Fullerene-based secondary cell electrodes

Abstract

This invention provides methods and materials for the manufacture of lithium ion rechargeable battery electrodes comprising fullerene compounds which have not been exposed to oxygen. Fullerene compounds are intercalated into carbonaceous materials to form electrodes having superior intercalation/deintercalation properties. Fullerene monomers, such as C 60 , C 70 , C 74 , C 76 , C 78 , C 80 , C 84 and C 80-100 and fluorinated derivatives thereof, are useful in the methods and materials of this invention. Materials incorporating C 74 are particularly preferred. The invention also provides fullerene polymer materials useful for lithium ion electrodes with greatly improved electrochemical properties.

1 . A composition comprising a carbonaceous material selected from the group consisting of graphite, pitch, coal pitch, coke, synthetic graphite, carbon black, lamellar graphite, carbon-arc generated soot and mixtures thereof, intercalated with C 74 , wherein said C 74  has not been exposed to oxygen.  
     
     
         2 . A composition of  claim 1  further comprising one or more additional fullerene wherein said additional fullerene has not been exposed to oxygen.  
     
     
         3 . A composition of  claim 2  wherein said additional fullerene is selected from the group consisting of C 60 , C 70 , C 76 , C 78 , C 84 , and mixtures thereof.  
     
     
         4 . A composition of  claim 1  comprising about 1% to about 99% fullerene by weight.  
     
     
         5 . A composition of  claim 1  comprising about 1% to about 50% fullerene by weight.  
     
     
         6 . A composition of  claim 1  comprising about 10% to about 20% fullerene by weight.  
     
     
         7 . A composition of  claim 1  further comprising a polymeric binder.  
     
     
         8 . A composition of  claim 7  wherein said polymeric binder is selected from the group consisting of polyvinylidene fluoride, polyethylene oxide, polyethylene oxide, polyethylene, polypropylene, polytetrafluoroethylene, polyacrylates, substituted derivatives thereof, copolymers thereof, and mixtures thereof.  
     
     
         9 . An anode for a lithium ion secondary battery comprising a composition of  claim 7 .  
     
     
         10 . A lithium ion secondary battery comprising an anode of  claim 9 .  
     
     
         11 . A method of making a carbonaceous anode, comprising: 
 (a) providing a carbonaceous material selected from the group consisting of graphite, pitch, coal pitch, coke, synthetic graphite, carbon black, lamellar graphite, carbon-arc generated soot and mixtures thereof;    (b) providing at least one fullerene selected from C 60 , C 70 , C 74 , C 76 , C 78 , C 80 , C 84 , C 80 - 100  and mixtures thereof, wherein said at least one fullerene has not been exposed to oxygen;    (c) mixing said carbonaceous material and said at least one fullerene to form a mixture which contains about 1% to about 50% fullerene;    (d) heating said mixture to a temperature of about 400° C. to about 900° C. and holding said mixture at a temperature of about 400° C. to about 900° C. for about 1 to about 8 hours to form a carbonaceous fullerene intercalate composition;    (e) annealing said composition at a rate of about 1° C./min to about 10° C./min until the composition reaches room temperature;    (f) mixing with said composition a polymeric binding material to form a fullerene intercalate-polymeric binder mixture which is about 3% to about 15% polymeric binder; and    (g) pressing said fullerene intercalate-polymeric binder mixture at a pressure of about 2 atm to about 100 atm for about 1 hour to about 8 hours to form a carbonaceous anode, wherein all of the steps (a)-(g) are conducted in an atmosphere lacking oxygen.    
     
     
         12 . A method of  claim 11  wherein said carbonaceous material is graphite.  
     
     
         13 . A method of  claim 11  wherein said at least one fullerene is C 74 .  
     
     
         14 . A method of  claim 11  wherein said mixture of step (c) contains about 1% to about 50% fullerene.  
     
     
         15 . A method of  claim 11  wherein said mixture of step (c) contains about 5% to about 20% fullerene.  
     
     
         16 . A method of  claim 11  wherein said mixture of step (c) contains about 10% to about 20% fullerene.  
     
     
         17 . A method of  claim 11  wherein said heating of step (d) is to a temperature of about 500° C. to about 600° C. for about 8 hours.  
     
     
         18 . A method of  claim 11  wherein said annealing is performed at a rate of about 1° C./min to about 5° C./min.  
     
     
         19 . An anode made according to a method of  claim 11 .  
     
     
         20 . A lithium ion secondary battery anode comprising a C 74  star polymer wherein said C 74  star polymer has been synthesized from C 74  that has not been exposed to oxygen prior to polymer formation.  
     
     
         21 . An anode of  claim 20  further comprising a polymeric binder selected from the group consisting of polyvinylidene fluoride, polyethylene oxide, polyethylene, polypropylene, polytetrafluoroethylene, polyacrylates, substituted derivatives thereof, copolymers thereof and mixtures thereof.  
     
     
         22 . An anode of  claim 20  wherein said C 74  star polymer is a C 74  bis-EDOT-arylene copolymer.  
     
     
         23 . A lithium ion secondary battery comprising an anode of  claim 20 .  
     
     
         24 . A composition comprising fluorinated graphite intercalated with fluorinated C 74 , wherein said fluorinated C 74  has not been exposed to oxygen prior to fluorination.  
     
     
         25 . A composition of  claim 24  wherein said fluorinated C 74  consists essentially of C 74 F 48 .  
     
     
         26 . A composition of  claim 24  comprising about  10 % to about 20% fullerene by weight.  
     
     
         27 . A composition of  claim 24  further comprising a polymeric binder.  
     
     
         28 . A cathode for a lithium ion secondary battery comprising a composition of  claim 27 .  
     
     
         29 . A lithium ion secondary battery comprising a cathode of  claim 28 .  
     
     
         30 . A method of making a carbonaceous cathode, comprising: 
 (a) providing fluorinated graphite;    (b) providing fluorinated C 74 ;    (c) mixing said fluorinated graphite and said fluorinated C 74  to form a mixture which contains about 1% to about 25% fluorinated C 74 ;    (d) heating said mixture to a temperature of about 100° C. to about 900° C. and holding said mixture at a temperature of about 100° C. to about 900° C. for about 1 hour to about 8 hours to form a fluorinated fullerene intercalate composition;    (e) annealing said composition at a rate of about 1° C./min to about 10° C./min until the composition reaches room temperature;    (f) mixing with said composition a polymeric binder to form a fluorinated C 74  intercalate-polymeric binder mixture which is about 3% to about 15% polymeric binder; and    (g) pressing said fluorinated C 74  intercalate-polymeric binder mixture at a pressure of about 2 atm to about 100 atm for about 1 hour to about 8 hours to form a carbonaceous cathode, wherein said fluorinated C 74  has not been exposed to oxygen prior to fluorination.    
     
     
         31 . A method of  claim 30  wherein said mixture of step (c) contains about 1% to about 20% fluorinated C 74 .  
     
     
         32 . A method of  claim 30  wherein said mixture of step (c) contains about 5% to about 20% fluorinated C 74 .  
     
     
         33 . A method of  claim 30  wherein said mixture of step (c) contains about 10% to about 20% fluorinated C 74 .  
     
     
         34 . A method of  claim 30  wherein said annealing is performed at a rate of about 1° C./min to about 5° C./min.  
     
     
         35 . A method of  claim 30  wherein said fluorinated C 74  is C 74 F 48 .  
     
     
         36 . A cathode made according to a method of claim  30 .