Increased demand on resource efficient battery technologies and development of materials has urged an interest on Me–air batteries, such as Zn–air and Al–air, due to their high theoretical specific energies as well as using low cost, safe and abundant materials. In this regard, while employing pure metals as anode material is one line of development [1,2], modification of the electrode by alloying with other elements is also subject to recent investigations [3]. Up to now, the influence of the alloying on the electrochemical properties of the electrode, i.e. interactions between the microstructure constituents, impact on the potential, corrosion behavior as well as the electrolyte decomposition (water or oxygen reduction), have not been systematically investigated for alloys in the Al/Zi system.

The main objective of this work is to characterize the electrochemical properties of Al-Zn alloys in neutral aqueous solutions. Al-Zn alloys with six different compositions were prepared in a muffle furnace and shaped to anodes. Microstructure of the anodes in the initial state was analyzed with respect to the fractions of its constituents. The electrochemical characterization of the prepared alloy anodes encompass (i) open circuit potential, (ii) potentiodynamic polarization measurements and corresponding determination of corrosion parameters, (iii) galvanostatic discharge/charge experiments under various current densities. The potentiodynamic polarization results are further discussed with Evans diagrams considering on possible scenarios for the galvanic interactions of the different microstructure constituents. A comprehensive analysis of the surface characteristics of the alloys is also carried out after the electrochemical experiments in order to reveal the interactions during discharge. Based on the electrochemical results on potentials, charge/discharge and corrosion behavior, the Al/Zi alloys are evaluated with respect to their suitability for application in batteries.

References:

[1] Sumboja, A., Ge, X., Zheng, G., Goh, F. W. T., Hor, T. S. A., Zong, Y., Liu, Z., Journal of Power Sources 332, 330–336 (2016).

[2] Fan, L., Lu, H., Leng, J., Electrochimica Acta 165, 22–28 (2015).

[3] Pino, M., Herranz, D., Chacon, J., Fatas, E., Ocon, P., Journal of Power Sources 326, 296–302 (2016)