Water soluble polymer binder for lithium ion battery

1. A method of making a positive electrode, the method comprising:

combining a positive active material, a water soluble binder comprising a (polystyrenebutadiene rubber)-poly (acrylonitrile-co-acrylamide) polymer, and a conductive additive to form a positive electrode mix in the absence of a thickening or wetting agent, the positive electrode mix having a pH between 7.0 and 11.7, the conductive additive from the group consisting of carbon black, acetylene black, graphite, and combinations thereof; and

applying the positive electrode mix to a current collector to form the positive electrode.

2. A method of making a positive electrode, the method comprising:

combining a positive active material, a water soluble binder comprising a (polystyrenebutadiene rubber)-poly (acrylonitrile-co-acrylamide) polymer, and a conductive additive to form a positive electrode mix in the absence of a thickening agent and a wetting agent.

3. The method of claim 2 , further comprising combining a positive active material, a water soluble binder comprising a (polystyrenebutadiene rubber)-poly (acrylonitrile-co-acrylamide) polymer, and a conductive additive to form a positive electrode mix, the positive active material from the group consisting of LiNiCoAlO 2 , LiMn 2 O 4 , LiNi y Co x M z O, where M=Mn, Al, Sn, In, Ga or Ti and 0.15<x<0.5, 0.5<y<0.8 and 0<z<0.15, Li[Li (1−2y)/3 Ni y Mn (2−y)/3 ]O 2 , Li[Li (1−y)/3 Co y Mn (2−2y)/3 ]O 2 and Li[Ni y Co 1−2y Mn y ]O 2 where x=(2−y)/3 and 0<y<0.5, LiNiCoO 2 .MnO 2 , lithium rich compounds Li 1+y (Ni 0.5 Co 0.2 Mn 0.3 ) 1−y O 2 , where y=(x/(2+x) and x=0-0.33, and xLi 2 MnO 3 (1−x)Li(NiCoMn)O 2 and Li (1+y) (Ni 0.5 Co 0.2 Mn 0.3 ) 1−y O 2 , where y=(x/(2+x) and x=0-0.33, and LiMPO 4 , where M is one or more of the first row transition-metal cations selected from the group consisting of V, Cr, Mn, Fe, Co, Ni, and combinations thereof.

4. The method of claim 2 , further comprising combining a positive active material, a water soluble binder, and a conductive additive, selected from the group consisting of carbon black, acetylene black, graphite, and combinations thereof, to form a positive electrode mix.

5. The method of claim 2 , further comprising applying the positive electrode mix to a current collector to form the positive electrode.

6. The method of claim 2 , further comprising combining a positive active material, a water soluble binder comprising a (polystyrenebutadiene rubber)-poly (acrylonitrile-co-acrylamide) polymer, and a conductive additive to form a positive electrode mix having a pH between 7.0 and 11.7.

7. The method of claim 2 , further comprising combining a positive active material, a water soluble binder comprising a (polystyrenebutadiene rubber)-poly (acrylonitrile-co-acrylamide) polymer, and a conductive additive to form a positive electrode mix, the (polystyrenebutadiene rubber)-poly (acrylonitrile-co-acrylamide) polymer comprising acrylonitrile units and acrylamide units and having a molar ratio acrylonitrile units to acrylamide units of between about 3:1 and about 1:1.

8. The method of claim 2 , further comprising combining a positive active material, a water soluble binder comprising a (polystyrenebutadiene rubber)-poly (acrylonitrile-co-acrylamide) polymer, and a conductive additive to form a positive electrode mix, the (polystyrenebutadiene rubber)-poly (acrylonitrile-co-acrylamide) polymer comprising polystyrenebutadiene units and acrylonitrile-co-acrylamide units and having a molar ratio polystyrenebutadiene units to acrylonitrile-co-acrylamide units of between about 0.25:0.75 and about 0.75:0.25.

9. The method of claim 2 , further comprising combining a positive active material, a water soluble binder comprising a (polystyrenebutadiene rubber)-poly (acrylonitrile-co-acrylamide) polymer, and a conductive additive to form a positive electrode mix, the (polystyrenebutadiene rubber)-poly (acrylonitrile-co-acrylamide) polymer comprising styrene units and butadiene units and having a molar ratio styrene units to butadiene units of between about 0.5:1.5 and about 1.5:0.5.

10. The method of claim 2 , further comprising combining a positive active material, a water soluble binder comprising a (polystyrenebutadiene rubber)-poly (acrylonitrile-co-acrylamide) polymer, and a conductive additive to form a positive electrode mix, the (polystyrenebutadiene rubber)-poly (acrylonitrile-co-acrylamide) polymer having an average molecular weight of between about 10,000 and 1,000,000.

11. The method of claim 2 , further comprising combining a positive active material, a water soluble binder comprising a (polystyrenebutadiene rubber)-poly (acrylonitrile-co-acrylamide) polymer, and a conductive additive to form a positive electrode mix, the (polystyrenebutadiene rubber)-poly (acrylonitrile-co-acrylamide) polymer having an average molecular weight of between about 100,000 and 200,000.

12. The method of claim 2 , further comprising combining a positive active material, a water soluble binder comprising a (polystyrenebutadiene rubber)-poly (acrylonitrile-co-acrylamide) polymer, and a conductive additive to form a positive electrode mix, the (polystyrenebutadiene rubber)-poly (acrylonitrile-co-acrylamide) polymer having the formula:

where a=b=m=n=0.25.

13. The method of claim 2 , further comprising combining a positive active material, a water soluble binder comprising a (polystyrenebutadiene rubber)-poly (acrylonitrile-co-acrylamide) polymer, and a conductive additive to form a positive electrode mix, the (polystyrenebutadiene rubber)-poly (acrylonitrile-co-acrylamide) polymer having the formula:

where a=0.3, b=0.2, m=0.333 and n=0.167.

14. The method of claim 2 , further comprising combining a positive active material, a water soluble binder comprising a (polystyrenebutadiene rubber)-poly (acrylonitrile-co-acrylamide) polymer, and a conductive additive to form a positive electrode mix, the positive active material comprising about 1 to 20 percent by weight of the positive electrode mix and the water soluble binder comprising about 1 to 10 percent by weight of the positive electrode mix.