An effective hybrid organic/inorganic inhibitor for alkaline aluminum-air fuel cells

An issue associated with aluminum-based batteries is the drastic parasitic corrosion of aluminum anode, which significantly restricts the utilization of aluminum. An effective approach is to add inhibitors in electrolytes to reduce the anode corrosion rate. In this work, Na2SnO3 and casein are proposed to act as a hybrid inhibitor in alkaline aluminum-air fuel cell. It is demonstrated that 0.05 M Na2SnO3 and 0.6 g L−1 casein offers the strongest corrosion protection, reducing the corrosion rate by approximately one order of magnitude. The corrosion inhibition is mainly attributed to the inhibition of cathodic reaction process. In addition, the analysis on the morphology and composition of the aluminum surface suggests that casein can greatly promote the deposition of tin to form a uniform and stable layer on the aluminum surface, due to the strong adsorption of polar functional groups in casein. Furthermore, the use of the hybrid inhibitor in aluminum-air fuel cell contributes to an increase of discharge capacity by 89.3%.