Influence of Rare Earth Samarium/Ytterbium Salt on Electrochemical Corrosion Behavior of Aluminum-Based Anode for Batteries

Abstract

Sm(OAc)3 and Yb(OAc)3 were used as new corrosion inhibitors for aluminum-based anodes for batteries. The potential effect of mixed rare earth salts was preliminarily explored. Electrochemical noise test illustrated the transient process of self-corrosion. 3D microscopic morphology of the electrode surface was constructed. Highlights: In this work, effects and mechanism analysis of samarium acetate and ytterbium acetate on enhancing the electrochemical corrosion performance of aluminum-based anode for aluminum-air batteries in 3.5 wt.% NaCl are studied by methods such as weight loss tests, electrochemical measurements, anode galvanostatic discharge tests and microscopic morphology analysis. The results show that samarium acetate and ytterbium acetate are ideal electrolyte additives, and exhibit obvious inhibitory effects on the self-corrosion of 7075 aluminum alloy. The optimal concentration is 200 mg/L. Moreover, corrosion inhibitors mainly reduce the self-corrosion speed of aluminum by suppressing the microcathodic reaction, thereby promoting the improvement of the discharge performance of aluminum-air batteries. Simultaneously, it is found that after mixing samarium acetate and ytterbium acetate in different proportions, the two rare earth salts have a mutual adjustment effect. By adding different rare earth salt components, the battery capacity densities of the anode are improved by 9.6% to 16.3%. Finally, a possible model is presented to illustrate the impact mechanism of different additives on the self-corrosion process and discharge performance of aluminum-air batteries.