Optimization For The Electrode Materials And The Electrolytes Of The Magnesium-air Battery

Oxygen reduction reaction electrocatalysts of carbon black and carbon aerogel supported Pt-based nanoparticles were synthesized by chemical impregnation reduction method. XRD, TEM, ICP and XPS techniques were utilized to characterize the physical properties of the as-prepared catalysts. The electrochemical measurement consisted of cyclic voltammetry(CV) and line scan of scanning electrochemical microscopy(SECM) conducted in alkaline medium as well as the single-cell tests. All the tests indicate that Pt-Zn/Carbon Aerogel, with the specific discharge capacity reaching 1349.5mAh g-1 in 3.5wt.% NaCl aqueous solution, exhibits the best catalytic performance among all the tested catalysts when using AZ31 foil as the anode material. The doping of Zn forms Pt-rich surface and use of carbon aerogels brings larger specific surface area, which have improved the catalytic activity per unit mass.This experiment tried several kinds of inorganic solution as the electrolytes, including the NaCl, NaNO3, MgCl2, Mg(NO3)2 and NaOH aqueous solution, and tested the potentialdynamic polarization curves of the pure Mg in these solution. Pure Mg and commercial Pt/C were also assembled as the anode and the cathode catalyst in the above-mentioned solution, respectively, to give the discharge curves. A series of tests show that 3.5wt.% NaCl solution is the most suitable for the application as the electrolyte of the Magnesium-air battery. Furthermore, hexamethylenetetramine and sodium stannate were added to 3.5wt.% NaCl solution as corrosion inhibitors. The corresponding electrochemical experiments reveal that the two reagents can both increase the discharge voltage and the specific discharge capacity of the Magnesium-air battery.As-cast pure magnesium, AZ31, NZ30 K, GW103 K and pressed GW83 K were studied by XRD and SEM techniques to acquire the information about their microstructure. Discharge curves can directly reflect the suitability of being chosen as the anode materials of the battery, and it turns out that NZ30 K is not a proper anode material since its specific capacity and stability are quiet poor in its discharge curve. GWK series’ discharge performance is slightly better than pure magnesium while AZ31 displays very high specific discharge volume of 1083.36 mAh g-1. Therefore, AZ31 is a relatively ideal anode material for the Magnesium-air battery. In order to explore the relation between the corrosion resistance and discharge abilities of the magnesium alloys, the potentialdynamic polarization curves of the magnesium alloys were acquired in 3.5wt.% NaCl aqueous solution. The corrosion current density calculated from the polarization curve reveals the corrosion resistance of the tested material. From the corrosion current densities of the different magnesium alloys, we can find no obvious difference among the corrosion resistance of the different magnesium alloys in our text apart from GW30 K, which performs much better than others in combating corrosion. Therefore, there’s no direct relationship between corrosion resistance and discharge capacity.