Magnesium Battery

Magnesium batteries are batteries that utilize magnesium cations as the active charge transporting agent in solution and as the elemental anode of an electrochemical cell. Both non-rechargeable primary cell and rechargeable secondary cell chemistries have been investigated. Magnesium primary cell batteries have been commercialised and have found use as reserve and general use batteries. Primary magnesium cells have been developed since the early 20th century. A number of chemistries for reserve battery types have been researched, with cathode materials including silver chloride, copper(I) chloride, palladium(II) chloride, copper(I) iodide, copper(I) thiocyanate, manganese dioxide and air (oxygen). For example, a water activated silver chloride/magnesium reserve battery became commercially available by 1943.

 Magnesium secondary cell batteries are an active topic of research, specifically as a possible replacement or improvement over lithium-ion–based battery chemistries in certain applications. A significant advantage of magnesium cells is their use of a solid magnesium anode, allowing a higher energy density cell design than that made with lithium, which in many instances requires an intercalated lithium anode. Insertion type anodes ('magnesium ion') have also been researched, primarily as heavy main group metal thin films or as Zintl phases, for instance Mg₂Sn.

A magnesium–air fuel cell has theoretical operating voltages of 3.1 V and energy densities of 6.8 kwh/kg. General Electric produced a magnesium air fuel cell operating in neutral NaCl solution as early as the 1960s. The magnesium air battery is a primary cell, but has the potential to be 'refuelable' by replacement of the anode and electrolyte. Magnesium air batteries have been commercialised and find use as land based backup systems as well as undersea power sources, using seawater as the electrolyte.