Polymer electrolyte
OwnerChristine Ruth Jarvis, Alison Jane Macklin +2inventors
InventorsChristine Ruth Jarvis, Alison Jane Macklin, William James Macklin, Fazlil Coowar
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Abstract
A polymer electrolyte comprises a polymer combined with a solution of a salt in a plasticising solvent, and the polymer is a terpolymer of vinylidene fluoride (VdF), hexafluoropropylene (HFP), and chlorotrifluoroethylene (CTFE). The proportion by weight of vinylidene fluoride is at least 85%. The polymer has a large enough molecular weight that its melt flow index, at 230 ° C. and 21.6 kg, is less than 5.0 g/10 min. The resulting polymer electrolyte may be referred to as a solid electrolyte or a gelled electrolyte, and is suitable for use as the separator/electrolyte in an electrochemical cell, such as a secondary lithium ion cell.
Claims10
A polymer electrolyte comprising a polymer combined with a solution of a salt in a plasticising solvent, wherein the polymer is a terpolymer of vinylidene fluoride (VdF), hexafluoropropylene (HFP), and chlorotrifluoroethylene (CTFE), the proportion by weight of vinylidene fluoride being at least 85%, and the polymer has a melt flow index, at 230° C. and 21.6 kg, of less than 5.0 g/10 min.
A polymer electrolyte as claimed in any one of the preceding claims in which the proportion by weight of chlorotrifluoroethylene is between 1 and 4%.
A polymer electrolyte as claimed in any one of the preceding claims wherein the molecular weight is sufficiently high that the melt flow index, at 230° C. and 21.6 kg, is less than 3.0 g/10 min.
A polymer electrolyte as claimed in any one of the preceding claims formed by immersing a microporous sheet of polymer in a plasticising electrolyte solution.
An electrochemical cell incorporating as electrolyte the polymer electrolyte as claimed in any one of the preceding claims.
A polymer electrolyte substantially as hereinbefore described with reference to FIG. 1 and FIG. 2, or FIG. 3, of the accompanying drawings.
The use, in the production of an electrochemical cell, of a polymer composition comprising a terpolymer of vinylidene fluoride, hexafluoropropylene, and chlorotrifluoroethylene.
Dependencies are inferred from the claim text.