The only certainty of electric car technology is that nobody is really certain of our future path.

Dozens of different battery technologies are under development all around the world to fix the common battery limitations--limited energy density, heavy weight, long recharging times--and one such path is that of lithium-air batteries.

Computer and technology company IBM is taking the lithium-air route, and explains the workings of the battery in the video above.

The basic concept of a battery is to turn a chemical reaction into an electrical output. A lithium-air battery draws oxygen from the air around us, which reacts with lithium molecules inside the battery. This generates electrical energy which is then used to power the car.

When recharging, the opposite reaction takes place, and oxygen is fed back out into the atmosphere.

There's a huge potential benefit to lithium-air batteries. They're much more energy-dense--five times that of lithium-ion, and similar to gasoline. This enables them to be lighter. You can either install a far lighter battery than you would with a current lithium-ion unit, but maintain the same range, or install a much greater density of battery packs--enough for a 500-mile range in an average car--with no weight penalty over today's units.

Companies like IBM are still ironing out the technology's limitations--the cathode can currently suffer degradation in humidity, which means somehow de-humidifying the ambient air the battery requires. There are also efficiency issues to overcome--potentially solveable with the use of highly conductive graphene components within the battery.

Lithium-air is a concept that works better in the lab than in practice right now, but with IBM, as well as Toyota and BMW working on the technology, it could well be a technology to transform the electric car from a high-tech curiosity into a realistic proposition for millions of drivers.