Metal-air batteries use the oxygen of the environment as a source of substance for a chemical reaction, unlike traditional batteries with a closed sealed design. This allows a significant increase in energy storage density. The main innovation in the new lithium-air battery is the use of a solid electrolyte instead of the usual liquid one. It is the liquid electrolyte that is the source of many of the problems and dangers of batteries, as it can leak or explode.
In earlier lithium air batteries, the lithium in the lithium metal anode moved through the liquid electrolyte to combine with oxygen during discharge, forming lithium peroxide (Li 2 O 2 ) or superoxide ( LiO 2 ) at the cathode. Lithium peroxide or superoxide is then split back into lithium and oxygen during charging. This cycle of chemical reactions stores and releases energy on demand.
The new solid electrolyte consists of a ceramic polymer material made from relatively inexpensive nanoparticle-based cells. This solid allows chemical reactions to be carried out, resulting in the formation of lithium oxide (Li 2 O) during discharge.
The new lithium-air battery is the first in which the four-electron reaction takes place at room temperature. In addition, the battery can use oxygen from the air, without the need to pressurize it from cylinders.
Metal-air batteries are considered the most promising line of work when trying to develop batteries with an energy density much higher than that of lithium-ion.