论文总字数：22836字

摘 要

镁基储氢合金因资源丰富、价格低廉、理论储氢量高以及环境友好等优点被认为是最理想的镍氢电池负极材料之一。但镁基储氢合金循环稳定性能不佳、耐腐蚀性差，这些缺陷制约着其大规模实际应用，因此，需对其进行改性处理。

本文利用多元合金化，通过燃烧合成法制备三元合金Mg₁₄In₃Ni₃，循环测试发现电极放电容量远小于理论值（490 mAh/g），为了进一步改善Mg-In-Ni合金的电化学性能，采用机械球磨引入Ni@C对合金表面修饰，制备Mg-In-Ni x wt.% Ni@C (x = 0, 10, 50, 100)复合体系合金电极，探索Ni@C的添加量对复合电极结构和电化学性能的影响。结果表明，Ni@C的添加能够提高电极的活性，放电容量有了明显的提升，最大值达到111.4 mAh/g。当添加量为50 wt.%时，复合电极具有最大的交换电流密度I₀（12.5 mA/g），最低的电荷转移电阻Rct（11.73 Ω）以及最好的的氢扩散能力D_H/a²（3.1*10^-5/s），动力学性能最佳。

关键词： Mg₁₄In₃Ni₃，Ni@C，表面修饰，电化学性能

Effect of Surface Modification on Electrochemical Performance of Mg-In-Ni Hydrogen Storage Alloy Electrode

Abstract

Magnesium-based hydrogen storage alloys are considered to be one of the most ideal anode materials for nickel-hydrogen batteries due to their abundant resources, low price, high theoretical hydrogen storage capacity and environmental friendliness. However, the magnesium-based hydrogen storage alloy has poor cycle stability and poor corrosion resistance, and these disadvantages limit its large-scale practical application. Therefore, it needs to be modified.

In this paper, the ternary alloy Mg₁₄In₃Ni₃ was prepared by combustion synthesis method using multi-alloying. It was shown in the cycle stability test that the discharge capacity of the electrode had a significant drop compared with theoretical value (490 mAh/g). In order to further improve the electrochemical performance of the Mg-In-Ni alloy, the catalyst Ni@C was introduced by ball milling to investigate the effect of different Ni@C addition content on the structure and electrochemical performance of electrodes. The results indicate that the addition of Ni@C increased the activity of the electrode, and the discharge capacity was obviously improved, which reached at the maximum value 111.4 mAh/g. With 50 wt.% Ni@C addition, the composite electrode had the largest exchange current density I₀ (12.5 mA/g), the lowest charge transfer resistance R_ct (11.73 Ω) and the best hydrogen diffusion capability D_H/a² (3.1*10^-5/s), which means the optimal kinetic performance.

Key Words: Mg₁₄In₃Ni₃; Ni@C ; surface modification; electrochemical performance

目录

摘 要 I

ABSTRACT II

第一章 文献综述 1

1.1引言 1

1.2 镍氢电池（Ni/MH）的工作原理 2

1.3储氢合金性能要求及分类 3

1.3.1 AB₅型合金 4

1.3.2 AB₃型合金 4

1.3.3 AB₂型合金 4

1.3.4 AB型合金 5

1.3.5 A₂B型合金 5

1.4镁基储氢合金改性方法 6

1.4.1 非晶化 6

1.4.2 纳米化 7

1.4.3非化学计量比化 7

1.4.4表面修饰 7

1.4.5多元合金化 7

1.5 课题的提出 8

第二章 实验内容与方法 10

2.1 实验原料 10

2.2 材料制备 10

2.2.1 燃烧合成 10

2.2.2 Ni@C的制备 10

2.2.3 Mg-In-Ni x wt.% Ni@C (x = 0, 10, 50, 100)复合体系的制备 11

2.3 材料成分、结构表征 11

2.3.1 材料成分分析 11

2.3.2 材料结构表征 11

2.4 样品电化学储氢性能测试 11

2.4.1 工作电极制备 11

2.4.2 电化学测试装置 12

2.4.3 电化学测试项目及方法 12

第三章 Ni@C表面修饰对Mg-In-Ni合金电极电化学性能的影响 15

3.1 引言 15

3.2 Mg-In-Ni x wt.% Ni@C (x = 0, 10, 50, 100)复合物结构表征 15

3.3 Mg-In-Ni x wt.% Ni@C (x = 0, 10, 50, 100)复合物电化学性能 17

第四章 结论与展望 23

4.1 结论 23

4.2 展望 23

参考文献 25

致谢 27

请支付后下载全文，论文总字数：22836字