Lithium sulfide

• Dilithiumsulfid
• Dilithiummonosulfid
• Lithium (I ) sulfide

Fixed

1.64 g · cm -3

1372 ° C

Reacts violently with water

Risk

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Lithium sulfide is a sulfide of the lithium and has the empirical formula Li2S.

Properties

It is a colorless solid which crystallizes in a Antifluoritstruktur. Lithium sulfide is so hygroscopic that it dissolves in the air. It reacts violently with water, forming an alkaline solution:

Due to the formed water hydrogen sulfide, which is in equilibrium with hydrogen sulfide, lithium sulfide smells sulfurous, rotten eggs.

Lithium sulfide is flammable.

Lithium sulfide crystallized - as sodium oxide Na2O - in the Antifluoritstruktur, that is, each lithium ion is surrounded tetrahedrally by four sulfide ions, each of eight cubic sulfide cations.

Production

Lithium sulfide can be obtained in high purity from the elements by using liquid ammonia at -33 ° C as the solvent:

This overall reaction proceeds also in the complete discharge of a lithium-sulfur battery.

Lithium sulfide can be obtained in pure form, hydrogen sulfide, when lithium is heated under vacuum at 150 ° C:

Possible occurrence in future accumulators

On the development of a lithium-sulfur battery is working hard. In the completely discharged state, it contains lithium sulfide is re-converted to sulfur loading. Since lithium sulphide Li2, is hardly soluble in organic solvents that are commonly used in lithium cells, it is present as a solid.

On the use of lithium sulfide as a component of solid electrolyte research is done .. With the help of these solid electrolytes accumulators can be made ​​that do not require liquid, which can be advantageous, for example, at elevated temperatures or miniaturized batteries.