Design,Preparation And Properties Of Metal/Carbon Composite Electrode Materials For Zinc-Air Battery

With the rapid development of electronic portable devices and transportation vehicles,the use of traditional fuels has led to energy depletion and environmental pollution problems.As a result,methods of energy supply and storage have also undergone major changes,new energy storage devices have attracted much research attention.From the technical and economic aspects,zinc-air batteries have a higher theoretical energy density of 1086 Wh kg-1,and the cost is lower than lithium-ion batteries,which is a viable option for future electric vehicle applications.In zinc-air batteries,the catalytic activity and stability of air electrodes play an important role in the improvement of battery performance.Therefore,it is important to choose a high catalytic efficiency and high stability oxygen evolution reaction/oxygen reduction reaction(OER/ORR)electrocatalyst.In this dissertation,two kinds of transition metal doped carbon-based composite catalysts were prepared.The highly conductive carbon was used to synthesize OER/ORR bifunctional catalytic materials with high catalytic activity and stability and assemble a stable zinc-air battery.The main results are summarized as follows:Metal/N-doped carbon materials were prepared by SiO2 template method,and the electrocatalytic performance of the materials was optimized by regulating the amount of metal.N in the carbon material can adjust the electronic structure of carbon,so that the carbon atoms have stronger adsorption to oxygen,the strong coupling between the transition metal and the N-C at the interface can generally provide an active site for the OER/ORR.Finally,Fe0.05Co0.5Ni0.05/NC catalyst has excellent OER/ORR bifunctional activity(an E10 of 1.59 V,an E1/2 of 0.80 V),and a zinc-air battery with stable circulation of 24000 min is assembled.With Na4Fe(CN)6 as the raw material,a carbon-coated FeCo alloy is obtained by a simple two-step ion exchange method.The FeCo alloy formed after the addition of the Co source promotes the formation of OER/ORR active sites,which facilitates the transport of intermediates in the electrocatalytic processwhich has excellent OER/ORR bifunctional activity,and the carbon layer coated on the periphery of the FeCo alloy has good conductivity and has high stability when used it as a positive electrode catalyst for a zinc-air battery.The battery can be stably cycled for more than 2500 minutes,and the charge-discharge potential difference is only 0.65 V.