多元稀土掺杂锂锰氧正极材料的结构及性能表征

采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、电池性能测试系统研究了多元稀土掺杂锂锰氧正极材料的相结构、形貌,并对其活化性能、循环稳定性能进行了表征。结果表明:采用Pechini法合成多元稀土掺杂LiMn2O4样品时,只有将掺杂元素的含量严格控制在一定范围内,所合成的LiMn2O4、LiLa0.03Mn1.97O4、LiLa0.012Ce0.012Mn1.976O4、LiLa0.012Nd0.012Mn1.976O4、LiCe0.012Nd0.012Mn1.976O4样品才具有纯尖晶石型LiMn2O4结构。当稀土掺杂元素含量较高时,所合成的LiLa0.015Ce0.015Mn1.97O4、LiLa0.015Nd0.015Mn1.97O4、LiCe0.015Nd0.015Mn1.97O4样品由LiMn2O4相及微量杂质相CeO2、Nd2O3、CeO2+Nd2O3组成。所有样品呈规则的近球形或球形,其粒径范围为0.5～2.8μm。适量的稀土元素掺杂将使LiMn2O4材料的初始容量减小、充放电效率及循环稳定性能增加,LiCe0.012Nd0.012Mn1.976O4样品具有较好的综合电化学性能,其初始容量为123.5mAh/g,经30次循环充放电后的容量为113.2mAh/g,为相同条件下LiMn2O4样品放电容量的1.27倍。     

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.     

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。     

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。     

微乳液法制备锂离子电池用 ZnMn2O4/Mn3O4亚微米棒及其转化反应机理

采用油包水微乳液法再经煅烧制备分级ZnMn2O4/Mn3O4复合亚微米棒.ZnMn2O4/Mn3O4电极在550次连续放电/充电循环中,在500 mA/g充放电电流条件下,其比容量从440 mA·h/g增加到910 mA·h/g,并在100 mA/g下提供1276 mA·h/g的超高比容量,远高于ZnMn2O4或Mn3...     

基于控制结晶法制备的锂离子电池正极材料球形锰酸锂

采用控制结晶法,以MnSO4,NH4HCO3和氨水为原料制备了球形MnCO3.所得产品的振实密度为2.1g/cm3,粉末粒度约为20 μm.研究了MnCO3在不同温度下的热分解性能,对热分解产物的差热/热重分析和X射线衍射分析发现,MnCO3的热分解反应分两步进行,在300℃时开始分解,生成中间产物MnO2;在520℃时,MnO2开始转化为Mn2O3,至560℃时完全转化为立方相的球形Mn2O3.实验所确定的MnCO3完全分解为立方相球形Mn2O3的最佳条件为在560℃下加热4 h.以LiCO3为锂源材料,在750℃下与球形Mn2O3一起焙烧,制备得到球形LiMn2O4.其在25℃和0.4C倍率下的首次充放电容量分别为131和125 mA·h/g,90次循环的容量保持率为84%.     

LiMn2O4/Li4Ti5O12复合材料的制备与电化学性能

以LiMn2O4、醋酸锂和钛酸四丁酯为原料,乙醇为溶剂,采用原位复合法制备LiMn2O4/Li4Ti5O12复合材料.采用X射线衍射分析、红外光谱、扫描电镜和电化学测试等手段对复合材料进行表征.结果表明,在LiMn2O4/Li4Ti5O12复合材料中晶态的LiMn2O4表面被无定形结构的Li4Ti5O12包覆,但Li4Ti5O12的存在并没有改变LiMn2O4的晶体结构.由于Li4Ti5O12的包覆,LiMn2O4的倍率性能和高温性能都得到显著提高:室温下2.0C放电时20次循环后LiMn2O4/Li4Ti5O12复合材料的可逆容量达到108.4mA·h/g,平均每次循环的容量损失只有0.053%;而55 ℃ 1.0C放电时,经60次循环后LiMn2O4/Li4Ti5O12的放电容量为109.9 mA·h/g,平均每次循环的容量损失为0.036%.     

PAA络合法制备LiMn_2O_4粉体及其电化学性能

采用络合法并结合热处理工艺制备LiMn2O4粉体,考察了热处理温度对LiMn2O4粉体结构、形貌及电化学性能的影响。结果表明:以聚丙烯酸(PAA)、硝酸锂和硝酸锰为原料,在一定温度下合成了稳定的溶胶和凝胶,在不同的煅烧温度下制得了LiMn2O4粉体。随着煅烧温度的升高,粉体颗粒逐渐增大,晶型趋于完整。700℃下煅烧10 h制得的LiMn2O4颗粒大小均匀,晶型完整且没有明显团聚现象。0.1 C倍率首次放电比容量达到118 mA·h/g,经80次循环后仍能达到112 mA·h/g,容量保持率高达95%,表现出良好的循环稳定性。     

F-掺杂LiMn2O4的合成及电化学性能

采用溶胶-凝胶法合成掺杂F^-的LiMn2O4。通过XRD、SEM对掺杂F-的LiMn2O4材料的组成、结构、微观形貌等进行分析与表征,测试不同F^-掺杂量的LiMn2O4在常温（20℃）、高温（55℃）下的电化学性能。结果表明：所合成的材料具有良好的尖晶石立方结构,无杂相;F^-的掺杂提高了材料的比容量,增强了材料的稳定性,改善了其在高温下的循环性能。当F^-的掺入量x由0增加到0.1时,材料的比容量由119.7 mA.h/g增加到124.9 mA.h/g,高温下充放电30个循环后容量保持率由79.4%增加到84.4%。     

LiMg_(0.03)(Ni_(0.77)Co_(0.1)Mn_(0.1))O_2·B_2O_3球形高镍材料的制备与性能

采用液相共沉淀法制备球形掺镁高镍三元材料前驱体,结合高温固相法制备了氧化硼包覆高镍三元材料LiMg0.03(Ni0.77Co0.1 Mn0.1)O2·B2O3,对样品物理性能、电化学性能及安全稳定性进行分析测定,并对性能改善的机理进行分析。结果表明:通过Mg元素体相掺杂和B2O3表面包覆制备的球形高镍三元材料LiMg0.03(Ni0.77Co0.1Mn0.1)O2·B2O3具有良好的电化学性能和物理性能,对锂负极初始放电容量达到181 m A·h/g,对碳负极300次循环后,放电容量保持率达到92%,压实密度达到3.9 g/cm3。同时,LiMg0.03(Ni0.77Co0.1 Mn0.1)O2·B2O3具有良好的热稳定性和抗过充电的能力,在充电态下热分解温度比未掺杂和未包覆的样品提升12℃。     

Synthesis and physicochemical properties of LiLa0.01Mnt.99O3.99F0.01 cathode materials for lithium ion batteries

Spinel lithium manganese oxide cathode materials were synthesized using the ultrasonic-assisted sol-gel method.The synthesized samples were investigated by differential thermal analysis (DTA) and thermogravimetry (TG),powder X-ray diffraction (XRD),scanning electron microscopy (SEM),cyclic voltammetry (CV),and the charge-discharge test.TG-DTA shows that significant mass loss occurs in two temperature regions during the synthesis of LiLa0.01Mn1.99O3.99F0.01.XRD data indicate that all samples exhibit the same pure spinel phase,and LiLa0.01Mn1.99O3.99F0.01 and LiLa0.01Mn1.99O4 samples have a better crystallinity than LiMn2O4. SEM images indicate 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 130,123,and 126 mAh·g-1,respectively,and the capacity retention rates of the initial value,after 50 cycles,are 84.8%,92.3%,and 92.1%,respectively.The electrode coulomb efficiency and CV reveal that the electrode synthesized by the ultrasonic-assistexi sol-gel (UASG) method has a better reversibility than the electrode synthesized by the sol-gel method.     

Synthesis and characterization of multidoped lithium manganese oxide spinel LiCo0.02La0.01Mn1.97O3.98Cl0.02

1 Introduction The cathode material plays an important role in the performance of lithium ion batteries. Lithium transition metal compounds with layered and spinel structure are favourites among cathode materials for lithium rechargeable batteries. In thi…     

Mg、F复合掺杂尖晶石LiMg0.1Mn1.9O3.95F0.05的合成和电化学行为研究

以己二酸为配位体采用溶胶-凝胶法合成了LiMn2O4,Mg掺杂或Mg和F复合掺杂的尖晶石锂镁氧化物正极材料.对合成出的样品采用X-射线衍射仪、X-光电子能谱、扫描显微电子镜、循环伏安测试和充放电测试仪进行了详细的研究.X-射线衍射结果表明,所有的样品都具有相同的纯尖晶石相,LiMg0.1Mn1.9O4和LiMg0.1Mn1.9O3.95F0.05与LiMn2O4的样品相比,具有较小的晶格参数和晶胞体积.X-光电子能谱试验结果表明,在LiMn2O4中,Mn3 和Mn4 的相对量分别为50.2%和49.8%,而LiMg0.1Mn1.9O3.95F0.05中Mn3 和Mn4 的相对量分别为48.4%和51.6%.扫描电镜结果显示,LiMg0.1Mn1.9O3.95F0.05颗粒尺寸略小、尺寸分布窄,形态结构更为规整.循环伏安实验显示,Mg和F复合掺杂的尖晶石具有更好的可逆性.LiMn2O4,LiMg0.1Mn1.9O4,LiMg0.1Mn1.9O3.95F0.05样品的首次放电能量和能量保持率分别为123、111、114 mAh·g-1和86.5%、92.3%、90.9%,且LiMg0.1Mn1.9O4和LiMg0.1Mn1.9O3.95F0.05具有比LiMn2O4更高的库仑效率.     

Powder electrochemical properties with different particle sizes of spinel LiAl0.05Mn1.95O4 synthesized by sol-gel method

An Al-doped spinel lithium manganese oxide was prepared by the adipic acid-assisted sol-gel method at 800℃, and the cathode materials （Liml0.05Mnl.9504） with different particle sizes were obtained through ball milling. The effects of particle size on the electrochemical performance of LiAl0.05Mnl.9504 samples were investigated by differential thermal analysis and thermogravimetry, X-ray diffraction, galvanostatic charge-discharge test, cyclic voltammetry, and electrochemical impedance spectroscopy. The results indicate that all samples with different particle sizes show the same pure spinel phase and good crystal structure; LiAlo.osMnl.9504 with Dso = 17.3 μm shows better capacity retention; LiAlo.osMnl.gsO4 cathode materials with small particle size have a bigger resistance of charge transfer than the large one, and the particle size has significant effects on the electrochemical performance of Al-doped spinel LiMn2O4 cathode materials.     

Synthesis and character of spinel LiMn2O4

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

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。     

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.     

Structure and electrochemical performance of spinel LiMn2O4 synthesized by mechanochemical process

1　INTRODUCTIONLithium ion battery was used in many areasbecause of its high voltage, high energy densityand long cycle life and so on. Spinel lithium man ganese oxide was one of the most promising mate rials in term of its environmental benign, low cost,easy preparation and temperature safety. Mainproblem is the poor cycle life. As we all know thatboth the structure and electrochemical performanceof material strongly depended on the preparingmethod and starting…