Preparation Of ZnMnO₃ And Its Performance In Aluminum-air Batteries

The research progress of aluminum-air battery is very rapid.It is a promising air battery with many advantages such as high theoretical voltage,large specific energy,environmental friendliness,light weight,long life and simple structure.The air electrode is an important part of the aluminum-air battery,which can affect the performance of the entire battery.The preparation of a highly active and stable catalyst is the key to improving the performance of the air electrode.The current catalysts include precious metals,metal organic chelates,spinel oxides,perovskite oxides,and new composite materials.Among them,ZnMnO₃ is a highly active and structurally stable perovskite composite metal oxide..In this dissertation,the problems facing aluminum-air batteries are used as the research background,and the preparation processes of air electrode catalysts ZnMnO₃and MnO₂ are studied.Use X-ray diffraction(XRD),scanning electron microscopy(SEM),energy spectrum analysis(EDS),thermogravimetric analysis(TG),cyclic voltammetry scan(CV),alternating current impedance test(EIS),linear scan(LSV),constant Flow discharge test and other methods were used to characterize the phase,surface morphology,electrochemical performance and discharge performance of the prepared samples.First,ZnMnO₃ was prepared by co-precipitation method,and the effects of experimental raw materials,feeding methods,and calcination processes on its performance were studied.MnSO₄·H₂O and Zn(NO₃)₂·6H₂O were used as raw materials,and the feeding method was cocurrent When the calcination temperature was 800°C and the calcination time was 4 h,a spherical structure product ZnMnO₃with high crystallinity,good dispersibility and regular morphology was obtained.The electrochemical workstation and blue power test system were used to characterize the samples prepared under different preparation process conditions.The results show that under the optimal process conditions,the oxygen reduction catalytic performance,discharge performance,and stability of the prepared ZnMnO₃ are better than others.The process parameters are more excellent.Secondly,in order to further explore the performance of ZnMnO₃,a detailed comparative study was performed with MnO_2,a commonly used catalyst for air electrodes.The results show that ZnMnO₃ as an aluminum-air battery catalyst exhibits better catalytic performance and oxygen reduction performance.At a current density of 100 m A·cm^-2,the discharge voltage can be maintained at about 0.89V,which is higher than 0.59V of MnO₂.The output voltage is about 0.3V,which can be used as a common catalyst for air electrodes of aluminum-air batteries.