摘要: 本文研究了一种用于锂离子电池的硅酸锰锂正极材料的合成技术与其电化学行为。研究中采用高温固相法并结合喷雾干燥合成纳米级硅酸锰锂锂离子电池正极材料,采取不同的合成温度(750℃、780℃及800℃)、不同的锂过量情况(3%、5%)来合成目标产物LiMnSiO4，制备出形貌规则、粒径一致性良好的LiMnSiO4正极材料，并通过X射线衍射（XRD）的物相组成、扫描电镜（SEM）的材料形貌特征，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。81096

研究中发现，在高温煅烧中会有少量锂源分解导致合成的材料有杂质相产生。通过加入过量锂来改善材料的性能，通过XRD对合成材料进行物相对比分析，发现不同过量锂含量的杂质衍射峰强度和位置都有略微差异，通过对样品进行组装电池和电化学行为测试，得出过量5%的锂含量电池电化学性能最好。首次放电比容量达到142。1mAh/g。

研究中发现，选择不同煅烧温度对获得纯相硅酸锰锂具有很大的影响。750℃下合成的LiMnSiO4电池首次充电比容量为126。8mAh/g，首次放电比容量为112。4mAh/g，通过20次充放电循环，LiMnSiO4的充电比容量保持率82。68%，放电的比容量保持率为91。30%。展示出良好的循环稳定性，有望今后得到应用。

毕业论文关键词: 硅酸锰锂；纳米球磨；喷雾干燥；高温固相法；循环性能；比容量

Electrochemical Behavior of a New Lithium Manganese Silicate Cathode Material

Abstract: In this paper, a synthesis technology and electrochemical behavior of lithium manganese silicate cathode materials for lithium ion batteries were studied。 (750 ℃, 780 ℃ and 800 ℃), different lithium excess (3%, 5%) were prepared by high temperature solid phase method and combined with spray drying to synthesize nanometer lithium manganese phosphate lithium ion battery cathode materials。 (XRD) and scanning electron microscopy (SEM) were used to prepare LiMnSiO4 cathode materials with good morphology and uniform particle size。 The results were characterized by X-ray diffraction (XRD) Discharge cycle test, cyclic voltammetry (CV) and impedance characterization of the electrochemical properties of the composites。

It was found that there was a small amount of lithium source decomposition in the high temperature calcination leading to the formation of impurities in the synthesized material。 The results show that the intensity and location of the impurity diffraction intensity of the different lithium content are slightly different。 By analyzing the samples and the electrochemical behavior of the samples, To obtain an excess of 5% of the lithium content of the best electrochemical performance of the battery。 The first discharge capacity reached 142。1 mAh / g。

It was also found that the choice of different calcination temperatures has a great effect on obtaining pure phase lithium manganese silicate。 The initial charge specific capacity of LiMnSiO4 battery was 126。8mAh / g and the first discharge specific capacity was 112。4mAh / g。 The charge capacity retention rate of LiMnSiO4 was 82。68% through 20 charge and discharge cycles, and the specific capacity retention rate For 91。30%。 Showing good cycle stability, is expected to be applied in the future。 

Keywords: LiMnSiO4, nano-milling, spray drying, high-temperature solid-state reaction, cycle performance, specific capacity

目录

1 绪论 1

1。1 引言 1

1。2 锂离子电池简介 2

1。2。1 锂离子电池发展状况 2

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