Effect of polysulfide-containing electrolyte on the film formation of the negative electrode

The improvement of cycling behaviour and self discharge of lithium—carbon intercalation electrodes as well as metallic lithium electrodes in polysulfide-containing propylene carbonate-based electrolyte is demonstrated. Cyclic voltammetry of LiCn electrodes indicates a more complex reductive behaviour only during the first charge/discharge cycle than in an additive-free electrolyte. The products of the polysulfide reduction seem to improve the properties and the quality of the film that is also produced in the absence of Sx2− and promotes its formation on Li or LiCn, respectively. The improvement may be related to thinner polymer—electrolyte interface layers (PEI layers) and/or a larger amount of insulated inorganic compounds in the PEI layers.