Solid polymer electrolytes

A chemically stable solid polymer electrolyte for use with a lithium metal anode of a polymer electrolyte battery, said electrolyte comprising:

• approximately 30 to 95% (by weight of solid polymer electrolyte) base polymer material comprising at least one ionically conductive polymer and having an initial conductivity of at least approximately 10−5 S/cm at 25° C. when combined with a lithium salt in the absence of solvent,
• approximately 1 to 25% (by weight of the solid polymer electrolyte) lithium salt,
• approximately 0.1-60% (by volume of the solid polymer electrolyte) inorganic filler having an average particle size less than 0.05 micron in diameter and a surface area of at least approximately 100 m2/g,
• approximately 0.1-80% (by volume of the solid polymer electrolyte) lithium ion conducting material having an average particle size less than 0.1 micron in diameter and an initial ionic conductivity of at least 2×10−3 S/cm at 25° C., wherein the solid polymer electrolyte does not contain a solvent.

A method of making a solid polymer electrolyte having a conductivity greater than 1×10−4 S/cm at 25° C. in the absence of solvent, the method comprising:

• mixing together
• a base polymer material comprising at least one ionically conductive polymer and having an initial conductivity of at least approximately 1×10−5 S/cm at 25” C. when combined with a metal salt in the absence of solvent,
• a metal salt,
• an inorganic filler having an average particle size less than 0.05 micron in diameter and a surface area of at least approximately 100 m2/g,
• an ion conducting material having an average particle size less than 0.1 micron in diameter and an initial ionic conductivity of at least 2×10−3 S/cm at 25° C.,
• optionally, a liquid organic solvent, and
• optionally, a curing agent, to form a mixture;
• optionally, maintaining the temperature of said mixture at the melting point of said base polymer material;
• forming said mixture into a solid polymer electrolyte;
• evaporating said liquid organic solvent, if an organic solvent is present, and
• optionally, curing said solid polymer electrolyte, such that a solvent-free solid polymer electrolyte is produced.

A method of making a solid polymer electrolyte for a lithium polymer electrolyte battery, the method comprising:

• mixing together
• approximately 30 to 95% (by weight of solid polymer electrolyte) base polymer material comprising at least one ionically conductive polymer and having an initial conductivity of at least approximately 1×10−5 S/cm at 25° C. when combined with a plasticizer lithium salt in the absence of solvent;
• approximately 1 to 25% (by weight of solid polymer electrolyte) plasticizer lithium salt;
• approximately 0.1-60% (by volume of solid polymer electrolyte) of an inorganic filler having an average particle size less than 0.05 micron in diameter and a surface area of at least approximately 100 m2/g;
• approximately 0.1-80% (by volume of solid polymer electrolyte) an ion conducting material chosen from the group consisting of glassy conductors and ceramic lithium ion conductors;
• and
• an anhydrous organic solvent, to form a base polymer/salt/inorganic filler/ionic conductor mixture;
• and
• forming said mixture into a solvent free lithium solid polymer electrolyte having a conductivity of at least 10−4 to 10−3 S/cm at 25° C. or below in the absence of solvent.

A method of making a solid polymer electrolyte for a lithium polymer electrolyte battery, the method comprising:

• mixing
• (a) approximately 30 to 95% (by weight of solid polymer electrolyte) base polymer material, having a conductivity of at least approximately 5×10−5 S/cm at 25° C. when combined with a metal salt in the absence of solvent, said base polymer material comprising at least two polymers, the first said polymer being an ionically conductive polymer, the monomers of which have a hetero atom with a lone pair of electrons available for the metal ions of a metal salt to attach to and move between during conduction, when said first polymer is mixed with a metal salt, and the second of said at least two polymers being more inert with respect to ionic conductivity when combined with said metal salt and having greater mechanical strength than said first polymer when each said polymer is in the form of a thin film,
• (b) approximately 1 to 25% (by weight of solid polymer electrolyte) plasticizer lithium salt,
• (c) approximately 0.1-60% (by volume of solid polymer electrolyte) of an inorganic filler having an average particle size less than 0.05 micron in diameter and a surface area of at least approximately 100 m2/g, and
• (d) approximately 0.1-80% (by volume of solid polymer electrolyte) ion conducting material chosen from the group consisting of glassy conductors and ceramic lithium ion conductors, to form a base polymer/salt/inorganic filler/ion conductor mixture;
• and
• casting or extruding said mixture to yield a solvent-free solid polymer electrolyte in the form of a film having a conductivity greater than 1×10−4 S/cm at 25° C. or below in the absence of solvent.

An automated resin melt-cast process for manufacturing a thin film solid polymer electrolyte comprising:

• mixing approximately 30 to 95% (by weight of solid polymer electrolyte) base polymer material comprising at least two polymers, the first said polymer chosen from the group consisting of polyethylene oxide (PEO), oxymethylene linked PEO, PEO-PPO-PEO crosslinked with trifunctional urethane, poly(bis(methoxy-ethoxy-ethoxide))-phosphazene (MEEP, a triol-type PEO crosslinked with difunctional urethane, poly((oligo)oxyethylene)methacrylate-co-alkali metal methacrylate, polyacrylonitrile (PMAN), polymethylmethacrylate (PMMA), polymethylacrylonitrile (PMAN), polysiloxanes and copolymers thereof, polyvinylidene fluoride or chloride and copolymers thereof, poly(chlorotrifluoro-ethylene), poly(ethylene-chlorotrifluoroethylene), poly(fluorinated ethylene-propylene), acrylate-based polymers, and combinations of the foregoing polymers either condensed or crosslinked to form a different polymer, and physical mixtures of any of the foregoing polymers, provided said first polymer is combinable with a lithium salt such that the ionic conductivity of said first polymer is enhanced;
• and
• wherein said second polymer is chosen from the group consisting of polyester (PET), polypropylene (PP), polyethylene napthalate (PEN), polyvinylidene fluoride (PVDF), polycarbonate (PC), polyphenylene sulfide (PPS), and polytetrafluoroethylene (PTFE),
• approximately 1 to 25% (by weight of solid polymer electrolyte) plasticizer lithium salt,
• approximately 0.1-60% (by volume of solid polymer electrolyte) of an inorganic filler having an average particle size less than 0.05 micron in diameter and a surface area of at least approximately 100 m2/g, and
• approximately 0.1-80% (by weight of solid polymer electrolyte) ion conducting material chosen from the group consisting of glassy conductors and ceramic lithium ion conductors, to form a base polymer/salt/inorganic filler/ionic conductor mixture;
• while maintaining the temperature of said mixture at the melting temperature of said base polymer material, mechanically extruding said mixture onto a chilling wheel to yield a melt-cast film;
• mechanically pulling said melt-cast film such that said melt-cast film is stretched to a final film thickness of approximately 4 microns or less to yield a solvent-free sheet film solid polymer electrolyte having a conductivity of at least 10−4 to 10−3 S/cm at 25° C. or below when combined with a plasticizer lithium salt in the absence of solvent.

A thin film lithium polymer electrolyte battery comprising:

• a resilient flexible hybrid polymeric electrolyte thin film having a conductivity of at least approximately 1×10−4 S/cm and containing
• a homogeneous blend of at least two polymers, one of which being an ionically conductive polymer having an initial conductivity of at least approximately 1×10−5 S/cm at 25° C. when combined with a lithium salt in the absence of solvent,
• a lithium salt,
• an inorganic filler having an average particle size less than 0.05 micron in diameter and a surface area of at least approximately 100 m2/g, and
• a lithium ion conducting material having an average particle size less than 0.1 micron in diameter and an initial ionic conductivity of at least 2×10−3 S/cm at 25° C., wherein said polymeric electrolyte thin film does not contain a solvent;
• and
• a pair of spaced-apart flexible thin film electrodes, each said electrode comprising a polymer substrate having an adherent electrically conductive layer disposed thereon, said polymeric electrolyte being tightly disposed between said pair of electrodes.