Current Progress on Rechargeable Magnesium–Air Battery

Rechargeable Mg–air batteries are a promising alternative to Li–air cells owing to the safety, low price originating from the abundant resource on the earth, and high theoretical volumetric density (3832 A h L −1 for Mg anode vs 2062 A h L −1 for Li). Only a few works are related to the highly reversible Mg–air batteries. The fundamental scientific difficulties hindering the rapid development of secondary Mg–air cells are attributed to the poor thermodynamics and kinetics properties mainly owing to the MgO or MgO 2 insulating film as the initial discharge product on air–breathing cathode, contributing to the increase of a large overpotential and a high polarization. Very recently, remarkable progress on rechargeable Mg–air batteries is trying to overcome the major limitations in organic electrolytes via the combination of the first–principle calculation and experimental study. Therefore, this progress report highlights a comprehensive and concise survey of the major progress in the history of secondary Mg–air batteries, and the detailed illustrations of corresponding reaction mechanisms. The overview is devoted to open up a new area for manipulating the nanostructures to control the ideal reaction pathway in novel cell configuration and to fully understand the future Mg–air battery with improved energy density and cycling ability.