(Left to right) Jürgen Fleig, Tobias Huber and Alexander Schmid. Photo: TU Wien.
(Left to right) Jürgen Fleig, Tobias Huber and Alexander Schmid. Photo: TU Wien.

Lithium-ion batteries are ubiquitous today - from electric cars to smartphones. But that does not mean they are the best solution for all applications. Researchers at the Vienna University of Technology (TU Wien) in Austria have now succeeded in developing an oxygen-ion battery that has some important advantages. Although it does not allow for quite as high energy densities as a lithium-ion battery, its storage capacity does not decrease irrevocably over time: it can be regenerated and thus may enjoy an extremely long service life.

In addition, this oxygen-ion battery can be produced without rare elements and is made of incombustible materials. A patent application for the new battery idea has already been filed, in conjunction with cooperation partners from Spain. The oxygen-ion battery could be an excellent solution for large-energy storage systems, such as required for storing the electrical energy generated by renewable sources. The researchers report this novel battery in a paper in Advanced Energy Materials.

“We have had a lot of experience with ceramic materials that can be used for fuel cells for quite some time,” says Alexander Schmid from the Institute for Chemical Technologies and Analytics at TU Wien. “That gave us the idea of investigating whether such materials might also be suitable for making a battery.”

The ceramic materials that the TU Wien team studied can absorb and release doubly negatively charged oxygen ions. When an electric voltage is applied, the oxygen ions migrate from one ceramic material to another, after which they can be made to migrate back again, thus generating electric current.

“The basic principle is actually very similar to the lithium-ion battery,” says Jürgen Fleig, also from the Institute for Chemical Technologies and Analytics. “But our materials have some important advantages.” Ceramics are not flammable – so fire accidents, which occur time and again with lithium-ion batteries, are practically ruled out. In addition, there is no need for rare elements, which are expensive or can only be extracted 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, a research assistant at TU Wien. “You can replace certain elements that are difficult to obtain with others relatively easily.”

The prototype of the battery still uses lanthanum – an element that is not exactly rare but not entirely common either. But the plan is to replace the lanthanum with something cheaper, and research into this is already underway. Cobalt or nickel, which are used in many batteries, are 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 no longer move," says Schmid. "Then they can no longer be used to generate electricity, the capacity of the battery decreases. After many charging cycles, that can become a serious problem."

The oxygen-ion battery, however, can easily be regenerated: If oxygen is lost due to side reactions, then it can simply be replenished with oxygen from the ambient air.

The new battery concept is not intended for smartphones or electric cars, because the oxygen-ion battery only achieves about a third of the energy density of lithium-ion batteries and runs at temperatures of between 200°C and 400°C. The technology is, however, extremely interesting for storing energy.

"If you need a large energy storage unit to temporarily store solar or wind energy, for example, the oxygen-ion battery could be an excellent solution," says Schmid. "If you construct an entire building full of energy-storage modules, the lower energy density and increased operating temperature do not play a decisive role. But the strengths of our battery would be particularly important there: the long service life, the possibility of producing large quantities of these materials without rare elements and the fact that there is no fire hazard with these batteries."

This story is adapted from material from TU Wien, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.