Aluminum-Ion Battery Keeps On Going

Researchers in the U.S. and Taiwan have developed an aluminum-ion battery that charges quickly and performs well even after thousands of charging cycles (Nature 2015, DOI: 10.1038/nature14340). The advance may lead to improved battery safety, given that the new battery does not use a flammable electrolyte solution as lithium-ion batteries do. And because its electrodes are made from aluminum and graphite, the battery has the potential to be inexpensive. Scientists have tried for years to capitalize on the potential benefits of aluminum-ion batteries. Success has remained elusive because of problems including cathodes that decompose upon repeated charging, quickly falling charge capacities, and short lifetimes. The team, led by Stanford University’s Hongjie Dai, has made headway in overcoming those issues. The group coupled a graphite foam cathode they made via vapor deposition with an aluminum metal anode and an AlCl₃-ionic liquid electrolyte, forming a flexible battery. They found that similar test cells made with other types of graphite began failing quickly when charged too fast. In contrast, the graphite foam cell retained full charge capacity for more than 7,500 cycles, even when charged in less than a minute, or some 75 times as fast.