Slurry including inorganic particles with improve dispersibility by controlling particle size and slurry viscosity

Patent metadata

Field	Value
Publication number	US-9991491-B2
Application number	US-201414258137-A
Country	US
Kind code	B2
Filing date	Apr 22, 2014
Priority date	Nov 30, 2012
Publication date	Jun 5, 2018
Grant date	Jun 5, 2018

Abstract

The present disclosure relates to an invention directed to controlling a viscosity of a slurry used to manufacture an electrochemical device, by adjusting a particle diameter of an inorganic matter that is an ingredient of the slurry, so that a sinking rate of the inorganic particles may remarkably slow down and dispersibility may be dramatically improved, and as a result, the content of the inorganic particles may relatively increase and the inorganic particles may be uniformly distributed in a coating layer on a substrate, thereby preventing a reduction in battery performance.

First claim

What is claimed is:

1. A slurry for a porous coating layer of a composite separator, comprising:
inorganic particles;
a polymer; and
a solvent,
wherein the inorganic particles have an average diameter ranging from 0.01 μm to 15 μm,
wherein the polymer consists essentially of any one selected from the group consisting of a polyvinylidene fluoride (PVdF), polyvinylidene fluoride-co-hexafluoropropylene, polyvinylidene fluoride-co-trichloroethylene, polyvinyl pyrrolidone, polyvinylacetate, polyethylene-co-vinyl acetate, cyanoethylpullulan, cyanoethylsucrose, pullulan, and polyimide, and mixtures thereof,
wherein the solvent is any one selected from acetone, tetrahydrofuran, methylene chloride, chloroform, dimethylformamide, N-methyl-2-pyrrolidone (NMP), cyclohexane and mixtures thereof,
wherein 10 to 50 parts by weight of the inorganic particles and 1 to 10 parts by weight of the polymer are present in the slurry based on 100 parts by weight of the solvent, and
wherein the slurry has a viscosity of which a lower bound is a value obtained from the following Equation 1 based on the average diameter of the inorganic particles and an upper bound is 10,000 cP:
η≥40 d 2   [Equation 1]

where η denotes the viscosity of the slurry in units of centipoise (cP), and d denotes the average diameter of inorganic particles in units of micrometers (μm).

2. The slurry according to claim 1 ,
wherein the lower bound of the viscosity of the slurry is a value obtained from the following Equation 2:
η=40 d 2   [Equation 2]

where η denotes the viscosity of the slurry in units of centipoise (cP), and d denotes the average diameter of inorganic particles in units of micrometers (μm).

3. The slurry of claim 1 ,
wherein the inorganic particles have an average diameter ranging from 0.2 μm to 2.5 μm, and
wherein the slurry has a viscosity ranging from 9 to 300 centipoise (cP).

4. The slurry according to claim 1 , wherein the inorganic particles are selected from the group consisting of an inorganic particle having a dielectric constant greater than or equal to 5, an inorganic particle having a lithium ion delivery capability, and a mixture thereof.

5. The slurry according to claim 4 , wherein the inorganic particle having the dielectric constant greater than or equal to 5 is any one selected from the group consisting of BaTiO 3 , Pb(Zr x ,Ti 1−x )O 3 wherein 0<x<1, Pb 1−x La x Zr 1−y Ti y O 3 , wherein 0<x<1, 0<y<1, (1−x)Pb(Mg 1/3 Nb 2/3 )O 3−x PbTiO 3 , wherein 0<x<1, HfO 2 , SrTiO 3 , SnO 2 , CeO 2 , MgO, NiO, CaO, ZnO, ZrO 2 , SiO 2 , Y 2 O 3 , Al 2 O 3 , SiC and TiO 2 , and mixtures thereof.

6. The slurry according to claim 4 , wherein the inorganic particle having the lithium ion delivery capability is any one selected from the group consisting of Li 3 PO 4 , Li x Ti y (PO 4 ) 3 , wherein 0<x<2, 0<y<3, Li x Al y Ti z (PO 4 ) 3 , wherein 0<x<2, 0<y<1, 0<z<3, (LiAlTiP) x O y -based glass, wherein 0<x<4, 0<y<13, Li x La y TiO 3 , wherein 0<x<2, 0<y<3, Li x Ge y P z S w , wherein 0<x<4, 0<y<1, 0<z<1, 0<w<5, Li x N y , wherein 0<x<4, 0<y<2, SiS 2 -based glass represented by Li x Si y S z , wherein 0<x<3, 0<y<2, 0<z<4, P 2 S 5 -based glass represented by Li x P y S z , wherein 0<x<3, 0<y<3, 0<z<7, and mixtures thereof.

7. A slurry for a porous coating layer of a composite separator, comprising:
inorganic particles;
a polymer; and
a solvent,
wherein the inorganic particles have an average diameter ranging from 0.01 μm to 15 μm,
wherein the polymer consists essentially of any one selected from the group consisting of a polyvinylidene fluoride (PVdF), polyvinylidene fluoride-co-hexafluoropropylene, polyvinylidene fluoride-co-trichloroethylene, and mixtures thereof,
wherein the solvent is any one selected from acetone, tetrahydrofuran, methylene chloride, chloroform, dimethylformamide, N-methyl-2-pyrrolidone (NMP), cyclohexane and mixtures thereof,
wherein 10 to 50 parts by weight of the inorganic particles and 1 to 10 parts by weight of the polymer are present in the slurry based on 100 parts by weight of the solvent, and
wherein the slurry has a viscosity of which a lower bound is a value obtained from the following Equation 1 based on the average diameter of the inorganic particles and an upper bound is 10,000 cP:
η≥40 d 2   [Equation 1]

where η denotes the viscosity of the slurry in units of centipoise (cP), and d denotes the average diameter of inorganic particles in units of micrometers (μm).

8. A slurry for a porous coating layer of a composite separator, comprising:
inorganic particles;
an organic binder polymer; and
a solvent,
wherein the inorganic particles have an average diameter ranging from 0.01 μm to 15 μm,
wherein the organic binder polymer consists essentially of polyvinylidene fluoride-co-hexafluoropropylene,
wherein the solvent is any one selected from acetone, tetrahydrofuran, methylene chloride, chloroform, dimethylformamide, N-methyl-2-pyrrolidone (NMP), cyclohexane and mixtures thereof,
wherein 10 to 50 parts by weight of the inorganic particles and 1 to 10 parts by weight of the polymer are present in the slurry based on 100 parts by weight of the solvent, and
wherein the slurry has a viscosity of which a lower bound is a value obtained from the following Equation 1 based on the average diameter of the inorganic particles and an upper bound is 10,000 cP:
η≥40 d 2   [Equation 1]

where η denotes the viscosity of the slurry in units of centipoise (cP), and d denotes the average diameter of inorganic particles in units of micrometers (μm).

9. The slurry of claim 8 , wherein the inorganic particles have an average diameter ranging from 0.2 μm to 2.5 μm, and wherein the slurry has a viscosity ranging from 9 to 300 centipoise (cP).

10. A slurry for a porous coating layer of a composite separator, comprising:
inorganic particles;
a polymer; and
a solvent,
wherein the inorganic particles are selected from the group consisting of an inorganic particle having a dielectric constant greater than or equal to 5, an inorganic particle having a lithium ion delivery capability, and a mixture thereof,
wherein the polymer consists essentially of any one selected from the group consisting of a polyvinylidene fluoride (PVdF), polyvinylidene fluoride-co-hexafluoropropylene, polyvinylidene fluoride-co-trichloroethylene, polyvinyl pyrrolidone, polyvinylacetate, polyethylene-co-vinyl acetate, cyanoethylpullulan, cyanoethylsucrose, pullulan, and polyimide, and mixtures thereof,
wherein 10 to 50 parts by weight of the inorganic particles and 1 to 10 parts by weight of the polymer are present in the slurry based on 100 parts by weight of the solvent, and
wherein the slurry has a viscosity ranging from 9 to 300 centipoise (cP).

11. An electrochemical device comprising a cathode, an anode, and a separator interposed between the cathode and the anode,
wherein the separator is manufactured using the slurry defined in claim 1 .

Assignees

• Lg Chemical Ltd
• Toray Industries

Inventors

• Lee Joo-Sung
• Yoon Su-Jin
• Han Da-Kyung
• Ryu Bo-Kyung
• Kim Jong-Hun

Classifications

• H01M4/139

  Processes of manufacture · CPC title

• H01M4/134

  Electrodes based on metals, Si or alloys · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• H01M4/131

  Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx · CPC title

• H01M2004/021

  Physical characteristics, e.g. porosity, surface area · CPC title