The Electrochemical Properties Of Magnesium Anode Materials

In this paper,the electrochemical performance of the magnesium anode materials was investigated in 3.5 wt.% NaCl solution using immersion hydrogen experiment and electrochemical measurement.And the microstructure was examined by optical microscopy(OM),scanning electron microscopy(SEM)equipped with Energy Dispersive Spectrometer(EDS)and X-ray diffraction(XRD).The main research work is divided into the following aspects:By changing the extrusion temperature(180?,200?,250?),pure magnesium with different grain sizes were obtained,the effect of grain size on the electrochemical performance was explored.The results show that the hydrogen evolution rate of pure magnesium with different grain sizes is in slight different,but the electrochemical behavior during the discharge process is obviously different.The discharge potential of the extruded pure magnesium anode at 250 °C reaches the most negative value,-1.571 V(vs.SCE)at the current density of 50 mA cm-2.The results indicate that pure magnesium anode is suitable for discharge at a small current.At high current discharge,the discharge product will soon cover the surface of the magnesium anode,making the discharge curve unstable and the discharge potential will shift toward positive direction with the extension of discharge time.The electrochemical properties of Mg-Al-Sn-Mn magnesium alloy anode materials were investigated through orthogonal design.The results show that the proper amount of Mn can not only inhibit the self-corrosion of Mg-Al-Sn-Mn magnesium alloy anode,but also improve the electrochemical activity of alloy through the formation of Al-Mn phase.Through orthogonal design test analysis,the extruded Mg-6Al-1Sn-0.4Mn alloy shows best electrochemical properties,the average discharge potential at the current density of 50 mA cm-2 is-1.602 V(vs.SCE),which is better than that of the other components in the orthogonal test results.Based on the orthogonal test,the electrochemical properties of the extruded AT61-0.4Mn-1In and Mg-6Al-6In alloys were studied,and the mechanism of the In element on the magnesium alloy anode material was discussed.The results show that the addition of 1 wt.% In element to the AT61-0.4Mn alloy has no significant effect on the grain size of the extruded alloy,but the discharge potential shift towards positive direction.At the same time,the self-corrosion behavior of extruded alloy is effectively suppressed,and the efficiency of use is improved and the activation time of the constant current discharge is shortened,the discharge potential is more stable.The average discharge potential of the extruded Mg-6Al-6In alloy anode at a current density of 50 mA cm-2 is-1.713 V(vs.SCE),which is more negative compared to the extruded AT61-0.4Mn alloy and the AT61-0.4Mn-1In alloy.