The study of aluminium anodes for high power density Al/air batteries with brine electrolytes

• Published in: Journal of power sources Vol. 178; no. 1; pp. 445 - 455
• Main Authors: Nestoridi, Maria, Pletcher, Derek, Wood, Robert J.K., Wang, Shuncai, Jones, Richard L., Stokes, Keith R., Wilcock, Ian
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 15.03.2008; Elsevier Sequoia
• Subjects: Al alloy electrochemistry; Al dissolution; Alloys; Aluminium; Aluminum; Anodic dissolution; Applied sciences; Brine-based batteries; Direct energy conversion and energy accumulation; Dissolution; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Exact sciences and technology; Inclusions; Pits; Tin; Al dissolution; Al alloy electrochemistry; Brine-based batteries; Power density; Open circuit; Gallium; Heat treatment; Stability; Anode; Secondary cell; Aluminium alloy; Corrosion; Aluminium air batteries; Electrochemistry; Tin; Microstructure; Performance; Current density
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2007.11.108

Aluminium alloys containing small additions of both tin (∼0.1 wt%) and gallium (∼0.05 wt%) are shown to dissolve anodically at high rates in sodium chloride media at room temperatures; current densities >0.2 A cm −2 can be obtained at potentials close to the open circuit potential, ∼−1500 mV versus SCE. The tin exists in the alloys as a second phase, typically as ∼1 μm inclusions (precipitates) distributed throughout the aluminium structure, and anodic dissolution occurs to form pits around the tin inclusions. Although the distribution of the gallium in the alloy could not be established, it is also shown to be critical in the formation of these pits as well as maintaining their activity. The stability of the alloys to open circuit corrosion and the overpotential for high rate dissolution, both critical to battery performance, are shown to depend on factors in addition to elemental composition; both heat treatment and mechanical working influence the performance of the alloy. The correlation between alloy performance and their microstructure has been investigated.