University of Illinois researchers say they’ve found a way to make batteries far smaller and much quicker to recharge. The technique works in the same way as traditional batteries, but makes much more efficient use of space.
As the BBC explains with admirable clarity, batteries work by electrons flowing from one type of electrode (an anode) to another type (a cathode). The new technique involves changing the way these electrodes are organized to fit more into a small space.
That increases the power of the battery for a given size, meaning you can either have more powerful batteries or get the same power from a smaller battery. The new design also means the electrons have to move a shorter distance, which helps make for faster recharging: up to a thousand times faster on paper.
The technique involves using polystyrene spheres to create a mold for a metal lattice structure. The spheres can then be dissolved, leaving space for the anodes and cathodes, which are arranged in alternating cylinders.
As an extremely simplified analogy, the result is a little like the saving in area when you switch from having your hands side by side and outstretched, to interlocking your fingers. The battery itself has a similar space saving but in three-dimensional layers.
At the moment the researchers are concentrating on microbatteries and say they’ve achieved a power-to-space ratio 2,000 times better than existing models. They say in principle the concept should scale to larger batteries such as those in cars.
Professor William King, who led the project, told the BBC the power improvements mean it’s conceivable a cellphone battery could hold enough power to jump-start a vehicle.
There are some potential practical problems with both the fundamental design and the concept of scaling. The way the battery is so tightly packed means that a short circuit could become a more significant problem.
Meanwhile the electrolyte used in the design (the substance that separates the anodes and cathodes to force the electrons to take a particular route) is combustible. That doesn’t seem to be an issue with the microbatteries, but could pose an unacceptable explosion risk when scaled up. The researchers say they are exploring using a safer electrolyte in larger units.
(Image credit: Beckman Institute for Advanced Science and Technology)