Sulfide and oxy-sulfide glass and glass-ceramic films for batteries incorporating metallic anodes
AssigneeGM Global Technology Operations LLC
InventorsThomas A. Yersak, James R. Salvador, Han Nguyen
Life of this patent
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Abstract
Thin amorphous or partially crystalline lithium-containing and conducting sulfide or oxysulfide glass electrode/separator members are prepared from a layer of molten glass or of glass powder. The resulting glass films are formed to lie face-to face against a lithium metal anode or a sodium metal anode and a cathode and to provide for good transport of lithium ions between the electrodes during repeated cycling of the cell and to prevent shorting of the cell by dendrites growing from the lithium metal or sodium metal anode.
Claims20
A method of forming an alkali metal ion-conducting, sulfide or oxy-sulfide containing, glass or glass ceramic electrolyte layer for face-to-face engagement with an alkali metal anode in an electrochemical cell, the alkali metal being one of lithium or sodium, the method comprising:
- forming a solid amorphous layer of a glassy, alkali metal-containing, sulfide or oxy-sulfide composition on a flat surface of a substrate material layer that is not chemically reactive with the alkali metal-containing composition, the composition of the solid amorphous layer having been formed from a mixture comprising (i) a glass former comprising a glass-forming sulfide or oxide and (ii) a glass modifier comprising an alkali metal-containing sulfide or oxide, at least one of the glass former and glass modifier comprising a sulfide or oxy-sulfide, the formed solid amorphous layer being of substantially uniform thickness and having a predetermined planar shape and dimensions, the formed solid amorphous layer then being at a temperature of at least about 100° C. below the temperature at which the amorphous layer will crystallize;
- heating the solid glassy layer on the substrate at a temperature and for a time sufficient to remove residual stress in the layer and to form an annealed, flexible, uniformly amorphous microstructure, or a microstructure characterized by recrystallized regions isolated in an amorphous matrix, the annealed layer having up to 15% by volume porosity and a smooth surface engaging the substrate and a smooth surface opposite the substrate;
- cooling the annealed layer to an ambient room temperature on the substrate;
- and
- removing the cooled annealed layer from the surface of the substrate, the thickness of the original formed layer enabling the thickness of the removed layer to be in the range of ten micrometers to two hundred micrometers, the removed layer being ready for cutting, if necessary into solid electrolyte area shapes, or for direct placement as a solid-state electrolyte layer against an alkali metal anode in a operable cell in an alkali metal battery, the composition and microstructure of the solid-state electrolyte layer being conductive of alkali metal ions during cycling of the battery cell and resistant to penetration of dendrites formed on the surface of the alkali metal anode.
A method of forming an alkali metal-conducting, sulfide or oxy-sulfide-containing, solid state electrolyte for face-to-face engagement with an alkali metal anode in an electrochemical cell, the alkali metal being one of lithium or sodium, the method comprising:
- applying to a suitable substrate a generally uniform layer of particles comprising an amorphous, glassy solid composition formed from a mixture initially comprising a glass former comprising a glass-forming sulfide, or oxide and a glass modifier comprising an alkali metal-containing sulfide or oxide, at least one of the glass former and glass modifier containing a sulfide or oxy-sulfide;
- heating the supported layer of particles to a predetermined temperature less than the temperature at which the amorphous solid recrystallizes;
- applying, a pressure to the supported layer of amorphous solid particles for a predetermined time, the predetermined time and pressure being sufficient to consolidate and compact the particles into a solid layer on the substrate;
- then,
- annealing the consolidated solid layer at a second predetermined temperature less than the temperature at which the amorphous solid recrystallizes but sufficient to relieve any stresses introduced into the layer by the consolidation operation stresses while retaining the solid in an amorphous state, or, optionally, at a second predetermined temperature sufficient to partially crystallize the solid layer, the solid layer having a porosity of up to fifteen percent by volume;
- and,
- slowly cooling the body to room temperature.
A method of forming an alkali metal-conducting, sulfide or oxy-sulfide-containing solid state electrolyte for face-to-face engagement with an alkali metal anode in an electrochemical cell, the alkali metal being one of lithium or sodium, the method comprising:
- preparing, under suitable atmosphere, a melt comprising a glass former comprising a glass-forming sulfide or oxide and a glass modifier comprising an alkali metal-containing sulfide or oxide, at least one of the glass former and glass modifier containing a sulfide or oxy-sulfide;
- heating a substrate to an elevated temperature sufficient to maintain the melt in a molten state, the substrate having opposing surfaces, at least one of the substrate surfaces being wettable by the melt but unreactive with the melt;
- applying the melt to the melt-wettable surface of the substrate while maintaining the substrate at the elevated temperature for a time sufficient for the melt to wet the melt-wettable substrate surface;
- then,
- cooling the melt-wettable substrate surface and the associated melt to a temperature below which the melt transforms to a solid, the cooling being conducted at a rate sufficient to suppress crystallization of the solid and the temperature being predetermined to render an amorphous solid;
- annealing the amorphous solid for a predetermined time at a temperature sufficient to relieve any solidification stresses while retaining the solid in an amorphous state, or, optionally, at a temperature sufficient to partially recrystallize the solid;
- and
- slowly cooling the solid to room temperature.
An alkali metal ion-conducting, sulfide or oxy-sulfide glass or glass ceramic, solid state electrolyte layer having a thickness in the range of ten micrometers to two hundred micrometers, the composition of the electrolyte layer being the reaction product of a mixture initially comprising (i) a glass former comprising a glass-forming sulfide or oxide and (ii) a glass modifier comprising an alkali metal-containing sulfide or oxide, at least one of the glass former and glass modifier comprising a sulfide, the solid-state electrolyte layer being further characterized as having a wholly amorphous microstructure or as having small recrystallized regions separated from each other in an amorphous matrix, the recrystallized regions having a size of up to five micrometers, the solid-state electrolyte layer comprising mobile lithium ions or mobile sodium ions associated with sulfur anions chemically anchored in the microstructure.
Dependencies are inferred from the claim text.