摘要：随着能源的不足，环境的恶化，人们以燃料电池来代替一次性能源，解决能源不足和环境污染问题。但燃料电池的应用受到了某些因素的限制，如电极的使用寿命短、催化剂的催化活性低等。我们需要研究导电性能好的电极催化层材料，提高催化剂的催化活性以及电极的使用寿命，使燃料电池得到更好的应用。本文就以石墨烯、氮化硼、碳化硅三种材料的作为研究对象，以原子缺陷以及应变大小作为研究变量，详细分析能带结构图以及Mulliken电荷分布，导电性，进而从电导的角度提交燃料电池的性能。从本文研究结果可知，空位对石墨烯导电性存在较大的影响，当出现一个C原子空位时，石墨烯的导电性增强，而当出现一对C空位时，石墨烯的导电性减弱。另一方面，应变的存在对石墨烯的导电性能影响较小。空位对氮化硼的导电性存在较大的影响，当出现一对原子空位时，氮化硼的导电性增强。另一方面，应变的存在对氮化硼的导电性能影响比较大，当出现一个N空位时，导电性增强；当出现一对原子空位时，应变的增加，增强了氮化硼的导电性。空位的出现，对碳化硅的导电性能有较大影响，当出现一个C空位和一个Si空位时，碳化硅的导电性增强，当出现一对原子空位时，导电性增强。除此之外，应变的存在对碳化硅的导电性能也有较大的影响，在无缺陷时的碳化硅的导电性增强，当出现一个C空位时，应变的增加，增强了碳化硅的导电性；当出现一个Si空位时，应变的存在，减弱了碳化硅的导电性；当出现了一对原子空位时，应变的增加，使得碳化硅的导电性先减弱后增强。

关键词：质子交换膜燃料电池；石墨烯；氮化硼；碳化硅

Abstract：With the lack of energy and the deterioration of the environment, great attentions have been focused on the fuel cells for the future application. In order to improve the performers, the conductive characteristic of the corresponding catalysts is necessary. Herein, the conductivity of the current two-dimensional catalysts (graphene, boron nitride and silicon carbide) has been studied in detail using the  density functional  theory calculation.The effect of the defects as well as the applied strain has been considered. Based on the  results of the band structure and Mulliken charge, the conductivity of graphene shows the dependence on the present of vacancy. For the graphene with a C vacancy (2C defect), the conductivities are enhanced (decreased). However, the effect of the applied strain on the conductivity could be neglected. For boron nitride, the influence of the defect and the strain is more complex.The conductivity of boron nitride with BN defect increases compared with the other structures. As the strain applied, the conductivity enhances for theboron nitride with N vacancy and BN defect.For the silicon carbide, the presence of defect would enhance the electrical conductivity. However, the different structure shows different conductivity behaviors as the presence of the strain. For silicon carbide without and with C vacancy, the conductivity enhances as the strain increases; for the case with Si vacancy, the presence of strain reduces the conductivity; for the presence of the SiC defect, the conductivity weakened and then enhanced.

Key words: proton exchange membrane fuel cell; graphene; boron nitride; silicon carbide

目录

第一章绪论 1

1.1燃料电池的研究背景以及意义 1

1.2燃料电池 2

1.2.1燃料电池原理及组成 2

1.2.2燃料电池的优缺点及分类 3

1.3质子交换膜燃料电池