【作者】 陈宇；

【导师】 张玉荣；

【作者基本信息】 福州大学 ， 无机化学， 2005， 硕士

【摘要】 本论文共分为四篇。第一篇为文献综述,介绍与本文相关的背景材料。主要涉及锂离子固体电解质（锂快离子导体）及锂离子电池正极材料、负极材料的研究进展情况。其中锂离子电池正极材料方面重点介绍了层状结构的LiMO₂ 化合物、尖晶石结构LiMn₂O₄ 正极材料等应用前景较为广阔的几种正极材料的研究进展,简单介绍了其他正极材料如钒氧化物、反尖晶石型的LiNiVO₄、橄榄石型的LiMPO₄ 等的研究进展;负极材料方面简单介绍了碳材料、氮材料、氧化物、新型合金作为负极材料的一些研究进展;锂离子固体电解质方面主要介绍了钙钛矿型锂离子固体电解质、具有NASICON 结构的LiM₂（PO₄）₃ 及其衍生物类锂离子固体电解质、LISICON 型固体电解质、正硅酸锂Li₄SiO₄ 为母体的固体电解质、Li₃N 及其衍生物固体电解质、玻璃态锂快离子导体、聚合物锂离子固体电解质和其它类型锂离子固体电解质等的研究进展。第二篇为新型钙钛矿型锂快离子导体（固体电解质）的合成与表征。以Li_3xLa_0.67-xTiO₃ 为母体、采用阴阳离子(Al³⁺、F^-)双掺或阴离子（F^-）单掺、通过高温固相反应（1200℃）合成了Li_3xLa_0.67-xTi_1-yAl_yO_3-yF_y 和Li_3x-yLa_0.67-xTiO_3-yF_y两个体系的钙钛矿型锂快离子导体。通过交流阻抗谱、X-射线粉末衍射、直流极化、红外光谱等来表征合成物的性能。研究结果表明掺杂体系在一定的组成范围内均可获得具有单一的钙钛矿结构的产物。电化学性质测试结果表明阴、阳离子双掺后样品的离子电导率和电化学稳定性等性质与母体材料相比均有较大的改善, 而阴、阳离子双掺的材料的电化学性能比单掺阴离子的更好。Li_3xLa_0.67-xTi_1-yAl_yO_3-yF_y（x=0.11）体系中起始组成为y=0.02 的合成物电导率最高,室温下为1.06×10^-3S/cm,略高于母体材料的室温电导率,573K 时达3.01×10^-2S/cm,该合成物的分解电压达2.3V,较母体的（1.5V）有较大提高,与预期的结果一致,为该类材料的实用化又向前推进一步。第三篇对以LiTi2（PO4）3为母体、以天然高岭石为起始原料、通过异价离子掺杂制得的三个系列新的矿物锂快离子导体Li_1.2+x-yY_xTi_1.9-xAl_0.1Si_0.1S_yP_2.9-yO₁₂（简称Y-S-Lisicon ） 、Li_1.2+x-yAl_0.1+xTi_1.9-xSi_0.1S_yP_2.9-yO₁₂ （ 简称Al-S-Lisicon ） 及Li_1.2+x-yY_xTi_1.9-xAl_0.1Si_0.1W_yP_2.9-yO₁₂（简称Y-W-Lisicon）的各性质进行表征。XRD分析显示在Y-S-Lisicon 系统中当x≤0.3,y<0.2+x 时均能得到类似于Nasicon 的更多还原

【Abstract】 This thesis includes four parts. Part one gives some backgrounds about this thesis. In this part, recent developments on lithium fast ion conductors and electrode materials including cathode materials and anode materials for lithium ion battery are reviewed. For cathode materials, layer-structured LiMO₂ and spinel-structured LiMn₂O₄ as well as their derivatives are discussed in detail, other kind of cathode materials such as vanadium oxide, LiNiVO4, olivine-type LiMPO₄ are also presented. Focus of anode materials is putting on carbon materials and metallic materials. For lithium fast ion conductors, emphasis is on perovskite-type together with LISICON-type solid state electrolytes. Part two deals with preparation and characterization of new perovskite-type lithium ion conductors. Two new lithium ion solid electrolyte systems of Li_3xLa_0.67-xTi_1-yAl_yO_3-yF_y and Li_3x-yLa_0.67-xTiO_3-yF_y prepared by high temperature（1200℃） solid state reaction are characterized by the methods of A.C. impedance, X-ray diffraction, D.C. polarizing and IR measurements. The results show that the Al³⁺ and F^-codoped samples have a better conductivities and higher decomposition voltage compared with their parent material. The results also show that Al³⁺ and F^-codoped samples have higher conductivity than those doped only with F^-. The maximum conductivity is 1.06×10^-3S/cm at room temperature and 3.01×10^-2S/cm at 573K for the initial composition of x=0.11,y=0.02 in Li_3xLa_0.67-xTi_1-yAl_yO_3-yF_y system, its decomposition voltage reaches up to 2.3V. Part three discusses the properties of mineral lithium fast ion conductors based on LiTi₂（PO₄）₃, which have been prepared by conventional solid state reaction using refined natural kaolinite as a starting material. In this part, three mineral lithium fast ion conductor systems of Li_1.2+x-yY_xTi_1.9-xAl_0.1Si_0.1S_yP₍2.9-y_O（12） （referred as Y-S-Lisicon）, Li_1.2+x-yAl_0.1+xTi_1.9-xSi_0.1S_yP_2.9-yO₁₂ （referred as Al-S-Lisicon） and Li1.2+x-yYxTi1.9-xAl0.1Si0.1WyP2.9-yO12（referred as Y-W-Lisicon） were studied. For Y-S-Lisicon system, XRD results show that a R c structure can be found in the composition range of x≤0.3,y<0.2+x . Conductivities and activation energies data show that the initial composition with x=0.1,y=0.15 possesses the maximum ionic conductivity of 2.93×10-5S/cm at room temperature and 3.62×10-2S/cm at 673K. For Al-S-Lisicon system, phase analysis shows that a R c structure can be found in the composition range of x=0.1,y<0.3 and x=0.2,y<0.4. The sample with initial composition of x=0.2,y=0.20 possesses the maximum ionic conductivity of 6.01×10-5S/cm at room temperature and 1.11×10-2S/cm at 573K, its activation energy is 28.60KJ/mol. For Y-W-Lisicon system, a R c structure can be found in the composition range of x=0.1,y<0.2 and x=0.2,y<0.2. A.C. impedance measurements indicate that the initial composition with x=0.1,y=0.10 possesses the maximum ionic conductivity of 1.65×10-5S/cm at room temperature, while at 573K, the initial composition with x=0.2,y=0.10 possesses the maximum ionic conductivity of 6.53×10-3 S/cm. The activation energies of this system are in the range of 41.52KJ/mol ～64.77KJ/mol in the temperature range of 373K ～573K. The decomposition voltage for the above three system is around 3.0 V. These results show that most of lithium fast ion conductors mentioned above are good fast ion conductors with good electrochemical stabilities. Part four is about cation and anion codoped LiMn2O4--LiMn2-xYxO4-yFy as cathode material of lithium ion battery, which has been synthesized by co-precipitation method. X-ray powder diffraction analysis shows that a spinel-structured phase together with other manganese oxides exists in the cathode material. The results of CV measurement show that two couples of redox peaks still appear around 4.0V when doping appropriate amount of Y3+ and F-. ESEM images indicate that the samples sintered at lower temperature have smaller and more homogeneous crystalline grain. The results of charge /discharge experiments of half–cell show that the samples sintered at 600℃possess the best electrochemical performance and that the initial charge capacity decreases with the increasing value of x for the same value of y. Concerning both capacity and cyclic ability, the sample with initial composition of x=0.05, y=0.10possesses the best electrochemical performance, whose charge and discharging capacity reach up to 132.80 mAh·g-1 and 94.84 mAh·g-1 respectively for the 1st cycle and maintain 113.77 mAh·g-1 and 93.83 mAh·g-1 respectively after 15 cycles with total discharge capacity decay of 1.06% for the first 15 cycles when tested at a charging rate of 0.20 mA/cm2 and discharging rate of 0.15 mA/cm2 in the potential range of 3.0-4.5V, which is better than that of undoped spinel LiMn2O4 prepared by the same route.更多还原