Composition useful in electrolytes of secondary battery cells
AssigneeMoltech Corporation
InventorsLeonid I. Boguslavsky, Yuriy V. Mikhaylik, Alexei B. Gavrilov, Terje A. Skotheim
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Abstract
Provided is a nonaqueous electrolyte element for use in secondary battery cells which comprises an effective lithium stripping enhancing amount of one or more soluble materials, such as a lithium polysulfide, which increases the lithium stripping efficiency. Also provided is a secondary lithium battery cell comprising said nonaqueous electrolyte element. Such a nonaqueous electrolyte element can be advantageously used in the manufacture of secondary electric-current producing cell elements, and provides many advantages in achieving extended cycle life and increased safety of secondary lithium batteries.
Claims26
A nonaqueous electrolyte composition for use in a secondary lithium battery cell comprising:
- (i) one or more solvents;
- (ii) one or more soluble lithium salts other than a lithium polysulfide;
- (iii) greater than 100 ppm and less than 1000 ppm of water;
- and,
- (iv) an effective lithium stripping enhancing amount of one or more soluble lithium polysulfides that increases the lithium stripping efficiency at the anode-electrolyte interface compared to said lithium stripping efficiency with none of said soluble lithium polysulfides present.
A secondary lithium battery cell comprising:
- (i) a cathode;
- (ii) an anode comprising lithium;
- and
- (iii) a nonaqueous electrolyte composition comprising:
- (a) one or more solvents;
- (b) one or more lithium salts other than a lithium polysulfide;
- (c) greater than 100 ppm and less than 1000 ppm of water;
- and,
- (d) an effective lithium stripping enhancing amount of one or more soluble lithium polysulfides that increases the lithium stripping efficiency at the anode-electrolyte interface compared to said lithium stripping efficiency with none of said soluble lithium polysulfides present, thereby effecting the improved cycling life and safety of the cell, wherein said amount of one or more soluble lithium polysulfides is present in an initial state of said electrolyte composition when said cell is in its fully charged state and before initial discharge.
A process for preparing a nonaqueous electrolyte composition useful in secondary lithium battery cells, comprising the steps of:
- (i) preparing a solution of one or more solvents;
- one or more soluble lithium salts other than a lithium polysulfide;
- greater than 100 ppm and less than 1000 ppm of water;
- and an effective lithium stripping enhancing amount of one or more soluble lithium polysulfides that increases the lithium stripping efficiency at the anode-electrolyte interface compared to said lithium stripping efficiency with none of said soluble lithium polysulfides present;
- and, optionally,
- (ii) combining said solution with other electrolyte materials selected from the group consisting of:
- ionically conductive solid polymers and ionically conductive gel polymers.
Dependencies are inferred from the claim text.