LiFeBO3/C正极材料的合成及电化学性能

摘要硼酸铁锂(LiFeBO3)材料作为最具潜力的锂离子电池正极材料之一，逐渐成为国内外的研究热点。本文本论文以提高LiFeBO3材料的电化学性能为主要目的，通过比较和分析不同煅烧温度和煅烧时间对材料结构、形貌和电化学性能的影响，来寻找最佳的制备条件。本文通过纳米球磨，喷雾干燥法和高温煅烧制备硼酸铁锂正极材料。经过试验发现，温度和时间对材料的合成有很大影响，XRD和SEM结果显示最佳的煅烧温度为500℃，最佳保温时间为7.5h，在这个煅烧条件下的LiFeBO3/C样品晶粒明显，颗粒表面光滑，结晶度较高，且样品的性能最佳。化学性能测试结果表明，材料在1.5V~4.5V电压范围内，0.1C倍率下，首次充放电比容量可达到169mAhg-1。在倍率为0.1C下循环50次后，LiFeBO3样品的放电容量仍能达到154mAhg-1。材料良好的电化学性能可以归因于电荷转移电阻的降低和锂离子扩散系数的提高。43779

毕业论文关键词：锂离子电池；正极材料；硼酸铁锂；煅烧；电化学性能

Synthesis and electrochemical property of LiFeBO3/C as Cathode material for lithium-Ion batteries

Abstract

Nowadays, LiFeBO3 is becoming a research focus all over the world as one of the most promising cathode materials of lithium-Ion batteries. This paper, aiming at improving the electrochemical property of LiFeBO3 material, tries to figure out the finest preparation condition via analyzing effects to structure of material, morphology and electrochemical property caused by different calcination temperatures and calcination times. LiFeBO3 material was synthesized by nano ball mill, spray drying,and high temperature calcination.Experiments demonstrate that different temperature and time have significant effects on the materials preparation. XRD and SEM show that the optimum calcination temperature is 500℃ and optimum calcination time is 7.5-hours. And LiFeBO3/C has uniform particle size, good crystallization and optimal electrochemical performance under such condition.Electrochemical property test results suggest that the initial specific dischargecapacity is 169mAhg-1 at 0.1C, at 0.1C between 1.5 V and 4.5 V, and it can deliver a discharge capacity of 154 mAhg-1 after 40 cycles.The excellent electrochemical performance may be attributed to the decrease of charge transfer resistance and the increase of the diffusion coefficient of lithium-ion.

Key Words: lithium-Ion batteries; cathode materials; LiFeBO3; calcination; electrochemical performance

1. 绪论 1

1.1 锂离子电池发展现状 1

1.2 锂离子电池的主要结构 1

1.3 锂离子电池的工作原理 2

1.4 锂离子电池的优势 2

1.5 锂离子电池正极材料 3

1.5.1 层状正极材料 3

1.5.2 聚阴离子正极材料 4

1.5.3 尖晶石结构正极材料 4

1.6 LiFeBO3 5

1.6.1 LiFeBO3的晶体结构 5

1.6.2 LiFeBO3材料的常见制备方法 5

1.6.3 LiFeBO3材料存在的问题 6

1.6.4 LiFeBO3材料的改性方法 6

1.7 课题主要内容 7

1.7.1 研究的意义 7

1.7.2 课题研究内容 8

2. 实验及表征 10 LiFeBO3/C正极材料的合成及电化学性能:http://www.751com.cn/huaxue/lunwen_44791.html