Bicontinuous separating layers for solid-state batteries and methods of forming the same
A bicontinuous separating layer includes a separating matrix having pores and a solid-state electrolyte disposed in the pores of the separating matrix. In certain variations, the bicontinuous separating layer is prepared by contacting a solid-state electrolyte liquid-state precursor with the separating matrix and heating the infiltrated separating matrix to a temperature between about 25° C. and about 300° C. The solid-state electrolyte liquid-state precursor includes a solvent and a solid-state electrolyte powder or a solid-state electrolyte precursor. In other variations, the bicontinuous separating layer may be prepared by contacting a solid-state electrolyte powder with a separating matrix to form a physical mixture and heating the physical mixture to a temperature between about 240° C. and about 500° C., where the separating matrix is defined by a polymer having a melting temperature greater than about 215° C., and the solid-state electrolyte has a melting temperature greater than about 300° C.
1 . A bicontinuous separating layer for an electrochemical cell, the bicontinuous separating layer comprising:
a separating matrix having pores with an average pore diameter being greater than or equal to about 0.03 micrometers to less than or equal to about 1 micrometer; and
a solid-state electrolyte disposed in at least a portion of the pores of the separating matrix, an average particle size for the solid-state electrolyte being greater than or equal to about 0.03 micrometers to less than or equal to about 1 micrometer,
the bicontinuous separating layer having an ionic conductivity greater than or equal to about 2.5×10 −5 S/cm at 25° C.
2 . The bicontinuous separating layer of claim 1 , wherein the separating matrix has a porosity greater than or equal to about 30 vol. % to less than or equal to about 80 vol. %, and the solid-state electrolyte occupies greater than or equal to about 60 % of a total porosity of the separating matrix.
3 . The bicontinuous separating layer of claim 1 , wherein the bicontinuous separating layer has a Gurley number greater or equal to about 300 s/100cc, and an areal resistance greater than or equal to about 2 Ω·cm 2 to less than or equal to about 100 Ω·cm 2 .
4 . The bicontinuous separating layer of claim 1 , wherein a thickness of the bicontinuous separating layer is defined by the separating matrix and an average thickness of the separating matrix is greater than or equal to about 10 micrometers to less than or equal to about 100 micrometers.
5 . The bicontinuous separating layer of claim 1 , where the separating matrix comprises one or more of: aramid, ultra-high molecular weight polyethylene, inorganic fibers, polymethyl pentene, or any combination thereof.
6 . The bicontinuous separating layer of claim 5 , wherein the solid-state electrolyte comprises a solid-state electrolyte material selected from the group consisting of: Li 3 PS 4 , Li 7 P 3 S 11 , Li 7 P 3 S (11−x) O x (where 0≤x≤1.25), Li 6 PS 5 M (where M is selected from the group consisting of: chloride (Cl), bromide (Br), iodine (I), and combinations thereof), Li 4 PS 4 M (where M is selected from the group consisting of: chloride (CI), bromide (Br), iodine (I), and combinations thereof), Na 3 PS 4 , Na (3−2x) PS (4−x) Se x (where 0≤x ≤0.1), and combinations thereof.
7 . The bicontinuous separating layer of claim 5 , wherein the separating matrix comprises the ultra-high molecular weight polyethylene, and the ultra-high molecular weight polyethylene is mixed with an inorganic filler up to a loading of about 80 wt. %, the inorganic filler being selected from the group consisting of: alumina, silica, titania, and combinations thereof.
8 . The bicontinuous separating layer of claim 1 , wherein the separating matrix comprises a polymer having a melting temperature greater than or equal to about 215° C.
9 . The bicontinuous separating layer of claim 8 , wherein the polymer is selected from the group consisting of: polycaprolactam, polybutylene terephthalate (PBT), polymethylpentene (PMP), polyethylene terephthalate (PET), poly (hexamethylene adipamide), cellulose, liquid crystalline polymer, polyether ether ketone (PEEK), polyaramid, fiberglass, and combinations thereof.
10 . The bicontinuous separating layer of claim 8 , wherein the solid-state electrolyte has a melting temperature less than or equal to about 300° C.
11 . The bicontinuous separating layer of claim 10 , wherein the solid-state electrolyte comprises Li 1.9 OHCl 0.9 .
12 . The bicontinuous separating layer of claim 1 , where the separating matrix comprises polymethyl pentene.