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摘要LiFePO4由于其高工作电压、大理论值容量和热稳定性，以及其原材料成本低，无毒性和环保的优点，引起了极大的关注。减少LiFePO4粒子至纳米级是提高其比容量、速率性能和循环寿命的重要的技术之一。有效调控LiFePO4的粒子尺寸是改善LiFePO4中锂离子的扩散能力的关键。本文中，主要采用溶剂热合成法，通过改变实验中反应物混合搅拌时长实现LiFePO4粒子的大小可控。得出结论，随着搅拌时间的延长，制得的LiFePO4均匀性增强，颗粒形状发生改变，在搅拌时长为1.5h的情况下，合成的样品其电化学性能最优， Li+脱嵌的能力增强，其表明电子的嵌入与脱出能力增强，引入蔗糖作为碳源，能够改善LiFePO4正极材料的电化学性能。这项研究表明，LiFePO4的粒子半径的大小对电极容量有很大的影响，LiFePO4颗粒尺寸越小能产生较好电化学性质的形貌与结构。41021
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毕业论文关键词：LiFePO4，锂电池正极，颗粒尺寸，溶剂热合成法
Abstract
LiFePO4 due to its high working voltage, large capacity and thermal stability of the theoretical value, and its low cost of raw materials, non-toxic and environmentally friendly advantages, has caused great attention.Reduce LiFePO4 to nanoscale particles is to improve the specific capacity and rate capability and cycle life of one of the important technologies.Effectively regulate the particle size of LiFePO4 is improving the capability of the diffusion of lithium ion in LiFePO4 is the key.This article mainly adopts the solvent thermal bonding method, by changing the experiment the reactant mixture stirring time realization of LiFePO4 controlled the size of the particles.Come to the conclusion that with the extension of mixing time, the uniformity of LiFePO4 was enhanced, particle shape change, in the case of the mixing time was 1.5 h, synthetic samples of the electrochemical performance of the optimal, Li+ embedded ability enhancement, its shows that electronic embedded and emergence, introduction of sucrose as carbon source, it can improve the electrochemical performance of LiFePO4 battery anode materials.The study shows that the size of the particle radius of LiFePO4 has a great influence on electrode capacity, LiFePO4 the smaller particle size can produce good electrochemical properties of the morphology and structure.
Keywords: LiFePO4, lithium battery, particle size, solvothermal synthesis
目 录
1 绪论 1
1.1 引言 1
1.2 锂离子电池的研究概况 1
1.2.1 锂离子电池的结构 1
1.2.2 锂离子电池的工作原理 2
1.2.3 锂离子电池正极材料 3
1.3 LiFePO4正极材料的研究概况 3
1.3.1 LiFePO4的结构与性能 3
1.3.2 LiFePO4的充放电机理 4
1.3.3 LiFePO4的改性方法 4
1.4 LiFePO4正极材料的制备方法 5
1.4.1 固相反应法 6
1.4.2 溶胶-凝胶法 6
1.4.3 微波法 6
1.4.4 喷雾热分解法 7
1.4.5 水热法 7
2 实验方法与仪器 7
2.1 实验原料 7
2.2 实验仪器 8
2.3 实验步骤 9
2.4 材料表征 9
2.4.1 X射线衍射分析（XRD） 10
2.4.2 扫描电镜（SEM） 10
2.5 电化学性能测试 10
2.5.1 制作电极 10
2.5.2 测试系统 10
3 实验数据测试与分析 11