Potatolike shaped graphite particles with low impurity rate at the surface, process for preparing same

Patent metadata

Field	Value
Publication number	US-2016060119-A1
Application number	US-201514933436-A
Country	US
Kind code	A1
Filing date	Nov 5, 2015
Priority date	Oct 25, 2000
Publication date	Mar 3, 2016
Grant date	—

Abstract

A method for modifying graphite particles having a prismatic shape or a cylindrical shape characterized by an edge function fe and a basal function fb, said method providing increase of the edge function and lowering of the basal function, wherein the method includes submitting the graphite particles to at least one physical means selected from attrition, jet mill, ball mill, hammer mill, or atomizer mill, in the presence of at least one chemical compound chosen from the group of compounds of the formula MF z , in which M represents an alkaline or alkaline-earth metal and z represents 1 or 2, NaCl and NH 4 F or a mixture thereof, said compound or compounds being added in solid form, at the beginning of the step using the physical means.

First claim

1 . A method for modifying graphite particles having a prismatic shape or a cylindrical shape characterized by an edge function fe and a basal function fb, wherein
fb=1−fe, fe=[(2B/La)+(T/d 002 )]/[(2B/d 100 )+(T/d 002 )], B is the length of the particles T is the thickness of the particles, La=d 100 (2n+1), n is the number of graphite layers of the particle d 100 and d 002 are the lattice parameters of the graphite
said method providing increase of the edge function and lowering of the basal function, wherein the method comprises submitting the graphite particles to at least one physical means selected from attrition, jet mill, ball mill, hammer mill, or atomizer mill, in the presence of at least one chemical compound chosen from the group consisting of compounds of the formula MF z , in which M represents an alkaline or alkaline-earth metal and z represents 1 or 2, NaCl and NH 4 F or a mixture thereof, said compound or compounds being added in solid form, at the beginning of the step using the physical means.

2 . Method according to claim 1 , for preparing modified graphite particles having impurities in their internal structure and having on their surface an amount of one or more impurities that varies between 2% and 4%, and at least one of the following three characteristics:
a tab density between 0.3 and 1.5 g/cc; a granulometric dispersion, such that the D90/D10 ratio varies between 2.2 and 4.2 and the particles have a size between 2 and 30 μm; and they have, attached to their surface, particles of NaCl and/or of NH 4 F; the mass of these particles of NaCl and/or of NH 4 F represents 1 to 10%, of the total mass of the modified graphite particles.

3 . Method according to claim 2 , in which the percentage of impurities by weight present in the said particles, expressed with respect to the total weight of modified graphite particles and measured according to the ash method, is between 1 and 10%.

4 . Method according to claim 2 , wherein the modified graphite particles are substantially devoid of surface impurities.

5 . Method according to claim 1 in which the interplane distance d 002 of the graphite particles varies from 33 to 3.4 Å and/or the BET varies between 0.5 g/m 2 and 50 g/m 2 .

6 . Method according to claim 1 , wherein MF z represents CaF 2 , BaF 2 , or LiF.

7 . Process according to claim 1 , wherein attrition means are selected from balls such as steel balls, ceramic balls or a mixture of steel and ceramic balls.

8 . Method according to claim 1 , comprising a further step of:
reduction the amount of surface impurities, by chemical purification of the graphite particles.

9 . Process according to claim 1 , in which the graphite particles to be modified have a size between 1 and 450 μm.

10 . Process according to claim 1 , for preparing modified graphite particles containing from 5 to 20% of at least one of the following compounds SiO 2 , MgO, ceramic compounds or a mixture thereof, said compounds being attached to the modified graphite particles by physical forces, wherein the physical means is attrition, and is carried out in the presence of an additive, selected from SiO 2 , TiO 2 , ZrO 2 , and in the presence of steel balls, ceramic balls or in the presence of a mixture of steel and ceramic balls.

11 . Process according to claim 1 , in which at least one step is carried out in a controlled atmosphere or in air, the controlled atmosphere being based on nitrogen, argon, helium or a mixture thereof.

12 . Process according to claim 1 in which the physical means comprise jet milling and attrition, attrition being carried out after jet milling.

13 . Method for modifying prismatic graphite particles, wherein said method comprises coating the prismatic particles with a metallic deposit, a carbon deposit, or a carbon and metal deposit.

14 . Method according to claim 13 , wherein the particles have a size between 1 and 50 μm.

15 . Method according to claim 13 , wherein the particles have a sphericity of 80% or more.

16 . Method according to claim 13 , in which the average thickness of the metallic and/or carbonated coating is between 50 nm and 2 μm.

17 . Method according to claim 13 , for preparing particles made up of a coated graphite core, said core making up at least 90% by weight of the total weight of the graphite-based particle, the remaining 10% being made up of at least one metal selected from the group comprising Ag, Si, Al and Cu and/or of carbon and/or of carbonated polymer, in prismatic or fiber form.

Assignees

• Hydro Quebec

Inventors

• Guerfi Abdelbast
• Brochu Fernand
• Kinoshita Kimio
• Zaghib Karim

Classifications

• H01M4/0402

  Methods of deposition of the material · CPC title

• C01P2006/12

  Surface area · CPC title

• H01M2004/027

  Negative electrodes · CPC title

• Y10T428/2918

  including free carbon or carbide or therewith [not as steel] · CPC title

• Y10T428/2967

  Synthetic resin or polymer · CPC title