论文总字数：21804字

摘 要

由于对传统化石能源的过于依赖，导致了能源危机、环境污染等一系列问题的产生。为了缓解这一问题，新型能源储存材料得到大力推崇。其中锂空气电池由于其超高的理论能量密度（3500 Wh kg^-1），是目前商用锂离子电池的十倍，受到了国内外研究学者的广泛关注。然而，目前锂空气电池还存在实际放电容量低、循环稳定性差和充放电过程过电位高的问题。而设计一种多孔、高比表面积的阴极催化能够有效的解决锂空气电池中的问题。本文采用水热法直接在碳布集流体上合成成本低、易于合成的过渡金属氧化物MnCo₂O₄，通过改变表面添加剂的量，来合成具有特定形貌的MnCo₂O₄，深入探究其在锂空气电池的催化作用。在本实验中，通过调整表面活性剂硫酸铵的添加量，调控钴酸锰在碳布上面的生长形貌，制备出三种不同的自支撑钴酸锰@碳布，分别为棉絮状、球状和三维丝状，并将其应用于锂空气电池的阴极。其中三维丝状材料在测试条件为定容500 mAh g^-1，电流密度340 mA g^-1的条件下，循环128次，过电位为1.064 V。在电流密度为340 mA g^-1的条件下，深度放电容量达到4029 mAh g^-1。其良好的电化学性能可能归因于特殊的表面形貌，能够提供更多的活性位点。

关键词：锂空气电池 钴酸锰 水热法 阴极催化剂

The Synthesis of Self-supported MnCo₂O₄ for the Application in the Li-O₂ Battery

ABSTRACT

Due to China's excessive dependence on traditional fossil energy, it has led to a series of problems such as energy crisis and environmental pollution. In order to alleviate this problem, new energy storage materials have been highly valued. Among them, lithium-air battery is ten times more than the current commercial lithium-ion battery due to its ultra-high theoretical capacity (3500 Wh kg^-1), which has attracted extensive attention from researchers at home and abroad. However, lithium-ion batteries currently have many problems, such as low actual discharge capacity, poor cycle stability, and high overpotential during charge and discharge. Designing a porous, high specific surface area cathode catalysis can effectively solve the problems in lithium air batteries.

In this experiment, by adjusting the addition amount of surfactant ammonium sulfate, the growth morphology of manganese cobalt oxide on carbon cloth was adjusted, and three different self-supporting MnCo₂O₄@carbon cloths were prepared, which were cotton-like, spherical and filamentous. And three-dimensional filamentous MnCo₂O₄@carbon has been applied to the cathode of a lithium air battery. The lithium air battery was cycled 128 times under the condition of a constant volume of 500 mA g^-1 and a current density of 340 mA g^-1, and the first cycle’s overpotential was 1.064 V. At a current density of 340 mA g^-1, the deep discharge capacity reached 4029 mA h g^-1. Its good electrochemical properties may be attributed to a special surface topography that provides more active sit.

KEYWORDS: Li-O₂ battery; MnCo₂O₄; Synthesis; Cathode catalyst

目 录

摘 要 I

ABSTRACT II

第一章 绪论 1

1.1 锂空气电池的简介 1

1.2 非水系锂空气电池的反应机理 3

1.3 锂空气电池的理论比能量密度的计算 3

1.4 锂空气电池的优点 4

1.5 锂空气电池目前仍然存在的问题 5

1.6 钴酸锰在锂空气电池中的研究现状 6

1.7 研究目的及主要研究内容 7

第二章 自支撑型钴酸锰的合成 8

2.1 实验药品和仪器 8

2.1.1实验药品…………………………………………………..8

2.1.2实验仪器…………………………………………………..8

2.2 自支撑钴酸锰@碳布集流体的制备 9

2.3 材料的表征 10

2.3.1XRD测试…………………………………………………..10

2.3.2SEM或FE-SEM测试 10

2.4 电化学性能测试 10

第三章 结果与讨论 12

第四章 结论与展望 17

参考文献 18

致 谢 22

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