Scientists have developed a new conductor material and a new electrode material that could pave the way for inexpensive sustainable batteries and the large-scale storage of renewable energies.
The energy transition for sustainable batteries depends on technologies that allow the temporary storage of electricity from renewable sources. Aluminium batteries are a possible new option, as they are made from abundant raw materials.
Scientists from ETH Zurich and Empa, Switzerland, are among the researchers involved in researching and developing these new batteries. The researchers have developed two new materials that could aid the development of aluminium batteries:
- A corrosive-resistant material for the conductive parts of the battery; and
- A material for the battery’s positive pole that can be adapted to a wide range of requirements.
Electrolyte fluid in batteries
Scientists are looking for a corrosion-resistant material for the conductive parts of aluminium batteries, as the electrolyte fluid in these batteries is aggressive and corrodes stainless steel.
Maksym Kovalenko, from ETH Zurich, and his colleagues have found what they are looking for in titanium nitride – a ceramic material that exhibits sufficiently high conductivity. Kovalenko said: “This compound is made up of the highly abundant elements titanium and nitrogen, and it’s easy to manufacture.”
This material can be easily produced in the form of thins films.
The researchers have developed aluminium batteries with the conductive parts made from titanium nitride in the laboratory. It is believed that it is possible to manufacture the conductors from a conventional metal and coat them with titanium nitride.
Is there an alternative to graphite?
The second new material to be used for the positive pole of the sustainable batteries. Since the negative electrode in these batteries is made of aluminium, the positive electrode is usually made of graphite.
The researcher team have now found a new material that rivals graphite in terms of the amount of energy a battery can store. This new material is a hydrocarbon called polypyrene which has a ‘chain like’ structure. Kovalenko said: “A lot of space remains between the molecular chains. This allows the relatively large ions of the electrolyte fluid to penetrate and charge the electrode material easily.”
One particular advantage of electrodes containing polypyrene is that the material’s properties can be influenced, and can therefore be adapted to each application.
As both titanium nitride and polypyrene are flexible materials, the researchers believe they are suitable for use in ‘pouch cells’ (batteries enclosed in a flexible film).
An increasing amount of energy is generated from solar and wind energy. However, as electricity is needed constantly, new technologies, such as new types of batteries, will be needed to store this electricity in a cost-effective manner.
Although existing lithium-ion batteries are ideal for electromobility due to their low weight, they are also quite expensive and therefore unsuitable for economical large-scale, stationary power storage.