NASICON- Solid Electrolyte

Sodium batteries are gaining more attention as an alternative to lithium ion batteries. They function using the same mechanism as the lithium ion battery and similarly research is being conducted in solid electrolytes for sodium ion batteries.

Solid electolytes are of interest because, unlike liquid electrolytes, they are inflammable and so are considered safer than traditional batteries.

For sodium batteries a fast ion conductor in the solid state has been developed called NASICONs (Sodium super ionic conductor). They have the general formula where  Na_1-xZr₂Si_xP_3-xO₁₂  where 0<x<3. In the example the formula is NaZr₂Si(PO₄)₃. The conduction is analogous to both that seen in alpha AgI and sodium chloride. Just like in sodium chloride the ions follow a curved path avoiding being too close to other ions within the struture. Similarly to alph AgI, the ion motion is a concerted motion with the moving ions not coming into contact with each other.

There is also an analogous LISICON structure as a comparison with Lithium batteries. For more on LISICON click here.

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M. Guin and F. Tietz, J. Power Sources, 2015, 273, 1056-1064