Performance Test Of Organic Electrolyte Lithium Air Battery And Its Positive Mass Transfer

Energy storage is one of the biggest problems faced by human society.Among the existing energy storage technologies,lithium-air batteries with chargeability and the highest theoretical energy density have received extensive attention from domestic and foreign scholars.At present,lithium-air batteries are faced with problems such as fewer cycles and overpotentials during charging and discharging.With the breakthrough of technology,it is expected to be applied to electric vehicles on a large scale,and the market prospect is broad.In this paper,the performance of lithium air battery is studied from two aspects of experiment and simulation.The purpose is to explore the performance attenuation mechanism,optimize battery operating parameters and improve the performance of lithium air battery.On the basis of reading a large number of domestie and foreign literatures,the research status of each major component of lithium air battery is summarized.At the same time,the working principle of organic electrolyte lithium air battery is introduced in detail and organic electrolyte lithium air battery test platform was built,and the charge and discharge test and the AC impedance test were carried out.,This paper is aimed at the problem of serious degradation of the performance of organic electrolyte lithium air battery.From the macroscopic perspective,two aspects of experimental testing and simulation analysis are used for research.In terms of testing,organic electrolyte lithium air battery test platform was built,organic electrolyte lithium air battery cell is assembled with self-made porous carbon positive electrode,the effect of electrode thickness and electrolyte dosage on battery performance was analyzed.At the same time,the equivalent circuit of the organic electrolyte lithium air battery was obtained by the AC impedance method,and the influence of the electrolyte amount on the impedance of the battery was further analyzed.It is found that the thickness of the positive electrode affects the discharge specific capacity of the battery,when the positive electrode is thinner,the discharge specific capacity is larger.The amount of electrolyte affects the redox process of organic electrolyte lithium air battery.In summary,the thickness of the positive electrode and the amount of electrolyte affect the electrochemical properties of the battery.Based on electrochemical theory,mass transfer,construction of two-dimensional transient model for internal material transfer in organic electrolyte lithium air battery,the model couples the mass transfer equation,the electrode dynamics equation,the mass transfer equation in the diaphragm and so on.Compared with the test results,the feasibility and correetness of the model were verified.The internal mass transfer and reaction mechanism were studied well.Based on the model,the internal mass transfer and reaction nechanism of the organic electrolyte lithium air battery were obtained.The distributions of lithium ion concentration and oxygen concentration were analyzed carefully,the influence on the distribution of electrolyte potential,overpotential and film thickness is further analyzed by electrode thickness,current density,porosity and oxygen diffusion coefficient.The simulation results showed that the electrolyte potential inside the battery becomes smaller by reducing the thickness of the positive electrode,reducing the discharge current density,and increasing the porosity.Battery overpotential reduction by reducing discharge current density and increased oxygen diffusion coefficient,conducive to battery charge and discharge performance.The research results have a deeper understanding of the mass transfer process of the positive electrode.