Non-aqueous electrochemistry of magnesium (Mg)

Several important aspects of non-aqueous magnesium electrochemistry are reviewed. It is important to develop effective magnesium (Mg) deposition processes. There is also a strong interest in research and development (R&D) of rechargeable Mg batteries. This chapter describes non-aqueous solutions that may be relevant to Mg electrochemistry, including conventional polar aprotic solvents and ionic liquids. It also describes several basic aspects of active metal surface chemistry and their possible passivation processes. The electrochemistry of magnesium in conventional electrolyte solutions and in ionic liquids is discussed. The chapter then describes electrolyte solutions possessing wide electrochemical windows in which Mg electrodes behave reversibly. These systems are based on ether solvents and complexes of the (RMgCl or R₂Mg)_x-(AlCl_3-nR_n)_y type in which R=alkyl or aryl groups. Finally, the chapter deals with another important aspect of non-aqueous Mg electrochemistry, i.e. the possibility of electrochemical intercalation of Mg ions into inorganic hosts. The development of electrolyte solutions with wide electrochemical windows in which Mg electrodes behave reversibly and hosts that can intercalate Mg ions are important milestones on the way to developing practical rechargeable Mg batteries.