尖晶石LiMn2O4和LiCoO2与电解液的相容性

研究锂离子电池正极活性材料尖晶石LiMn2O4和LiCoO2与6种电解液充、放电时的相容性。用X射线衍射检测自制的LiCoO2试样和尖晶石LiMn2O4试样的结构；用粉末微电极循环伏安法测定6种电解液在导电剂乙炔黑表面的氧化电位；将制得的尖晶石LiMn2O4试样和LiCoO2试样在上述电解液中进行恒电流充放电实验。结果表明：充电至高电位3．3～4．3V（vs Li／Li^＋）时，如果正极活性材料表面与电解液发生不可逆反应并在其上覆盖一薄层电子不可导的钝化膜，则将导致活性材料的充、放电效率降低，放电容量减少，即正极活性材料与电解液的相容性差；反之，则相容性好；尖晶石LiMn2O4与上述6种电解液的相容性都很好，普适性强；LiCoO2与上述6种电解液的相容性差别较大，呈选择性。     

以Mn3O4为前驱体制备尖晶石型LiMn2O4及其性能

采用改进的固相反应法合成了高性能的锂离子电池正极材料LiMn2O4。首先,以廉价的MnSO4为原料,通过水解氧化法制备纳米级Mn3O4前驱体;然后,将Mn3O4和Li2CO3混合均匀,在750℃固相反应20 h,得到尖晶石型LiMn2O4。用X射线衍射(XRD)和扫描电镜(SEM)对Mn3O4前驱体和LiMn2O4样品进行表征,用充放电测试和循环伏安技术对LiMn2O4样品进行电化学性能研究。结果表明:所制备的LiMn2O4具有完整的尖晶石型结构,且晶体粒子分布均匀。所制备的LiMn2O4材料在3.0~4.4 V之间,室温(25℃)下,在0.2C倍率下首次放电比容量为130.6 mA.h/g;在0.5C倍率下首次放电比容量为127.1 mA.h/g,30次循环后,容量仍有109.5 mA.h/g,且样品具有较好的高温性能。     

Synthesis and character of spinel LiMn2O4

1　INTRODUCTIONTheincreasingconcernsonportableelectricele mentsdemandmoreandmoreelectrochemicalener gy .Countriesallovertheworldhaveputlargequan tityofmanuallabors ,materialresourcesandfinancialresourcesonbasicresearchanddevelopmentonnewtypeofrechargeablebatteries[1,2 ] .However ,thisnewtypeofbatteriesisbasedonstudyinganddevel opingperfectperformanceofmaterials ,especiallyonmaterialsofthelithiumbatteries.LixMn2 O4 cathodematerialshavebeenwidelystudiedoverthelasttwodecadesasapotentialcand…     

Mg-Y共掺杂高电压钴酸锂正极材料的合成及其性能研究

将Co3O4、Li2CO3、Mg(OH)2 和Y2O3 按一定化学计量比称取并混合均匀后,采用高温固相法合成LiCo1-x-yMgxYyO2正极材料并探究了Mg-Y 共掺杂对钴酸锂高电压性能的影响.采用X 射线衍射(XRD)和扫描电镜(SEM)分别表征其晶体结构和形貌.LiCo1-x-yMgxYyO2正极材料高电压性能...     

耐久型高倍率性能锰酸锂微球的合成(英文)

以Mn2+和NH4HCO3为原料,通过控制结晶法合成球形MnCO3前驱体模板。以LiNO3和MnCO3为原料,按照一定的摩尔比机械混合,在700°C下煅烧8h,合成高倍率性能和长循环性能的球形尖晶石LiMn2O4材料。分别考查原料的摩尔比、反应时间以及反应温度对前驱体MnCO3形貌和产率的影响。采用X射线粉末衍射和扫描电镜对合成的MnCO3和LiMn2O4进行表征,对LiMn2O4样品进行室温条件下的充放电性能测试。电化学测试结果表明:尖晶石锰酸锂微球在10C的放电倍率下的首次放电容量达90mA·h/g(1C放电容量为148mA/g),800次循环后容量保持率达到75%。该方法合成的LiMn2O4微球作为高功率型锂离子电池的正极材料有着较好的应用前景。     

Synthesis and characterization of Li_(1.3)Al_(0.3)Ti_(1.7)(PO_4)_3-coated LiMn_2O_4 by wet chemical route

Li1.3Al0.3Ti1.7(PO4)3-coated LiMn2O4 was prepared by wet chemical route. The phase,surface morphology,and electrochemical properties of the prepared powders were characterized by X-ray diffraction,scanning electron micrograph,and galvanostatic charge-discharge experiments. Li1.3Al0.3Ti1.7(PO4)3-coated LiMn2O4 has similar X-ray diffraction patterns as LiMn2O4. The corner and border of Li1.3Al0.3Ti1.7(PO4)3-coated LiMn2O4 particles are not as clear as the uncoated one. The two powders show similar values of l...     

Microwave synthesis of LiCoO2 cathode materials

1INTRODUCTION LiCoO2isacommerciallyusedcathodemateri alforlithiumionbattery.Comparedwithothercathodematerials,suchasLiNiO2,LiMn2O4and theirdopedcompounds,LiCoO2hastheadvanta gesofhighpotential,excellentreversibility,longcyclelifeandreliableperformance[14].Thereare mainlyseveralmethodsforsynthesisofLiCoO2,suchasconventionalceramicmethod[5,6],sol gel synthesis[7],andlow temperaturesolutioncom bustion[8].Amongthesemethods,theconvention alceramicmethodhasbeenappliedtoindustrial productio…     

电解二氧化锰预处理对制备锰酸锂性能的影响(英文)

分别采用酸洗、预烧、浸渍掺铬的方式对电解二氧化锰(EMD)进行预处理,研究EMD预处理对制备锰酸锂性能的影响。采用XRD、ICP等手段对预处理的EMD及制备的锰酸锂进行表征,并通过Li/LiMn2O4电池的充放电测试对其电化学性能进行评估。结果表明,酸洗后EMD中的钠、硫等无机杂质含量显著降低;预烧能够有效去除EMD吸附的水分和有机杂质,扩大孔径,增多反应活性位点;对EMD进行浸渍掺铬的预处理,能够得到更加均质的掺铬锰酸锂材料LiCr0.05Mn1.95O4,并表现出较好的结构稳定性及容量保持率。     

Structure and electrochemical properties of LiMn2O4

LiMn2O4, a cathode material of lithium ion battery, was prepared by the citric acid complexing method using lithium acetate and manganese acetate as raw materials. The type of atom location confused degree, the confused degree and judgement method in LiMn2O4 were analyzed. The effect of sintering temperature on structure and electrochemical properties of LiMn2O4 was also investigated. The results show that the atom location confused degree increases with the decrease of the X-ray diffraction peak intensity ratio of LiMn2O4, Ⅰ111/Ⅰ311. The type of atom location confused degree depends on the variation tendency of Ⅰ111/Ⅰ311 and Ⅰ311/Ⅰ400 value. If the variation tendency is the same, it belongs to the 16c type location confusion, however, if the variation tendency is contrary, it belongs to the anti-spinel type location confusion. When the sintering temperature is low, it is apt to produce the anti-spinel location confusion in LiMn2O4. With the increase of sintering temperature, the confused degree with the anti-spinel type gradually reduces, however, the confused degree with 16c type increases to some extent. When the atom location confusion with the anti-spinel type appears in LiMn2O4, both the initial discharging capacity and cycling properties of LiMn2O4 reduce. However, the atom location confusion with 16c type does not affect the charge and discharge properties of LiMn2O4.     

SYNTHESIZING KINETICS AND MICRO-CHARACTERIZATIONOF SPINEL LiMn2O4 FOR LITHIUM-ION BATTERYCATHODE MATERIAL

1. IntroductionLithiumion cells are the third generation of rechargeable batteries following by nickel-cadmium cells and nickel-hydrogen cells. They could be named aJs "green batteries" byvirtue8 of lower self resistance, little self discharge, no memorizing effect and no pollution.Recently, cathode materials has been much more studied such as lithiumrich transitionmetal oxides that are lithium-cobalt system, lithium-nickel system and lithium-manganesesystem[1l21. The consumption of cobalt is…     

Synthesis and Electrochemical Studies on Spinel Phase LiMn2O4 Cathode Materials Prepared by Different Processes

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锂离子电池及相关材料进展

新能源技术对人类社会未来可持续发展至关重要,锂离子电池可望大规模应用于电动汽车和太阳能、风能等清洁电能的储存。电动汽车电池还面临重量、体积、寿命、安全、成本和系统可靠性等诸方面的挑战。评述了钴酸锂、锰酸锂、三元材料和磷酸铁锂等正极材料;石墨、钛酸锂等负极材料;电解质材料和隔膜材料等的研究和应用,重点介绍了正极材料的掺杂和表面修饰改性技术。并对电池技术的进步和新一代锂离子电池应用于电动车辆和智能电网的前景进行了展望。     

Electrochemical performances and structure characteristic of LiMn2O4-xYx（Y=F, Cl, Br） compounds

Spinel LiMn2 O4-x Yx (Y=F, Cl, Br) compounds were prepared by solid-state reaction and the electrochemically galvanostatic charge-discharge cycles were performed using as-prepared compounds as cathode material. The influence of halogens on their lattice constants and the relation of electrochemical properties and their lattice constants were investigated. It is concluded that when the lattice constants are smaller than that of LiMn2O4, the reversible capacity fade is suppressed and the initial capacity sacrifice is observed. When the content of fluorine is 0.05, the lattice constant of LiMn2O3.95 F0.05 is larger than that of LiMn2O4, the initial capacity is improved. An efficient method was found to control the lattice constants of LiMn2O4 through the addition of halogen, and to improve the electrochemical performance of LiMn2O4. The LiMn2O3.95 F0.05 shows excellent electrochemical charge-discharge performance, with high initial capacity of 143 mAh/g and nearly no capacity loss after 116 cycles.     

合成温度对LiMn1.95Mg0．05O4结构与性能的影响

用柠檬酸辅助溶胶一凝胶法在不同温度下合成了LiMn1.95Mg0．05O4正极材料。用X射线衍射、充放电测试以及电化学阻抗谱分析技术研究了不同合成温度对LiMn1.95Mg0．05O4结构和电化学性能的影响。结果表明：合成温度对LiMn1.95Mg0．05O4正极材料的晶相结构、电化学性能有显著影响,LiMn1.95Mg0．05O4尖晶石相的生成和长大与其合成的温度有密切的关系,合成的最佳温度为750℃;在750℃条件下合成的LiMn1.95Mg0．05O4具有较高的电化学活性和较好的晶相结构;高温合成有利于提高LiMn1.95Mg0．05O4正极材料的放电容量,低温合成有利于提高其循环性能。     

掺杂元素La、F对尖晶石LiMn2O4材料结构及性能的影响

采用X-射线衍射仪(XRK)、扫描电子显微镜(SEM)、电池测试系统等研究了掺杂元素La、F对高温固相合成尖晶石型LiMn2O4材料的相结构、貌、活化性能、循环稳定性能的影响.结果表明:掺杂元素La、F可有效地提高LiMn2O4样品的充放电效率、循环稳定性能:随着掺杂元素F含量的增加,LiMn2O4-xFx样品的初始容量降低、循环稳定性能呈现出先增后减的变化规律;当掺杂元素La、F的含量较少时,LiLay,Mn2-yO4-xFx样品具有纯的尖晶石LMn2O4结构,样品呈球形或近球形,粒径范围为0.5～2.5 μm,LiLa0.02Mn1.98O3.95F0.05样品的初始放电容量为123.6mAh/g,经30次循环充放电后的容量为114.6mAh/g,容量保持率为92.7%,具有较好的活化性能和循环稳定性能.     

锰酸锂电池储存后容量衰减机理

采用商品化的LiMn2O4制作锰酸锂/石墨电池,研究其储存性能,并对储存前后的正极、负极和电解液进行表征分析。结果表明:半荷电常温储存一个月,电池容量衰减3.7%,循环性能得到改善。X射线衍射和透射电镜结果表明:LiMn2O4晶格发生收缩,正极表面形成一层固体电解质(SEI)膜。交流阻抗研究表明:正极阻抗由储存前的62.69Ω增大到储存后的84.64Ω,负极阻抗由储存前的183.1Ω增大到储存后的301Ω。红外光谱分析表明:电解液溶剂和电解质盐均不同程度地发生了分解,锰酸锂电池储存后容量衰减主要是由电极极化、Mn溶解、电解液分解、负极SEI膜增厚等原因造成。     

掺Cr对LiMnO2的影响

采用固相反应合成了LiMnO2和LiMn0.9Cr0.1O2，Cr的加入改变了LiMnO2的结构，与LiMnO2正交结构(空间群Pmnm)相比，LiMn0.9Cr0.1O2具有单斜结构(空间群C2／m)。充放电过程中，LiMnO2和LiMn0.9Cr0.1O2结构产生向尖晶石结构的不可逆转变。在首次放电过程中，LiMnO2只存在2．9V的电压平台，随着循环次数的增加，在2．9V和4V电压平台容量都有所增加。与LiMnO2不同，LiMn0.9Cr0.1O2在首次放电过程中存在有2．9V和4V电压平台，随着循环次数的增加，4V电压平台容量逐渐减小，在一定循环次数下，只有2．9V的电压平台存在。因此，Cr的掺杂不仅改变了LiMnO2的结构，而且改变其电化学行为。     

Surface modification and characterization of F-Co doped spinel LiMn2O4

Spinel LiCo0.09Mn1.91O3.92F0.08 as cathode material was modified with LiCoO2 by the sol-gel method, and the crystal structure, morphology and electrochemical performance were characterized with XRD, SEM, EDS, AAS and charge-discharge test in this paper. The results show that a good clad coated on parent material can be synthesized by the sol-gel method, and the materialswith modification have perfect spinel structure. LiCo0.09Mn1.91O3.92F0.08 materials coated by LiCoO2 improve the stability of crystal structure and decrease the dissolution of Mn into electrolyte. With the LiCoO2 content increasing, the specific capacity and cycle performance of samples are improved. The capacity loss is also suppressed distinctly even at 55 ℃.     

Preparation and characterization of LiMn1. 5 Me0.5O4（Me=Ti, Fe, Ni, Zn） for lithium-ion battery cathode materials

Based on synthesizing pure spinel type lithium manganese oxides, the derivations such as LiMn1.5Ti0.5O4, LiMn1.5Fe0.5O4, LiMn1.5Ni0.5O4 and LiMn1.5Zn0.5O4 were prepared using solid-step-sintering method. The structures were characterized by using XRD, SEM and laser granulometer. The electrochemical measurement results show that the element of iron or nickel can raise the discharging plateau voltage of LiMn2O4 , and element titanium improves the electrochemistry property of LiMn2O4 little, while element zinc destroys the electrochemistry property of LiMn2O4. The influence of elements of titanium, iron, nickel, or zinc on the structure of LiMn2O4 pure phase was discussed from the viewpoint of structural chemistry.     

锂离子电池正极材料锰酸锂派生物LiMn1.75Me0.25O4(Me=Ti, Fe, Ni)的制备与表征

在合成纯相尖晶石型锰酸锂的基础上 ,采用固相分段法制备了锰酸锂派生物LiMn1.75Ti0 .2 5O4 ,LiMn1.75Fe0 .2 5O4 和LiMn1.75Ni0 .2 5O4 。用XRD ,SEM和粒度测试仪分别对试样进行了表征。电化学检测表明 ,Fe和Ni元素能够提高锰酸锂的放电平台电压 ,Ti元素不能改善锰酸锂的电化学性能。从结构化学角度初步探讨了Fe ,Ni和Ti元素对纯相尖晶石型锰酸锂结构的影响。