Negative electrode, negative active material, method of preparing the negative electrode, and lithium battery including the negative electrode

Abstract

A negative electrode including: a current collector; a negative active material layer formed on the current collector; and a polymer coating layer that is formed on the negative active material layer and comprises a fluorinated acrylate type polymer.

What is claimed is: 
     
         1 . A negative active material comprising:
 a core that intercalates or deintercalates lithium, and   a coating layer formed on at least a portion of the core,   wherein the core comprises at least one material selected from the group consisting of a carbonaceous negative active material and a metal-based negative active material, and the coating layer comprises a fluorinated acrylate type polymer.   
     
     
         2 . The negative active material of  claim 1 , wherein the fluorinated acrylate type polymer is a repeating unit represented by Formula 1 below: 
       
         
           
           
               
               
           
         
         wherein: 
         R 1  to R 3  are each independently a hydrogen atom, a fluorine atom, a C 1  to C 20  alkyl group, a fluorine atom-substituted C 1  to C 20  alkyl group, a C 2  to C 20  alkenyl group, a fluorine atom-substituted C 2  to C 20  alkenyl group, a C 6  to C 20  aryl group, or a fluorine atom-substituted C 6  to C 20  aryl group, 
         R 4  to R 6  are each independently a hydrogen atom, a fluorine atom, CH 3 , CHF 2 , CH 2 F, or CF 3 , 
         X is CH 2 , CHF, or CF 2 , 
         a is an integer of 0 to 10, and b is an integer of 0 to 10, 
         the weight average molecular weight of the fluorinated acrylate type polymer is in the range of about 200 to about 500,000, and 
         any one of R 1  to R 6  comprises at least one fluorine atom. 
       
     
     
         3 . The negative active material of  claim 1 , wherein the fluorinated acrylate type polymer is at least one material selected from the group consisting of poly(2,2,2-trifluoroethyl (meth)acrylate), poly(2,2,3,3-tetrafluoropropyl(meth)acrylate), poly(2,2,3,3,3-pentafluoropropyl (meth)acrylate), poly(2,2,3,4,4,4-hexafluorobutyl(meth)acrylate), poly(2,2,3,3,4,4,4-heptafluorobutyl(meth)acrylate), poly(2,2,3,3,4,4,5,5-octafluoropentyl(meth)acrylate), poly(3,3,4,4,5,5,6,6,6-nonafluorohexyl(meth)acrylate), and poly(1,1,1,3,3,3-hexafluoroisopropyl (meth)acrylate). 
     
     
         4 . The negative active material of  claim 1 , wherein the fluorinated acrylate type polymer further comprises a repeating unit represented by Formula 2 below: 
       
         
           
           
               
               
           
         
         wherein R 7  is H, or CH 3 , and R 8  is a linear or branched C 1  to C 9  alkyl group, and 
         the weight average molecular weight of the fluorinated acrylate type polymer is about 200 to about 500,000. 
       
     
     
         5 . A lithium battery comprising:
 a positive electrode;   the negative electrode comprising the negative active material of  claim 1 ; and   an electrolyte.   
     
     
         6 . The lithium battery of  claim 5 , further comprising a separator disposed between the positive electrode and the negative electrode.