From smartphones to electric cars, there’s a lot riding on future battery developments. While lithium-ion batteries have become standard, their future growth is seen as unstable for a number of reasons. Even the creator of the lithium-ion battery thinks it needs to change.
Now, researchers from the Chalmers University of Technology in Sweden and the National Institute of Chemistry in Slovenia have made what they believe is a major breakthrough in a possible replacement: aluminum-ion batteries.
Batteries consist of both of an anode, a negative electrode, and a cathode, a positive electrode. According to the team’s press release, the new battery would have “twice the energy density as previous versions, is made of abundant materials, and could lead to reduced production costs and environmental impact.”
While previous aluminum-ion battery concepts used graphite as a cathode, which provides low energy production, the team replaced it with an organic, nanostructured cathode, made of the carbon-based molecule anthraquinone.
“The material costs and environmental impacts that we envisage from our new concept are much lower than what we see today, making them feasible for large scale usage, such as solar cell parks, or storage of wind energy, for example,” says Patrik Johansson, Professor at the Department of Physics at Chalmers, in the press statement. “Additionally, our new battery concept has twice the energy density compared with the aluminium batteries that are ‘state of the art’ today.”
Having an organic molecule in the cathode material would allow for storage of positive charge-carriers from the electrolyte, the catalyst that makes a battery conductive. Ions would be able to move freely between the battery’s two electrodes, making higher density storage possible.
“Because the new cathode material makes it possible to use a more appropriate charge-carrier, the batteries can make better usage of aluminium’s potential,” says Chalmers researcher Niklas Lindahl. “Now, we are continuing the work by looking for an even better electrolyte. The current version contains chlorine–we want to get rid of that.”
The team has a long road ahead. There are currently a grand total of zero aluminum-ion batteries on the commercial market, with everything from keeping heat down to size standing in the way of everyday use. But could the design be a blueprint for the future?
“Of course, we hope that they can,” says Johansson.
“But above all, they can be complementary, ensuring that lithium-ion batteries are only used where strictly necessary. So far, aluminium batteries are only half as energy dense as lithium-ion batteries, but our long-term goal is to achieve the same energy density. There remains work to do with the electrolyte, and with developing better charging mechanisms, but aluminium is in principle a significantly better charge carrier than lithium, since it is multivalent–which means every ion ‘compensates’ for several electrons. Furthermore, the batteries have the potential to be significantly less environmentally harmful.”
Aluminum isn’t the only material that scientists across the globe are looking at as a replacement. A team of scientists in India is convinced that the future battery lies in lead.