Extending the life of low-cost, compact, lightweight batteries
Metal-air batteries are one of the lightest and most compact types of batteries available, but they can have a major limitation: When not in use, they degrade quickly, as corrosion eats away at their metal electrodes. Now, MIT researchers have found a way to substantially reduce that corrosion, making it possible for such batteries to have much longer shelf lives. While typical rechargeable lithium-ion batteries only lose about 5 percent of their charge after a month of storage, they are too costly, bulky, or heavy for many applications. Primary (nonrechargeable) aluminum-air batteries are much less expensive and more compact and lightweight, but they can lose 80 percent of their charge a month. The MIT design overcomes the problem of corrosion in aluminum-air batteries by introducing an oil barrier between the aluminum electrode and the electrolyte — the fluid between the two battery electrodes that eats away at the aluminum when the battery...