摘要:橄榄石结构的磷酸锂铁(LiFePO4)由于原料来源广泛、价格便宜、循环性能优良等突出特点,成为最有前途的锂离子正极材料之一。但由于其固有的晶体结构,LiFePO4具有极低的电子电导率,大电流放电性能差,成为限制其应用的最大障碍。本文以合成高性能掺杂Co元素的LiFeCoPO4电极材料为研究目标。9317
本论文采用水热合成法制备了锂离子电池正极材料LiFeCoPO4,采用XRD、循环伏安测试等方法研究了材料的结构和电化学性能。结果表明:LiFeCoPO4样品具有与LiFePO4相同的橄榄石结构,当LiOH•H2O、NH4H2PO4、FeSO4•7H2O、CoCl2•6H2O的质量比为1:1:2:0.042,并加入适量蔗糖为碳源时合成的掺杂Co电极材料的性能最佳。
关键词: LiFePO4;正极材料;掺杂
Study on the synthesis of LiFeCoPO4
Abstract: Olivine-structured LiFePO4 has became one of the most promising cathode material for its wide material source, low row materials cost, excellent circle performance and so on. Its intrinsic crystal structure, however, results in properties of low electronic conductivity and poor discharge capability at high rate, which has been the greatest obstacle for application of LiFePO4. The main work is to synthetic high-performance doping the Co element of LiFeCoPO4 for research objectives.
LiFeCoPO4 cathode materials for Li ion battery were synthesized by hydrothermal synthesis method. The structures and electrochemical performance of materials were studied by XRD and CV Test. The result showed that LiFeCoPO4 samples had the same olivine structure as LiFePO4. When the mass ratio of LiOH•H2O, NH4H2PO4, FeSO4•7H2O, CoCl2•6H2O is 1:1:2:0.042, adding an appropriate amount of sucrose, the doping Co electrode material showed the best performance.
Key words: LiFePO4; cathode materials; doping
目录
第1章 绪论 1
1.1锂电池的研究背景及概况1
1.1.1 锂电池的发展背景1
1.1.2 锂电池的设计理念2
1.1.3 锂电池的发展现状3
1.2锂离子电池电极材料组成及其工作原理4
1.2.1 锂离子电池的正极材料4
1.2.2 LiCoO2正极材料4
1.2.3 LiNiO2正极材料4
1.2.4 LiMnO2正极材料5
1.2.5 锂离子电池的负极材料5
1.2.6 锂离子电池的电解质5
1.2.7 锂离子电池的工作原理6
1.3 课题的目的和意义7
1.3.1 课题的目的7
1.3.2 课题的意义8
1.4 实验方案设计9
1.4.1 水热法原理简介10
1.5可行的实验手段和方法10
1.5.1样品的制备10
1.5.2材料表征10
1.5.3 电化学测试11
第2章 实验设备及设备简介12
2.1 HY-800oC高温节能管式炉12
2.2 CS电化学工作站12
2.3 KQ3200DE型数控超声波清洗器13
2.4 高温烘箱14
2.5 GH-252电子天平14
2.6 日本理学DMAX-B型X射线衍射仪15
第3章 实验内容16
3.1 实验原料16
3.2材料合成16
3.2.1 磷酸亚铁的制备16
3.2.2 LiFePO4的合成16
3.2.3 LiFe1-xCoxPO4的合成17
3.3 测试方法18
3.3.1 循环伏安测试18
3.3.2 XRD测试19
第4章 结果分析21
4.1 LiFeCoPO4循环伏安及XRD测试结果分析21
4.1.1 样品121
4.1.2 样品226
4.1.3 样品329
4.1.4 样品432
4.2 性能对比37
4.2.1 四个样品的XRD图谱对比37
4.2.2 四个样品的电化学性能对比38 LiFeCoPO4的合成研究+文献综述:http://www.youerw.com/cailiao/lunwen_7980.html