Separator including microbial cellulose, method of producing the separator, and use of the separator

1. A separator comprising microbial cellulose nanofibers, wherein the separator has a tensile strength of 39 MPa to 290 MPa, and the cellulose nanofiber has an average degree of polymerization of about 4,000 to about 20,000,

and wherein the separator further comprises a binder comprising 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-oxidized cellulose nanofibers.

2. The separator of claim 1 , wherein the cellulose nanofiber has a diameter of about 4 nm to about 100 nm.

3. The separator of claim 1 , wherein the cellulose nanofiber has a diameter of about 20 nm to about 50 nm.

4. The separator of claim 1 , wherein the separator has a porosity of about 30% to about 70%.

5. The separator of claim 1 , wherein the separator has an air permeability of about 50 sec/100 cc to about 2000 sec/100 cc.

6. The separator of claim 1 , further comprising a cross-linking agent that cross-links the cellulose nanofibers.

7. The separator of claim 6 , wherein the cross-linking agent comprises isocyanate, polyvinyl alcohol (PVA), polyamide epichlorohydrin (PAE), or combination thereof.

8. The separator of claim 1 , wherein the binder comprises methyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl methyl cellulose, carboxyl methyl cellulose, ethyl cellulose, polyvinylidene fluoride-co-hexafluoropropylene, polyvinylidene fluoride-co-trichloroethylene, polymethylmethacrylate, polyacrylonitrile, polyvinylpyrrolidone, polyvinylacetate, polyethylene-co-vinyl acetate, polyimide, polyethylene oxide, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethylpullulan, cyanoethylpolyvinylalcohol, cyanoethylcellulose, cyanoethylsucrose, pullulan, polyvinylalcohol, or combination thereof.

9. The separator of claim 1 , wherein the microbial cellulose is from a microorganism of the genus Acetobacter, Gluconacetobacter, Enterobacter, Achromobacter, Agrobacterium, Alcaligenes, Azotobacter, Pseudomonas, Rhizobium, Sarcina, Klebsiella , or Escherichia.

10. The separator of claim 1 , wherein the microbial cellulose is from Gluconacetobacter xylinum.

11. A method of producing a separator of claim 1 , the method comprising:

culturing a microorganism to obtain a microbial cellulose; and

preparing a separator comprising a cellulose nanofiber from the obtained microbial cellulose, wherein the separator has a tensile strength of 39 MPa to 290 MPa.

12. The method of claim 11 , wherein preparing of the separator comprises passing the microbial cellulose through a microchannel while applying pressure thereto.

13. The method of claim 12 , wherein the pressure is 10 MPa to 300 MPa.

14. The method of claim 12 , further comprising pressing the cellulose nanofiber to provide a pressed, non-woven fabric that provides the separator.

15. A lithium ion battery comprising a separator according to claim 1 .

16. The separator of claim 1 , wherein the separator has a porosity of about 45% to about 90%.