Research supported by MIT Lincoln Laboratory has examined a way to substantially reduce corrosion in metal-air batteries—increasing longer shelf life.
Anatomy of a metal-air battery.
Image Retrieved from Science Direct: Recent progress in rechargeable alkali metal–air batteries
Metal-air batteries are lightweight, inexpensive and the most compact types of batteries available. However, when not in use the batteries will degrade quickly, as the corrosion eats away at their metal electrodes—serving as a major limitation.
Although typical rechargeable lithium-ion batteries lose about 5 percent of their charge after a month of storage—these batteries are expensive, bulky, and heavy for many applications.
Learn more about how batteries work:
This is why the primary non-rechargeable aluminum-air batteries are preferable because they are inexpensive, compact and lightweight--but also lose 80 percent of their charge a month.
To overcome such an issue, researchers at MIT worked to design a new battery system.
The new system involves placing a thin membrane between the battery’s electrodes that takes advantage of an aluminum property called “underwater oleophobicity". Since the membrane is an oil barrier between the aluminum electrode and the electrolyte— the aluminum, when placed in water, will repel the oil. The oil will then be rapidly pumped away and replaced with an electrolyte—cutting the loss of energy to 0.02 percent a month.
“Researchers demonstrating the ability of aluminum to repel oil underwater.”
Image Credit: Massachusetts Institute of Technology (Courtesy of the researchers)
The result produces an aluminum-air prototype with a much longer shelf life than conventional aluminum-air batteries. Professor of mechanical engineering, Douglas P. Hart, explains that aluminum-air batteries are the "highest chemical energy-density storage materials we know of".
The study reports that this method of corrosion suppression exploits the same property of aluminum that promoted corrosion in the first place.
Former MIT graduate student, Brandon J. Hopkins, hope that the study can allow the use of aluminum-air batteries to "extend beyond current niche applications".
Findings were published in the journal Science and researchers have filed patents on the process.