Research On The Structure And Lifetime Of Gas Diffusion Electrode In Aluminum-air Battery

In the continuously developing modern society,the growing human demand for energy and the diminishing contradiction of existing energy resources have formed an energy crisis.Therefore,the development of renewable energy and clean energy technologies is particularly important.As a metal battery,aluminum-air battery has high specific energy,simple principle,low manufacturing cost,rich and convenient source of raw materials,and is an ideal clean energy source.However,there are still some problems in the process of industrialization of aluminum air batteries.The first problem is that the service life of the air electrode is low,the electrode is prone to polarization,and the air electrode is prone to liquid leakage.In response to these problems,this paper uses the test method of forced discharge of aluminum air battery cells to study the long-term working life of the air electrode,and tests the physical characterization and electrochemical performance of the air electrode.Through long-term testing of the air electrode of the aluminum air battery,it was found that the catalytic layer responsible for the core reaction in the air electrode cracked to a large extent,resulting in overflow of the electrolyte,and at the same time,more surface of the catalytic layer and the diffusion layer remained The crystallization product of the electrolyte causes delamination and blockage of the electrode structure.The cracking of the diffusion layer and the decrease of the hydrophobicity lead to the leakage of the electrolyte.In view of the problem of low service life of the air electrode,the pore structure and internal hydrophilicity and hydrophobicity of the air electrode were optimized and modified,and ammonium oxalate pore-forming agent was selected for the diffusion layer to improve the internal pore structure.The results show that using 10% ammonium oxalate pore-forming agent can effectively improve the performance of the air electrode,making the voltage of the single cell reach 1.25 V under the current condition of 100 m A/cm~2.Increasing the PTFE content in the diffusion layer can increase the hydrophobicity of the surface of the diffusion layer,and the diffusion layer with 60% PTFE content can effectively increase the service life of the air electrode.In order to further optimize the structure of the air electrode,this paper established a gradient porosity porous electrode seepage model.The electrode model with gradient porosity can be used to prevent water penetration.The air in the gradient porosity diffusion layer is designed according to the model.Electrode structure,after a long time electrode test,this air electrode increases the service life of the air electrode by about 66%.