Advances in magnesium electrochemistry - A challenge for nanomaterials

In this review, very recent studies related to magnesium electrochemistry (in connection with R&D of Mg batteries) have been reported. These include the study of new electrolyte solutions, based on complexes with the formal stoichiometry, Mg(AlCl_4-nR_n)₂ in ethers, their unique structures and analysis by electrochemical and spectroscopic methods, the study of Mg deposition processes by microelectrodes and microscopy, and the study of Mg insertion into hosts based on the so-called Chevrel phase structure (Mg_0-2Mo₆X₈, X=S, Se). The ionic mobility of Mg²⁺ ions and their ease of diffusion within these structures are discussed. It is demonstrated that the use of a nanostructured active mass may be highly important for reducing the diffusion length considerably, and hence, for increasing the kinetics of transport of the bivalent cations. We deal herein with some key factors that may affect the possibility of smooth and reversible Mg insertion into inorganic host materials, and the possible advantages in the use of nanoparticles for these systems.