High temperature melt integrity battery separators via spinning

Abstract

A method for preparing a high temperature melt integrity separator, the method comprising spinning a polymer by one or more of a mechanical spinning process and an electro-spinning process to produce fine fibers.

What is claimed: 
     
         1 . A web comprising fine fibers, wherein:
 the fine fibers have an individual average diameter of about 10 nm to about 50 μm; and   the web:
 has a thickness of about 10 μm to about 200 μm; and 
 has a MacMullin number equal to or lower than 10. 
   
     
     
         2 . The web of  claim 1 , wherein the web:
 has a thickness of less than or equal to 63 μm;   has an apparent porosity of greater than or equal to 67; and   has a MacMullin number equal to or lower than 6.   
     
     
         3 . The web of  claim 2 , wherein the web:
 has a thickness of less than or equal to 44 μm; and   has an apparent porosity of greater than or equal to 73; and   has a MacMullin number equal to or lower than 4.   
     
     
         4 . The web of  claim 3 , wherein the web has a MacMullin number equal to or lower than 3. 
     
     
         5 . The web of  claim 4 , wherein the web has an apparent porosity of greater than or equal to 75. 
     
     
         6 . The web of  claim 1 , wherein the web has an average pore size in the range of about 0.01 μm to about 20 μm. 
     
     
         7 . The web of  claim 1 , wherein the web has an electrolyte contact angle of equal to or lower than about 30° in 1:1:1 EC:DMC:EMC and 1 mol/L LiPF 6 . 
     
     
         8 . The web of  claim 1 , wherein the fine fibers comprise a polyetherimide. 
     
     
         9 . The web of  claim 1 , wherein the polyetherimide comprises structural units based on para-phenylene diamines. 
     
     
         10 . The web of  claim 1 , wherein the fine fibers comprise one or more of polyetherimide, poly(amic acid), aromatic polyamide, poly(amide-imide), and polyphenylene oxide. 
     
     
         11 . The web of  claim 1 , wherein the fine fibers comprise a thermoplastic polymer having a glass transition temperature higher than about 180° C. 
     
     
         12 . The web of  claim 1 , wherein the fine fibers comprise poly(4-methylpentene), poly(amide-imide), polyoxymethylene, polyphthalamide, polysulfone, polyethersulfone, polyphenylsulfone, polyetherimide, polyketone, polyetherketone, polyetheretherketone, polyphenylene sulfide, or a copolymer or blend thereof. 
     
     
         13 . A method of forming the web of  claim 1 , the method comprising:
 providing a polymer solution comprising a chemical-resistant polymer in a solvent;   spinning the polymer solution into the fine fibers; and   forming the web from the fine fibers.   
     
     
         14 . The method of  claim 13 , wherein spinning the polymer solution into fine fibers comprises an electro-spinning method. 
     
     
         15 . The method of  claim 13 , wherein spinning the polymer solution into fine fibers comprises a force-spinning method. 
     
     
         16 . The method of  claim 13 , wherein spinning the polymer solution into fine fibers comprises a mechanical spinning method. 
     
     
         17 . The method of  claim 13 , wherein spinning the polymer solution into fine fibers comprises a shear-spinning method. 
     
     
         18 . The method of  claim 17 , wherein the shear-spinning method comprises injecting the polymer solution into an anti-solvent medium, and wherein flow rate and viscosity of the anti-solvent medium are configured to generate shear forces on the injected polymer solution to form fine fibers. 
     
     
         19 . The method of  claim 13 , wherein spinning the polymer solution into fine fibers comprises a centrifugal force spinning method. 
     
     
         20 . A web comprising fine fibers, wherein:
 the fine fibers:
 comprise a thermoplastic polymer having a glass transition temperature higher than about 180° C.; and 
 have an individual average diameter of about 10 nm to about 50 μm; and 
   the web:
 has a thickness of less than or equal to 63 μm; 
 has an apparent porosity of greater than or equal to 67; 
 has a MacMullin number equal to or lower than 6; and 
 has an average pore size in the range of about 0.01 μm to about 20 μm.