脱出O2-,等效脱出不可嵌入的Li2O;Li2MnO3与分解的电解液发生离子交互反应后,H＋占据不可逆位置,阻碍了Li＋的嵌入;多周循环晶体结构改变,形成不可逆结构并有新相生成。本文综合介绍近几年关于Li2MnO3结构、常温脱嵌锂机理、高温下电解液分解及循环后结构变化等方面的研究现状。     

水热法合成尖晶石型Li4Ti5O12及其电化学性能

以钛酸丁酯和乙酸锂为原料、三乙醇胺为结构导向剂,通过水热法合成前驱物,然后采用固相烧结制备Li4Ti5O12,探讨不同的钛锂比和煅烧温度对Li4Ti5O12结构和电化学性能的影响,并通过XRD、SEM、恒电流充放电和循环伏安测试对其进行表征.结果表明:当钛和锂的摩尔比为1:0.82、煅烧温度为800 ℃时,制备得到平均粒径为200 nm的纯相尖晶石型Li4Ti5O12,并具有良好的电化学性能;在0.1C倍率下,其首次放电比容量高达到181.7 mA-h/g,经过50次循环后放电比容量仍有151.5 mA-h/g,从第5次到第50次循环,平均每个循环放电比容量衰减量仅为6 μA-h/g;当电流倍率增大到2.0C时,其首次放电比容量仍然保持135 mA-h/g,从第5次到第50次循环,平均每个循环放电比容量衰减量为0.48 mA-h/g.     

复合锰源前驱体制备的尖晶石锰酸锂的结构与性能

以复合锰氧化物为锰源前驱体,采用多段高温热处理工艺合成了尖晶石锰酸锂(LiMn2O4),采用X射线衍射(XRD)、扫描电镜(SEM)、电化学阻抗谱(EIS)和充放电测试等研究了其晶体结构、微观形貌和电化学性能.结果表明:随着类球形Mn3O4组分在复合锰源前驱体中的占比提高,合成的尖晶石锰酸锂的晶格常数增大,晶胞体积变大...     

水热法制备Li_4Ti_5O_（12）负极材料及其电化学性能

以钛酸四丁酯和乙酸锂为原料,水热法制备前驱体,再经过短时间的高温煅烧制备Li4Ti5O12负极材料。利用XRD、SEM和恒电流充放电方法分别测定材料的结构、形貌以及材料的电化学性能。结果表明：制备出的产物Li4Ti5O12颗粒具有尖晶石型结构,其中800°C、6h烧结出的样品具有约800nm的粒径,并表现出优良的电化学性能,0.1C和5C首次放电容量分别达到158.7（mA.h）/g和109.3（mA.h）/g,不同倍率下循环20次容量保持率较好。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

THERMODYNAMICS STUDY ON THE DECOMPOSITION OF CHROMITE WITH KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

INFLUENCE OF HEAT TREATMENT ON DAMPING BEHAVIOUR OF THE MAGNESIUM WROUGHT ALLOY AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

An Easy Way to Quantify the Adhesion Energy of Nanostructured Cu/X(X=Cr,Ta,Mo,Nb,Zr) Multilayer Films Adherent to Polyimide Substrates

An approach based on film buckling under simple uniaxial tensile testing was utilized in this paper to quantitatively estimate the interfacial energy of the nanostructured multilayer films(NMFs) adherent to flexible substrates. The interfacial energies of polyimide-supported NMFs are determined to be *5.0 J/m2 for Cu/Cr, *4.1 J/m2 for Cu/Ta,*2.8 J/m2 for Cu/Mo, *1.1 J/m2 for Cu/Nb, and *1.2 J/m2 for Cu/Zr NMFs. Furthermore, a linear relationship between the adhesion energy and the interfacial shear strength is clearly demonstrated for the Cu-based NMFs, which is highly indicative of the applicability and reliability of the modified models.     

High-Speed Friction Stir Welding of SiC_p/Al–Mg–Si–Cu Composite

A 17 vol% SiCp/Al–Mg–Si–Cu composite plate with a thickness of 3 mm was successfully friction stir welded(FSWed) at a very high welding speed of 2000 mm/min for the first time. Microstructural observation indicated that the coarsening of the precipitates was greatly inhibited in the heat-affected zone of the FSW joint at high welding speed, due to the significantly reduced peak temperature and duration at high temperature. Therefore, prominent enhancement of the hardness was achieved at the lowest hardness zone of the FSW joint at this high welding speed, which was similar to that of the nugget zone. Furthermore, the ultimate tensile strength of the joint was as high as 369 MPa, which was much higher than that obtained at low welding speed of 100 mm/min(298 MPa). This study provides an effective method to weld aluminum matrix composite with superior quality and high welding efficiency.     

A STUDY OF TEMPERATURE-DEPENDENT VALENCE BOND STRUCTURE OF TITANIUM

On the basis of energy and shape method for the determination of the valence bond (VB) structures of crystal, the valence bond structure of titanium is redetermined at room temperature and calculated in the whole temperature range of 0-1943K. The outer shell electronic distribution of Ti is e_c~(2.9907) · (s_c~(0.4980) d_c~(2.4927)) ef1.0093 in crystal. The temperature dependences of the VB structures of hcp and bcc phases are the same. The VB structures of hcp and bcc phases monotonically increase or decrease with the increase in temperature, but show discontinuous changes at the phase-transformation temperature 1155K.     

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。