锂离子电池用复合导电剂浆料制备与性能

采用超声波混合、抽滤的方法把多壁碳纳米管(MWCNTs)和乙炔黑混合制备了锂离子电池用复合导电剂浆料,用扫描电子显微镜(SEM)和恒流充放电测试考察了复合导电剂的结构和其作为导电剂对LiCoO2电极放电比容量的影响.SEM的分析结果表明MWCNTs和乙炔黑实现了纳米层次的均匀混合.复合导电剂悬浮液和浆料分别被用作导电剂制成了两种LiCoO2电极,前一种电极为Cathode A,后一种电极为Cathode B,考察了不同MWCNTs含量时,两种电极0.5 C第10次放电比容量的差异.实验结果表明,随着MWCNTs含量的增加,两种电极放电比容量的差值增大,说明低含量MWCNTs的复合导电剂浆料是一种理想的锂离子电池导电剂.     

锂离子电池用复合导电剂浆料制备与性能

采用超声波混合、抽滤的方法把多壁碳纳米管（MWCNTs）和乙炔黑混合制备了锂离子电池用复合导电剂浆料，用扫描电子显微镜（SEM）和恒流充放电测试考察了复合导电剂的结构和其作为导电剂对LiCoO2电极放电比容量的影响。SEM的分析结果表明MWCNTs和乙炔黑实现了纳米层次的均匀混合。复合导电剂悬浮液和浆料分别被用作导电剂制成了两种LiCoO2电极，前一种电极为Cathode A，后一种电极为Cathode B，考察了不同MWCNTs含量时，两种电极0．5C第10次放电比容量的差异。实验结果表明，随着MWCNTs含量的增加，两种电极放电比容量的差值增大，说明低含量MWCNTs的复合导电剂浆料是一种理想的锂离子电池导电剂。     

钛掺杂对不同形貌LiCoO2电化学性能的影响

采用SEM、XRD、恒电流充放电、电化学交流阻抗谱等方法研究了钛掺杂对不同形貌LiCoO2电化学性能的影响. 结果表明, 钛掺杂在不改变材料晶体结构的情况下, 能显著地改善LiCoO2的电化学性能, 且在较高倍率放电制度下(1 C), 掺杂对不同形貌LiCoO2的放电电压平台的影响效果不同. 掺杂后的二次粒子团聚体以1 C放电, 20次循环后3.8 V平台(电压大于3.8 V时的放电容量占总放电容量的百分比) 的保持率为60％, 优于掺杂后的大粒径一次粒子分散体的平台保持率(40％). 电化学交流阻抗谱研究表明, 钛掺杂对于抑制LiCoO2二次粒子在高倍率放电制度下循环过程中电化学阻抗的增加更为有效.     

数学模拟方法研究导电剂形貌对锂离子电池高倍率放电性能的影响

制备了正极中只含有一种导电剂(KS-6或Super-P)的锂离子电池,比较了它们的倍率放电性能并对放电过程进行了模拟。以Super-P为正极导电剂的电池15C放电容量为1C容量的84.3%,以KS-6为正极导电剂的电池15C放电容量为1C容量的21.8%,前者的倍率放电性能明显优于后者。数学模拟结果显示,以KS-6为导电剂的正极的Bruggeman系数为3.1,以Super-P为导电剂的正极的Bruggeman系数为2.76,前者明显大于后者,认为这是由于KS-6的片状形貌使其容易相互平行排列造成的。大电流放电时,以KS-6为导电剂的正极中出现了电解质耗竭而导致该区域内电化学反应停止的现象,从而导致电池放电容量急剧降低。     

锂空气电池空气电极LiCoO2电催化性能研究

自设计建立锂空气电池实验装置,研究以掺入LiCoO2作为电催化剂的空气正极的电化学性能及其放电前后催化剂结构的变化.循环伏安、XRD及充放电测试等表明,LiCoO2能够很大程度地改善空气电极的放电性能.尤其是在放电前,将掺有LiCoO2的空气正极充电至4.1 V,此时LiCoO2的Co元素呈现较高的价态（Co3＋/Co...     

磷酸铁锂离子电池正极材料掺碳纳米管的研究

应用球磨法于LiFePO4掺杂多壁碳纳米管,制成LiFePO4/MWCNTs复合电极,然后以其组装成锂离子电池.研究不同比例掺杂多壁碳纳米管对复合材料电极电化学性能的影响.XRD、SEM表征及电化学性能测试表明,多壁碳纳米管含量为10%(bymass)的LiFePO4/MWCNTs电极比其它比例的复合电极具有更优良的充放电性能,而且极化小、稳定性强、充放电平台更平稳,导电率更高.在常温0.1C下充放电,首次充、放电比容量分别为139和128.5mAh.g-1,库仑效率达92.4%,循环40次后,电极比容量损失率仅为5.3%.     

聚吡咯/多壁碳纳米管及其聚氨酯导电复合材料的制备和性能

以羧基化多壁碳纳米管(MWCNTs)做模版剂,采用化学氧化法将吡咯(Py)在羧基化MWCNTs表面聚合制备PPy/MWCNTs导电材料,将其添加到溶剂型聚氨酯(PU)溶液中制备了PPy/MWCNTs/PU导电复合材料,研究了Py用量对PPy/MWCNTs及其PU复合材料性能的影响.研究表明,随Py用量的增加,PPy/MWCNTs的长度不变,管径增大,sp~2和sp~3杂化C含量先提高后减少,N的掺杂梯度降低,PPy/MWCNTs的导电率高于羧基化MWCNTs和PPy.当Py用量为羧基化MWCNTs的20%时,其导电率最大.PPy/MWCNTs中N元素的掺杂程度及其管径变化是引起PPy/MWCNTs/PU复合材料的性能不同的主要原因.增加Py用量,MWCNTs中亲水的羧基因对PPy掺杂而消耗,相同导电材料用量时纳米导电粒子数目相对减少,PPy/MWCNTs/PU复合材料的耐水性能提高,定向应力、储能模量和玻璃化温度降低,导电率先增加后减小.当Py用量为羧基化MWCNTs的15%时,导电率最大.     

采用新颖喷墨打印技术制备的薄膜LiCoO2电极及其电化学性能

采用喷墨打印技术制备了LiCoO2薄膜电极. 用X射线衍射、扫描电镜(SEM)、循环伏安和恒电流充放电试验对薄膜电极进行结构表征和电化学性能测试. SEM结果表明, 所制备的薄膜电极表面粒子分布均匀, 厚度约为1.27 μm. 经过轻微热处理(450 ℃, 30 min)的薄膜LiCoO2电极呈现出稳定的充放电循环性能. 当以20 μA/cm2进行充放电时, 第50次循环容量保持率约为首次放电容量(81 mA·h/g)的87%, 10次循环后的充放电过程的充放电效率均接近100％.     

锂离子电池MnO/TiN负极研究

以乙酸锰和钛酸四丁酯为原料,柠檬酸为络合剂,采用溶胶-凝胶法制备钛酸锰（MnTiO3）粉体,而后将其粉体高温氨气氮化,可得到MnO/TiN复合材料. 使用X射线衍射（XRD）、X射线能量色散谱（EDS）和场发射扫描电子显微镜（FESEM）表征材料的物相结构与组分、观察其形貌. 采用循环伏安、恒流充放电和电化学阻抗方法测试电极电化学性能. 结果表明,MnO/TiN电极在100 mA?g-1和1 A?g-1倍率放电下,比容量分别为394 mAh?g-1和146 mAh?g-1,均高于单纯MnO电极比容量和倍率性能,这归因于复合材料中的TiN提供了导电网络,并有效地抑制了电极在充放电过程中的体积膨胀效应.     

PEG包覆涂层对含碳纤维导电剂的锂硫正极材料的影响

通过球磨混合及聚乙二醇（PEG）包覆处理制备含有高模量碳纤维（HMCF）的硫基复合材料.采用X射线衍射(XRD)和扫描电子显微镜(SEM)测定材料的结构和形貌,采用X-光电子扫描能谱（XPS）验证了PEG包覆在材料的表面,较系统地研究了PEG含量对含有高模量碳纤维的硫正极比容量、循环稳定性和倍率性能等性能的影响.结果表明：和常用的导电剂乙炔黑(AB)相比,HMCF导电剂具有结晶度高,接触角小,吸液性能好等优点.当PEG涂层量为1.09%时,硫正极初始放电容量为1312.5 mAh·g^-1,在电流密度为200 mA·g^-1充放电时,50次循环以后可逆容量保持为650 mAh·g^-1,和没有PEG涂层相比,循环稳定性提高了39.9%.     

利用手持技术改进测定乙醇分子结构实验

利用压强传感器代替排水集气法,改进测定乙醇分子结构实验的仪器装置,并探索最佳反应条件。另外,设计两个空白实验,结合压强变化曲线对实验误差进行相关讨论。     

光谱仪测试范围的扩展

由于石化行业的生产需要，其材质的使用具有多样性和广泛性，经常会出现顾客委托的测试样品的一个或几个元素跨越光谱仪现有测试程序测量范围的情况。本法通过对光谱仪测试原理的认识，根据光谱仪的测试能力及标样的采集，实现了一个或几个元素测量范围的扩展，并对其测量的影响因素进行了研究。     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

Influence of viscosity of medium on processes of oxygen quenching of excited states of mesoporphyrin

The oxygen quenching rate constants for singlet and triplet excited states of the dimethyl ester of mesoporphyrin IX increase with decreasing viscosity of the medium and reach a maximum at a viscosity of approximately 0.4 mPa·sec, after which the rate constants begin to decrease. The drop in rate constant with increasing fluidity of the medium may be related to a nonequilibrium character of the elementary act in the interaction of the reactants in the solvent cage. In viscous media such as isopropyl alcohol, isobutyl alcohol, and isoamyl alcohol, the reaction radius is greater than the sum of the radii of the reacting particles. The long-range character of these processes is due to the relatively weak dependence of the quenching probability on distance.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 2, pp. 161–167, March–April, 1989.     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

     

物质分配系数的测定实验改进

实验教学目的是从解决实际问题出发,以实验技术训练和实验设计思想培养为目标。介绍了将单一的物质分配系数测定实验改进为综合实验,提高了实验效果及实验资源利用率。     

Neutral diterpenoids of oleoresins of five species of conifers of Transcarpathia

The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 812–816, November–December, 1988.     

Calculation of enthalpies of hydrogenation of hydrocarbons

Sets of hydrogen molecule equivalents have been developed which permit the calculation of hydrogenation of different types of carbon-carbon bonds from ab initio total energies (3-21G and 6-31G* basis sets, and, to a more limited extent, for MP2/6-31G* data) of reactants and products. The calculated enthalpies of hydrogenation are in good agreement with experiment for unstrained molecules, with average errors on the order of 2 kcal/mol. The 6-31G* equivalents allow the enthalpies for strained molecules to be calculated accurately, but the 3-21G equivalents do not. The equivalents for both basis sets have been tested by calculating the enthalpies of hydrogenation of carbon-carbon bonds in nitrogen- and oxygen-containing organic molecules, free radicals, and classical carbocations. The results are in good agreement with experiment in most cases.     

非那雄胺合成工艺改进

非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。