Li2ZrO3包覆LiNi0.8Co0.1Mn0.1O2的复合材料及其电化学性能

以Zr（NO₃）₄·5H₂O和CH₃COOLi·2H₂O为原料,采用湿化学法,将Li₂ZrO₃包覆在LiNi_0.8Co_0.1Mn_0.1O₂锂离子电池正极材料的表面,研究Li₂ZrO₃不同包覆比例对LiNi_0.8Co_0.1Mn_0.1O₂电化学性能的影响。SEM、TEM、EDS谱图分析表明,Li₂ZrO₃层均匀地包覆在LiNi_0.8Co_0.1Mn_0.1O₂表面,其厚度约为8 nm。与纯相相比,1%（质量分数） Li₂ZrO₃包覆的LiNi_0.8Co_0.1Mn_0.1O₂复合材料在1.0 C下首次放电比容量为184.7 mA·h·g^-1、100次循环之后放电比容量为169.5 mA·h·g^-1,其容量保持率达到91.77%,表现出良好的循环稳定性。循环伏安（CV）和电化学阻抗（EIS）测试结果表明,Li₂ZrO₃包覆层抑制了正极材料与电解液之间的副反应,减小了材料在循环过程中的电荷转移阻抗,从而提高了材料的电化学性能。     

Li3VO4修饰富镍LiNi0.8Co0.1Mn0.1O2正极材料的电化学性能

采用湿法融合技术及高温固相法合成Li₃VO₄包覆的LiNi_0.8Co_0.1Mn_0.1O₂正极材料。通过X射线衍射（XRD）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）等方法研究材料的结晶相、形貌、微观结构。研究表明,Li₃VO₄均匀地包覆在LiNi_0.8Co_0.1Mn_0.1O₂表面,未改变原材料的材料结构和形貌,包覆层厚度为1～2 nm。不同含量的Li₃VO₄对LiNi_0.8Co_0.1Mn_0.1O₂正极材料进行修饰研究表明,3%（质量）Li₃VO₄包覆的LiNi_0.8Co_0.1Mn_0.1O₂在1 C下100次循环后容量保持率为94.13%,具有最佳的倍率性能和循环性能。此外,循环伏安（CV）和交流阻抗（EIS）分析表明,Li₃VO₄能提高Li⁺电导率,抑制活性材料与电解液之间的副反应,提高材料的电化学性能。     

层状锂离子电池正极材料LiNi0.8Co0.1Mn0.1O2的制备及性能

采用共沉淀法得到前驱体Ni0.8Co0.1Mn0.1(OH)2,利用前驱体与LiOH×H2O的高温固相反应得到高振实密度的锂离子电池层状正极材料LiNi0.8Co0.1Mn0.1O2 (2.3~2.5 g/cm3). 初步探讨了合成条件对材料电化学性能的影响. 通过X射线衍射(XRD)、扫描电镜(SEM)、热重-差热分析(TG/DTG)以及恒电流充放电测试对合成的样品进行了测试和表征. 结果表明,在750℃、氧气气氛下合成的材料具有较好的电化学性能. 通过XRD分析可知该材料为典型的六方晶系a-NaFeO2结构;SEM测试发现产物粒子是由500~800 nm的一次小晶粒堆积形成的二次类球形粒子. 电化学测试表明,其首次放电容量和库仑效率分别为168.6 mA×h/g和90.5%, 20次循环后容量为161.7 mA×h/g,保持率达到95.9%,是一种具有应用前景的新型锂离子电池正极材料.     

共沉淀法制备Li[Ni1/3Co1/3Mn1/3]O2及电化学性能研究

采用NH3-NaOH共沉淀法合成了L[Ni1/3Co1/3Mn1/3]O2正极材料,通过改变NH3·H2O浓度及加料方式研究材料的电化学性能.采用XRD、SEM对晶体的结构和形貌作表征.将正极材料Li[Ni1/3Co1/3Mn1/3]O2制成电极极片,组装成电池进行测试.分析测试结果表明,合成的极材料Li[Ni1/3Co1/3Mn1/3]O2具有典型的α-NaFeO2结构,粒径分布较好,呈类球形.     

基于水热/溶剂热法制备不同形貌LiNi0.8Co0.1Mn0.1O2 锂离子电池正极材料

基于水热/溶剂热法制备LiNi_0.8Co_0.1Mn_0.1O₂电极材料,以镍、钴、锰乙酸盐为原料,以六亚甲基四胺为沉淀剂、水或乙醇为溶剂,通过调节溶剂组分控制Ni_0.8Co_0.1Mn_0.1（OH）₂（NCM）的成核与生长速率,从而合成两种形貌不同的Ni_0.8Co_0.1Mn_0.1（OH）₂前驱体,再经过混锂煅烧获得LiNi_0.8Co_0.1Mn_0.1O₂正极材料,研究比较了其电化学性能。以水为溶剂通过水热法合成的前驱体样品呈现出由一次片状颗粒紧密堆积组成的长方体状二次颗粒形貌,经混锂煅烧得到的产物表现出较高的放电比容量,在0.5C倍率下首次放电比容量可达到189.70 mA·h/g,循环200次容量保持率为69.72%。以乙醇为溶剂通过溶剂热法合成得到球形二次颗粒前驱体,最终得到的产物具有多孔球形结构,表现出了优异的循环性能,0.5C首次放电比容量为178.65 mA·h/g,循环200次容量保持率仍高达94.55%。     

正极材料LiNi0.8Co0.1Mn0.1O2的合成工艺优化及电化学性能

采用高温固相法合成锂离子电池富镍三元材料LiNi_0.8Co_0.1Mn_0.1O₂,对其工艺条件进行优化,对产物进行X射线衍射（XRD（,扫描电镜（SEM（以及电化学性能分析。结果表明：在氧气气氛下,锂与金属元素摩尔比为1.05:1、烧结时间15 h、烧结温度750℃为最佳合成工艺条件。按最佳工艺合成的样品在1C首次放电容量高达174.9 mA·h·g^-1,50次循环后比容量为158.5 mA·h·g^-1,容量保持率为90.62%,表现出良好的循环稳定性。XRD和SEM表征表明,在氧气气氛下烧结的样品有良好的层状结构,阳离子混排程度小,具有较好的类球形,粒径均匀分布在10~20 μm。循环伏安（CV（和电化学阻抗（EIS（结果表明,工艺条件的优化有助于提高正极材料的电化学性能。     

锂离子电池高镍三元正极材料LiNi0.8Co0.1Mn0.1O2的性能研究

富镍正极材料(LiNi0.8Co0.1Mn0.1O2)具有高容量的优点,是锂离子电池正极材料最有潜力的材料之一。为确定最佳合成条件,本工作研究了合成温度对材料性能的影响,并详细分析了材料电化学性能衰减的原因以及循环过程中材料结构的变化。采用热重/差示扫描量热法(TG/DSC)、X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(HRTEM)、能谱仪(EDS)、X射线光电子能谱(XPS)等手段对合成的正极材料进行了物化表征,并对其电化学性能进行测试。结果表明,在低温段500℃保温4 h,高温段750℃保温14 h合成的正极材料NCM750在0.2 C首次放电比容量为186.2 mAh/g,首次充放电效率为82.5%,1 C放电比容量为185.1 mAh/g,100次循环后仍有175.2 mAh/g,容量保持率为95.2%。在此条件下合成的材料具有结构稳定,粒径均匀,电化学性能优异等优点,本工作对富镍正极材料的合成及结构变化进行研究,有助于加深对材料的了解。     

微波共沉淀法制备锂离子电池正极材料LiNi0.8Co0.2O2

采用微波共沉淀法合成了制备LiNi0.8Co0.2O2的前驱体球形α-Ni0.8Co0.2(OH)2,将其与LiOH·H2O混合,在氧气氛围下,用不同的烧结温度分别烧结10小时获得LiNi0.8Co0.2O2正极材料。用XRD、SEM对所制备的正极材料进行结构和形貌分析,用恒流充放电测试材料的电化学性能。结果表明,烧结温度对材料结构和电化学性能影响较大,所合成材料均具有α-NaFeO2的层状结构,烧结温度越高材料结晶越完善。900℃烧结的LiNi0.8Co0.2O2材料初级颗粒结晶最完善而且其二次团聚粒子的平均粒径最小,其表现出的电化学性能也最好,首次放电容量为189.1mA·h·g-1,首次循环放电效率达到92.5%。30循环后放电容量保持在148 mA·h·g-1,显示出较好的循环稳定性。     

电解液添加剂PHS对LiNi0.8Mn0.1Co0.1O2锂离子电池性能的影响

以2-苯基-1-基1H-咪唑-1-磺酸酯(PHS)作为电解液添加剂,用于LiNi0.8Mn0.1Co0.1O2(NCM811)/石墨软包电池中.充放电测试和电化学测量的结果表明,PHS的添加可以提高NCM811/石墨软包电池的常温、低温和高温循环性能,令电池能够在-20～60°C的温度范围内工作,极大地提升了锂离子电池...     

K+掺杂LiNi1/3Co1/3Mn1/3O2材料的制备及电化学性能研究

锂离子电池正极材料LiNi_1/3Co_1/3Mn_1/3O₂具有放电比容量大、热稳定性好、成本低、安全性能好等优点,但其倍率性能有待进一步提升。本文采用水热法制备了K⁺掺杂LiNi_1/3Co_1/3Mn_1/3O₂材料LNCM-xK。通过X射线衍射谱、场发射扫描电镜和X射线光电子能谱表征LNCM-xK的形貌和结构,通过电化学工作站和蓝电测试系统测试其电化学性能。结果表明:K⁺掺杂能有效降低阳离子混排程度,改善LiNi_1/3Co_1/3Mn_1/3O₂材料的电化学性能,其中当x=0.125时K⁺掺杂LiNi_1/3Co_1/3Mn_1/3O₂样品(LNCM-0.125K)阳离子混排程度最低;LNCM-0.125K样品电化学性能最佳,0.2 C下50次循环后容量保持率为96.15%;在不同电流密度(0.2 C,0.5 C,1 C,2 C,5 C)下进行倍率性能测试,连续充放电30次后LNCM-0.125K样品容量保持率为97.00%。     

Effects of Al2O3 and LiAlO2 Co-coating on electrochemical properties of LiNi0.8Co0.1Mn0.1O2 cathode materials

Lithium-ion batteries are widely used in aerospace, power vehicles, portable electronic devices and other fields because of their environmental friendliness, rechargeable cycle and high energy density. The nickel-cobalt-manganese ternary materials with high nickel has high specific discharge capacity and is regarded as one of the most promising cathode materials. However, with the increase of the number of cycles, the cycle performance becomes worse and the specific capacity decays sharply. In this work, Al₂O₃ and LiAlO₂ were coated on the surface of NCM811 by combining ball milling mixing and solid-phase synthesis to prepare the AL-NCM811 cathode material. The coating thickness formed by Al₂O₃ and LiAlO₂ was 10–70 nm, which effectively improves the cycle stability and rate performance of NCM811 material. When charged and discharged at 0.1C, the first discharge specific capacity and capacity retention rate after 100 cycles of 0.5AL-NCM811 were 196.26 mAh/g and 96.47%, respectively, while those of NCM811 were only 193.78 mAh/g and 72.18%, respectively. When the current density was 5.0C, the discharge specific capacity of 0.5AL-NCM811(139.16 mAh/g) was 55.368 mAh/g higher than that of NCM811(83.80 mAh/g).     

Enhanced electrochemical performance of LiNi0.8Co0.1Mn0.1O2 via titanium and boron co-doping

Titanium and boron are simultaneously introduced into LiNi_0.8Co_0.1Mn_0.1O₂ to improve the structural stability and electrochemical performance of the material. X-ray diffraction studies reveal that Ti⁴⁺ ion replaces Li⁺ ion and reduces the cation mixing; B³⁺ ion enters the tetrahedron of the transition metal layers and enlarges the distance of the [LiO₆] layers. The co-doped sample has spherical secondary particles with elongated and enlarged primary particles, in which Ti and B elements distribute uniformly. Electrochemical studies reveal the co-doped sample has improved rate performance (183.1 mAh·g^-1 at 1 C and 155.5 mAh·g^-1 at 10 C) and cycle stability (capacity retention of 94.7% after 100 cycles at 1 C). EIS and CV disclose that Ti and B co-doping reduces charge transfer impedance and suppresses phase change of LiNi_0.8Co_0.1Mn_0.1O_2.     

钴掺杂对Li1.2Mn0.6Ni0.2O2电化学性能的影响

利用共沉淀法制备了锂离子电池正极材料Li1.2Mn0.6Ni0.2O2和Li1.2Mn0.588Ni0.196Co0.016O2,并利用XRD、SEM和充放电测试对其晶体结构、形貌和电化学性能进行了表征.XRD结果表明:掺杂钴材料后,材料的层状结构保持完整,阳离子混排程度降低.电化学性能测试结果表明:掺钴材料的首次充放电效率和倍率放电性能明显优于Li1.2Mn0.6Ni0.2O2,且表现出较优的循环性能,其1、2、5C放电比容量分别为230.3、215.6、155.6 mA·h/g,1 C下循环50次的容量保持率为90.9％.     

Ultrathin-Y2O3-coated LiNi0.8Co0.1Mn0.1O2 as cathode materials for Li-ion batteries: Synthesis,performance and reversibility

Nickel-rich lithium material LiNi_xCo_yMn_1-x-yO₂(x > 0.6) becomes a new research focus for the next-generation lithium-ion batteries owing to their high operating voltage and high reversible capacity. However, the rate performance and cycling stability of these cathode materials are not satisfactory. Inspired by the characteristics of Y₂O₃ production, a new cathode material with ultrathin-Y₂O₃ coating was introduced to improve the electrochemical performance and storage properties of LiNi_0.8Co_0.1Mn_0.1O₂ for the first time. XRD, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive spectroscopy (EDS) and XPS were used to mirror the crystal and surface of LiNi_0.8Co_0.1Mn_0.1O₂ particles, results i that a uniform interface formed on as-prepared material. The impacts on the electrochemical properties with or without Y₂O₃ coating are discussed in detail. Notably, galvanostatic discharge-charge tests appear that Y₂O_3-coated sample especially 3% coating displayed a better capacity retention rate of 91.45% after 100 cycles than the bare one of 85.07%.     

Cr掺杂对富锂锰基正极材料Li1.2Ni0.2Mn0.6O2结构和电化学性能的影响

采用共沉淀-高温固相合成法制备锂离子电池正极材料Li_1.2Ni_0.2Mn_0.2-x/2Mn_0.6-x/2Cr_xO₂（x=0,0.04,0.08,0.12）。利用X射线衍射（XRD）、扫描电镜（SEM）、恒电流充放电测试和电化学交流阻抗谱（EIS）对掺杂不同Cr含量的正极材料的结构、形貌和电化学性能进行分析测试。结果表明：制备出的Li_1.2Ni_0.2Mn_0.2-x/2Mn_0.6-x/2Cr_xO₂正极材料均具备层状固溶体结构。Cr掺杂不会改变材料的结构,而且能够有效抑制循环过程中材料由层状向尖晶石结构转变的过程。当Cr的掺杂量为8%（即x=0.08）时,得到的正极材料Li_1.2Ni_0.16Mn_0.56Cr_0.08O₂具有最好的电化学性能。0.1C的首次放电比容量由未掺杂的230.4 mA·h·g^-1增加到246.6 mA·h·g^-1,在0.2C电流下50次循环后的容量保持率由93.5%提高至95.36%,5C的放电比容量由91.5 mA·h·g^-1增加到104.2 mA·h·g^-1。而且x=0.08时制备的样品具有最小的电荷转移阻抗。