论文总字数：32216字

摘 要

随着锂离子电池的应用领域越来越广，人们对其能量密度方面的需求不断增长，开发新型高比容量负极材料已成为重中之重。一氧化硅因具有较高的理论比容量（2680mAh/g）而备受关注。然而由于其循环过程中大的体积变化（~200%），较低的电导率和首次库伦效率，SiO材料仍不足以满足市场需求。研究表明合理的微纳结构能够有效提高电池性能。多孔结构的设计可以缓解体积膨胀，较大的比表面积增加了与电解液的接触，其网络状结构也加快了锂离子和电荷的传输，是研究的热点之一。因此，本文通过球磨SiO粉体细化，在研究SiO粒径对所组装电池性能影响的基础上，优化选择合适的SiO粒径，采用金属辅助化学蚀刻法制备多孔SiO材料。探究蚀刻工艺参数对材料孔隙率、孔径分布、比表面积及其对所组装电池电化学性能的影响，初步分析其嵌脱锂机制，并研究固定蚀刻工艺参数下多孔SiO的微观结构的演化，探索其化学蚀刻机制。得到主要结论如下：

（1）SiO粉体的球磨细化研究表明，球磨不会改变SiO的物相组成，但可有效降低SiO的团聚体和一次颗粒粒径，在球料比为8:1，转速为400 rpm，球磨时间为 6 h的球磨工艺下制备出的平均粒径为412nm的SiO，表面相对平整，近似椭球状，分散性及综合电化学性能最好，首次放电容量可以达到2148.8mAh/g，50次循环后可逆比容量达到1282.5 mAh/g。

（2）蚀刻温度对SiO微观结构及其电化学性能的研究表明，随着温度的升高，多孔氧化亚硅孔径变大，孔隙率增加，孔隙分布也更加均匀；但温度过高时，孔洞结构会受到破坏。电化学性能测试表明，合适的孔径和孔隙率有助于获得优良的电化学性能，推荐蚀刻温度为50℃。

（3）AgNO₃浓度对SiO微观结构及其电化学性能的影响研究表明，AgNO₃浓度越高，多孔SiO孔径越小、孔隙率越高。合适的孔径和孔隙率有助于获得优良的电化学性能，推荐AgNO₃浓度为10 mM。

（4）固定蚀刻参数下多孔SiO微观结构随时间的演化规律研究表明，Ag主要起催化作用，蚀刻最先发生在Ag覆盖的区域。但过长的蚀刻时间将导致整个SiO表面的均匀腐蚀，难以得到多孔结构。

关键词: 锂硅电池 多孔SiO 行星球磨 化学蚀刻法 微观结构 电化学性能

Study on the Preparation and Electrochemical Properties of Porous Silicon Oxide for Lithium Silicon Battery

ABSTRACT

As the application fields of lithium-ion batteries become wider and wider, the demand for its energy density is increasing, and the development of high specific capacity anode materials have become a top priority. Silicon monoxide has attracted widespread attention because of its good theoretical specific capacity (2680mAh/g). However, due to its volume expansion during cycling, low electrical conductivity, and low initial coulomb efficiency have seriously affected commercial development, silicon monoxide is still insufficient to meet market demand. Research shows that a reasonable nano-microstructure can effectively improve battery performance. Porous structure is one of the research hotspots, which can relieve volume expansion, increase the contact with electrolyte and accelerate the transfer of lithium ions and charges. Therefore, in this paper, the silicon monoxide powder is refined by ball milling, and on the basis of studying the influence of the particle size on the performance of the assembled battery, the appropriate particle size of silicon monoxide is optimized, and then the preparation of porous silicon monoxide is prepared by chemical etching method. Try to explore the effect of the etching process parameters on the porosity, pore size distribution, specific surface area of the samples and the electrochemical performance of the assembled batteries. Initially analyze their lithium insertion and removal mechanism, and then study the evolution of microstructure of porous silicon monoxide under fixed etching process parameters, and lastly discuss the chemical etching mechanism. The main conclusions obtained are as follows:

（1）Ball milling study on SiO powder shows that ball milling does not change the phase composition of SiO, but can effectively reduce the agglomerates and primary particle sizes of SiO. The silicon monoxide with an average particle size of 412 nm, which was prepared under the ball milling process with a ball-to-material ratio of 8:1, a rotation speed of 400 rpm, and a ball milling time of 6h, has a smooth surface, good dispersion and better overall electrochemical performance. The first discharge capacity can reach 2148.8 mAh/g, and the reversible specific capacity can reach 1282.5 mAh/g after 50 cycles.

(2) The effect of etching temperature on the microstructure and electrochemical performance of silicon monoxide shows that, with the increase of temperature, the particle size becomes larger, the porosity increases, and the pore distribution is more uniform; but when the temperature is too high, the pore structure will be destroyed. Electrochemical tests shows that excellent electrochemical performance can be obtained by the appropriate pore size and porosity, the recommended etching temperature is 50 ℃.

(3) The influence of silver nitrate concentration on the microstructure and electrochemical performance of porous silicon monoxide shows that, the concentration of silver nitrate affects the porosity and pore size of porous silicon monoxide. The higher the concentration, the smaller the pore size is and the higher the porosity is. The better electrochemical performance can be obtained by proper pore size and porosity, the recommended concentration of silver nitrate is 10mM.

（4）The microstructure of porous silicon monoxide evolution study with time under fixed etching parameters shows that, silver mainly plays a catalytic role, and etching occurs first in the area covered by silver. However, excessively long etching time will lead to uniform corrosion of the entire silicon monoxide surface, making it difficult to obtain a porous structure.

Key Words: Lithium silicon battery; Porous silicon monoxide; Planetary grinding；Chemical etching method; Microstructure; Electrochemical performance

目 录

摘 要 I

Abstract II

目 录 IV

第一章 绪论 1

1.1课题研究背景及意义 1

1.2 锂离子电池概述 2

1.3 锂离子电池硅基负极材料简介 3

1.3.1 硅基负极材料的优势及劣势分析 3

1.3.2 改性硅基负极材料 3

1.4 锂离子电池氧化亚硅负极材料研究进展 4

1.4.1 氧化亚硅负极材料简介 4

1.4.2氧化亚硅负极材料改性研究进展 4

1.4.3 多孔SiO的制备及其研究进展 6

1.5 选题依据及主要研究内容 8

第二章 实验材料、设备、内容及方法 9

2.1实验材料及设备 9

2.1.1 实验材料 9

2.1.2 实验设备 9

2.2 实验内容 10

2.3 实验方法 11

2.3.1多孔氧化亚硅的制备及原理 11

2.3.2电池装配 13

2.3.3 材料的物化性质表征 13

2.3.4 材料及电池的电化学性能表征 15

第三章 实验结果与讨论 16

3.1 SiO的粒径优化 16

3.1.1 bm-SiO粉的XRD表征 16

3.1.2 bm-SiO粉的激光粒度表征 16

3.1.3 bm-SiO的TEM表征 17

3.1.4 不同球磨时间bm-SiO负极材料的电化学性能 18

3.2 刻蚀温度对多孔SiO微观结构及电化学性能的影响 19

3.2.1刻蚀温度对多孔SiO微观结构的影响 20

3.2.2刻蚀温度对多孔SiO负极电化学性能的影响 21

3.3 AgNO3浓度对多孔SiO的微观结构及其电化学性能的影响 21

3.3.1 AgNO3浓度对多孔SiO微观结构的影响 22

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