The Cathode Reaction Mechanism And Performance Experiments Of High Temperature PEM Fuel Cells

Known as a new type of energy conversion device, proton exchange membrane(PEM) fuel cell with its clean and high efficiency characteristics, has been considered to be a technology with the most development potential by far. And some of the automobile enterprises have already developed cars with PEM fuel cells. High temperature PEM fuel cell is a kind of PEM fuel cells, with hydrothermal easy management and other advantages. However, the technology of high temperature PEM fuel cell is not so developed that cannot put on the market. To improve the performance of fuel cell is a priority in the research of high temperature PEM fuel cell today. The reaction in the cathode is one of the key factors affecting the performance of the high temperature PEM fuel cell. As a result, study on the reaction characteristics in the cathode of high temperature PEM fuel cell is very important in improving the performance of the fuel cell. In order to improve the high temperature PEM fuel cell performance, this paper tested the high temperature PEM fuel cell and analyzed the cathode reaction characteristics.This paper summarized lots of high temperature PEM fuel cell related literature through reading. And combined with the current development of it, this paper introduced the birth of the fuel cell, the development and the application of the fuel cell as yet at first. And introduced the development of the high temperature PEM fuel cell, summarized the technology and related theory of it at the same time. After that this article introduced the fuel cell test system constructed by the lab and the structure of the fuel cell, discussed the principle of the high temperature PEM fuel cell as well.The flow field plates was processed in this paper, used ab-PBI membrane in the high temperature PEM fuel cell. And then the volt ampere characteristic test of high temperature PEM fuel cell was taken using the fuel cell test station of the lab. The effect of the cell temperature, gas flow rate and the pre-tightening force of the fuel cell device do to the fuel cell was analyzed. According to the analysis, the high temperature PEM fuel cell performs the best under the temperature of 453 K in all of the temperature tested in the experiment. As to the gas flow rate, the fuel cell performs better when the gas flow rate grows. And the fuel cell performs better when the pre-tightening force of the device grows.The structure of the fuel cell’s cathode catalyst Pt was constructed in this paper by using the software of Materials Studio, based on the theory of molecular dynamics and quantum mechanics. And then the model was simulated by using the first principles molecular dynamics. The simulation process includes the next several steps: For the first, the oxygen moved to the Pt(111) surface and absorbed to the surface chemically was simulated. Then four hydrogen atoms moved to the oxygen atoms that absorbed to the Pt surface and reacted with oxygen atoms one by one. Based on the data of the simulation, the oxygen’s adsorption on the Pt(111) surface needs longer time than any other reaction of the ORR. And the first step costs the longest time in the four stepson of the ORR, which can be considered to be the key step of ORR. The following reaction would be mainly four-electron reduction in the ORR. It can be also inferred from the simulation that the reaction of the oxygen and the hydrogen goes faster when the temperature of the fuel cell grows.