Electrolyte Modification For Aluminum Air Battery

With the increasing energy demand,aluminum-air batteries with high energy density and high safety have attracted extensive attention as advanced energy conversion device.However,the commercial application of aluminum-air batteries still needs to solve the problems of serious self-corrosion of aluminum alloy anodes and low anode utilization rate.In this paper,from the perspective of the modification of aluminum-air battery’s electrolyte,two corrosion inhibition methods researched are the modification of the electrochemical environment of water molecules in the electrolyte and the effect of interface charge distribution on corrosion inhibition performance of surfactants.The details are as follows:（1）The electrochemical environment of water molecules in the electrolyte is regulated by adding polyhydroxy sucrose additive to the 4 M KOH electrolyte.And it is achieved the purpose of inhibiting the reactivity of water molecules and reducing the occurrence of self-corrosion reactions.Through this research,we obtained an aluminum-air battery with 4 M KOH+2 M sucrose electrolyte.At current densities of 10 m A cm^–2and 20m A cm^–2,the specific capacities of this battery are as high as 2330 m Ah g^–1and 2344 m Ah g^–1,respectively,which are significantly higher than the356 m Ah g^–1and 575 m Ah g^–1 of the aluminum-air battery with 4 M KOH electrolyte.（2）By adding different types of surfactants to the 4 M KOH electrolyte,it is proved that the interface charge distribution can significantly affect the corrosion inhibition performance of surfactants and composite corrosion inhibitors by changing the direction of the electric field in the electrolyte.Through this research,it is concluded that under open circuit conditions,the order of corrosion inhibition performance is CTAB>APG>SDBS,sodium stannate/CTAB>sodium stannate>sodium stannate/SDBS.Under energized condition,the order of corrosion inhibition performance is SDBS>APG>CTAB,sodium stannate/SDBS>sodium stannate/CTAB>sodium stannate.Finally,under open circuit conditions,the corrosion rate of aluminum alloy is only 0.430 mg cm^–2 h^–1 in 4 M KOH+0.03 M Na₂Sn O₃+0.5 m M CTAB electrolyte,which is significantly lower than 8.509 mg cm^–2 h^–1in 4 M KOH electrolyte.Under discharge condition,the specific capacity of the aluminum-air battery with4 M KOH+0.03 M Na₂Sn O₃+0.5 m M SDBS electrolyte reaches 2388.2m Ah g^–1,which is significantly higher than that of the Al-air battery with4 M KOH electrolyte of 782.3 m Ah g^–1.