Magnesium air cell has magnesium anode metal as fuel and air as oxidizer and saltwater or seawater as an electrolyte.

The principal advantage of the Mg-air cells, safe saltwater electrolyte, allows the easiest technical development, as emergency powers, and already displayed on markets. It has some disadvantages, large water requirement, and resulting low wet energy density, excessive heating at large current, large volume of magnesium hydroxide slurry, and low current density with hydrogen evolution from corrosion reaction, although there may be some chemical additives called hydrogen inhibitor alleviating the reaction.

Accordingly, the position of Mg-air cells is limited as a small emergency powe packs with dry storage and then filling water for activation. It is expected also as maritime power systems using seawater electrolyte.

The cell is useful as an emergengy backup power becasuse it can be dry stored without any internal discharge, and then generate full energy after the water introduction.

MEET developed several types of magmesium air cells.

The first one is CMAB(collapsibel magnesium air battery) for personal power backup. This type is tried as a military item and now on the stage of mass production.

The second one is a simple and easy system made of rigid plastic called Wattery.

Wattery® is the trade name of the simplest magnesium air fuel cell made by MEET. Co., Ltd. The Wattery has following features.

•High energy density – metal fuel(magnesium alloy plate) has very high energy density > 1,000Wh/kg. 28 gram of Mg card is equal to  8 pieces (1200 gram) of D-sized alkaline batteries at 1 ampere drain.

•Safe and readily available electrolyte – seawater, saltwater and urine.

•Stable discharge characteristic.

•Easy to handle.

•Economic.

•Nontoxic waste.

•Infinite shelf life at dry package.