Lithium-ion batteries are everywhere today – from electric cars to smartphones. But this does not mean that it is the best solution for all areas of application. TU Wien has now successfully developed an oxygen ion battery which has some significant advantages. Although it does not allow such high energy densities as the lithium-ion battery, its storage capacity does not decline irreversibly over time: it can be replenished and thus may enable a very long service life.
In addition, oxygen ion batteries can be produced without trace elements and are made of non-combustible materials. A patent application for the new battery idea has already been filed with cooperation partners from Spain. The oxygen ion battery can be an excellent solution for large energy storage systems, for example to store electrical energy from renewable sources.
Ceramic materials as a new solution
“We’ve had a lot of experience with ceramic materials that can be used for fuel cells for some time,” says Alexander Schmid of the Institute of Chemical Technologies and Analytics at TU Wien. “This gave us the idea of checking if these materials are also suitable for making a battery.”
The ceramic materials studied by the TU Wien team can absorb and release double-negatively charged oxygen ions. When a voltage is applied, oxygen ions migrate from one ceramic material to another, after which they can be made to migrate again, thus generating an electric current.
“The basic principle is actually very similar to a lithium-ion battery,” says Professor Jürgen Flieg. “But our materials have some important advantages.” Ceramic is non-flammable – so accidents of fire, which happen again and again with lithium-ion batteries, are practically excluded. In addition, there is no need for rare items that are expensive or can only be mined in an environmentally harmful way.
“In this respect, the use of ceramic materials is a great advantage because they can be adapted very well,” says Tobias Huber. “You can replace some hard-to-get items with others relatively easily.” The battery prototype still used lanthanum – an element that’s not exactly rare but not entirely common either. But even lanthanum will be replaced by something cheaper, and research on this is already underway. Cobalt or nickel, which are used in many batteries, is not used at all.
But perhaps the most important advantage of the new battery technology is its potential longevity: “In many batteries you have the problem that at some point the charge carriers can’t move,” says Alexander Schmid. “And then it can no longer be used to generate electricity, the battery capacity decreases. After several charge cycles, this can become a serious problem.”
However, an oxygen ion battery can be replenished without any problems: if oxygen is lost due to side reactions, the loss can simply be compensated for by oxygen from the surrounding air.
The new battery concept is not intended for smartphones or electric cars, because the oxygen ion battery achieves only about a third of the energy density one would use from lithium-ion batteries and operates at temperatures between 200 and 400 degrees Celsius. However, the technology is very exciting for energy storage.
“If you need a large energy storage unit to temporarily store solar or wind energy, for example, an oxygen ion battery can be an excellent solution,” says Alexander Schmid. “If you build a whole building full of energy storage units, the decrease in energy density and the increase in operating temperature do not play a decisive role. But the strengths of our battery will be especially important there: long service life, the possibility of producing large quantities of these materials without trace elements, And the fact that there is no fire hazard with these batteries.”