Researchers from Cambridge University have found a way to make a lithium-air battery which is going to be released for commercial usage sooner than expected. Before going to lithium-air battery, it is better to explain how a normal battery works.
A normal battery has three basic parts, a positive terminal (cathode), a negative terminal (anode) and an electrolyte. The electrolyte generates current by allowing ions to move between terminals. Lithium primary cells use lithium to form the anodes whereas the cathodes can be made from different materials such as iron disulfide, silicon and sulphur dioxide. Lithium-air batteries on the other hand, pull oxygen from the air and use it as a reactant for the cathode whereas the anode is made from lithium material. The advantage of lithium-air battery from the others is that the cathode material is external to the cell. Therefore, it allows for greater gravimetric energy density.
To measure different batteries’ performance, a term ‘specific energy’ is normally used. It is basically representing the amount of energy that a battery can store per unit weight. The unit used is watt-hours stored per kilogram (Wh/kg).
Lithium-ion batteries normally can store 100Wh/kg or 200 Wh/kg. Lithium-air battery on the other hand, is able to store up to 10,000 Wh/kg in theory. With the release of lithium air batteries for commercial purposes, it could mean the end of combustion engines. According to a study of battery technologies by RAND, it was unlikely that conventional battery technology could safely exceed a specific energy of 250Wh/kg.
There is no confirmation whether the commercialization of lithium-air battery will become a reality as there are technical challenges that still need to be solved. Some of those them has been solved by the researchers at University of Cambridge.