Separation membrane comprising coating layer and battery using same

Abstract

Disclosed herein is a high thermal resistant polyolefin-based separator including a coating layer containing polyamic acid. Specifically, the separator includes a polyolefin-based substrate film, and a coating layer containing polyamic acid formed on one or both surfaces of the polyolefin-based substrate film, wherein the polyamic acid contains one or more functional groups selected from the group consisting of a sulfone group, a trifluoromethyl group, an alkyl group, and a phenyl ether group. Also, disclosed herein is an electrochemical battery having improved thermal stability by using the separator including a coating layer containing polyamic acid.

1 . A separator, comprising:
 a polyolefin-containing substrate film; and   a coating layer including polyamic acid on at least one surface of the substrate film, wherein the polyamic acid is represented by the following Chemical Formula 1 or 2:   
       
         
           
           
               
               
           
         
         wherein: 
         R 1 , R 5  and R 7  are, independently of one another, an unsubstituted or substituted aromatic hydrocarbon having 6 to 30 carbon atoms; an unsubstituted or substituted aliphatic hydrocarbon having 2 to 20 carbon atoms; or an unsubstituted or substituted alicyclic hydrocarbon having 3 to 24 carbon atoms; 
         R 2 , R 6  and R 8  are, independently of one another, an unsubstituted or substituted aromatic hydrocarbon having 6 to 30 carbon atoms; an unsubstituted or substituted aliphatic hydrocarbon having 2 to 20 carbon atoms; an unsubstituted or substituted alicyclic hydrocarbon having 3 to 24 carbon atoms; —R 3 —Ar 5 —R 4 —, wherein R 3  and R 4  are, independently of each other, an alkylene having 1 to 5 carbon atoms; and Ar 5  is an arylene having 6 to 15 carbon atoms that is unsubstituted or mono- to tri-substituted by CH 3 , OH, SH or NH 2 ; 
         n is an integer of 30 to 10000; and 
         x is an integer of 15 to 5000, and y is an integer of 15 to 5000. 
       
     
     
         2 . The separator as claimed in  claim 1 , wherein R 1 , R 5  and R 7  are, independently of one another, an aromatic hydrocarbon represented by the following Chemical Formula 3, and R 2 , R 6  and R 8  are, independently of one another, an aromatic hydrocarbon represented by the following Chemical Formula 4: 
       
         
           
           
               
               
           
         
         wherein, in Chemical Formula 3: 
         Ar 1  to Ar 4  are, independently of one another, an unsubstituted or substituted arylene having 6 to 15 carbon atoms; 
         X 1  to X 3  are, independently of one another, a single bond, O, S, C(═O), S(═O) 2 , C(═O)NH, an unsubstituted or substituted alkylene having 1 to 10 carbon atoms, or an unsubstituted or substituted silylene; and 
         m, l and o are, independently of one another, 0 or 1; with the provisos that: 
         if m is 1, and l and o are 0, X 2  and X 3  are a single bond, and Ar 2  is an unsubstituted or substituted trivalent arylene having 6 to 15 carbon atoms; 
         if m and l are 1, and o is 0, X 3  is a single bond, and Ar 3  is an unsubstituted or substituted trivalent arylene having 6 to 15 carbon atoms; and 
         if m, l and o are all 0, X 1  to X 3  are a single bond, and Ar 1  is an unsubstituted or substituted tetravalent arylene having 6 to 15 carbon atoms;
   —(Ar 6 )—X 4 —(Ar 7 ) p —X 5 —(Ar 8 ) q —X 6 —(Ar 9 ) r   [Chemical Formula 4]
 
 
         wherein, in Chemical Formula 4: 
         Ar 6  to Ar 9  are, independently of one another, an unsubstituted or substituted arylene having 6 to 15 carbon atoms; 
         X 4  to X 6  are, independently of one another, a single bond, O, S, C(═O), S(═O) 2 , C(═O)NH, an unsubstituted or substituted alkylene having 1 to 10 carbon atoms, or an unsubstituted or substituted silylene; and 
         p, q and r are, independently of one another, 0 or 1; with the provisos that: 
         if p is 1, and q and r are 0, X 5  and X 6  are a single bond; 
         if p and q are 1, and r is 0, X 6  is a single bond; and 
         if p, q and r are all 0, X 4  to X 6  are a single bond. 
       
     
     
         3 . The separator as claimed in  claim 1 , wherein the polyamic acid contains a sulfone group. 
     
     
         4 . The separator as claimed in  claim 3 , wherein the sulfone group is a meta-aryl sulfone group. 
     
     
         5 . The separator as claimed in  claim 1 , wherein the polyamic acid contains a sulfone group and a trifluoromethyl group. 
     
     
         6 . The separator as claimed in  claim 1 , wherein the polyamic acid includes a first repeating unit containing a phenyl ether group and a second repeating unit containing a sulfone group, and a ratio of the first repeating unit to the second repeating unit is 5:5 to 1:9. 
     
     
         7 . The separator as claimed in  claim 1 , wherein the polyamic acid includes a first repeating unit containing a sulfone group and a second repeating unit containing a trifluoromethyl group, and a ratio of the first repeating unit to the second repeating unit is 9:1 to 7:3. 
     
     
         8 . The separator as claimed in  claim 1 , wherein the polyamic acid has a structure of following Chemical Formula 9: 
       
         
           
           
               
               
           
         
         wherein a ratio of repeating units x to y is 9:1 to 7:3. 
       
     
     
         9 . The separator as claimed in  claim 8 , wherein one or more aryl sulfone groups in the repeating unit x or y of the Chemical Formula 9 are a meta-aryl sulfone group. 
     
     
         10 . The separator as claimed in  claim 1 , wherein the coating layer contains inorganic particles. 
     
     
         11 . The separator as claimed in  claim 10 , wherein the inorganic particles include one or more of Al 2 O 3 , SiO 2 , B 2 O 3 , Ga 2 O 3 , TiO 2  or SnO 2 . 
     
     
         12 . The separator as claimed in  claim 1 , wherein the separator has a breaking temperature of 180° C. or more under a condition of 0.005 N, and a heating rate of 5° C./min. 
     
     
         13 . An electrochemical battery, comprising:
 a cathode, an anode, the separator as claimed in  claim 1 , and an electrolyte.   
     
     
         14 . The electrochemical battery as claimed in  claim 13 , wherein the electrochemical battery is a lithium secondary battery.