Conductive polymer binder for a novel silicon/graphene anode in lithium ion batteries

1. A composite electrode for use in a lithium-ion battery, comprising:

a silicon-graphene active material with a specific capacity between 500 and 2200 mAh/g and a conductive polymer binder,

wherein the conductive polymer binder has a polymeric composition with repeating units of the formula:

wherein m+n=1-10 million; and m/n ratio is 9/1 to 1/9,

wherein the conductive polymer binder is a copolymer of 1-pyrenemethyl methacrylate and methacrylic acid and the methacrylic acid present in the copolymer is in an amount from about 30 to 78 mol %,

wherein the silicon-graphene active material is synthesized from silicon nanoparticles combined with graphene sheets, and

wherein the electrode further comprises a graphene additive.

2. The composite electrode of claim 1 , wherein the m/n ratio is 7/3.

3. The composite electrode of claim 1 , wherein the 1-pyrenemethyl methacrylate present in the copolymer is in an amount from about 22 to 70 mol %.

4. The composite electrode of claim 1 , wherein the methacrylic acid present in the copolymer is in an amount from about 10 to 51 wt % and the 1-pyrenemethyl methacrylate present in the copolymer is in an amount from about 49 to 90 wt %.

5. The composite electrode of claim 1 , wherein the electrode is comprised of about 1 to 20 wt % of polymer binder and about 80 to 99 wt % of silicon-graphene active material.

6. The composite electrode of claim 1 , wherein the silicon-graphene active material contains about 10 to 99 wt % of Si and about 1 to 90 wt % of C.

7. The composite electrode of claim 1 , wherein the electrode is comprised of about 5 to 20 wt % of polymer binder, about 75 to 90 wt % of silicon-graphene active material and about 1 to 15 wt % of graphene additive.

8. A method for making a composite electrode for use in a lithium ion battery comprising the steps of:

forming a solution of a solvent and a conductive polymer binder;

adding a silicon-graphene active material to the solution to form a slurry;

mixing the slurry to form a homogeneous mixture;

depositing a thin film of said thus obtained mixture over top of a substrate; and

drying the resulting composite to form said electrode,

wherein the silicon-graphene active material has a specific capacity between 500 and 2200 mAh/g, and is synthesized from silicon nanoparticles combined with graphene sheets,

wherein the conductive polymer binder has a polymeric composition with repeating units of the formula:

wherein m+n=1-10 million; m/n ratio is 9/1 to 1/9,

wherein the conductive polymer binder is a copolymer of 1-pyrenemethyl methacrylate and methacrylic acid and the methacrylic acid present in the copolymer is in an amount from about 30 to 78 mol %,

wherein the electrode further comprises a graphene additive.

9. The method of claim 8 , wherein the m/n ratio is 7/3.

10. The method of claim 8 , wherein the 1-pyrenemethyl methacrylate present in the copolymer is in an amount from about 22 to 70 mol %.

11. The composite electrode of claim 8 , wherein the methacrylic acid present in the copolymer is in an amount from about 10 to 51 wt % and the 1-pyrenemethyl methacrylate present in the copolymer is in an amount from about 49 to 90 wt %.

12. The method of claim 8 , wherein the electrode is comprised of about 1 to 20 wt % of polymer binder and about 80 to 99 wt % of silicon-graphene active material.

13. The method of claim 8 , wherein the silicon-graphene active material contains about 10 to 99 wt % of Si and about 1 to 90 wt % of C.

14. The method of claim 8 , wherein the electrode is comprised of about 5 to 20 wt % of polymer binder, about 75 to 90 wt % of silicon-graphene active material and about 1 to 15 wt % of graphene additive.