Porous membranes filled with nano-particles and related methods
View Patent ↗A membrane includes a porous membrane or layer made of a polymeric material having a plurality of surface treated (or coated) particles (or ceramic particles) having an average particle size of less than about 1 micron dispersed therein. The polymeric material may be selected from the group consisting of polyolefins, polyamides, polyesters, co-polymers thereof, and combinations thereof. The particles may be selected from the group consisting of boehmite (AlOOH), SiO 2 , TiO 2 , Al 2 O 3 , BaSO 4 , CaCO 3 , BN, and combinations thereof, or the particles may be boehmite. The surface treatment (or coating) may be a molecule having a reactive end and a non-polar end. The particles may be pre-mixed in a low molecular weight wax before mixing with the polymeric material. The membrane may be used as a battery separator.
1. A membrane comprising:
a porous membrane or layer made of a polymeric material having a plurality of surface treated and then wax-coated particles having an average particle size of less than about 1 micron dispersed therein, wherein the wax is polyethylene, polypropylene, or a combination of polyethylene and polypropylene and has a molecular weight of from 800 to 5000.
2. The membrane of claim 1 wherein said polymeric material being selected from the group consisting of polyolefins, polyamides, polyesters, co-polymers thereof, and combinations thereof.
3. The membrane of claim 2 wherein said polyolefins is selected from the group consisting of polyethylene, polypropylene, polybutylene, polymethylpentene, co-polymers thereof, and combinations thereof.
4. The membrane of claim 1 wherein said plurality of surface-treated and then wax-coated particles comprises 0.1-30% by weight of said polymeric material.
5. The membrane of claim 1 wherein said surface-treated and then wax-coated particles comprise ceramic particles selected from the group consisting of boehmite (AlOOH), SiO 2 , TiO 2 , Al 2 O 3 , BaSO 4 , CaCO 3 , BN, and combinations thereof with a surface treatment or coating.
6. The membrane of claim 1 wherein said surface treatment comprises a molecule having a reactive end and a non-polar end.
7. The membrane of claim 1 wherein said average particle size is less than about 500 nanometers.
8. A battery separator comprising the membrane of claim 1 .
9. The battery separator of claim 8 wherein said membrane is a layer of a multi-layered separator.
10. A battery comprising: a negative electrode, a positive electrode, a separator sandwiched between said negative electrode and said positive electrode, an electrolyte in communication between said negative electrode and said positive electrode, and said separator including a membrane comprising: a porous membrane or layer made of a polymeric material having a plurality of surface-treated and then wax-coated particles having an average particle size of less than about 1 micron dispersed therein and wherein the wax is polyethylene, polypropylene, or a combination of polyethylene and polypropylene and has a molecular weight of from 800 to 5000.
11. A membrane comprising: a microporous membrane made of a polymeric material having a plurality of surface-treated and then wax-coated boehmite particles dispersed therein and wherein the wax is polyethylene, polypropylene, or a combination of polyethylene and polypropylene and has a molecular weight of from 800 to 5000.
12. The membrane of claim 11 wherein said polymeric material is selected from the group consisting of polyolefins, polyamides, polyesters, co-polymers thereof, and combinations thereof.
13. The membrane of claim 11 wherein said plurality of surface-treated and then wax-coated boehmite particles comprise 0.1-30% by weight of said polymeric material.
14. A battery separator comprising the membrane of claim 11 .
15. The battery separator of claim 14 , wherein said membrane is a layer of a multi-layer separator.
16. The membrane of claim 11 , wherein said surface treatment comprises a molecule having a reactive end and a non-polar end.
17. A battery comprising: a negative electrode, a positive electrode, a separator sandwiched between said negative electrode and said positive electrode, an electrolyte in communication between said negative electrode and said positive electrode, and said separator including a membrane comprising a microporous membrane made of a polymeric material having a plurality of surface-treated and then wax-coated boehmite particles dispersed therein and wherein the wax is polyethylene, polypropylene, or a combination of polyethylene and polypropylene and has a molecular weight of from 800 to 5000.