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摘要：本文设计了锂离子电池的铬酸锂基正极材料的改性研究，进行 Ti 掺杂改性反应 1.5LiOH+0.25Cr2O3+0.5TiO2→Li1.5Cr0.5Ti0.5O2.5+0.75H2O 对尖晶石型LiCrO2进行改性。运用纳米合成工艺及高温煅烧的反应原理，制备出形貌规则、粒径一致性好的 LiCrO2正极材料，并通过 X 射线衍射（XRD）的物相组成，通过充放电循环测试、循环伏安法（CV）和阻抗表征合成材料的电化学性能。本实验采取不同的合成温度(600℃、700℃及 800℃)、不同的锂含量以及不同的包碳量来合成目标产物 Li1.5Cr0.5Ti0.5O2.5，以合成电化学性能较好的锂离子电池。 通过实验我们发现铬酸锂基本上是不具备电化学性能的，但通过掺杂 Ti 之后电化学性能有明显的改善， Li1.5Cr0.5Ti0.5O2.5的首次充电比容量为171.2mAh/g，首次放电比容量为 107.8mAh/g，比 LiCrO2有了很大的提升。通过 20 次充放电循环，Li1.5Cr0.5Ti0.5O2.5 的充电比容量保持率 98.56%，放电的保持率为 96.79%，展示出优异的循环稳定性；并且充放电过程中氧化还原峰的间距为 0.312V，具有较好的可逆性。 57156
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毕业论文关键词：改性铬酸锂；纳米球磨；喷雾干燥；高温固相法；倍率性能；循环性能 Synthesis and electrochemical behavior of a new cathode materials based on lithium chromate Abstract：This design modification of the lithium-ion battery cathode materials for lithium chromate, dual ion substitution reaction 1.5LiOH + 0.25Cr2O3 + 0.5TiO2 → Li1.5Cr0.5Ti0.5O2.5 + 0.75H2O of chrome spinel lithium LiCrO2 modified. The use of nano-synthesis reaction principle and high temperature calcination to prepare a regular morphology, particle size consistency good LiCrO2 cathode material, and by X-ray diffraction (XRD) phase composition, morphology, by charging and discharging cycle test, cyclic voltammetry (CV) and electrochemical impedance characterize the performance of a synthetic material. In this study, to take a different synthesis temperature (600 ℃, 700 ℃ and 800 ℃), different lithium content and the amount of different packages to synthesize carbon target product Li1.5Cr0.5Ti0.5O2.5, to synthesize a good electrochemical performance Lithium Ion Battery. Through experiments we found that Lithium chromate basically do not have the electrochemical properties, but after the adoption of doping Ti electrochemical performance improved significantly, Li1.5Cr0.5Ti0.5O2.5 initial charge capacity was 170mAh / g, the first discharge capacity of 100mAh / g, has been greatly improved than LiCrO2. By 20 cycles of charge, the charging capacity retention ratio Li1.5Cr0.5Ti0.5O2.5 was 99.61%, 94.03% retention rate of discharge, exhibit excellent cycle stability; and the charge-discharge process of redox peaks spacing 7 to 0.312V, with good reversibility.
KeyWords: LiCrO2, nano-milling, spray drying, high-temperature solid-state reaction, rate performance, cycle performance
目录
第一章绪论 1
1.1引言 .. 1
1.2 锂离子电池简介 1
1.2.1 锂离子电池发展状况 1
1.2.2 锂离子电池的结构和工作原理 . 2
1.2.3 锂离子电池正极材料 3
1.3 锂离子电池的正极材料 LiCrO2的研究进展 . 3
1.3.1LiCrO2结构和电化学性能 .. 4
1.3.2LiCrO2的制备方法 .. 4
1.3.3 LiCrO2的改性研究 . 5
1.4 课题的主要内容 6
1.4.1 课题研究的目的和意义 . 6
1.4.2 课题研究内容 6
1.4.3 实验方案设计 7
第二章实验及表征 8
2.1 实验原料 8
2.2 实验仪器 8