Catalysts and methods for lowering electrode pyrolysis temperature

Abstract

Systems and methods are disclosed that provide for pyrolysis reactions to be performed at reduced temperatures that convert non-conductive precursor polymers to conductive carbon suitable for use in electrode materials, which may be incorporated into a cathode, an electrolyte, and an anode, where the pyrolysis method may include one or more catalysts or reactive reagents.

1 . A method of making an electrode active material comprising:
 forming an electrode active material directly on a current collector, said forming comprising:
 mixing together components comprising carbon, silicon powder, and a carbon precursor polymer to form a slurry; 
 coating the slurry directly on the current collector; and 
 reacting an amount of a catalyst or a reagent with said electrode active material under conditions effective to pyrolyze the carbon precursor polymer to conductive carbon;
 wherein the carbon precursor polymer is selected from the group consisting of polyimide (PI), polyamideimide (PAI), N-Methyl-2-Pyrrolidone (NMP), carboxymethyl cellulose (CMC), polyacrylic acid (PAA), polypyrrole (PPy), polyethylene terephthalate (PET), polypropylene (PP), polyacrylonitrile, polytetrafluoroethylene, polyhexafluoropropylene, polyethylene oxide, polypropylene oxide, polyphosphazene, polysiloxane, polyvinyl acetate, polyvinyl alcohol, polymethylmethacrylate, polymethacrylic acid, polystyrene, polycarbonate, phenolic resin, and lignin; 
 wherein the catalyst or the reagent comprises a metal halide, a metal oxide, a metal alloy, an organometallic compound, or a gas that reacts with hydrogen; and 
 wherein the conditions effective to pyrolyze the carbon precursor polymer to conductive carbon comprise a temperature range of about 200° C. to about 900° C. 
 
   
     
     
         2 . The method according to  claim 1 , wherein the conditions comprise a temperature range of about 400° C. to about 750° C. 
     
     
         3 . The method according to  claim 1 , wherein said conditions effective to pyrolyze are performed under a controlled atmosphere. 
     
     
         4 . The method according to  claim 3 , wherein said controlled atmosphere is an inert atmosphere in which an amount of atmospheric oxygen is purged, limited, or reduced. 
     
     
         5 . The method according to  claim 3 , wherein said controlled atmosphere is a partial pressure of catalyst provided as a gas. 
     
     
         6 . The method according to  claim 1 , wherein the catalyst comprises a nickel catalyst selected from the group consisting of NiCl 2 , Al/Ni alloy, Ni(acac) 2 , nickel acetate, nickelocene, or a copper catalyst selected from the group consisting of CuCl 2 , Cu(acac) 2 , copper (II) acetate, and Tetrakis(acetonitrile)copper(I) tetrafluoroborate. 
     
     
         7 . The method according to  claim 6 , wherein the amount of catalyst is from about 0.0001 mol % to about 100 mol % relative to the amount of precursor material that undergoes pyrolysis. 
     
     
         8 . The method according to  claim 7 , wherein the amount of catalyst is from about 0.0001 mol % to about 10 mol % relative to the amount of precursor material that undergoes pyrolysis. 
     
     
         9 . The method according to  claim 8 , wherein the amount of catalyst is from about 0.0001 mol % to about 1 mol % relative to the amount of precursor material that undergoes pyrolysis. 
     
     
         10 . The method according to  claim 1 , wherein the current collector comprises at least one of copper, aluminum, or titanium. 
     
     
         11 . A method of forming an anode, the method comprising:
 mixing raw anode active material with an amount of a catalyst, carbon precursor polymer, and solvent to form a slurry;   coating the slurry onto a substrate;   drying the slurry to remove the solvent; and   reacting the dried slurry comprising the catalyst and raw anode active material under conditions effective to convert carbon precursor polymer to conductive carbon;
 wherein the carbon precursor polymer is selected from the group consisting of polyimide (PI), polyamideimide (PAI), N-Methyl-2-Pyrrolidone (NMP), carboxymethyl cellulose (CMC), polyacrylic acid (PAA), polypyrrole (PPy), polyethylene terephthalate (PET), polypropylene (PP), polyacrylonitrile, polytetrafluoroethylene, polyhexafluoropropylene, polyethylene oxide, polypropylene oxide, polyphosphazene, polysiloxane, polyvinyl acetate, polyvinyl alcohol, polymethylmethacrylate, polymethacrylic acid, polystyrene, polycarbonate, phenolic resin, and lignin; 
 wherein the catalyst or the reagent comprises a metal halide, a metal oxide, a metal alloy, an organometallic compound, or a gas that reacts with hydrogen; and 
 wherein the conditions effective to convert carbon precursor polymer to conductive carbon comprise a temperature range of about 200° C. to about 900° C. 
   
     
     
         12 . The method according to  claim 11 , wherein the substrate comprises a current collector comprising at least one of copper, aluminum, or titanium. 
     
     
         13 . The method according to  claim 12 , wherein the conditions comprise a temperature range of about 400° C. to about 750° C. 
     
     
         14 . The method according to  claim 12 , wherein said conditions effective to convert are performed under a controlled atmosphere. 
     
     
         15 . The method according to  claim 14 , wherein said controlled atmosphere is an inert atmosphere in which an amount of atmospheric oxygen is purged, limited, or reduced. 
     
     
         16 . The method according to  claim 14 , wherein said controlled atmosphere is a partial pressure of catalyst provided as a gas. 
     
     
         17 . The method according to  claim 12 , wherein the catalyst comprises a nickel catalyst selected from the group consisting of NiCl 2 , Al/Ni alloy, Ni(acac) 2 , nickel acetate, nickelocene, or a copper catalyst selected from the group consisting of CuCl 2 , Cu(acac) 2 , copper (II) acetate, and Tetrakis(acetonitrile)copper(I) tetrafluoroborate. 
     
     
         18 . The method according to  claim 17 , wherein the amount of catalyst is from about 0.0001 mol % to about 100 mol % relative to the amount of precursor material that undergoes pyrolysis. 
     
     
         19 . The method according to  claim 18 , wherein the amount of catalyst is from about 0.0001 mol % to about 10 mol % relative to the amount of precursor material that undergoes pyrolysis. 
     
     
         20 . The method according to  claim 19 , wherein the amount of catalyst is from about 0.0001 mol % to about 1 mol % relative to the amount of precursor material that undergoes pyrolysis.