Two-faced graphene offers sodium-ion battery a tenfold boost in capacity

Summary

This article makes the following points:

Sodium is the sixth most abundant metal globally, making it a much cheaper alternative to lithium.

But a sodium-ion battery's performance is poor compared to lithium-ion batteries.

Part of the reason is due to sodium ions being bigger than lithium ions. 

When cycling a battery (intercalation), ions freely move in and out of the graphite electrode. 

However, bulkier sodium ions can't be stored efficiently, reducing the sodium-ion battery's performance to about a tenth of a lithium-ion battery.

Swedish Scientists have turned to a Janus graphene featuring molecules on only one side that act as both spacers and active interaction sites for sodium ions.

The molecules facilitate electrostatic interactions between the stacked sheets and create more space between them, resulting in a tenfold increase in capacity.

Professor Aleksandar Matic stated, "It was really exciting when we observed the sodium-ion intercalation with such high capacity." 

References

Mar 2021 IEEE Spectrum Sodium-Ion Batteries Poised to Pick Off Large-Scale Lithium-Ion Applications

Jul 2021 Bloomberg News Tesla Battery Supplier CATL Debuts Cheaper Sodium-Ion Batteries

Aug 2021 Reuters CATL's new sodium ion battery to help ease lithium shortages