The Study On The Sodium And Potassium Electrolytic Solutions In Mg-MnO₂ Battery

Nowadays,Magnesium and its alloy was widely used in automobile,aviation,motorcycle and electronics fields and so on.Magnesium is an active metal and is one of the lightest engineering structural metal-materials in the world.It has extensive sources and is non-toxic,non-pollution.when used as electrode materials its advantages of high theoretical capacity,steady discharge potential and wide range of work temperature extrude.Consequently,these advantages make magnesium and its alloys exhibit great potential in battery field.China has abundant magnesium resources as well as the largest reserves in the world,this makes unique superiority of researching and developing on magnesium batteries.While the poor corrosion resistance together with negative difference effect quite reduced the current efficiency of magnesium negative electrode.Moreover,the passivation film formed on magnesium electrode surface when contact with electrolyte will lead the voltage delay action of battery by blocking transportation of ion and electron.On account of magnesium electrode is easy to be precipitated in traditional magnesium salt electrolyte after a long time immersion and the amount of corrosion inhibitor add to electrolyte was restricted,potassium salt as well as sodium salt were studied as new electrolyte to improve the electrolyte property.This paper was established by discussing both electrolyte system and corrosion inhibitor for Mg-MnO₂batteries.Suitable electrolyte recipes and composite ratio and experimental temperature were selected via electrochemical test results of OCP,CP,EIS,LSV and Tafel plots.In addition,methods of weight-loss,SEM etc.were used to assist investigate electrochemical performance?corrosion resistance,delayed action and activation potential?of AZ31B as well as LZ91 magnesium alloy which enhanced by single?NaF,Na₂SiO₃,KMnO₄?and binary additive.The results indicate that:1.0 mol/L Na₂SO₄ coordinate 0.3 mol/L K₂SO₄ was the best suitable ratio of electrolyte for AZ31B and LZ91 magnesium alloys matches better with electrolyte of 1.0 mol/L Na₂SO₄ coordinate 0.4 mol/L K₂SO₄.As to both two magnesium alloys electrochemical performance can be mostly heightened at temperature of 25?.NaF-Na₂SiO₃ proved its better ability on enhancing discharge performance,activation potential and corrosion resistance of electrode when compared with single additive or other additives.It makes the electrode activation potential maximized,the passivation range expand and the corrosion current density reduced.Hence,it can be used as an ideal binary inhibitor additive suitable for Mg-MnO₂ battery system.The delay time was reduced from 1.0 s to 0.2 s and potential-drop was reduced with 7 mmol/L NaF-5 mmol/L Na₂SiO₃ was took as additive of electrolyte for AZ31B magnesium alloy.It also expressed the most positive corrosion potential and the minimum corrosion current density.When 11 mmol/L NaF-5 mmol/L Na₂SiO₃ was added to electrolyte as corrosion inhibitor on LZ91 magnesium alloy,the delay time of1.8 s was cut?from 2.1 s to 0.3 s?and 1.9 V potential-drop was reduced.Results of weight-loss data and SEM morphology also proved that the additives selected in this experiment play an important role in promoting the electrochemical behaviors of magnesium alloys in battery field.