Preparation And Properties Of Modified Perovskite Catalyst For Aluminum-air Battery

Aluminum-air(Al-air)battery is a new type of clean energy,which has the advantages of environmental friendliness,wide raw materials,strong environmental adaptability,strong endurance and safe working process.It has great potential for development and use.However,the slow oxygen reduction reaction(ORR)of the Alair battery cathode hinders its widespread use.It is an effective way to improve the cathode performance by adding catalysts to the cathode.Among them,perovskite materials have the general structural formula of ABO3,which can adjust the atomic types of A and B sites,and then change their structure,electronic distribution,magnetic properties and other related properties.They are easy to prepare and have good catalytic effect on redox reaction,and are often used as electrode catalyst materials.In this paper,SrCoO3 perovskite metal oxide is used as the basic material,and La and Mn are doped at A and B positions for modification,and finally compounded with graphene nanosheets.The microstructure,phase characteristics and battery discharge performance of the prepared catalyst were tested and analyzed by means of material analysis methods such as scanning electron microscopy,linear voltammetry polarization curve,AC impedance spectrum and constant current discharge test of Alair battery.At the same time,combined with first-principles calculations,the reasons for the influence of different anode materials on the performance of the battery under the same cathode catalyst are analyzed from the energy band theory.The main research results are as follows:When SrCoO3 is doped with 50% Mn,the particles of Sr Co0.5Mn0.5O3 material are refined and the lattice stability decreases.When SrCoO3 is loading with 20% graphene nanosheets,the catalytic performance of the material will be reduced.The simultaneous application of the two methods can better improve the ORR catalytic performance of SrCoO3.The loading of graphene nanosheets on SrCoO3 perovskite materials with relatively large particles will affect the adsorption capacity of oxygen.The graphene nanosheets are mixed with Sr Co0.5Mn0.5O3 with small particle size,which increases the contact area with oxygen and the material looseness,and improves the conductivity of SrCo0.5Mn0.5O3 and the number of oxygen adsorption sites.After doping La at the A site,the electron transfer resistance of La0.2Sr0.8CoO3 increases during the reaction,and the electron transfer resistance decreases significantly after loading graphene nanosheets.The loading performance of ultrasonic exfoliated graphene nanosheets is higher than that of in-situ growth.The electrochemical properties and full cell discharge performance of G-La0.2Sr0.8CoO3 and G+ La0.2Sr0.8CoO3 composites are higher than that of Pt/C catalyst.The high catalytic performance of G-La0.2Sr0.8CoO3 is due to the improved conductivity of graphene nanosheets and the four electron transfer path during the catalytic reaction,which effectively inhibits the occurrence of side reactions.The discharge results of Al-air batteries composed of cathode constructed by G-La0.2Sr0.8CoO3 catalyst and different aluminum alloy anodes are significantly improved compared with pure aluminum anodes.