Corrosion Performance Of AA5052 Alloyas Anode In Alkaline Electrolyte Containg Inhibitor Foral-airbatteries

Aluminium-air batteries have been proposed as a kind of green energy storage devices,which have advantages of envirnoment-friendly,high specific capacity,high energy density and discharge stability.Al-air batteries comprises three main component: aluminium or its alloy served as anode,air as cathode and neutral or alkaline solution as electrolyte.Aluminum and its alloy suffers seriously self-corrosion in alkaline electrolyte,which induces coulombic loss on discharge and the anode utilization.These problems have retarded the development and business applications of Al-air batteries.At present,most researchers impove aluminium corrosion-resistant and enhance anode performance by chemical processes-adding inhibitor to electrolyte or adding alloy elements in pure aluminium.In this paper,the inhibition effect of sorbic acid and zinc oxide,fumaric acid,maleic acid and L-aspartic acid and L-malic acid on corrosion behavior of 5052 aluminum alloy(AA5052)anode in alkaline solution was studied by using the hydrogen evolution method,electrochemical test,surface analysis method and the quantum chemistry calculation.There are mainly results:(1)The self-corrosion of the AA5052 alloy in 4 mol/L NaOH solution is markedly inhibited by sorbic acid and zinc oxide as complex electrolyte additives.The maximal inhibition effect is 80.4% by adding 30 mM sorbic acid+2mM ZnO.There is a synergistic effect between sorbic acid and zinc oxide on corrosion inhibition of AA5052 alloy.Zn film formed on the AA5052 alloy surface and sorbic acid absorbed on the Zn film and its defects.The complex film prevent AA5052 alloy from self-corrosion,which is not only inhibited the cathodic hydrogen evolution reaction,but also suppressed the aluminum anodic dissolution reaction.AA5052 aluminium electrode has a good discharge performance in the applied electrolyte with sorbic acid and zinc oxide additives.(2)Isomeric unsaturated diacid compounds,i.e.maleic acid(MA)and fumaric acid(FA),are used as corrosion inhibitor in the 4 mol/L NaOH-ethylene glycol solution for AA5052 alloy.Inhibition efficiency is in the following order: maleic acid > fumaric acid.It shows that MA has the better inhibition effect for the self-corrosion of AA5052 alloy and its protection efficiency is 84.3%.The polarization curves show that MA is a mixed-type inhibitor.Quantum chemical calculation results suggest that the complex of seven-membered rings are formed between the two carboxyl groups(-COOH)and aluminium ions in maleic acid.The complex formed by MA/Al3+ has lower total energy compared with that by FA/Al3+.AA5052 aluminium electrode has good discharge performance in the applied electrolyte with isomeric unsaturated diacid additives.(3)The corrosion inhibition ability of L-malic acid(MaA)and L-aspartate acid(AsA)against the corrosion of AA5052 alloy in 4 mol/L NaOH-ethylene glycol solution has been investigated.The presence of MaA and AsA in corrosion solution shows a remarkable inhibition of hydrogen evolution of AA5052 alloy.Compared with MaA,AsA has the better inhibition effect for the self-corrosion of AA5052 alloy and its max protection efficiency is 82.1%.Quantum chemistry calculation shows that the Mulliken charges of the N atom of amine group on the AsA is lower than the Mulliken charge of O atom of hydroxyl group on the MaA;the total Mulliken charge of the former is lower than the latter,and AsA has higher EHOMO and lower energy gap ?N,indicating that amine group and carboxyl group on the AsA with Al3+ is easier to form coordination bonds.