Studying Of Performance Of Rare Earth-magnesium Anode For Magnesiun Air Battery

Magnesium al oy has low density,high electrochemical activity and lower the standard electrode potential and high energy density batteries,have good application prospect as become a hot research topic in the fields of chemical power source.However,the serious hydrogen evolution,voltage hysteresis and unstable discharging platform,hindered the wide applicatio n of magnesium al oy anode materials.Based on AZ31 magnesium al oy and adding rare earth elements(Y,Gd)preparation new types rare earth magnesium al oys,therefore made a series research of the electrochemical properties and magnesium-air battery discharge performance,to develop high performance magnesium al oy anode materials provide a reference basis.In this paper use linear scanning voltammetry(LSV),Tafel,electrochemical impedance spectroscopy(EIS),metal ographic experiment,XRD analysis and battery constant current discharge were studied.Y and Gd rare earth elements,and the new magnesium al oy electrode and the MnO2 system air electrode and 3.5wt% NaCl electrolyte were composed of magnes ium air cell,and the microstructure and electrochemical properties of the new magnesium al oy were tested at 5mA/cm2,10mA/cm2 and 20mA/cm2 current density of the discharge voltage with the discharge time of the law,and study the battery constant current discharge performance.The main results were as follows:(1)AZ31-Y and AZ31-Y-Gd rare earth magnesium al oys were prepared by adding different rare earth elements in AZ31.The microstructures of AZ31-Y-Gd al oy were the smal est and the grain size was the smal est,and the grain refinement effect was obvious.The equilibrium potential of the electrode was relatively negative and the electrochemical activit y was opposite to that of the AZ31-Y-Gd al oy.And the corrosion resistance is the best.The equilibrium potential of the cast AZ31 al oy is relatively positive,the resistance of the charge transfer process is smal,and the corrosion resistance of the electrode is the worst.(2)AZ31,AZ31-Y and AZ31-Y-Gd magnesium cathode assembly of magnesium air battery,the open circuit voltage is very close to 1.60 V or so.At the current densities of 5mA/cm2,10mA/cm2 and 20mA/cm2,the three kinds of magnesium al oy materials show a high discharge platform and a better discharge stability,such as the integrated discharge performance,at 10mA/cm2 current density The The discharge voltage of AZ31-Y-Gd is the highest and the discharge process voltage decreases smoothly,and the overall discharge effect is the best.The AZ31 discharge voltage is the lowest and the discharge voltage fluctuates in a large range.(3)AZ31 was added to different concentrations of rare earth elements Y and Gd to prepare AZ31-x% RE rare earth magnesium al oy.With the increase of rare earth content,the new phase Al2 Gd,Al2Y and Mg24Y5 appeared in the microstructure,the number of precipitates increased,the grain size gradually decreased,and the matrix structure was obviously refined.When the content of rare earth(Y + Gd)is 3%,AZ31-3%RE has the smal est grain size and uniform structure.Electrochemical performance test shows that AZ31-3%RE has a higher equilibrium potential,higher The electrochemical activity of AZ31-2% RE al oy was the best,and the equilibrium potential of AZ31-1.5%RE was higher than that of charge and the charge transfer resistance was smaller.Poor chemical performance.(4)Three AZ31-x% RE magnesium negative air battery open circuit voltage difference is not,the voltage value of 1.60 V or so.At the discharge current density of 10mA/cm2,the discharge voltage of AZ31-3%RE is about 1.0V and the discharge is more stable.AZ31-2%RE is equivalent to AZ31-3%RE discharge voltage,but the voltage fluctuates slightly;AZ31-1.5%RE discharge voltage is the lowest,and the discharge voltage fluctuates periodically,the integrated discharge performance is the worst.