Fire hazard averted with new oxygen-ion battery
Lithium-ion batteries play an important role in numerous areas of everyday life. Due to their high energy density, the turn to e-mobility seems unthinkable without them, and they can also be found in most smartphones and home storage units. However, they are less suitable for other applications. This is because a decisive disadvantage of lithium batteries is that their storage capacity decreases significantly over time.
Researchers at TU Wien have now succeeded in developing a type of battery that does not have such high energy densities, but is much more durable. The new battery is based on oxygen ions and can be regenerated after the loss of storage capacity. Another important advantage in the production of oxygen-ion batteries is that they do not require rare elements. Together with Spanish partners, the idea for the battery has already been registered as a patent.
An advantage thanks to ceramic materials
Their experience with the use of ceramic materials in fuel cells gave the researchers the idea of testing the same materials for the production of batteries. Here, the functional principle is similar to that of lithium-ion batteries in many respects. A decisive advantage, however, is the higher level of safety: because ceramics are a non-combustible material, the danger of fires and explosions, which repeatedly occur with lithium-ion batteries, is eliminated.
The ceramic material has the ability to absorb oxygen ions with a double negative charge. If an electrical voltage is applied, a movement of the charge carriers takes place: They move from one ceramic material to the other; they move in the opposite direction when the charge falls.
And now the second decisive advantage that oxygen batteries have over lithium-ion batteries comes into play. While the latter fatigue after a certain time, i.e. their charge carriers no longer move because the lithium has volatilised in side reactions, a loss of oxygen is not a problem: it can be replaced at any time by oxygen from the surrounding air.
Excellent for large, stationary energy storage systems
Due to these properties, oxygen-ion batteries have a long service life with a lower energy density. This makes them unsuitable for energy-intensive applications in vehicles or smartphones, but all the more suitable for stationary energy storage, as used in renewable energies. Because they can be regenerated again and again, they can be used to store wind or solar energy.
Since the operating temperature is between 200 and 400 °C, it is advisable to install cells in large storage tanks. For example, entire buildings can be equipped with modules for energy storage. And this is where another important advantage of the new battery type becomes apparent: its flexibility.
Renunciation of rare elements
Thanks to the use of ceramic materials, it is possible to replace certain raw materials with others. Although lanthanum is still used in the prototype, this element, which is not widely used, will sooner or later be replaced by other, more common materials. This will not only save costs, but also avoid the risks to the environment and human rights associated with mining. Nickel and cobalt are already completely dispensed with in the new battery type.