Carbon material, method for producing carbon material, and non-aqueous secondary battery using carbon material

Abstract

A method for producing a carbon material may include: granulating a raw carbon material by applying mechanical energy comprising impact, compression, friction, and/or shear force. The granulating may be carried out in the presence of a granulating agent. The granulating agent may be liquid during the granulating of the raw carbon material. Alternatively or in addition, the granulating agent may include no organic solvent, an organic solvent having no flash point, or no organic solvent having a flash point of 5° C. or higher.

1 . A method for producing a carbon material, the method comprising:
 granulating a raw carbon material by applying mechanical energy comprising impact, compression, friction, and/or shear force,   wherein the granulating is carried out in the presence of a granulating agent,   wherein the granulating agent is liquid during the granulating of the raw carbon material, and   wherein the granulating agent comprises no organic solvent or no organic solvent having a flash point of 5° C. or higher.   
     
     
         2 . The method of  claim 1 , wherein the granulating agent has a contact angle θ with a graphite of less than 90°, the contact angle being measured by the following method:
 onto a surface of HOPG, 1.2 µL of a granulating agent is added dropwise, and when wetting and spreading has settled down and a rate of change in contact angle θ of the granulating agent added dropwise in one second has reached 3% or lower, the contact angle is measured using a contact angle meter (DM-501 automatic contact angle meter available from Kyowa Interface Science Co., Ltd), 
 when a granulating agent having a viscosity at 25° C. of 500 cP or lower is used, a value at 25° C. is employed as a measurement of the contact angle θ, and when a granulating agent having a viscosity at 25° C. of higher than 500 cP is used, a value at an increased temperature where the viscosity is not higher than 500 cP is employed. 
 
     
     
         3 . The method of  claim 1 , wherein the granulating agent has a viscosity of 1 cP or more during the granulating. 
     
     
         4 . The method of  claim 1 , wherein the granulating agent has a viscosity at 25° C. in a range of from 1 cP to 100,000 cP. 
     
     
         5 . The method of  claim 1 , wherein the raw carbon material comprises a flake graphite, crystalline graphite, and/or vein natural graphite. 
     
     
         6 . The method of  claim 1 , wherein the raw carbon material has a d 002  of 0.34 nm or less. 
     
     
         7 . The method of  claim 1 , wherein the granulating comprises granulating the raw carbon material in the presence of a second agent comprising a metal, metal oxide, amorphous carbon, and/or green coke. 
     
     
         8 . The method of  claim 1 , wherein the granulating is carried out at a temperature in a range of from 0 to 250° C. 
     
     
         9 . The method of  claim 1 , wherein the granulating comprises:
 placing the graphite in an apparatus comprising a rotatable member that rotates at a high speed in a casing, the apparatus comprising a rotor equipped with a plurality of blades in the casing; and   applying impact, compression, friction, and/or shear force to the graphite in the apparatus by rotating the rotor at a high speed.   
     
     
         10 . The method of  claim 1 , further comprising:
 depositing a carbonaceous material having lower crystallinity than the raw carbon material on the granulated carbon material obtained in the granulating.   
     
     
         11 . The method of  claim 1 , wherein the granulated carbon material obtained in the granulating is a spheroidally granulated carbon material. 
     
     
         12 . A carbon material, having: 
 (1) a Raman R value, given by equation (1H)
         R =        IB     /     IA               1   H       ,         
 R being the Raman R value, IB being an intensity of peak PB near 1,360 cm 
 -1 , IA being an intensity of peak PA near 1,580 cm -1  by Raman spectrum analysis, of 0.31 or greater; and   (2) a thermal weight loss ratio per unit area, given by equation (2H)
           L     TW       =       Δ   TG     /     SA           2   H       ,         
 ΔTG being thermal weight loss, as a percentage, on heating from 400° C. to 600° C. at 2° C./min in air atmosphere, measured with differential thermal balance, SA being specific surface area in m 
 2 /g of carbon material determined by BET method, and L TW  being the thermal weight loss ratio per unit area, of 0.05 to 0.45.   
     
     
         13 . The carbon material of  claim 12 , which is a spheroidized graphite made of flake graphite, crystalline graphite, and/or vein graphite. 
     
     
         14 . The carbon material of claim  121 , which has a roundness, as determined by flow-type particle image analysis, of 0.88 or greater. 
     
     
         15 . A carbon material, comprising:
 a carbonaceous material on a particle surface,   wherein the carbon material satisfies an inequality (1D):
                   Y10     d     +   0.26     X   d     ≥   α           ­­­(1D)               
 Y 
 d  being tap density of the carbon material in g/cm 3 , X d  being specific surface area in m 2 /g of the carbon material determined by BET method, and α being at least 12.60.   
     
     
         16 . The carbon material of  claim 15 , wherein the specific surface area of the carbon material determined by BET method is 2 m 2 /g or greater. 
     
     
         17 . The carbon material of  claim 15 , wherein the specific surface area of the carbon material determined by BET method is 4 m 2 /g or greater. 
     
     
         18 . The carbon material of  claim 15 , wherein α in the inequality (1D) is 13.00. 
     
     
         19 . The carbon material of  claim 15 , wherein the carbonaceous material is an amorphous carbon derived from a coal-tar pitch. 
     
     
         20 . The carbon material of  claim 15 , having a d50 volume-based average particle diameter in a range of from 1 to 50 µm. 
     
     
         21 . The carbon material of  claim 15 , wherein the tap density of the carbon material is in a range of from 1.00 to 1.40 g/cm 3 . 
     
     
         22 . The carbon material of  claim 15 , comprising a plurality of graphites selected from the group consisting of at least one of flake graphite, crystalline graphite, and vein graphite. 
     
     
         23 . The carbon material of  claim 15 , having a 1st discharge capacity of 300 mAh/g or more.