How to Identify Hazardous 1,3-Propane sultone in Spent Lithium Ion Battery Material

The decomposition of 1,3-Propane sultone(PS) was investigated using chromatographic techniques combined with high-resolution accurate mass spectrometry. The sulphur-containing decomposition products were analysed for deformation and ageing marker molecules were defined.

The observed PS decomposition yielded the characteristic 1-propanesulfonate by electrochemical ring opening. Based on this, 1-propanesulfonate was defined as the ionic labelling molecule for electrochemical PS decomposition. In addition, volatile methyl and ethyl esters of 1-propanesulfonate were identified. Their formation was mainly caused by the temperature increase after PS ring opening during cell formation. Both ionic and volatile decomposition markers can be used for the target identification of hazardous ps-containing lithium-ion battery materials, despite the possible depletion of the initial additive molecules.

Ionic Markers for 1,3-Propane Sultone Aging in Lithium ion batteries (LIBs)

1-propanesulfonate was detected in all electrochemically aged electrolytes. This proves literature reports on electrochemical ring–opening resulting in alkyl sulfonate species. To prove the selectivity of 1-propanesulfonate as PS aging marker, the electrolyte aging matrix was repeated with the unsaturated sultone PES, also applied as additive in LIB electrolytes. Electrochemical ring-opening of PES was also described in literature. Among others, unsaturated, but also saturated RSO3^- species were presumed to be formed.

For all investigated aging conditions of PES containing electrolytes, target analysis of 1-propanesulfonate was performed analogously to the PS containing electrolytes, but without positive identification. Therefore, the hydrogenation of the unsaturated, ring-opened species appears to be highly unfavorable. Thus, 1-propanesulfonate can be applied as characteristic ionic aging marker for PS decomposition.

References:

[1] CHRISTOPH PESCHEL. Defining Aging Marker Molecules of 1,3-Propane Sultone for Targeted Identification in Spent LiNi0.6Co0.2Mn0.2O2||AG Cells[J]. Energy technology, 2022, 11 5. DOI:10.1002/ente.202200189.

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