Binder for lithium cell, composition for producing electrode, and electrode

1. A binder for a lithium cell comprising polyacrylic acid cross-linked by a cross-linking agent selected from the compounds described in the following general formulae [1], [2] and [4] to [13] and the polymer described in the following general formula [14], provided that the one which includes a functional group-containing vinylidene fluoride-based polymer is excluded;

wherein k represents an integer of 1 to 6,

wherein R 25 and R 26 each independently represent a hydrogen atom or a methyl group, R 20 represents an alkylene group having 1 to 20 carbon atoms, a group represented by the following general formula [2-1],

R 17 —O r   [2-1]

wherein R 17 represents an alkylene group having 1 to 6 carbon atoms, r represents an integer of 1 to 6,

or the group represented by the following general formula [2-2]

R 18 —O t R 19 —  [2-2]

wherein R 18 and R 19 each independently represent an alkylene group having 1 to 6 carbon atoms, t represents an integer of 1 to 12,

wherein R 7 to R 10 each independently represent an alkylene group having 1 to 6 carbon atoms, 1 represents an integer of 1 to 6, m represents an integer of 0 to 6, v1 and v2 each independently represent an integer of 0 or 1,

wherein R 31 to R 38 each independently represent a hydrogen atom, a vinyl group or a vinylketone group, and at least two or more groups thereof are a vinyl group or a vinylketone group,

wherein R 12 to R 14 each independently represent an alkylene group having carbon 1 to 6 atoms,

wherein Ar 1 represents an aryl group having 6 to 10 carbon atoms, R 15 represents an alkylene group having 1 to 6 carbon atoms, q represents an integer of 2 to 4,

wherein Ar 2 and Ar 3 each independently represent an arylene group having 6 to 10 carbon atoms, R 16 represents an alkylene group having 1 to 6 carbon atoms,

wherein Ar 4 represents an arylene group having 6 to 10 carbon atoms,

wherein, R 11 represents an alkylene group having 1 to 6 carbon atoms,

wherein R 21 represents an alkylene group having 1 to 6 carbon atoms which has or does not have a substituent, an arylene group having 6 to 10 carbon atoms which has or does not have a substituent, or a group represented by the following general formula [12-A]

wherein R 35 represents an alkyl group having 1 to 6 carbon atoms, R 36 represents an alkylene group having 1 to 6 carbon atoms, Ar 5 represents an arylene group having 6 to 10 carbon atoms which may have b pieces of R 35 as substituents, b represents an integer of 0 to 4,

or the group represented by the following general formula [12-B]

wherein R 37 represents an alkylene group having 1 to 6 carbon atoms, R 35 , R 36 , Ar 5 and b are the same as described above,

wherein R 22 each independently represents an alkyl group having 1 to 6 carbon atoms which has or does not have a substituent, an aryl group having 6 to 10 carbon atoms which has or does not have a substituent, or the group represented by the following general formula [13-A]

wherein R 40 represents an alkyl group having 1 to 6 carbon atoms, R 41 represents an alkylene group having 1 to 6 carbon atoms, Ar 6 represents an arylene group having 6 to 10 carbon atoms which have c pieces of R 40 as substituents, c represents an integer of 0 to 5,

wherein R 23 represents an alkylene group having 1 to 6 carbon atoms which has or does not have a substituent, an arylene group having 6 to 10 carbon atoms which has or does not have a substituent, or a group represented by the following general formula [14-A] or [14-B]

wherein R 30 represents an alkyl group having 1 to 6 carbon atoms, R 31 represents an alkylene group having 1 to 6 carbon atoms, Ar 7 represents an arylene group having 6 to 10 carbon atoms which may have a pieces of R 30 as substituents, a represents an integer of 0 to 4,

or the group following general formula [14-C]

wherein R 32 represents an alkylene group having 1 to 6 carbon atoms, R 30 , R 31 , Ar 7 , and a are the same as described above,

and s represents an integer of 10 to 10000.

2. The binder according to claim 1 , wherein the cross-linked polyacrylic acid is the neutralized one.

3. The binder according to claim 1 , wherein the cross-linked polyacrylic acid is the neutralized one with sodium hydroxide.

4. The binder according to claim 1 , wherein a cross-linking agent is a compound represented by the general formula [2], the general formula [4], the general formula [9], the formulae [10-1] to [10-4], or the general formula [11], or a polymer described in the general formula [14].

5. The binder according to claim 1 , wherein a cross-linking agent is a compound described in the general formula [2], the general formula [4], or the formulae [10-1] to [10-4].

6. The binder according to claim 1 , wherein viscosity of the cross-linked polyacrylic acid is 30 to 10000 mPa·S under 60 rpm of a rotational viscometer, or 10000 to 450000 mPa·S under 0.6 rpm of a rotational viscometer, provided that as viscosity measured in a dispersed solution of the cross-linked polyacrylic acid in water in a concentration of 1% by weight.

7. A composition for producing an electrode of a lithium cell comprising 1) an active material containing silicon, 2) a conductive assistant, and 3) a cross-linked-type polyacrylic acid, provided that the one containing a functional group-containing vinylidene fluoride-based polymer is excluded, wherein the cross-linked-type polyacrylic acid is the polyacrylic acid cross-liked by a cross-linking agent selected from the compounds described in the following general formulae [1], [2] and [4] to [13] and the polymer represented by the general formula [14]:

wherein k represents an integer of 1 to 6,

wherein R 25 and R 26 each independently represent a hydrogen atom or a methyl group, R 20 represents an alkylene group having 1 to 20 carbon atoms, and a group represented by the following general formula [2-1],

where R 17 represents an alkylene group having 1 to 6 carbon atoms, r represents an integer of 1 to 6, or the group represented by the following general formula [2-2]

wherein R 18 and R 19 each independently represent an alkylene group having 1 to 6 carbon atoms, t represents an integer of 1 to 12,

wherein R 7 to R 10 each independently represent an alkylene group having 1 to 6, v1 and v2 each independently represents an integer of 0 or 1,

wherein R 31 to R 38 each independently represent a hydrogen atom or a vinyl group, and at least two or more groups thereof are a vinyl group.

wherein R 12 to R 14 each independently represent an alkylene group having 1 to 6 carbon atoms,

wherein Ar 1 represents an aryl group having 6 to 10 carbon atoms, R 15 represents an alkylene group having 1 to 6 carbon atoms, q represents an integer of 2 to 4,

wherein Ar 2 and Ar 3 each independently represent an arylene group having 6 to 10 carbon atoms, R 16 represents an alkylene group having 1 to 6 carbon atoms,

wherein Ar 4 represents an arylene group having 6 to 10 carbon atoms,

wherein, R 11 represents an alkylene group having 1 to 6 carbon atoms,

wherein R 21 represents an alkylene group having 1 to 6 carbon atoms which has or does not have a substituent, an arylene group having 6 to 10 carbon atoms which has or does not have a substituent, or a group represented by the following general formula [12-A]

wherein R 35 represents an alkyl group having 1 to 6 carbon atoms, R 36 represents an alkyl group having 1 to 6 carbon atoms, Ar 5 represents an arylene group having 6 to 10 carbon atoms which may have b pieces of R 35 as substituents, b represents an integer of 0 to 4, or the group represented by the following general formula [12-B]

wherein R 37 represents an alkylene group having 1 to 6 carbon atoms, R 35 , R 36 , Ar 5 and b are the same as described above,

wherein R 22 each independently represents an alkyl group having 1 to 6 carbon atoms which has or does not have a substituent, an aryl group having 6 to 10 carbon atoms which has or does not have a substituent, or the group represented by the following general formula [13-A]

wherein R 40 represents an alkyl group having 1 to 6 carbon atoms, R 41 represents an alkylene group having 1 to 6 carbon atoms, Ar 6 represents an arylene group having 6 to 10 carbon atoms which have c pieces of R 40 as substituents, c represents an integer of 0 to 5,

wherein R 23 represents an alkylene group having 1 to 6 carbon atoms which has or does not have a substituent, an arylene group having 6 to 10 carbon atoms which has or does not have a substituent, or a group represented by the following general formula [14-A] or [14-B]

wherein R 30 represents an alkyl group having 1 to 6 carbon atoms, R 31 represents an alkylene group having 1 to 6 carbon atoms, Ar 7 represents an arylene group having 6 to 10 carbon atoms which may have a pieces of R 30 as substituents, a represents an integer of 0 to 4, or the group following general formula [14-C]

wherein R 32 represents an alkylene group having 1 to 6 carbon atoms, R 30 , R 31 , Ar 7 , and a are the same as described above, and s represents an integer of 10 to 10000.

8. The composition according to claim 7 , wherein the active material containing silicon is the one comprising silicon or silicon and carbon.

9. The composition according to claim 7 , wherein the electrode is a negative electrode.

10. The composition according to claim 7 , wherein the cross-linked-type polyacrylic acid is the neutralized one.

11. The composition according to claim 7 , wherein the cross-linked polyacrylic acid is the neutralized one with sodium hydroxide.

12. The composition according to claim 7 , wherein the cross-linking agent is a compound described in the general formula [2], the general formula [4], the general formula [9], the formulae the general formula [9], the formulae [10-1] to [10-4], or the general formula [11], or a polymer described in the general formula [14].

13. The composition according to claim 7 , wherein the cross-linking agent is a compound described in the general formula [2], the general formula [4], or the formulae [10-1] to [10-4].

14. The composition according to claim 7 , wherein viscosity of the cross-linked polyacrylic acid is 30 to 10000 mPa⋅S under 60 rpm of a rotational viscometer, and 10000 to 450000 mPa⋅S under 0.6 rpm of rotational viscometer, provided that as viscosity measured in a dispersed solution of the cross-linked polyacrylic acid in water in a concentration of 1% by weight.

15. An electrode for lithium cell having 1 ) an active material containing silicon, a 2 ) conductive assistant, 3 ) a cross-linked-type polyacrylic acid, and 4 ) a current collector, provided that the one containing a functional group-containing vinylidene fluoride-based polymer is excluded, wherein the cross-linked-type polyacrylic acid is the polyacrylic acid cross-liked by a cross-linking agent selected from the compounds described in the following general formulae [1], [2] and [4] to [13] and the polymer represented by the general formula [14]:

wherein k represents an integer of 1 to 6,

wherein R 25 and R ≈ each independently represent a hydrogen atom or a methyl group, R 20 represents an alkylene group having 1 to 20 carbon atoms, and a group represented by the following general formula [2-1],

wherein R 17 represents an alkylene group having 1 to 6 carbon atoms, r represents an integer of 1 to 6, or the group represented by the following general formula [2-2]

wherein R 18 and R 19 each independently represent an alkylene group having 1 to 6 carbon atoms, t represents an integer of 1 to 12,

wherein R 7 to R 10 each independently represent an alkylene group having 1 to 6 carbon atoms, 1 represents an integer of 1 to 6, m represents an integer of 0 to 6, v1 and v2 each independently represents an integer of 0 or 1,

wherein R 31 to R 38 each independently represent a hydrogen atom or a vinyl group, and at least two or more groups thereof are a vinyl group,

wherein R 12 to R 14 each independently represent an alkylene group having 1 to 6 carbon atoms,

wherein Ar 1 represents an aryl group having 6 to 10 carbon atoms, R 15 represents an alkylene group having 1 to 6 carbon atoms, q represents an integer of 2 to 4,

wherein Ar 2 and Ar 3 each independently represent an arylene group having 6 to 10 carbon atoms, R 16 represents an alkylene group having 1 to 6 carbon atoms,

wherein Ar 4 represents an arylene group having 6 to 10 carbon atoms,

wherein, R 11 represents an alkylene group having 1 to 6 carbon atoms,

wherein R 21 represents an alkylene group having 1 to 6 carbon atoms which has or does not have a substituent, an arylene group having 6 to 10 carbon atoms which has or does not have a substituent, or a group represented by the following general formula [12-A]

wherein R 35 represents an alkyl group having 1 to 6 carbon atoms, R 36 represents an alkyl group having 1 to 6 carbon atoms, Ar 5 represents an arylene group having 6 to 10 carbon atoms which may have b pieces of R 35 as substituents, b represents an integer of 0 to 4, or the group represented by the following general formula [12-B]

wherein R 37 represents an alkylene group having 1 to 6 carbon atoms, R 35 , R 36 , Ar 5 and b are the same as described above,

wherein R22 each independently represents an alkyl group having 1 to 6 carbon atoms which has or does not have a substituent, an aryl group having 6 to 10 carbon atoms which has or does not have a substituent, or the group represented by the following general formula [13-A]

wherein R 40 represents an alkyl group having 1 to 6 carbon atoms, R 41 represents an alkylene group having 1 to 6 carbon atoms, Ar 6 represents an arylene group having 6 to 10 carbon atoms which have c pieces of R 40 as substituents, c represents an integer of 0 to 5,

wherein R 23 represents an alkylene group having 1 to 6 carbon atoms which has or does not have a substituent, an arylene group having 6 to 10 carbon atoms which has or does not have a substituent, or a group represented by the following general formula [14-A] or [14-B]

wherein R 30 represents an alkyl group having 1 to 6 carbon atoms, R 31 represents an alkylene group having 1 to 6 carbon atoms, Ar 7 represents an arylene group having 6 to 10 carbon atoms which may have a pieces of R 30 as substituents, a represents an integer of 0 to 4, or the group following general formula [14-C]

wherein R 32 represents an alkylene group having 1 to 6 carbon atoms, R 30 ,R 31 , Ar 7 , and a are the same as described above, and s represents an integer of 10 to 10000.

16. The electrode according to claim 15 , wherein the active material containing silicon is the one comprising silicon or silicon and carbon.

17. The electrode according to claim 15 , wherein the electrode is a negative electrode.

18. The electrode to claim 15 , wherein the cross-linked polyacrylic acid is the neutralized one.

19. The electrode according to claim 15 , wherein the cross-linked polyacrylic acid is the neutralized one with sodium hydroxide.

20. The electrode according to claim 15 , wherein the cross-linking agent is a compound described in the general formula [2], the general formula [4], the general formula [9], formula [10-1]to [10-4], or the general formula [11], or a polymer described in the general formula [14].

21. The electrode according to claim 15 , wherein the cross-linking agent is compound described in the general formula [2], the general formula [4]or the formulae [10-1]to [10-4].

22. The electrode according to claim 15 , wherein viscosity of the cross-linked polyacrylic acid is 30 to 10000 mPa⋅S under 60 rpm of a rotational viscometer, and 10000 to 450000 mPa⋅S under 0.6 rpm of a rotational viscometer, provided that as viscosity measured in a dispersed solution of the cross-linked polyacrylic acid in water in a concentration of 1 % by weight.