If you think of metals in a battery, you probably think of lithium, mercury, lead, nickel, and cadmium. But researchers in Australia and China want you to think about aluminum. Unlike most battery metals, aluminum is abundant and not difficult to dispose of later.
Their battery design uses water-based electrolytes and is air-stable. It is also flame retardant. The battery can provide 1.25V at a capacity of 110 mAh/g over 800 charge cycles. The idea of using aluminum in a battery isn’t new. Aluminum is potentially more efficient since each aluminum ion is equivalent to three lithium ions. The batteries, in theory, have higher energy density compared to lithium-ion, but suffer from short shelf life and, so far, practical devices aren’t that close to the theoretical limits of the technology.
Aluminum ion transport is slow, however, so batteries made with the metal tend to have low cathode efficiency. Organic polymer cathodes can help but have their own set of problems. The new battery addresses some of these concerns, but, of course, it remains to be seen if this technology will be competitive with other technologies.