Li(Ni1/3Co1/3Mn1/3)O2/Ag电极材料的制备及电化学性能

以碳酸盐为沉淀剂,采用共沉淀法合成晶型良好的亚微米级Li(Ni1/3Co1/3Mn1/3)O2粉末,并将其与AgNO3复合,采用无电流分解沉积法制备出了Ag表面修饰的Li(Ni1/3Co1/3Mn1/3)O2/Ag电极材料.利用X-射线衍射、扫描电镜及电化学测试等方法表征材料的结构、形貌和电化学性能.结果表明:Ag单质的存在可明显改善Li(Ni1/3Co1/3Mn1/3)O2的电化学性能,尤其是倍率特性,以0.2C、0.5C、1C倍率放电进行测试,经过40次循环后比容量分别为156.2、144.3、137.7mAh·g-1,其容量保持率分别为96.2％、95.3％、93.9％.Ag的表面修饰能使Li(Ni1/3Co1/3Mn1/3)O2电荷转移阻抗大幅度减小,阻抗从65Ω减小到50Ω.     

层状LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2正极材料的多元掺杂改性

采用共沉淀法制备锂离子电池掺杂型层状LiNi1/3Co1/3Mn1/3-xMxO2(M=Mg、Al、Cr)正极材料。采用X射线衍射、扫描电镜、充放电实验和交流阻抗实验对LiNi1/3Co1/3Mn1/3-xMxO2正极材料的结构、形貌、电化学性能以及动力学参数进行表征。结果表明:当掺杂量x=0.05时,Mg2+、Al3+掺杂的正极材料在2.8～4.3V、0.1C下的首次放电比容量分别为139.2、151.6mA·h/g,20次循环后的容量保持率分别为98.8%和96.7%;掺杂Mg2+或Al3+均能提高LiNi1/3Co1/3Mn1/3O2的交换电流密度和锂离子扩散系数。结合实验结果和掺杂离子的离子半径和化学稳定性,解释了掺杂离子在LiNi1/3Co1/3Mn1/3O2晶格中的占位及其在充放电过程中的作用。     

LiOH-Li_2CO_3低共熔混合锂盐体系合成LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2

利用低共熔组成的0.24LiCO3-0.76LiOH混合锂盐体系,与钴、镍、锰的球形氢氧化物按1.1:1混合,无需前期球磨,直接经二段控温程序制备出锂离子正极材料LiNi1/3Co1/3Mn1/3O2。X射线衍射分析表明合成的Li(Ni1/3Co1/3Mn1/3)O2结晶度高,具有规整的层状α-NaFeO2结构,扫描电镜显示产物颗粒均匀,振实密度高达2.89g·cm-3,显著高于用单一锂盐制备的同样产品(2.4g·cm-3)。充放电测试表明,材料具有良好的电性能,首次充放电容量为176和166mhA·g-1,循环50次后,材料的电性能没有明显的衰减。     

前处理工艺对Li[Ni1/3Mn1/3Co1/3]O2正极材料结构、形貌和电化学性能的影响（英文）

以[Ni1/3Co1/3Mn1/3]3O4和氢氧化锂为原料,分别采用球磨法和液相法前处理工艺制备层状正极材料Li[Ni1/3Mn1/3Co1/3]O2。采用X？射线衍射（XRD）、场发射扫描电镜（FESEM）、恒流充放电等手段对材料的物理和电化学性能进行表征。结果表明：采用不同前处理工艺制备出的Li[Ni1/3Mn1/3Co1/3]O2材料在结构、形貌和电化学性能上有较大差异;与球磨处理法制备的材料相比,采用液相法前处理工艺制备的Li[Ni1/3Mn1/3Co1/3]O2不但保持了前驱体较好的球形形貌,同时还具有较好的循环稳定性和倍率性能;该样品在20mA/g电流密度下,首次放电容量为178mA·h/g,50次循环后,容量保持率达98.7%;在1000mA/g电流密度下,样品容量为135mA·h/g。     

合成条件对氢氧化物共沉淀法制备锂离子电池层状正极材料Li[Ni_（1/3）Co_（1/3）Mn_（1/3）]O_2的影响

以共沉淀法制备的过渡金属氢氧化物前驱体合成锂离子电池层状正极材料Li[Ni1/3Co1/3Mn1/3]O2。考察氨与过渡金属阳离子的配位效应对Li[Ni1/3Co1/3Mn1/3]O2材料的结构和电化学性能的影响。SEM分析结果表明,当NH3·H2O与过渡金属阳离子的总摩尔比为2.7：1时,获得了分布均一的颗粒为过渡金属氢氧化物共沉淀,合成的Li[Ni1/3Co1/3Mn1/3]O2材料的平均粒径约为500nm,振实密度接近2.37g/cm3,接近商品化的LiCoO2正极材料的振实密度。XRD分析结果表明,合成的Li[Ni1/3Co1/3Mn1/3]O2材料具有六角晶格层状结构。Li/Li[Ni1/3Co1/3Mn1/3]O2电池在2.8-4.5V电压范围内的0.1C倍率测试结果表明,首次放电容量达181.5mA·h/g,0.5C倍率循环50次后的放电容量为170.6mA·h/g。     

低冰镍衍生的具有高结构稳定性和快速扩散动力学的钠离子掺杂层状LiNi1/3Co1/3Mn1/3O2正极(英文)

通过共沉淀法合成钠离子(Na⁺)掺杂的高稳定性Li_1-xNa_xNi_1/3Co_1/3Mn_1/3O₂(NCM-Na)正极材料。首先论证采用低冰镍提取镍作为合成材料镍源的可行性。其次,在化学试剂合成的NCM(Ni,Co,Mn)材料中预先引入最优含量的Na⁺,占据部分Li⁺位点,实现具有更低Li⁺/Ni²⁺阳离子混排的稳定结构,从而提高其电化学性能。结果表明,当Na⁺掺杂量为1%(质量分数)(x=0.01)时,获得的NCM-Na正极材料在1C电流密度下,循环100次后容量保持率从76.84%提高至89.21%。特别是在5C大电流密度下,循环200次后,可逆放电比容量依然维持在110 mA·h·g^-1。这为杂原子掺杂耦合材料化冶金开发低成本、高性能锂离子电池三元LiNi_1/3Co_1/...     

Li_(1+x)Ni_(0.166)Co_(0.166)Mn_(0.667)O_(2.175+x/2)正极材料的喷雾干燥法合成及电化学性能

采用喷雾干燥法制备锂离子电池用层状富锂锰基正极材料Li(1+x)Ni0.166Co0.166Mn0.667O(2.175+x/2)(x=0.3,0.4,0.5,0.6),通过X射线衍射(XRD)、扫描电子显微镜(SEM)、等离子体发射光谱(ICP)、热重-差热分析(TG-DSC)、比表面积、粒度分布和恒流充放电等测试手段对材料的结构、形貌及电化学性能进行表征。结果表明:所制得的富锂锰基正极材料为三方层状结构(mR3)的LiNi1/3Mn1/3Co1/3O2和单斜层状结构(C2/m)的Li2MnO3组成的固溶体,且具有多孔球形形貌。当x=0.4时,材料具有最优的电化学性能。在2.0~4.8 V电压范围内,25 mA/g电流密度下材料的首次放电比容量高达277.5 mA·h/g,20周循环后容量保持率达95.3%,500 mA/g电流密度下放电比容量仍达192.5 mA·h/g。     

AlF3包覆锂离子电池正极材料Li1.2(Mn0.54Ni0.16Co0.08)O2的制备、表征及电化学性能（英文）

采用溶胶-凝胶法合成锂离子电池正极材料Li1.2(Mn0.54Ni0.16Co0.08)O2,并用Al F3对这种材料进行表面包覆改性。采用X射线衍射(XRD)、扫描电子显微镜(SEM)、高分辨率透射电子显微镜(HRTEM)等表征材料的结构和形貌。结果表明,合成的Li1.2(Mn0.54Ni0.16Co0.08)O2具有典型的层状α-Na Fe O2结构,AlF3均匀包覆在Li1.2(Mn0.54Ni0.16Co0.08)O2材料表面,包覆层厚度为5~7 nm。电化学测试表明,包覆Al F3后材料的电化学性能得到提高,在1C倍率下,包覆的AlF3材料的首次放电容量为208.2 m A·h/g,50次循环后容量保持率为72.4%,而未包覆AlF3的材料的首次放电容量和容量保持率分别为191.7 m A·h/g和51.6%。     

Zn对锂电池材料LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2结构和电化学性能的影响

采用共沉淀法掺入少量Zn得到Li(Ni1/3Co1/3Mn1/3)1-xZnxO2材料。通过X射线衍射、光电子能谱(XPS)和电化学测试研究掺杂对其晶体结构、元素价态和电化学行为的影响。结果表明:掺入Zn增大晶格常数;在粉末颗粒表面的Zn含量是颗粒内部的数十倍;掺杂后Co、Mn依然保持+3、+4价,但是Ni由+2、+3混合价态组成;掺入少量Zn阻止电极在4.5V电位下的不可逆氧化反应;掺入Zn有效改善高截止电压下的循环容量保持能力,其作用与改变材料表面状态有关。     

锰掺杂对锂离子电池正极材料Li3V2（PO4）3/C性能的影响（英文）

采用溶胶-凝胶法合成Li3V2-2/3xMnx(PO4)3(0≤x≤0.12)。采用XRD、SEM、XPS、恒流充放电和电化学阻抗谱(EIS)研究Mn掺杂对Li3V2(PO4)3/C结构和电化学性能的影响。XRD研究表明:掺杂少量的Mn2+不会影响材料的结构,所有样品均具有单一相态的单斜结构(P21/n空间群)。XPS分析表明:在Li3V1.94Mn0.09(PO4)3/C中,V和Mn的化合价分别为+3和+2,原料中的柠檬酸在煅烧过程中分解成C而残留在Li3V1.94Mn0.09(PO4)3/C中。电化学测试表明:掺杂Mn改善了电极材料的循环性能和倍率性能,正极材料Li3V1.94Mn0.09(PO4)3/C表现出最好的循环稳定性和倍率性能。在40mA/g的放电电流密度下,循环100次后,Li3V1.94Mn0.09(PO4)3/C的放电容量从158.8mA·h/g衰减到120.5mA·h/g,容量保持率为75.9%,而未掺杂样品的放电容量从164.2mA·h/g衰减到72.6mA·h/g,容量保持率为44.2%。当放电电流密度增加到1C时,Li3V1.94Mn0.09(PO4)3/C的初始放电容量仍能达到146.4mA·h/g,循环100次后,放电容量保持为107.5mA·h/g。EIS测试表明,掺杂适量的Mn2+减小了电荷转移阻抗,这有利于Li+的脱嵌。     

球形LiNi1/3Co1/3Mn1/3O2的合成及其电化学性能

以化学共沉淀法制备的球形Ni1/3Co1/3Mn1/3CO3为前驱体合成了球形LiNi1/3Co1/3Mn1/3O2,研究LiNi1/3Co1/3Mn1/3O2合成工艺对产物形貌的影响.结果表明直接以前驱体Ni1/3Co1/3Mn1/3CO3与Li2CO3反应合成的LiNi1/3Co1/3Mn1/3O2的一次颗粒较大,以前驱体分解后的氧化物与Li2CO3反应合成的LiNi1/3Co1/3Mn1/3O2的一次颗粒相对细小;合成的LiNi1/3Co1/3Mn1/3O2均为具有层状结构的纯相物质;球形正极材料LiNi1/3Co1/3Mn1/3O2充放电过程中存在一个材料活化的过程,在前10周期充放电时,电池容量处于增加的状态;在2.7～4.3 V的电压范围内1 C倍率下电池的放电比容量达到149 mA·h/g,0.2 C倍率下为158 mA·h/g,经50次循环后容量无衰减.     

不同金属离子价态的前驱体制备球形LiNi1/3Mn1/3Co1/3O2的性能比较

利用共沉淀法和控制结晶氧化法在不同条件下分别制备出低价态球形Ni1/3Co1/3Mn1/3(OH)2和高价态球形Ni1/3Co1/3Mn1/3OOH前驱体,并分别和LiOH·H2O在不同温度烧结合成出球形锂离子正极材料Li(Ni1/3Co1/3Mn1/3)O2.XPS分析表明,制备的高价态球形Ni1/3Co1/3Mn1/3OOH前驱体其过渡金属Ni、Co和Mn的价态分别是2+,3+,4+,XRD分析表明,高价态球形Ni1/3Co1/3Mn1/3OOH前驱体比低价态球形Ni1/3Co1/3Mn1/3(OH)2前驱体具有较高的活性,能够在低温下合成出Li(Ni1/3Co1/3Mn1/3)O2,而且制备的产物结晶度高,阳离子混排程度小,具有规整的层状a-NaFeO2结构.充放电实验表明,由高价态球形Ni1/3Co1/3Mn1/3OOH前驱体制备的Li(Ni1/3Col/3Mn1/3)O2具有优良的充放电性能和循环性能.     

Synthesis of LiNi1/3CO1/3Mn1/3O2 cathode material via oxalate precursor

Using oxalic acid and stoichiometrically mixed solution of NiCl2, CoCl2, and MnCl2 as starting materials, the triple oxalate precursor of nickel, cobalt, and manganese was synthesized by liquid-phase co-precipitation method. And then the LiNi1/3Co1/3Mn1/3O2 cathode materials for Li-ion battery were prepared from the precursor and LiOH-H2O by solid-state reaction. The precursor and LiNi1/3Co1/3Mn1/3O2 were characterized by chemical analysis, XRD, EDX, SEM and TG-DTA. The results show that the composition of precursor is Ni1/3Co1/3Mn1/3C2O4·2H2O. The product LiNi1/3Co1/3Mn1/3O2, in which nickel, cobalt and manganese are uniformly distributed, is well crystallized with a-NaFeO2 layered structure. Sintering temperature has a remarkable influence on the electrochemical performance of obtained samples. LiNi1/3Co1/3Mn1/3O2 synthesized at 900 ℃ has the best electrochemical properties. At 0.1C rate, its first specific discharge capacity is 159.7 mA·h/g in the voltage range of 2.75-4.30 V and 196.9 mA·h/g in the voltage range of 2.75-4.50 V; at 2C rate, its specific discharge capacity is 121.8 mA·h/g and still 119.7 mA·h/g after 40 cycles. The capacity retention ratio is 98.27%.     

Preparation of LiNi1/3Co1/3Mn1/3O2 cathode materials from spent Li-ion batteries

A recycling process including separation of electrode materials by ultrasonic treatment, acid leaching, Fe-removing, precipitation of cobalt, nickel, manganese and lithium has been applied successfully to recycle spent lithium-ion batteries and to synthesize LiNi1/3Co1/3Mn1/3O2. When ultrasonic treatment with 2-nitroso-4-methylphenol（NMP） at 40 ℃ for 15 min, the electrode materials are separated completely. Above 99% of Co, Ni, Mn and Li, 95% of Fe in the separated electrodes are acid-leached in the optimized conditions of 2 mol/L H2SO4, 1：2 H2O2：H2SO4 （molar ratio）, 70 ℃, 1：10 initial S：L ratio, and l h. 99.5% of Fe and less than 1% of Co, Ni, Mn in the leaching solution can be removed in the conditions of initial pH value 2.0-2.5 adjusted by adding 18% Na2CO3, 90 ℃ and stirring time 3 h. After adjusted to be equal by adding NiSO4, COSO4 and MnSO4 solution, 97.1% of Ni, Co, Mn in the Fe-removing surplus leaching solution can be recovered as Ni1/3Co1/3Mn1/3（OH）2. 94.5% of Li in the surplus filtrate after the deposition of Co, Ni and Mn can be recovered as LiECO3. The LiNi1/3Co1/3Mnl/3O2, prepared from the recovered compounds, is found to have good characteristics of the layered structure and elecrtochemical performance.     

Surface modification of spherical LiNi1/3Co 1/3 Mn1/3O2 with Al2O3 using heterogeneous nucleation process

To improve the cycle stability at high voltage and high charge/discharge rate, spherical LiNi1/3Co1/3Mn1/3O2 was coated with Al2O3 by using heterogeneous nucleation process, and the physical and electrochemical properties were studied. The SEM images show that there is a uniform coating on the modified spherical LiNi1/3Co1/3Mn1/3O2. The electrochemical tests indicate that the properties of LiNi1/3Co1/3Mn1/3O2 coated with 0.5% aluminum oxide are the best. The initial capacities are 150 and 173 mA.h/g at the rate of I C in the voltage range of 2.7-4.3 V and 2.7-4.6 V, respectively, and the discharge capacities maintain about 99% and 85% after 30 cycles, respectively. While those of the bare LiNi1/3Co1/3Mn1/3O2 are only 90% and 75%, respectively. The CV tests of LiNi1/3Co1/3Mn1/3O2 show that Al203-coating can restrain the oxide-reduction peak currents fading during the charge/discharge course.     

锂离子电池正极材料LiNi1/3Co1/3Mn1/3O2的制备及性能研究

采用溶胶-凝胶法制备了锂离子电池正极材料LiNi1/3Co1/3Mn1/3O2,并考察了烧结温度对材料结构、表面形貌和电化学性能的影响.XRD和SEM测试结果表明,900℃下烧结得到的样品是粒径在0.3～0.5 μm范围的球形粒子,具有最佳的阳离子有序度;充放电测试结果表明,其在0.1C倍率下首次放电容量达到148.8...     

Effect of calcination temperature on characteristics of LiNi1/3Co1/3Mn1/3O2 cathode for lithium ion batteries

LiNi1/3Co1/3Mn1/3O2 was synthesized by sol-gel method and effect of calcination temperature on characteristics of LiNi1/3Co1/3Mn1/3O2 cathode was investigated. The structure and characteristics of LiNi1/3Co1/3Mn1/3O2 were determined by XRD, SEM and electrochemical measurements. The results show that the compound LiNi1/3Co1/3Mn1/3O2 has layered structure with hexagonal lattice. With the increase of calcination temperature, the basicity of the material decreases, and the size of primary particle rises. The LiNi1/3Co1/3Mn1/3O2 calcined at 900 ℃ for 12 h shows excellent electrochemical performances with large reversible specific capacity of 157.5 mA-h/g in the voltage range of 2.75-4.30 V and good capacity retention of 94.03% after 20 charge/discharge cycles. Capacity of LiNi1/3Co1/3Mn1/3O2 increases with enhancement of charge voltage limit, and specific discharge capacities of 179.4 mA.h/g, 203.1 mA.h/g are observed when the charge voltages limit are fixed at 4.50 V and 4.70 V, respectively.     

正极材料Li（Ni1／3Co1／3-xMn1／3）MxO2（M=Ti，Mg）的合成及性能

采用草酸盐前驱体合成Ti4+、Mg2+掺杂正极材料Li(Ni1/3Co1/3-xMn1/3)MxO2(M=Ti, Mg).利用XRD和SEM对其结构和形貌进行表征,并采用循环伏安、交流阻抗、恒流/恒压充放电测试其电化学性能.结果表明:Ti4+、Mg2+掺杂后晶胞体积增大,大倍率充放电时LiNi1/3Co1/3Mn1/3O2的电化学反应阻抗Rct降低,其大倍率充放电性能得到改善,Ti4+掺杂效果更好;当掺杂量x＝0.025时,材料晶型完整,具有单一的a-NaFeO2层状结构;1C倍率时Li(Ni1/3Co1/3-0.025Mn1/3)Ti0.025O2的第二循环放电容量为143.2 mA-h/g,2C时为128.0 mA-h/g,经100次循环后容量分别为132.5和115.8 mA-h/g,容量保持率为92.53%和90.47%.     

锂离子电池正极材料LiNi_1/3Co_1/3Mn_1/3O_2的研究进展

介绍了一种新型的锂离子电池正极材料LiNi1/3Co1／3Mn1／3O2的最新研究状况,描述了材料的晶体及电子结构,以及电化学性能;重点总结了现今国内外制备此材料的几种主要合成方法及研究进展;同时,介绍了不同掺杂元素（Fe、B、Al、Ti）对材料的改性作用。     

Li(Mn1/3Ni1/3Co1/3)1-yMyO2(M=Al,Mg,Ti)正极材料的制备及性能

采用液相共沉淀合成锰镍钴氢氧化物前驱体, 在前驱体中掺入元素M(M=Al, Mg, Ti), 与锂结合生成Li(Mn1/3Ni1/3Co1/3)0.98M0.02O2材料, 结果表明掺杂可有效提高材料的循环性能. X射线衍射结果表明 随掺钛量增大(0≤y≤0.15), 晶格畸变增大, 半高宽变大, 晶粒粒径增大; 其中掺钛量y=0.1的材料电化学性能表现最好, 以20 mA/g电流充放电, 在2.5～4.6 V电压区首次放电容量可达215 mA·h/g.