论文总字数：20091字

摘 要

锂离子电池是目前重点研究的储能设备之一，目前锂离子电池主要使用的是石墨为负极，但是石墨类的电池已满足不了现在的需要，硅基材料具有高比容量的特点，成为了发展趋势。SiO具有2680mAh/g左右的理论比容量，但是在脱嵌锂的过程中存在着严重的体积效应，会导致材料颗粒化，影响循环性能，且硅基材料的导电性较差。首先，本文探究用蔗糖、PEI和蔗糖 PEI为碳源对SiO/Ni材料进行包覆，制备碳包覆后的电极材料，组装成电池，对其进行电化学性能测试和表征，最终确定包覆SiO/Ni的最佳碳源，并研究包碳量对锂硅电池性能的影响。研究表明：蔗糖 PEI为碳源，按照SiO/Ni:C=7:3和活性物质:导电剂:粘结剂=7:2:1的比例制备的负极并组装成电池的电化学性能最好，其首次放电比容量达到1521.8mAh/g，首次放电比容量达到930.3mAh/g，首次库伦效率为61.13%，50次循环的可逆比容量为826.3mAh/g，容量保持率为54.30%。在此基础上，本文探究SiO/Ni:C中不同碳包覆量对电池性能的影响，分析表明SiO/Ni:C=7:3的碳包覆比例最为适中，具有良好的离子电导率，锂硅电池也具有最佳的循环性能和库伦效率。

关键词：锂硅电池；硅碳复合材料；碳包覆；电化学性能

Preparation and performance of SiO/Ni@C anode material

for lithium silicon battery

ABSTRACT

Lithium-ion batteries are one of the energy storage devices that are currently the focus of research，At present, lithium-ion batteries mainly use graphite as the negative electrode, but graphite batteries cannot meet the current needs, and silicon-based materials have the characteristics of high specific capacity, which has become a development trend. SiO has a theoretical specific capacity of about 2680mAh/g, However, there is a serious volume effect in the process of De-embedded lithium, which will cause the material to granulate and affect the cycle performance. And the conductivity of silicon-based materials is poor. This paper explores the coating of SiO/Ni materials with sucrose, PEI and sucrose PEI as carbon sources, manufactures carbon-coated electrode materials, assembles them into batteries, and performs electrochemical performance testing and characterization to determine the coating The best carbon source of SiO/Ni, and study the effect of carbon content on the performance of lithium silicon battery. Studies have shown that: Sucrose PEI is the carbon source, The negative electrode prepared according to the ratio of SiO / Ni: C=7:3 and active material: conductive agent : binde=7:2:1 and assembled into the battery has the best electrochemical performance Its first discharge specific capacity reached 1521.8mAh/g, The first discharge specific capacity reached 930.3mAh/g, The first Coulomb efficiency is 61.13%,The reversible specific capacity of 50 cycles was 826.3mAh/g, and the capacity retention rate was 54.30%. On this basis, this paper explores the effect of different carbon coating amounts in SiO/Ni:C on battery performance, And explored that the SiO/Ni:C=7:3 carbon coating ratio is the most moderate and has good ionic conductivity, so it has the best cycle performance and Coulomb efficiency.

KEY WORDS: Lithium silicon battery; Silicon carbon composite materials; Carbon coating; Electrochemical property

目 录

摘 要 Ⅰ

ABSTRACT Ⅱ

第一章 绪 论 1

1.1研究背景及意义 1

1.2 锂离子电池及其负极材料简介 1

1.3 SiO材料作为锂硅电池负极材料研究现状 2

1.3.1 SiO的纳米化 2

1.3.2 SiO的歧化 2

1.3.3 碳包覆氧化亚硅负极的制备 3

1.3.4 SiO_x与第二相的复合 3

1.4小结 4

第二章 研究目的、内容及方法 5

2.1研究目的 5

2.2研究内容 5

2.3实验药品与仪器 5

2.3.1 实验药品 5

2.3.2 实验仪器 6

2.4研究方法 6

2.4.1 bm-SiO/Ni/C复合材料的制备 6

2.4.3 材料表征 8

2.4.4 电池电化学性能测试 8

第三章 实验结果与分析 10

3.1 碳源的选择 10

3.1.1碳化温度的确定 10

3.1.2不同碳源制备bm-SiO/Ni/C复合材料与bm-SiO的XRD分析 10

3.1.3不同碳源所制备的bm-SiO/Ni/C电极的电化学性能表征 11

3.2不同碳包覆量对锂硅电池性能的影响 13

3.2.1 不同bm-SiO/Ni：C质量比所制备bm-SiO/Ni/C的XRD表征 13

3.2.2不同SiO/Ni：C质量比所制备bm-SiO/Ni/C复合材料的TEM表征 14

3.2.3不同SiO/Ni：C质量比所制备bm-SiO/Ni/C复合材料的电化学性能 14

第四章 结论与展望 15

4.1本文结论 15

4.2 问题与展望 15

参考文献 17

致 谢 20

第一章 绪 论

1.1研究背景及意义

目前，锂离子电池通常以石墨作为负极材料，其理论比容量只有372mAh·g^-1，且倍率性能较差，振实密度小^[1]，已远远达不到发展所需。所以，选择一种具有高比容量的材料来替换石墨作为锂离子的负极材料已经迫在眉睫。硅材料因其所拥有的超高比容量（4200mAh·g^-1）而备受瞩目，且硅基材料还具有工作电压低、安全性好、原料来源广泛等诸多优点^[2]。

请支付后下载全文，论文总字数：20091字