Separators for lithium-containing electrochemical cells and methods of making the same

1. A porous separator for a lithium-containing electrochemical cell comprising:

a porous substrate having a first side and an opposing second side; and

an active layer comprising a mixture of lithium ion-exchanged zeolite particles and a polymeric binder, wherein the lithium ion-exchanged zeolite particles have:

(i) an average pore size diameter of less than or equal to about 1 nm;

(ii) an average particle diameter of less than or equal to about 20 μm;

(iii) lithium cations present in an amount greater than or equal to about 90 at. % of extra-framework cations in the lithium ion-exchanged zeolite particles; and

(iv) less than or equal to about 5 at. % of one or more of the following cations: Na + , K + , Mg 2+ , Ca + , H + , and NH 4 + ;

wherein the active layer is present on both the first and second sides of the porous substrate, and the active layer has a thickness of less than or equal to about 20 μm.

2. The porous separator of claim 1 , wherein the lithium ion-exchanged zeolite particles are present in the active layer in an amount of about 40 to about 95 wt. %.

3. The porous separator of claim 1 , wherein the lithium ion-exchanged zeolite particles have one or more of the following:

(i) an average pore size diameter of about 0.01 nm to about 1 nm;

(ii) an average particle diameter of about 10 nm to about 20 μm; and

(iv) a SiO 2 :Al 2 O 3 ratio of about 10 to about 50.

4. The porous separator of claim 1 , wherein the lithium ion-exchanged zeolite particles have pore openings defined by 8-member rings, 9-membered rings, 10-membered rings, 12-membered rings or a combination thereof.

5. The porous separator of claim 1 , wherein the lithium ion-exchanged zeolite particles comprise a zeolite material having a framework type selected from the group consisting of NAT, EDI, THO, ANA, YUG, GOO, MON, HEU, STI, BRE, FAU, MFI, LTL, LTA, and a combination thereof.

6. The porous separator of claim 1 , wherein the lithium ion-exchanged zeolite particles comprise a zeolite material selected from the group consisting of zeolite A, zeolite Y, zeolite L, ZSM-5, and a combination thereof.

7. The porous separator of claim 1 , wherein the lithium ion-exchanged zeolite particles comprise less than or equal to about 1 at. % of one or more of Na + , K + , Mg 2+ , Ca + , H + and NH 4 + cations.

8. The porous separator of claim 1 , wherein the active layer has a thickness of about 50 nm to about 20 μm.

9. The porous separator of claim 1 , wherein the lithium ion-exchanged zeolite particles are formed from precursor zeolite particles comprising H + and NH 4 + cations in an amount greater than one or more cations selected from the group consisting of Na + , K + , Mg 2+ , and Ca + .

10. A lithium-containing electrochemical cell comprising:

a negative electrode layer;

a positive electrode layer spaced apart from the negative electrode layer:

a porous separator disposed between confronting surfaces of the negative electrode layer and the positive electrode layer, wherein the porous separator comprises:

a porous substrate having a first side and an opposing second side; and

an active layer comprising a mixture of lithium ion-exchanged zeolite particles and a polymeric binder, wherein the lithium ion-exchanged zeolite particles have:

(i) an average pore size diameter of less than or equal to about 1 nm;

(ii) an average particle diameter of less than or equal to about 20 μm;

(iii) lithium cations present in an amount greater than or equal to about 95 at. % of extra-framework cations in the lithium ion-exchanged zeolite particles; and

(iv) less than or equal to about 1 at. % of one or more of the following cations: Na + , K + , Mg 2+ , Ca + , H + , and NH 4 + ;

wherein the active layer is present on both the first and second sides of the porous substrate, and the active layer has a thickness of less than or equal to about 20 μm; and

a liquid electrolyte infiltrating the negative electrode layer, the positive electrode layer, and the porous separator.

11. The lithium-containing electrochemical cell of claim 10 , wherein the positive electrode layer comprises sulfur.

12. The lithium-containing electrochemical cell of claim 10 , wherein the lithium ion-exchanged zeolite particles are present in the active layer in an amount of about 40 to about 95 wt. %.

13. The lithium-containing electrochemical cell of claim 10 , wherein the lithium ion-exchanged zeolite particles are formed from precursor zeolite particles comprising H + and NH 4 + cations in an amount greater than one or more cations selected from the group consisting of Na + , K + , Mg 2+ , and Ca + .