雾热解法合成锂离子电池正极材料LiMn2O4

采用喷雾热解的方法合成了单相的尖晶石LiMn2O4的颗粒，结构研究结果表明用这种喷雾造粒的方法可以得到颗粒细小匀的LiMn2O4粉体，其组装的电池具有良好的电化学容量和循环性能，表明这是一种可推广的合成锂离子电池正极材料LiMn2O4粉体的方法。     

柠檬酸溶解废锂离子电池正极材料的研究

探求废锂离子电池正极材料LiMn2O4在柠檬酸溶液中的溶解条件,为废旧电池的进一步回收利用奠定基础。采用单因素与正交实验相结合的方法,对废锂离子电池正极材料LiMn2O4在柠檬酸溶液中的溶解条件进行研究,结果表明,废锂离子电池正极材料LiMn2O4在柠檬酸溶液中适宜的溶解条件为:柠檬酸浓度1.0mol.L-1、溶解温度45℃、H2O2加入量5.0%、料液比60g.L-1,在此条件下正极材料LiMn2O4在柠檬酸溶液中的溶解率达到99.56%。对柠檬酸溶解废锂离子电池正极材料LiMn2O4的机理进行了探讨,认为在加入H2O2之前,尖晶石LiMn2O4中的Mn3+发生歧化反应生成Mn2+以及MnO2,而Mn4+在溶液中水解生成MnO2。MnO2与柠檬酸发生氧化还原反应生成丙酮二羧酸及Mn2+。加入H2O2之后,H2O2作为还原剂能够将剩余的MnO2全部还原为Mn2+,使正极材料LiMn2O4在柠檬酸溶液中的溶解率得以提高。     

锂离子电池正极材料研究的新动向和挑战

调研了全球锂离子电池正极材料LiCoO2、LiNiO2、LiMn2O4、LiFePO4 LiNi0.8 Co0.2 O2和Li(CoMnNi)1/3O2的学术研究论文和技术专利申请与授权数按年和语言分布情况。综述了前4种材料作锂离子电池正极材料尚存在的问题和解决对策进展。例如,通过掺杂其他元素、表面包覆、细化材料颗粒及改善正极结构设计来提高正极材料的充放电容量、寿命、功率密度和电池高功率密度使用时的安全性。     

LiCoO2掺杂对锰酸锂结构和性能的影响

用固相反应合成了LiCoO2掺杂改性的LiMn2O4锂离子电池正极材料,优化了LiMn2O4的改性路径及制备条件.利用SEM、XRD对产物的结构进行了表征,并测试了产物的电化学性能.结果表明:所得产物均具有尖晶石型LiMn2O4结构.LiCoO2的掺入增加了尖晶石结构的稳定性,改善了尖晶石型LiMn2O4的充放电循环性能.     

改性LiMn_2O_4的高温电化学性能

采用高温固相反应法制备改性的LiMn2O4锂离子电池正极材料.利用SEM、XRD等方法表征产物的结构特性.结果表明:所得产物均具尖晶石型LiMn2O4结构,该样品经Li2CO3改性后用作锂离子电池正极,于常温和高温下的循环性能均得到明显改善.     

稀土掺杂对锂离子电池正极材料LiMn2O4结构及电性能的影响

利用微波加热技术合成稀土掺杂基锂离子电池正极材料LiMn2-xRExO4(RE=Y，Nd，Gd，Ce)，通过XRD、循环伏安及恒电漉充放电测试研究了稀土掺杂离子对合成正极材料结构及电化学性能的影响。XRD测试结果表明，合适的掺杂量可以起到扩展锂离子脱嵌通道和稳定骨架结构的作用，稀土离子的引入可以部分取代原有的三价锰离子，由于稀土离子的离子半径较三价锰离子大，因此稀土掺杂锰酸锂材料的晶胞参数比未掺杂材料大，在一定程度上扩充了锂离子迁移的三维通道，更有利于锂离子的嵌入与脱嵌；循环伏安及恒电漉充放电测试结果表明稀土掺杂有效提高了LiMn2O4材料的电化学循环可逆性及循环稳定性。     

尖晶石型LiMn2O4电池材料的元素掺杂

尖晶石型LiMn2O4正极材料因资源丰富、无毒、安全及制备简单、技术较成熟等优点而成为最具竞争力的新一代商用锂离子二次电池的正极材料之一.由于LiMn2O4的循环稳定性、高温(＞55℃)稳定性和大电流放电等因素限制了推广应用.本文从材料的结构组成对锂离子嵌脱过程的作用机理,论述了元素掺杂对尖晶石型LiMn2O4正极材料电化学特性的影响,指出了元素掺杂本体改性锰酸锂正极材料的方法和特点.     

LiCoO2/LiMn2O4复合薄膜电极制备及其在高温下的电化学性能

LiCoO2/LiMn2O4复合薄膜电极制备及其在高温下的电化学性能;锂离子电池;表面包覆     

Al3+对尖晶石型LiMn2O4正极材料的表面掺杂包覆改性

采用表面掺杂包覆改性的方法对LiMn2O4尖晶石型锂离子电池正极材料进行改性.以Al为表面掺杂元素,Al(NO3)3为原料,研究了Al3+掺杂量为7.1%(原子分数)时不同温度(300、400、500、600、700、750、800℃)下的改性效果.研究发现,随着热处理温度的升高,改性样品的最大比容量先升高后降低,在700℃达到最大值;循环衰减先增大后降低再增大;这是由于随着热处理温度的升高,包覆层逐渐分解并与LiMn2O4颗粒反应固溶,在750℃完全固溶,衰减达到极小值,而后固溶层向颗粒内部扩散,导致包覆层对颗粒免受电解液溶解的保护能力变弱,因而容量衰减增大.其中700℃热处理5h的样品最大比容量为133.6mAh·g-1,循环50周衰减3.4%.研究表明Al3+表面掺杂包覆改性有利于促进LiMn2O4尖晶石型锂离子电池正极材料的商业化生产,具有大规模应用的前景.     

LiTi2O4用作锂离子电池负极的研究进展

LiTi2O4具有长的嵌锂反应循环寿命、较低的电位和良好的导电性,是继碳素材料和Li4Ti5O12之后的又一新型锂离子电池负极材料,有望在大电流和动力锂离子电池中得到较大的应用.本文介绍了LiTi2O4负极材料的晶体结构、物理特性、制备方法、电化学性能及其应用研究进展,并分析了其微观导电机理.     

Ni(II), Pd(II), Cu(II) And Zn(II) complexes with N-(2-Pyridyl)Carbonylaniline (L), Syntheses and X-Ray Crystal structures of [Cu(L)2(H2O)2](No3)2, [Cu(L)2(H2O)2](Clo4)2 and [Zn(L)2(H2O)2](Clo4)2

Reaction of the N-(2-pyridyl)carbonylaniline ligand (L) with Cu(NO₃)₂, Cu(ClO₄)₂, Zn(ClO₄)₂, Ni(NO₃)₂ and PdCl₂ gives complexes with stoichiometry [Cu(L)₂(H₂O)₂](NO₃)₂, [Cu(L)₂(H₂O)₂](ClO₄)₂, [Zn(L)₂(H₂O)₂] (ClO₄)_2, [Ni(L)₂(H₂O)Cl](NO₃) and PdLCl₂. The new complexes were characterized by elemental analyses and infrared spectra. The crystal structures of [Cu(L)₂(H₂O)₂](NO₃)₂, [Cu(L)₂(H₂O)₂](ClO₄)₂, and [Zn(L)₂(H₂O)₂](ClO₄)₂ were determined by X-ray crystallography. The cation complexes [M(L)₂(H₂O)₂] contain copper(II) and zinc(II) with distorted octahedral geometry with two N-(2-pyridyl)carbonylaniline (L) ligands occupying the equatorial sites. The hexa-coordinated metal atoms are bonded to two pyridinic nitrogens, two carbonyl oxygens and two water molecules occupying the axial sites. Both the coordinated water molecules and uncoordinated amide NH groups of the N-(2-pyridyl)carbonylaniline (L) ligands are involved in hydrogen bonding, resulting in infinite hydrogen-bonded chains running in one and two-dimensions.     

Variation of 2 D Hydrogen Bond Topology in Diaqua-tetrafluoromanganates(III): 2-picoH[MnF4(H2O)2], TMEDAH2[MnF4(H2O)2]2, and TMBDAH2[MnF4(H2O)2]2

The crystal structures of three new diaqua-tetrafluoro-manganate(III) compounds with different organic N-cations have been determined: 2-picoH[MnF₄(H₂O)₂] 1 (2-pico = 2-methyl-pyridine), space group P2₁/c, a = 9.439, b = 13.662, c = 7.641 Å, β = 91.31°; R = 0.059; TMEDAH₂[MnF₄(H₂O)₂]₂ 2 (TMEDA = N,N,N′,N′-tetramethyl ethane diamine), space group P2₁/c, a = 5.421, b = 15.970, c = 9.677 Å, β = 96.37°, R = 0.031, and TMBDAH₂[MnF₄(H₂O)₂]₂ 3 (TMBDA = N,N,N′,N′-tetramethyl-1,4-butane-diamine), space group P2₁/n, a = 12.631, b = 5.577, c = 12.976 Å, β = 98.10°, R = 0.040. All three compounds show 2 D H-bonding networks of [MnF₄(H₂O)₂]^– anions separated by the organic cations. However, the topology of the anionic H-bonding nets is different for each compound. The anions are strongly elongated by the Jahn-Teller effect and are arranged in a ferrodistortive way in compounds 1 and 2 , whereas in compound 3 the arrangement is described as in a herringbone-like antiferrodistortive variant.     

Kristallstrukturen der Fluorochloroplatinate(IV) cis-[(C5H5N)2CH2][PtF4Cl2], trans-[(C5H5N)2CH2][PtF4Cl2] · H2O und [(C5H5N)2CH2][PtF5Cl]

Crystal Structures of the Fluorochloroplatinates(IV) cis-[(C₅H₅N)₂CH₂][PtF₄Cl₂], trans-[(C₅H₅N)₂CH₂][PtF₄Cl₂] · H₂O, and [(C₅H₅N)₂CH₂][PtF₅Cl] The complex ions cis-[PtF₄Cl₂]^2?, trans-[PtF₄Cl₂]^2? and [PtF₅Cl]^2? have been synthesized by stereoselective ligand exchange reactions utilizing the trans effect and are separated by ion exchange chromatography on diethylaminoethyl cellulose. These anions form stable AB-type salts with the doubly charged cation dipyridiniomethane, [(C₅H₅N)₂CH₂]²⁺. X-ray structure determinations on single crystals of cis-[(C₅H₅N)₂CH₂][PtF₄Cl₂] ( 1 ) (monoclinic, space group P2₁/n with a = 10.379(10), b = 9.635(2), c = 13.738(2) Å, β = 99.142(10)°, Z = 4), trans-[(C₅H₅N)₂CH₂][PtF₄Cl₂] · H₂O ( 2 ) (triclinic, space group P1 with a = 7.757(4), b = 10.059(7), c = 10.408(6) Å, α = 82.49(5), β = 68.92(4), γ = 75.46(4)°, Z = 2) and [(C₅H₅N)₂CH₂][PtF₅Cl] ( 3 ) (orthorhombic, space group Pnma with a = 10.394(3), b = 13.320(2), c = 9.2694(10) Å, Z = 4), reveal the perfect ordering of the anion sublattice. The stronger trans influence of Cl compared with F is observed in asymmetric axes $ {\rm F}^ \bullet $? Pt? Cl′. The bond lengths Pt? $ {\rm F}^ \bullet $ are 0.026 Å (1.4%) longer and the Pt? Cl′ distances are 0.078 Å (3,3%) shorter in comparison with those of symmetrically coordinated axes. The weakening of the Pt? $ {\rm F}^ \bullet $ bond and the strengthening of the Pt? Cl′ bond is better recognizable from shifts of the stretching vibrations by 8% to lower and by 13% to higher frequencies, respectively. Correspondingly, the valence force constants are found to be 15% lower and 22% higher. The trans influence is observed most distinctly in the ¹⁹F-nmr spectra exhibiting the coupling constant ¹J($ {\rm F}^ \bullet $Pt) to be 29% smaller than ¹J(FPt).     

Synthesis and Crystal Structure of (CH_2)_3(3,5-Me_2Pz)_2. [PhBr_2Sn(CH_2)SnBr_2Ph].2HBr.H_2O (Pz=pyrazole)

1 INTRODUCTION The coordination chemistry of tin or organotin toward poly(pyrazol-1-yl)borate ligands has been extensively investigated in recent years owing to the antitumor activity of some related organotin derivatives containing N-donor ligands. A number of organotin(Ⅳ) complexes containing poly(pyrazol- 1-yl)borate ligands have been synthesized and characterized[1~3], some of which have also shown interesting structural characteristics and reactivities[4~6]. Recently, poly(pyrazol…     

Syntheses,characterizations and crystal structures of two new complexes, [Co2(CH2 =C(CH3)CO2)4(phen)2(H2O)2] and [Pb2(CH2 =C(CH3)CO2)4(phen)2]

Two new complexes, [Co₂(CH₂=C(CH₃)CO₂)₄(phen)₂(H₂O)₂] (1) and [Pb₂(CH₂=C(CH₃)CO₂)₄(phen)₂] (phen = 1,10-phenanthroline) (2), have been synthesized and structurally characterized by single crystal X-ray diffraction methods. There are two cocrystallized conformers of [Co(CH₂=C(CH₃)CO₂)₂(phen)(H₂O)] in the asymmetric unit of 1 with the Co atoms displaying similar coordination modes. In the asymmetric unit of 2, there exist two crystallographically independent [Pb(CH₂=C(CH₃)CO₂)₂(phen)] molecules with the Pb atoms showing completely different coordination geometries. Weak intermolecular interactions such as hydrogen bonding and π–π stacking are responsible for the supramolecular assembly and stabilization of the crystal structures of 1 and 2. The complexes are characterized by elemental analysis, IR spectra, and UV–Vis spectra. The fluorescent properties of 2 are also discussed.     

Crystal structures and thermal decomposition oftrans-Pd(Creat)2Cl2·2H2O andcis-Pt(Creat)2I2·3H2O

New complexes of the formulaetrans-Pd(Creat)₂Cl₂·2H₂O (I) andcis-Pt(Creat)₂I₂·3H₂O (II) have been prepared and their structures and stabilities studied by X-ray diffraction and thermal analysis. Both compounds have a squareplanar geometry, the two Cl atoms and N1 creatinine atoms are coordinated to Pd intrans configuration, while in compoundII the I atoms and N1 atoms are coordinated incis configuration. In spite of the earlier differences, the TG and DTA curves of the complexes show that their stability is very similar. Since an extended hydrogen bond system is present in the crystals, especially inII, the possible consequences in biological media are discussed briefly.

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Kristallstrukturen und thermische Zersetzung vontrans-Pd(Creat)₂Cl₂·2H₂O undcis-Pt(Creat)₂I₂·3H₂O

Zusammenfassung Es wurden neue Komplexe der Formelntrans-Pd(Creat)₂Cl₂·2H₂O (I) undcis-Pt(Creat)₂I₂·3H₂O (II) hergestellt und ihre Strukturen und Stabilitäten mittels Röntgenstrukturanalyse bzw, thermischer Analyse untersucht. Beide Komplexe haben quadratisch-planare Struktur, die zwei Cl-Atome und die N1-Creatinin-Atome sind an Pd intrans-Konfiguration koordiniert, währenddessen in VerbindungII die I-Atome und die N1-Atome incis-Konfiguration zueinander stehen. Trotz früherer Differenzen zeigen die TG- und DTA-Kurven der Komplexe, daß ihre Stabilitäten sehr ähnlich sind. Da besonders inII ein ausgedehntes Wasserstoffbindungssystem vorhanden ist, werden auch mögliche Konsequenzen bezüglich biologischer Wirksamkeit kurz diskutiert.

     

Synthesis and Crystal Structure of the Dicopper(II) Complex [Cu2{Ph2P(=O)(o‐C6H4)CO2}2(THF)2(H2O)2][BF4]2 by Oxidation of [Cu{Ph2P(o‐C6H4)C(=O)H}2(NCMe)][BF4] with Aqueous H2O2

Treatment of [Cu(pcho)₂(NCMe)][BF₄] 1 (pcho = 2‐(diphenylphosphino)benzaldehyde) with aqueous H₂O₂ in THF solvent affords [Cu₂(dpb)₂(THF)₂(H₂O)₂] [BF₄]₂ 2 (dpb = 2‐(diphenylphosphinoxide)‐benzoate) after crystallization from diethyl ether. This reaction involves oxidation of Cu(I) to Cu(II) ion, phosphine to phosphinoxide, and benzaldehyde to benzoate species. The crystal structure of 2 consists of two copper(II) atoms bridged by two carboxylate moieties of the dpb ligands. The coordination about each copper(II) atom is a distorted trigonal bipyramid.     

某些内-双环[2.2.2]辛烯(或辛烷)基-2-甲醛缩醛的合成及香气

某些缩醛的香气比其母体醛优雅,且性质稳定,成为近年来调香中使用的一类新化合物。因此,我们继合成了一系列双环[2.2.2]辛     

Darstellung und Kristallstrukturen von Ag[N(CN)2](PPh3)2, Cu[N(CN)2](PPh3)2 und Ag[N(CN)2](PPh3)3

Preparation and Crystal Structures of Ag[N(CN)₂](PPh₃)₂, Cu[N(CN)₂](PPh₃)₂, and Ag[N(CN)₂](PPh₃)₃ The coordination compounds Ag[N(CN)₂](PPh₃)₂ ( 1 ), Cu[N(CN)₂](PPh₃)₂ ( 2 ), and Ag[N(CN)₂](PPh₃)₃ ( 3 ) are obtained by the reaction of AgN(CN)₂ or CuN(CN)₂ with triphenylphosphane in CH₂Cl₂. X‐ray structure determinations were performed on single crystals of 1 , 2 , and 3 · C₆H₅Cl. The three compounds crystallize monoclinic in the space group P2₁/n with the following unit cell parameters. 1 : a = 1216.07(9), b = 1299.5(2), c = 2148.4(3) pm, β = 99.689(13)°, Z = 4; 2 : a = 1369.22(10), b = 1257.29(5), c = 1888.04(15) pm, β = 94.395(7)°, Z = 4; 3 · C₆H₅Cl: a = 1276.6(4), b = 1971.7(3), c = 2141.3(5) pm, β = 98.50(3)°, Z = 4. In all structures the metal atoms have a distorted tetrahedral coordination. The crystal structure of 3 · C₆H₅Cl shows monomeric molecular units with terminal coordinated dicyanamide. The crystal structure of 1 is built up by dinuclear units, which are bridged by dicyanamide ligands. However, the crystal structure of 2 corresponds to a onedimensional coordination polymer, bridged by dicyanamide anions.     

Synthesis and crystal structure of two new Bi(III) complexes {(Me2NCS2)3Bi}2 and {[(CH2)5NCS2]2BiI}2

Six bismuth(III) complexes containing dithio-ligands formulated as (R₂NCS₂)₃Bi [R₂NCS₂M?=?Me₂NCS₂Na, C₄H₈NCS₂Na, Bz₂NCS₂Na] and [(R₂NCS₂)₂BiI]₂ [R₂NCS₂M?= C₅H₁₀NCS₂Na, ⁿ Bu₂NCS₂Na, OC₄H₈NCS₂Na] have been obtained by reactions of bismuth(III) halides with dithiocarbamate ligands in 1?:?2 or 1?:?3 stoichiometry. All compounds were characterized by elemental and IR analyses. The crystal structures of complexes 1 and 4 have been determined by X-ray single crystal diffraction. The structure analyses reveal that Bi^III in complex 1 adopts a distorted pentagonal–pyramidal coordination, due to its stereochemically active lone pair of electrons. A long Bi?·?S contact of 3.218 (3)?Å leads to dimeric associations of molecules in the crystal structure. The structure of complex 4 is six-coordination with a distorted octahedral configuration. Intramolecular S?·?S weak interactions contribute to the stability and lead to a one-dimensional chain structure.