A group of researchers from the Chalmers University of Technology in Sweden has come up with a new idea to make high-performance electrode materials for sodium batteries. To do this, they use a new type of graphene that is responsible for storing sodium. The results showed that it can be compared to the lithium-ion batteries that are used today.
Lithium is a material that works very well for storing energy , but it is very expensive and today there are concerns about its long-term supply and the problems it can cause in the environment.
Sodium, an alternative to lithium
However, sodium is a much cheaper material and that makes it an attractive material to use when producing batteries.
Currently sodium ion batteries cannot compete with lithium batteries since there is a limiting material that is graphite. The ions are sandwiched in it, so they can go in and out and be stored for energy use.
Sodium ions are larger than lithium ions and interact differently. This causes that they cannot be stored efficiently in the graphite structure. That is why researchers have been looking for some method to solve this.
To fix this, a molecule spacer was added to one side of the graphene layer. This means that when the layers are stacked, the molecule creates a larger space between the graphene and gives an interaction point that causes a greater capacity.
A huge increase in battery capacity
The sodium intercalation capacity in graphite is about 35 milliamp hours per gram , but with the new graphene a capacity of 332 milliamp hours per gram was achieved.
Thus, much more ability to intercalate sodium ions was achieved. Although these are only early tests at the moment, the research is promising and may aid in future battery development.
A curious fact about this new graphene is that they call it Janus graphene in honor of the Roman god of two faces Janus, since this type of graphene has an asymmetric chemical functionalization on opposite faces.
This material is still far from being used in different industrial applications , but the results show that designing very thin graphene sheets is possible to generate greater energy storage.
Therefore, this new research could be the first stone to produce high capacity sodium ion batteries in the future.