Coated carbonaceous particles particularly useful as electrode materials in electrical storage cells, and methods of making the same

Abstract

A process for the production of coated carbonaceous particles, and the coated carbonaceous particles produced thereby of which process comprises the steps of: providing particles of a carbonaceous material; providing particles of a carbonaceous material; providing a coating of a fusible, carbon residue forming material onto the surface of said particles; stabilizing the coated particles by subjecting said particles to an oxidation reaction using an oxidizing agent; subsequently carbonizing the coated particles; and, optionally thereafter graphitizing the coated particles. The coated carbonaceous particles find particular use in electrodes of electrical storage cells, especially rechargeable lithium ion storage cells.

1 . A process for the production of coated carbonaceous particles of which process comprises the steps of: 
 providing particles of a carbonaceous material;    providing a coating of a fusible, carbon residue forming material onto the surface of said particles;    stabilizing the coated particles by subjecting said particles to an oxidation reaction using an oxidizing agent;    subsequently carbonizing the coated particles; and,    optionally thereafter graphitizing the coated particles.    
     
     
         2 . The process according to  claim 1  wherein the carbonaceous particles are a pulvurent carbonaceous material selected from the group consisting of: pitches, calcined petroleum cokes, uncalcined petroleum cokes, highly crystalline cokes, coal tar cokes, synthetic graphites, natural graphites, soft carbons derived from organic polymers, and soft carbons derived from natural polymers.  
     
     
         3 . The process according to  claim 2  wherein the carbonaceous particles are a pulvurent carbonaceous material selected from the group consisting of: calcined petroleum cokes, uncalcined petroleum cokes, highly crystalline cokes, synthetic graphites, and natural graphites.  
     
     
         4 . The process according to  claim 1  wherein the carbonaceous particles have an average particle size of up to about 150 μm.  
     
     
         5 . The process according to  claim 4  wherein the carbonaceous particles have average particles sizes between about 5 μm and about 70 μm.  
     
     
         6 . The process according to  claim 5  wherein the carbonaceous particles have average particle sizes between about 5 μm and about 45 μm.  
     
     
         7 . The process according to  claim 1  wherein the carbon residue forming material is coated onto the surface of the carbonaceous particles by liquefying the carbon residue forming material, and contacting the liquefied carbon residue forming material with the fine particles of the carbonaceous material.  
     
     
         8 . The process according to  claim 1  wherein the carbon residue forming material is coated onto the surface of the carbonaceous particles by selectively precipitating a carbon residue forming material onto the carbonaceous particles.  
     
     
         9 . The process according to claim wherein the carbon residue forming material is coated onto the surface of the carbonaceous particles in amounts of between 1% wt. and 50% wt.  
     
     
         10 . The process according to  claim 1  wherein the carbon residue forming material is coated onto the surface of the carbonaceous particles in amounts of between 2.5% wt. and 25% wt.  
     
     
         11 . The process according to  claim 1  wherein the oxidizing agent and the carbon residue forming material is applied to the fine particles of the carbonaceous material in a single step.  
     
     
         12 . The process according to  claim 1  wherein the oxidizing agent is a solid oxidizing agent selected from the group consisting of: inorganic and organic oxidizing agents.  
     
     
         13 . The process according to  claim 12  wherein the oxidizing agent is selected from the group consisting of: alkali nitrates and alkali sulfates such as are represented by MNO 3  and M 2 SO 4 , where M denotes alkali metal; M′O x  where M′ represents a transition metal, inorganic salts, and organic salts.  
     
     
         14 . The process according to  claim 1  wherein the oxidizing agent is a liquid oxidizing agent.  
     
     
         15 . The process according to  claim 14  wherein the oxidizing agent is selected from the group consisting of: oxidizing acids, aqueous solutions containing oxidizing salts, non-aqueous solutions containing oxidizing salts, peroxides and aryl quinones.  
     
     
         16 . The process according to  claim 1  wherein the oxidizing agent is a gaseous oxidizing agent.  
     
     
         17 . The process according to  claim 16  wherein the oxidizing agent is a gaseous oxidizing agent selected from the group consisting of: oxygen, sulfur fumes, gaseous oxides, nitrogen oxide gas, ambient air and halogens.  
     
     
         18 . Coated carbonaceous particles having a coating layer formed of an oxidized fusible carbon residue forming material.  
     
     
         19 . Coated carbonaceous particles according to  claim 18  having a coating layer formed of a graphitized, fusible oxidized carbon residue forming material.  
     
     
         20 . Coated carbonaceous particles according to  claim 18  having a substantially smooth coating.  
     
     
         21 . The coated carbonaceous particles according to  claim 18  wherein the carbonaceous particles are a pulvurent carbonaceous material selected from the group consisting of: petroleum pitches, calcined petroleum cokes, uncalcined petroleum cokes, highly crystalline cokes, coal tar cokes, synthetic graphites, natural graphites, soft carbons derived from organic polymers, and soft carbons derived from natural polymers.  
     
     
         22 . The coated carbonaceous particles according to  claim 18  wherein the fine carbonaceous particles are a pulvurent carbonaceous material selected from the group consisting of: calcined petroleum cokes, uncalcined petroleum cokes, highly crystalline cokes, synthetic graphites, and natural graphites.  
     
     
         23 . Coated carbonaceous particles comprising coated fine carbonaceous particles having a coating layer formed of an oxidized, fusible carbon residue forming material according to  claim 18 .  
     
     
         24 . An electrical storage cell comprising coated carbonaceous particles according to  claim 18 .  
     
     
         25 . An electrical storage cell according to  claim 24 , wherein the electrical storage cell is a rechargeable electrical storage cell.  
     
     
         26 . A method for the manufacture of an electrical storage cell which comprises the step of: 
 incorporating into an anode of the electrical storage cell the coated carbonaceous particles according to  claim 18 .    
     
     
         27 . A process for the production of coated carbonaceous particles having substantially smooth coatings formed of an oxidized, carbon residue forming material which process comprises the steps of: 
 providing particles of a carbonaceous material;    providing a coating of a fusible, carbon residue forming material onto the surface of said particles by contacting the particles of the carbonaceous material with a liquid carbon residue forming material;    stabilizing the coated particles by subjecting said particles to an oxidation reaction using an oxidizing agent;    subsequently carbonizing the coated particles; and,    optionally thereafter graphitizing the coated particles.    
     
     
         28 . Coated carbonaceous particles having substantially smooth coatings formed of an oxidized, carbon residue forming material produced by the process of  claim 27 .  
     
     
         29 . Coated carbonaceous particles having substantially smooth coatings formed of an oxidized, carbon residue forming material.