The Study On The Electrochemical Behavior Of Magnesium Composite Electrode

Magnesium alloy has great potential in the energy field because of its abundant reserves, high physical properties and excellent electrochemical behavior. The research and development of new highly efficient environment-friendly materials are a new direction to replace the traditional electrode materials. In this dissertation, we proposed"composite anode"taking place of the traditional single electrode materials, based on the study of magnesium anode. Through the formation of galvanic pairs of"double electrodes", the corrosion resistance of compound magnesium anode and electrochemical behavior was investigated. At the same time, the examination also included the influence of composite electrolyte of the corrosion resistance and electrochemical activity about AZ31 magnesium alloy. In order to optimizate electrolyte composition by using the role of bromide ion in pitting, to improve the passivation phenomenon and voltage delay. The main test methods are weight loss, open circuit potential-time(OCP), linear sweep voltammetry(LSV), electrochemical impedance spectroscopy(EIS) and chronopotentiometry(CP). These results palyed an important role in the practical application of magnesium alloy.The study of composite electrolyte showed that with the higher concentration of magnesium bromide, pH decreases acidity, bromide ion effect of pitting was obvious. Mg alloy corrosion resistance decreases. When concentration of magnesium bromide was 0.05mol/L, corrosion rate of AZ31 was slower than other concentrations, but its electrochemical activity was increased.The results of compound anode showed a significant difference in corrosion resistance and electrochemical behavior than before. Mg-Zn compound anode showed the best corrosion resistance and a better overall performance than others. There were ideal composite electrode materials,AZ31 was better than AZ21 because of its high current efficiency. When AZ31 compounded with Al(A), its electrochemical activity reduced, but corrosion resistance increased.AZ31-Al(B) composite electrode was more active, but its corrosion rate was faster than single AZ31.The electrochemical activity of AZ21-Al(A) was increased a little, but corrosion resistance reduced so much, AZ21-Al(B) composite electrode was the worst in most of all electrodes.This success exploration of composite electrolyte and compound anode materials provided a basic for developing Mg-MnO2 battery, which can instead of the traditional Zn-MnO2 battery.