论文总字数：23306字

摘 要

锂离子电池具有高能量密度、循环寿命长、自放电小、无记忆效应和环境友好等优点，是目前应用最为广泛的商业电池。商用的碳负极材料理论容量低（372 mAh/g），无法满足高能量密度和大功率充放电等要求。在其它负极材料中，Fe₂O₃负极材料具有高的理论容量且来源广、环境友好，但导电性差，在充放电过程中存在巨大的体积变化并伴随着容量的快速衰减。本文通过将二维MXene材料与Fe₂O₃纳米复合结构，Ti₃C₂T_x MXene具有独特二维结构和良好的导电性，过构筑合适的纳米结构把两者优势结合在起来，充分发挥它们各自的优势，开发新型高性能的负极材料。

本文选择MXene家族中最典型的Ti₃C₂T_x，采用LiF HCl腐蚀工艺制备出稳定的Ti₃C₂T_x MXene纳米片悬浮液，采用水热合成的方式制得Ti₃C₂T_x/Fe₂O₃复合材料，采用冷冻干燥方法制备具有蓬松结构的Ti₃C₂T_x/Fe₂O₃冻干粉，制得电极后，研究锂离子电池的电化学性能。得到结论如下：

（1）在120ºC的条件下，水热合成4h，能使Fe₂O₃颗粒均匀附着在MXene片上。

（2）Ti₃C₂T_x/Fe₂O₃复合电极的容量在所有倍率条件下明显高于纯Ti₃C₂T_x电极，具有良好的倍率性能和电化学稳定性。

（3）Ti₃C₂T_x/Fe₂O₃电极的循环稳定性明显低于纯Ti₃C₂T_x电极。衰减率高达55%以上。Ti₃C₂T_x/Fe₂O₃电极的循环稳定性不理想。

（4）不同载流量对Ti₃C₂T_x/Fe₂O₃电极容量有影响，就100 μm、150 μm、200 μm三种载流量来说，载流量为150 μm时，容量最高。但不同的载流量对Ti₃C₂T_x/Fe₂O₃电极的充放电性能没有明显的影响。

关键词：锂离子电池 MXene Fe₂O₃ 水热合成 电化学性能

Preparation and Electrochemical Properties of Ti₃C₂T_x (MXene)/Fe₂O₃ Composite Anode Material for Lithium Ion Batterry

ABSTRACT

Lithium-ion batteries are currently widely used in electronic devices, mainly because of its following features: high energy density, long cycle life, no memory effect, and no pollution to the environment. In recent years, with the development of science and technology, The requirements for the performance of lithium-ion batteries also have higher standards. MXene stands out in energy storage applications. Since its discovery in 2011, two-dimensional MXene materials have received more and more attention in theoretical recognition and conditions.

In this experiment, Ti₃AlC₂ matrix was etched by using LiF HCl as an etchant, and Ti₃C₂T_x was prepared by ultrasonic stripping. Then Ti₃C₂T_x and Fe₂O₃ were compounded by hydrothermal synthesis as electrode material. Simultaneous characterization and electrochemical performance testing.This paper mainly studies the preparation and electrochemical performance of Ti₃C₂T_x/Fe₂O₃ lithium-electric composite anode materials. The results show:

(1)Using LiF HCl as an etchant, hydrothermal synthesis at 120°C for 4h can give Fe₂O₃ particles uniformly distributed on MXene composites.

(2)The capacity of Ti₃C₂T_x/Fe₂O₃ composite electrode is obviously higher than that of pure Ti₃C₂T_x electrode under all magnification conditions,indicating that Ti₃C₂T_x/Fe₂O₃ has good rate performance and electrochemical performance stability.

(3) The cycling stability of Ti3C2TX/Fe2O3 electrode is significantly lower than that of pure Ti3C2Tx electrode. The attenuation rate is as high as more than 55%.

(4) Different current carrying capacities have an effect on the capacity of Ti₃C₂T_x/Fe₂O₃ electrodes. For three current carrying capacities of 100 μm, 150 μm, and 200 μm, the maximum capacity is obtained when the current carrying capacity is 150 μm. Different current carrying capacities have no effect on the charge and discharge performance of Ti₃C₂T_x/Fe₂O₃ electrodes.

Key words: lithium ion battery; MXene; Fe₂O₃; Hydrothermal synthesis; electrochemical performance

目录

摘要 I

ABSTRACT II

第一章 绪论 1

1.1引言 1

1.2 锂离子电池的研究进展 1

1.2.1 锂离子电池的特点 2

1.2.2锂离子电池的性能指标 3

1.2.3锂离子电池负极材料的研究进展 4

1.3 MXene材料的研究进展 6

1.3.1 MXene的制备 6

1.3.2 MXene的结构和形貌 6

1.3.3 MXene材料的性能 7

1.3.4 MXene的应用 8

1.4课题的提出和研究内容 9

第二章 实验部分 10

2.1实验设备 10

2.2实验原料与试剂 11

2.3实验步骤及流程 11

2.3.1MAX的腐蚀 11

2.3.2 腐蚀料的洗涤 11

2.3.3 多层MXene的剥离 12

2.3.4 Fe₂O₃铁盐溶液的制备及水热合成 12

2.3.5 电极片的制备 13

2.3.6 电池的装配 14

2.4表征与测试方法 14

2.4.1 X射线衍射分析（XRD） 14

2.4.2 扫描电子显微镜分析（SEM） 15

2.4.3透射电子显微镜分析（TEM） 15

2.4.4 X射线光电子能谱分析 15

2.4.5 BET比表面积测试 15

2.5 电化学性能测试 15

2.5.1 恒流充放电性能测试 15

2.5.2循环伏安测试 15

第三章 结果与讨论 17

3.1 Ti₃C₂T_x/Fe₂O₃冻干粉的表征 17

3.2 Ti₃C₂T_x/Fe₂O₃复合材料的电化学性能研究 20

3.3 不同面载量对Ti₃C₂T_x/Fe₂O₃电极的影响 22

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