| As an environment-friendly power generation which directly from chemical energy into electrical energy, fuel cell technology will become the ideal chose to solve the increasing prominent problems of energy crisis and environmental protection in today's world. Solid oxide fuel cell (SOFC) plays an important role in the fuel cell with many advantages of non-corrosive, non-precious metal catalyst used and various fuels could be adopted, so that SOFC can achieve the cogeneration of heat and power, not only to establish the large industrial power plants but also to build independent power station.Although materials and their structure are the mass-production bottleneck of all the fuel cells including SOFC, the thorough research on the internal reaction mechanism is more essential. In particular, SOFC works in a closed system with high temperature, in order that the measurement of the internal materials'state and the battery reactions become very difficult, expensive and even impossible. In the other hand, simulation research such as Monte Carlo approach is considered as an important and affordable method to relevance the battery's interior mechanism and its macroscopic performance through the dynamic simulation at molecular level.The SOFC lattice models of Ni-YSZ anode, LSM cathode and Ni-YSZ/YSZ/ LSM battery were established respectively, based on which the electrode perfermence and battery reaction mechanism were investigated in this thesis, the main content and research results are as follows:1. The influence rules of Ni content and accumulation behavior on anode perfermence were simulated on Ni-YSZ lattice model, the results indicated that: anode performance enhanced distinctly at 30% Ni content, and the Ni granules'accumulation reduce the site number of H2 chemical adsorption on anode surface, and then decrease the electronic transference number.2,The influence rules of various parameters on cathode perfermence were investigated by MC approach on LSM lattice model, the results illustrated that: ?the ionic conductivity increased along with the Sr doping content increasing within 0.1-0.4, but that decreased along with the Sr doping content increasing if the value above 0.4 content. The catalytic active site of Mn and La affect the cathode polarization with different mechanism, and the synergism between Mn and La site could reduce the polarized effect and enhance the electrode performance. Two different active states of oxygen and both affect the cathode performance, indicating that both of them perhaps exist simultaneously in the oxygen catalytic process on LSM cathode.3,Through the overall battery model built and the simulation, it was obtained that: cathode reaction probability don't varied the battery performance such as voltage or electric current, but influence the battery reaction process to equilibrium state, i.e., increasing cathode reaction probability could accelerate battery to stable power generation stage, and enhance the battery performance. The simulated polarization curves of athode and cathode consistent with the experimental result, indicated that reducing the resistance within electrolyte, especially the interface resistance between electrolyte and anode would alleviate the polarization problem.Overall, the working mechanism of SOFC could be revealed at molecular level by Ni-YSZ/YSZ/LSM lattice model construction and Monte Carlo simulation. Further research on this issue is expected to provide advising recommendations for the SOFC industrial producation, and useful references to mechanism research of other fuel cell. |
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