(NH4)2S直接沉淀法分离Li+-Mn2+中的锂和锰

以 (NH4 ) 2 S为沉淀剂 ,探讨了正尖晶石结构的 L i Mn2 O4 中锂、锰的分离和回收问题 ,重点讨论了 L i+ - Mn2 +体系的分离方法。实验以 3m ol/ L H2 SO4 溶解试样 ,以 6 % H2 O2 为还原剂将锰离子转化为 Mn2 + ,然后用 6 mol/ L NH3· H2 O调节并控制体系的 p H为 4 .2～ 6 .1,加入 1m ol/ L(NH4 ) 2 S使 Mn2 +离子沉淀完全 ,室温下过滤。分离结果表明 :硫化锰中杂质锂的摩尔百分含量为 0 .0 36 % ,滤液中杂质锰相对锂离子的摩尔百分含量为 0 .0 4 4 %。含锂的滤液和分离后的 Mn S分别以 L i2 CO3、Mn SO4 的形式回收 ,其锂、锰的一次回收率分别达到 77.89%和 97.5 6 % ,纯度分别达到 98.8%和 99.5 % ,是未来失效锂电池正极材料和锂离子筛分材料 L i Mn2 O4 的一种较为合理的分离回收方法     

电解液对超级电容器Mn_3O_4电极材料性能的影响

以应用于超级电容电极的锰氧化物材料为主要研究对象,用溶剂热法制备四氧化三锰(Mn3O4)电极材料,以X线衍射(XRD)和扫描电子显微镜(SEM)对材料性能进行了表征,采用循环伏安法、恒电流充放电法和电化学阻抗法对材料电性能进行了测试,分别以1 mol/L硫酸钠(Na2SO4)和6 mol/L氢氧化钾(KOH)为电解液研究了不同电解液对Mn3O4电极材料性能的影响.结果表明,当电流密度为0.5 A/g时,Mn3O4在KOH电解液中的比电容为48 F/g,相比在Na2SO4电解液中所得的比电容22 F/g要大.     

金属Mn对烧成Al2O3-C材料力学性能的影响

主要研究了金属Mn对al2O3-C复合材料力学性能的影响，并与添加金属Al，Si的Al2O3-C材料的力学性能进行了对比．在Al2O3-C复合材料中，添加Mn粉的力学性能优于添加Al和Si粉的试样，同时加入Si和Mn时，可显著提高材料的力学性能．还对Mn的作用机理作了理论分析．     

3,3,′4,4′-偶氮苯四甲酸配合物的合成、结构与表征

合成了3,3,′4,4′-偶氮苯四甲酸（H4L）及锰的配合物[Mn2L（H2O）10].4H2O,并用元素分析、荧光光谱、XRD粉末衍射和单晶衍射仪对它们进行了表征。研究结果表明化合物H4L.2H2O通过O-H…O氢键的作用构成2D的网络结构;配合物[Mn2L（H2O）10].4H2O中心锰离子为六配位,其中溶剂分子水和配体L均参与配位,分子间通过O-H…O氢键构成了1D的Z字链结构,而1D链之间通过O-H…O和O-H…N形成2D的网络结构。配合物具有很好的荧光特性。     

锂离子电池正极材料LiNi_(0.8)Co_(0.2)的掺杂改性研究

采用共沉淀法和成LiNi0.8Co0.2O2,探讨影响锂离子电池正极材料LiNi0.8Co0.2O2电化学性能及结构的因素.为了提高材料的电化学性能,对材料进行了掺杂改性的研究,分别掺入Al、Mn、Mg和Fe四种元素.通过在2.8～4.2V范围内的充放电测试分析,掺入Mn的正极材料LiNi0.8Co0.1Mn0.1O2具有最高的放电比容量以及最低的容量损失,其首次放电容量为168.84 mAh/g,十次循环后的放电容量为166.9 mAh/g.     

锂离子电池正极材料锰掺杂LiNi_（0.8）Co_（0.2）O_2的合成及其性能

采用共沉淀法对LiNi0.8Co0.2O2进行Mn元素的掺杂改性,考察不同掺杂量对LiNi0.8Co0.2O2材料的结构和电化学性能的影响,并对LiNi0.8-xMnxCo0.2O2（0≤x≤3）进行X射线衍射和扫描电镜分析以及循环伏安测试。充放电测试结果显示：未掺杂Mn的LiNi0.8Co0.2O2材料的初始放电比容量为164.32 mAh/g,50次循环以后为161.86 mAh/g。经掺Mn后LiNi0.8Co0.2O2材料的初始放电比容量为163.13 mAh/g,并且50次循环以后还能保持在162.33 mAh/g左右,效率达到99%以上。研究表明,掺Mn后的LiNi0.8Co0.2O2材料具有更加稳定的层状结构,并且其循环性能得到很大程度的提高。     

LiNi0.5Mn1.5O4正极材料的γ-Al2O3包覆及其性能

以氢氧化铝溶胶为前驱体在LiNi0.5 Mn1.5 O4正极材料表面制备尖晶石结构γ-Al2 O3包覆层,借助XRD、SEM、TEM及电化学方法对电极材料的主要性能进行了研究。结果表明：LiNi0.5 Mn1.5 O4表面γ-Al2 O3包覆层形成条件为600℃下煅烧0.5 h,较佳包覆量约为3％（摩尔比）;γ-Al2 O3包覆层形貌完整,厚度约为5～10 nm,（311）晶面间距约0.24 nm;γ-Al2O3包覆的LiNi0.5Mn1.5O4正极材料30周充放电循环（0.2 C）后的比容量为112.1 mAh／g,4 C倍率下的比容量为82.0 mAh／g,容量保持率较基体分别提高了约10％和17.2％。因此,γ-Al2 O3包覆层减小了LiNi0.5 Mn1.5 O4与电解液的接触,有效抑制了基体与电解液之间的副反应,其电化学反应可逆性、循环稳定性及倍率性能得到了提高,有望用作动力锂离子电池正极材料。     

LiAl0.05Mn1.95O4正极材料锂离子嵌脱动力学研究

采用超声辅助溶胶凝胶法成功制备了LiAl0.05Mn1.95O4正极材料,并利用循环伏安和电化学阻抗谱研究了不同合成方法对LiAl0.05Mn1.95O4正极材料锂离子嵌脱动力学的影响.结果表明:超声辅助溶胶凝胶法制备的尖晶石材料具有更好的可逆性和最小的电荷转移电阻;LiMn2O4(sol-gel)、LiAl0.05Mn1.95O4(sol-gel)和LiAl0.05Mn1.95O4(UASG)的交换电流密度分别为2.57×10-2、4.16×10-2、5.08×10-2mA.cm-2,固相锂离子扩散系数分别为3.27×10-10、4.94×10-10、6.91×10-10cm2.s-1,表明超声辅助溶胶凝胶法制备的样品具有较好的锂离子嵌脱动力学.     

锂离子电池正极材料LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2研究进展

评述了锂离子电池正极材料层状LiNi1/3Co1/3Mn1/3O2的最新研究进展,阐述其结构特征和存在的优缺点,介绍LiNi1/3Co1/3Mn1/3O2正极材料的制备方法,以及离子掺杂和包覆改性对该正极材料性能的影响,展望其发展方向.     

LiNi_(0.5)Mn_(1.5)O_4正极材料的γ-Al_2O_3包覆及其性能

以氢氧化铝溶胶为前驱体在Li Ni0.5Mn1.5O4正极材料表面制备尖晶石结构γ-Al2O3包覆层,借助XRD、SEM、TEM及电化学方法对电极材料的主要性能进行了研究。结果表明:Li Ni0.5Mn1.5O4表面γ-Al2O3包覆层形成条件为600℃下煅烧0.5 h,较佳包覆量约为3%(摩尔比);γ-Al2O3包覆层形貌完整,厚度约为5~10 nm,(311)晶面间距约0.24 nm;γ-Al2O3包覆的Li Ni0.5Mn1.5O4正极材料30周充放电循环(0.2 C)后的比容量为112.1 m Ah/g,4 C倍率下的比容量为82.0 m Ah/g,容量保持率较基体分别提高了约10%和17.2%。因此,γ-Al2O3包覆层减小了Li Ni0.5Mn1.5O4与电解液的接触,有效抑制了基体与电解液之间的副反应,其电化学反应可逆性、循环稳定性及倍率性能得到了提高,有望用作动力锂离子电池正极材料。     

Characteristics of LiCoO2, LiMn2O4 and LiNi0.45Co0.1Mn0.45O2 as cathodes of lithium ion batteries

LiNi0. 45 Co0. 10 Mn0. 4sO2 was synthesized from Li2CO3 and a triple oxide of nickel, cobalt and manganese at 950 ℃ in air. The structures and characteristics of LiNi0. 45 Co0.10 Mn0. 45 O2, LiCoO2 and LiMn2 O4 were investigated by XRD, SEM and electrochemical measurements. The results show that LiNi0.4s Co0.10 Mn0. 45 O2 has a layered structure with hexagonal lattice. The commercial LicoO2 has sphere-like appearance and smooth surfaces, while the LiMn2 O4 and LiNi0.45 Co0. 10 Mn0. 45 O2 consist of cornered and uneven particles. LiNi0. 45 Co0.10 Mn0. 45 O2 has a large disLiMn2 O4 and LiCoO2, respectively. LiCoO2 and LiMn2 O4 have higher discharge voltage and better rate-capability than LiNi0. 45Co0.10 Mn0. 45 O2. All the three cathodes have excellent cycling performance with capacity retention of above 89.3 % at the 250th cycle. Batteries with LiMn2 O4 or LiNi0.45 Co0.10 Mn0. 45 O2 cathodes show better safety performance under abusive conditions than those with LiCoO2 cathodes.     

尖晶石型LiMn_2O_4电子结构的第一性原理研究

基于密度泛函理论（Density Functional Theory,DFT）的第一性原理（First Principles）,应用超软赝势平面波法（Ultra-soft Pseudo-potential Plane-Wave,UPPW）对能带结构、总态密度和分态密度进行了研究,并计算了LiMn2O4晶体的原胞总能量.计算结果表明,锂离子电池正极材料LiMn2O4晶体是一种直接能隙半导体,是Li离子的良导体,较适合做锂离子电池的正极材料.在LiMn2O4晶体中,由于Mn的3d电子轨道和O的2p电子轨道重叠较强,Mn-O键相互作用较强,为主要成键区域,在充放电循环过程中具有较好的稳定性,Li较容易失去电子以离子状态存在.     

Synthesis and Performance of LiMnO_2 as Cathodes for Li-ion Batteries

1　IntroductionLithiummanganates (LiMn2 O4 orLiMnO2 )areoftensuggestedascathodematerialsforlithiumionbatteries,andhavebecomeofmajorinterestlatelybecausemanga neseisnotonlyrelativelyinexpensivebutalsohasthede siredpropertiesfortheelectrode.Inparticular,spinel typelithiummanganate(LiMn2 O4)hasbeenstudiedandisknowntoexhibitexcellentrechargeableproperties.Assuch,thisspinelcompoundhasapotentialforpracticaluseinthenearfuture[1].Asecondlithiummanganate,LiMnO2 compoundshavetwostructure types,orth…     

Kinetic study of LiMn2O4 in process of lithium intercalation

Exchange current density of spinel LiMn2 O4 was studied by linear polarization. The relationship of the kinetic property with the structure of spinel LiMn2 O4 was investigated by studying the effect of the doping and surface coating on the kinetic properties of electrode material. The results show that the exchange current density of spinel LiMn2 O4 electrode increases with the increase of the amount for lithium intercalation at first, and then decreases. The maximal exchange current density appeares at the 80%-90% lithium intercalation. The similar phenomenon was observed on the doped spinel LiMn2 O4 electrode. Doping can enhance the exchange current density of spinel LiMn2 O4 material. However, the degree of the doping effect varies with the doped element varying. Surface coating can also enhance the exchange current density of spinel material, and the increment of value is higher than that of doped ones.     

层状锰酸锂的制备方法研究

层状LiMnO2被认为是最有发展前途的锂离子电池正极材料之一,是目前新能源材料研究的热点.本文研究了高温固相法+碳热还原法,离子交换法,水热合成法和流变相法等多种工艺制备层状LiMnO2,通过实验结果对比了各种制备工艺工业化的可行性,为层状LiMnO2实现商业化提出了建议.研究结果表明:水热合成法在160℃下,Li/Mn=2∶1时,可得到层状LiMnO2;而流变相法在Li/Mn=1∶1时,即可得到LiMnO2.     

锂离子电池正极材料LiCexNdxMn2-2xO4（x=0～0.018）的Pechini合成及表征

采用X射线衍射仪、电池测试系统等,研究了采用Pechini法合成的锂离子电池正极材料LiCexNdxMn2-2xO4（x=0、0.012、0.014、0.016、0.018）的组织结构、首次充放电性能、循环稳定性能等。结果表明：当稀土元素掺入量较少（x≤0.014）时,样品由尖晶石型LiMn2O4相组成,否则,样品中将出现微量的杂质相（CeO2、Nd2O3）;适量的稀土元素掺杂将使LiMn2O4样品的初始容量减小、循环稳定性能增加。LiCe0.014Nd0.014Mn1.972O4样品具有较好的循环稳定性能,其初始放电容量为124.8 mAh/g,经30次循环充放电后的容量保持在116.3 mAh/g,容量保持率为93.2%。     

Sol-Gel Synthesis of Normal Spinel LiMn_2O_4 and Its Characteristics

1　ＩｎｔｒｏｄｕｃｔｉｏｎＮｏｒｍａｌｓｐｉｎｅｌＬｉＭｎ2 Ｏ4 ｐｏｓｓｅｓｓｅｓｓｐｅｃｉｆｉｃｍｅｍｏｒｙｅｆｆｅｃｔｆｏｒｌｉｔｈｉｕｍｉｏｎ .Ｍａｎｇａｎｅｓｅｉｓｒｉｃｈｉｎｎａｔｕｒａｌｒｅ ｓｏｕｒｃｅｓａｎｄｈａｓｎｏｐｏｌｌｕｔｉｏｎｔｏｔｈｅｅｎｖｉｒｏｎｍｅｎｔ .Ｅｘｔｒａｃ ｔｉｏｎｏｆｍｉｃｒｏ ｌｉｔｈｉｕｍｆｒｏｍｓｅａｗａｔｅｒａｎｄｓａｌｔ ｌａｋｅｂｒｉｎｅｂｙｌｉｔｈｉｕｍｍａｎｇａｎｅｓｅｏｘｉｄｅｉｓｒｅｇａｒｄｅｄａｓｔｈｅｍｏｓｔｐｒｏｓｐｅｃ ｔｉｖｅ…     

Structure characteristics and electrochemical properties of LiMn2O4 modified by LiCoO2

In order to improve the cycle performance of LiMn2O4, the modified LiMn2O4 was prepared by solid-state reactions using LiMn2O4 and LiCoO2 as precursors. XRD and EDS were used to study the structure properties of the modified LiMn2O4. The electrochemical properties of the modified LiMn2O4 were also investigated, The results show that Li and Co atoms could insert into the LiMn2O4 crystal lattice and a newly formed spinel phase, modified LiMn2O4 was obtained. The modified LiMn2O4 exhibits excellent cycle ability at room and elevated temperatures compared to pure LiMn2O4. The improved electrochemical stability of the modified LiMn2O4 attributes to the entrance of Li and Co ions inserted into the spinel crystal structure.     

尖晶石锂锰氧化物大电流充放电性能研究进展

锂锰氧化物资源丰富、成本低廉、工艺简单，最有希望替代锂钴氧化物正极材料，论文综述了尖晶石型锂锰氧化物的制备方法、性能改善等方面的研究进展．介绍了影响锂锰氧化物正极材料大电流充放电性能的主要因素，及相关的改善方法，如表面包覆锂钴氧、用纳米不锈钢纤维代替传统的乙炔黑、制备烧结电极等．     

Structure and electrochemical properties of La, F dual-doped LiLa0.01Mn1.99O3.99F0.01 cathode materials

The cathode materials LiMn2O4 and rare earth elements La-doped or La and F dual-doped spinel lithium manganese oxides were synthesized by the citric acid-assisted sol-gel method. The synthesized samples were investigated by differential thermal analysis (DTA) and thermogravimetry (TG) measurements, X-ray diffraction (XRD), scanning electronic microscope (SEM), cyclic voltammetry (CV), and charge-discharge test. XRD data shows that all the samples exhibit the same pure spinel phase, and the LiLa0.01Mn1.99O3.99F0.01 and LiLa0.01Mn1.99O4 samples have smaller lattice parameters and unit cell volume than LiMn2O4. SEM indicates that LiLa0.01Mn1.99O3.99F0.01 has a slightly smaller particle size and a more regular morphology structure with narrow size distribution. The charge-discharge test reveals that the initial capacities of LiMn2O4, LiLa0.01Mn1.99O4, and LiLa0.01Mn1.99O3.99F0.01 are 129.9, 122.8, and 126.4 mAh·g-1, and the capacity losses of the initial values after 50 cycles are 14.5%, 7.6%, and 8.0%, respectively. The CVs show that the La and F dual-doped spinel displays a better reversibility than LiMn2O4.