Effect Of Corrosion Inhibitor On Electrochemical Performance Of The Aluminum-air Battery Anode

As the aluminum-air battery has the superiority such as high specific energy density,friendly to environment and no pollution,etc.It is an ideal choice for new green energy.However,the severe self-corrosion of the anode alloy in the alkaline electrolyte solution is a major problem to its widely using.Adding corrosion inhibitor to the electrolyte solution has the advantages such as easy operation,low cost,and the like,so it is a simple and efficient method.In this study,experimental tests including H₂evolution measurement,electrochemical measurement,constant cuttent discharge measurement and morphology test combining the theoretical tests including quantum chemical simulation,crystal morphology simulation and Monte Carlo method are used to investigate the effect of cerium acetate?Ce?CH₃COOH?₃?/L-glutamic?L-Glu?hybrid inhibitor and calcium oxide?Ca O?/L-aspartic?Asp?hybrid inhibitor on self-corrosion inhibition and electrochemical performance for Al-0.5Mg-0.1Sn-0.1Ga alloy and AA5052 alloy anode of alkaline Al-air batteries,respectively.The main results are as follows:The Ce?CH₃COOH?₃/L-Glu hybrid corrosion inhibitor is cathodic inhibitor that has very little effect to the anode activity and can effectively inhibits the self-corrosion of Al-0.5Mg-0.1Sn-0.1Ga alloy.Adding 10m M Ce?CH₃COOH?₃ and 8 m M L-Glu to the electrolyte can obtain the maximum inhibition efficiency of 77.85%.At the constant discharge density of 20m A cm^-2,the working voltage and capacity density of anode alloy increase from-1.737V and 2298.851 m Ah g^-1 to-1.835 V and 2985.075 m Ah g^-1by adding 10m M Ce?CH₃COOH?₃with 8 m M L-Glu.By comprehensive analysis of experimental and theoretical research results,the inhibition mechanism can be concluded:At the beginning,Ce?OH?₃ formed by Ce?CH₃COOH?₃ at the alkaline solution adsorb on the alloy via the geometric covering effect.This boosts the adsorption of L-Glu on the alloy.Later,the Ce?OH?₃/L-Glu and Al/L-Glu composite membranes effectively reduce the self-corrosion rate and has very little effect on the anode activity performance.The Ca O/L-Asp hybrid corrosion inhibitor has little influence on the discharge activity of AA5052 alloy.But it has very effective inhibitory effect to the anode corrosion.Maximum inhibition efficiency can be obtained by adding 10m M Ca O with4m M L-Asp.The hybrid inhibitor retards anodic process of self-corrosion reaction,so it is more suitable in the case where discharge current density is not very large.By adding 10m M Ca O with 4m M L-Asp,the capacity density of AA5052 is increased from1152.07m Ah g^-1to 2155.17m Ah g^-1 at the constant discharge density of 20m A cm^-2.By comprehensive analysis of experimental and theoretical research results,the inhibition mechanism can be summarized as follow:In alkaline electrolyte,Ca?OH?₂ can be formed by Ca O.Subsequently,Ca?OH?₂ absorb on the anode surface through geometric coverage effect.This boosts the adsorption of L-Asp on the anode surface.The active parts of L-Asp are O atom of two-COOH and the N atom of-NH₂.By the formation of Ca?OH?₂-L-Asp and Al-L-Asp monolayer membranes,the self-corrosion rate of AA5052 alloy is effectively reduced.