Surface Modification And Electrocatalytic Properties Of A Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3-?-based Bifunctional Oxygen Electrodes

With the increasing demands for clean and sustainable energy,the development of renewable energy technologies has become a challenge in modern society.The metal-air battery is a highly efficient,environmentally friendly energy conversion and storage device.However,the high overpotential and energy loss at the air electrode of the metalair batteries severely limit its wide application.Therefore,the oxygen electrode catalyst plays an important role in the design of metal-air batteries.In this paper,the Ba0.5Sr0.5Co0.8Fe0.2O3-?(BSCF)was studied as a perovskite-type oxygen electrode catalyst.The preparation of hybrid catalysts have been reported as an effective way to increase the bifunctional catalytic activity.Cobalt and iron oxides were used to modify the surface of perovskite BSCF to prepare composite oxygen electrode catalysts.The specific surface area and electrical conductivity of the composite oxygen electrode catalyst are improved,and a synergistic effect is generated between the two components,so that the bifunctional catalytic activity is improved.In this paper,BSCF-based hybrid oxygen catalysts were prepared by sol-gel method and impregnation method.The crystalline structure and surface morphology of the sample were studied by XRD and SEM,respectively,the three-electrode method was used to test the electrocatalytic activity of BSCF-based hybrid catalysts by a rotating disk electrode device and electrochemical workstation.The optimal preparation process of oxygen electrode catalyst was explored.The prepared catalysts were applied to the air electrode of a home-made zinc-air battery,and which was tested for discharge and cyclic chargedischarge performance.From the SEM images,it can be found that Co3O4 is uniformly modified on the surface of the BSCF catalyst.The ORR and OER catalytic activity of the hybrid oxygen electrode catalyst have been improved by testing the electrochemical performance of the sample.The optimum calcination temperature in the process was determined to be 400°C,and the best Co3O4 loading was 5%.Experiments confirmed that modification of Fe OOH can improve the ORR catalytic activity of BSCF.The discharge and cycle chargedischarge tests of zinc-air batteries with hybrid oxygen electrode catalysts were performed.The results show that BSCF-based hybrid oxygen electrode catalysts have good bifunctional catalytic activity and long-term stability.