Study On Corrosion Inhibition Behavior Of Aluminum Air Battery Anode Material Containing Rare Earth

Aluminum-air battery has a wide application prospect due to its high specific energy,large raw material reserves and no pollution of corrosion products.However,the high self-corrosion rate in alkaline solution hinders the application of aluminum-air battery.It is an effective solution to alloying aluminum anode and adding compound corrosion inhibitor to electrolyte solution.In this paper,the effects of rare earth elements Y,YB,cerium acetate and glutamine,cerium acetate and serine,calcium oxide and glutamine,calcium oxide and asparagine four composite corrosion inhibitors on the electrochemical properties and discharge efficiency of Al-0.5Mg-0.1Ga-0.1Sn anodized aluminum alloy were investigated by means of metallographic analysis,electrochemical test,galvanostatic discharge test and surface morphology analysis.The main results are as follows:Al-Mg-Sn-Ga-x Y and Al-Mg-Sn-Ga-x Yb five-element aluminum alloys were prepared by medium frequency induction melting furnace,and their electrochemical properties were tested respectively.The results show that the grain size of the alloy is the smallest and the particles of the second phase are evenly distributed when the Y content is 0.1%.When Yb content is 0.3%,the intergranular corrosion of the alloy decreases and the grain size is uniform.When Y decreases the reaction rate of hydrogen evolution,the alloy has the best electrochemical performance.Yb makes the alloy homogenize and corrode obviously.When the discharge density is 0.02 A·cm^-2,the energy density of the anodic aluminum alloy containing Y and Yb is up to2777.778 m A·h·g^-1and 2631.578 m A·h·g^-1,respectively.The self-corrosion of Al-0.5Mg-0.1Sn-0.1Ga alloy can be effectively inhibited by two kinds of inorganic corrosion inhibitors composed of calcium oxide.When the two composite corrosion inhibitors are 10 m M Ca O+6 m M Asn and 10 m M Ca O+8m M Gln,the self-corrosion current is the smallest.Discharge test analysis shows that the best discharge current of 10 m M Ca O+6 m M Asn and 10 m M Ca O+8 m M Gln is0.02 A·cm^-2,and the discharge voltage is-1.77 V and-1.81 V,respectively.The energy densities are 3333.333 m A·h·g^-1and 3846.153 m A·h·g^-1,respectively.Combined with the corrosion morphology analysis,inorganic corrosion inhibitor calcium oxide formed calcium hydroxide and asparagine and glutamine respectively formed a dense composite corrosion inhibition film,the self-corrosion area decreased,inhibit the anode self-corrosion.The self-corrosion of Al-0.5Mg-0.1Sn-0.1Ga alloy was also effectively inhibited by two kinds of composite corrosion inhibitors of cerium acetate.The optimal compound concentration of the two composite corrosion inhibitors is 10 m M Ce（CH₃COOH）₃+8 m M Gln and 10 m M Ce（CH₃COOH）₃+10 m M Ser,in which the anode activity is increased and the hydrogen evolution reaction is inhibited.The optimal discharge currents of 10 m M Ce（CH₃COOH）₃+8 m M Gln and 10 m M Ce（CH₃COOH）₃+10 m M Ser are 0.02 A·cm^-2,and the discharge voltages are-1.76 V and-1.78 V,respectively.The energy densities are 3571.429 m A·h·g^-1and 4166.667m A·h·g^-1,respectively.Combined with the corrosion morphology,it can be seen that cerium acetate spontaneously forms a composite corrosion inhibition film with cerium hydroxide,glutamine and serine in alkaline solution,which prevents the diffusion and transfer of corrosion particles and inhibits the self-corrosion of the anode.