Research On All-solid-state High-temperature Iron-air Battery And Negative Electrode Materials

In order to alleviate the problem of energy shortage,finding efficient energy storage equipment and improving energy storage efficiency has become one of the focuses of scientific research.For energy storage batteries,the high-temperature batteries with molten salt as electrolytes can provide efficient reaction kinetics.Combined with the characteristics of high energy density and low cost of iron-air batteries,high-temperature molten salt iron-air batteries have been developed.At the same time,semi-solid-state and all-solid-state high-temperature iron air batteries have been developed,which further improves the volatility,fluidity and corrosiveness of high-temperature molten salt,and shows broad prospects in the field of large-scale energy storage technology.However,the research of all-solid-state high-temperature iron air batteries is in the preliminary stage,their performance are low,and there is a lack of research on the structure optimization of electrode materials and reaction mechanism.This topic mainly studied the structure optimization and reaction mechanism of all-solid-state high-temperature iron air battery cathode material with yttrium stabilized zirconia（YSZ）as electrolyte,so as to improve the battery performance.We have developed battery performance evaluation software to assist in performance testing.It is divided into the following two aspects:1 We tested the performance of all-solid-state high-temperature iron air batteries with YSZ as electrolyte,and characterized the composition of negative electrode materials before and after reaction by means of Scanning Electron Microscope（SEM）,X-ray Diffraction（XRD）and Raman.Finally,it was determined that the conversion process of trivalent iron and zero valent iron occurred in the negative electrode of all-solid-state high-temperature iron air batteries.The attenuation process of the batteries was studied by Electrochemical Impedance Spectroscopy（EIS）.The corresponding ohmic impedance increased from 8.6Ω·cm²to 17.1Ω·cm²when the energy efficiency of the batteries decreased from 60%to 45%.We studied the effects of different Fe₂O₃particle sizes on the energy efficiency,coulomb efficiency and polarization voltage by constant current charging and discharging.Finally,it was concluded that the batteries had excellent performance when the Fe₂O₃ particle size was 30 nm.their energy efficiency,coulomb efficiency and charging voltage were 67%,98.5%and 1.5 V respectively.2 We prepared Ag-Fe₂O₃composite structure by metal organic framework（MOF）method.It was confirmed that silver was successfully loaded and evenly distributed by SEM,XRD,Transmission Electron Microscope,Infrared spectrum and other characterization methods.The negative electrode was sintered by ultrafast high temperature thermal shock,which significantly improved the problem of silver volatilization in the sintering process.The performance of the batteries was tested with Ag-Fe₂O₃as the negative electrode.The test results showed that the silver loaded batteries had better performance and significant advantages in reducing the polarization voltage.Their energy efficiency,coulomb efficiency and charging voltage were 66.2%,98%and 0.99 V respectively.