摘要橄榄石型LiFePO4是下一代锂离子电池中最具前景的正极材料。为了提升LiFePO4的电化学性能，我们分别以P123和CTAB作为表面活性剂，通过水热法来制备b轴向的LiFePO4正极材料，并对制备的样品分别进行了循环伏安法(CV)，X射线衍射（XRD）以及电化学交流阻抗测试(EIS)来分析其电化学性能。XRD测试结果表明，三个样品的X射线衍射峰与LiFePO4标准XRD图谱(PDF卡No. 83-2092和No. 81-1173)一致，且FOM值均小于5.0。循环伏安测试中在同一扫描速度1mV/s时添加P123表面活性剂2.0g的样品的电位差最小,为1.53V，具有对称性良好的Fe离子氧化还原峰,电化学可逆性好。其交流阻抗图谱随着循环伏安测试的进行，加入了2.0g P123 的LiFePO4样品溶液内阻增大，传荷电阻减小，锂离子扩散程度稳定。实验结果表明，添加P123表面活性剂2.0g的LiFePO4样品电化学改性效果最好。19694
关键词： LiFePO4；表面活性剂；b轴向；电化学性能
Abstract
Olivine-structured LiFePO4 is one kind of cathode material showing the most promise for next-generation lithium-ion batteries. In order to improve the electrochemical performance of LiFePO4, we take P123 and CTAB as surfactant, preparing b axial LiFePO4 cathode material by hydrothermal method. The prepared LiFePO4 were characterized by X-ray diffraction (XRD), Cyclic Voltammetry(CV) and Electrochemical Impedance Spectra(EIS). XRD results show that X-ray diffraction peaks of the three samples are consistent with standard XRD spectrum of LiFePO4 (PDF card No. 83-2092 and No. 81-1173). FOM values are all less than 5.0. LiFePO4 with 2.0g surfactant named P123 has minimum potential difference (1.53 V) when the CV tests set in the same scan rate of 1 mV/s. It has excellent electrochemical reversibility and symmetry of Fe ion redox peak. AC impedance spectroscopy shows that the LiFePO4 with 2.0g P123 has increased solution resistance, decreased transfer resistance and stabilized lithium ion diffusion with cycling. The results show that LiFePO4 with 2.0g surfactant named P123 has the best electrochemical modification effect.
KeyWords: LiFePO4；surfactant；b axial；electrochemical performance
目 录
1 绪论 1
1.1 选题的目的和意义 1
1.2 锂离子电池的发展和现状 1
1.3 锂离子电池的特点 2
1.4 锂离子电池正极材料的分类及简介 3
1.4.1 钴酸锂（LiCoO2 ) 3
1.4.2 镍酸锂 （LiNiO2） 4
1.4.3 锰酸锂 （LiMn2O4） 4
1.5 LiFePO4 正极材料的结构特征 5
1.6 LiFePO4 正极材料的优缺点 6
1.6.1 优点 6
1.6.1 缺点 6
1.7 LiFePO4电化学性能 6
1.8 LiFePO4 正极材料的制备 7
1.8.1 高温固相法 8
1.8.2 水热法 8
1.8.3 氧化-还原法 8
1.8.4 溶胶凝胶法 8
1.8.5 微波工艺法 9
1.8.6 球磨活化法 9
1.9 LiFePO4材料的改性 9
1.9.1 引入导电性材料 9
1.9.2 掺杂金属阳离子 9
2 实验部分 10
2.1 实验仪器 10 b轴向LiFePO4的探讨+文献综述:http://www.youerw.com/cailiao/lunwen_11143.html