The love-hate relationship that we maintain with lithium-ion batteries is leaning more and more toward the second half. Charging time, size, weight, capacity, and safety are parameters that have deteriorated significantly over the years, but at Stanford University they have created something that could replace lithium entirely: a aluminum-ion battery capable of supporting 7,500 charge cycles and restoring its energy in just one minute.
The Problem with Lithium
In early March, United Airlines and Delta Air Lines decided to prohibit the transport of several types of lithium batteries on their commercial flights. The reason is not hard to understand: a lithium battery with a bad attitude could bring down an airplane. FAA tests and the risk of "chain reactions" add to the hundreds of incidents per year at airports and on planes around the globe involving lithium batteries, but we cannot leave this technology behind for another very simple reason: there is no direct replacement. Besides representing a risk, lithium batteries face an ever-increasing challenge in terms of energy density and user demands. Larger batteries equal longer charging times, and nobody wants that either. The most logical option is to return to the laboratory, and that is how we come across a new development from Stanford University.
The Aluminum Battery
Professor Hongjie Dai presented, along with his colleagues, a new type of the so-called aluminum-ion batteries. The idea of replacing lithium with aluminum is not new. In fact, other institutions such as Oak Ridge National Laboratory and Cornell University have worked on them, yet Stanford's new design sits a bit above the rest. First, aluminum batteries do not explode or burn. In the video we can see how they drill one of their prototypes with a drill, and the only thing the battery does is lose performance. Then we must not forget the flexibility of aluminum. Lithium batteries detest any kind of bending, but the aluminum battery is much more tolerant. Then we come across cost, since the price of aluminum is much lower than that of lithium. And finally, we reach its charging time: this aluminum battery needs only one minute (the announcement does not indicate what the battery capacity would be to charge it in that time), and it withstands more than 7,500 cycles, while the best lithium batteries tolerate about a thousand.
The anode is aluminum, the cathode is made of graphite, and the electrolyte composition resembles a "liquid salt" at room temperature. So far everything sounds very good, but reality tells us that aluminum-ion batteries have two critical aspects to improve. The first is none other than voltage. With its current design, the batteries can deliver about two volts, when most devices need 3.6v. And the second is energy density, approximately a fifth of a lithium battery. Even so, the development looks promising. I just hope it doesn't get stuck in the limbo of announcements and manages to reach the market...
