Electrochemical slurry compositions and methods for preparing the same
Embodiments described herein generally relate to semi-solid suspensions, and more particularly to systems and methods for preparing semi-solid suspensions for use as electrodes in electrochemical devices such as, for example batteries. In some embodiments, a method for preparing a semi-solid electrode includes combining a quantity of an active material with a quantity of an electrolyte to form an intermediate material. The intermediate material is then combined with a conductive additive to form an electrode material. The electrode material is mixed to form a suspension having a mixing index of at least about 0.80 and is then formed into a semi-solid electrode.
1. A method of preparing a semi-solid electrode, the method comprising:
combining a quantity of an active material with a quantity of an electrolyte and a conductive additive to form an electrode material;
mixing the electrode material to form a suspension having a mixing index of at least about 0.80;
controlling a temperature of the electrode material during mixing to control evaporation of the electrolyte therefrom;
forming the electrode material into a semi-solid electrode;
forming a second electrode; and
forming an electrochemical cell by combining the semi-solid electrode and the second electrode.
2. The method of claim 1 , wherein the electrode material is a stable suspension when it is formed into the semi-solid electrode.
3. The method of claim 1 , wherein the electrode material is mixed until the suspension has a mixing index of at least about 0.90.
4. The method of claim 3 , wherein the electrode material is mixed until the suspension has a mixing index of at least about 0.95.
5. The method of claim 4 , wherein the electrode material is mixed until the suspension has a mixing index of at least about 0.975.
6. The method of claim 1 , further comprising:
mixing the electrode material until the electrode material has an electronic conductivity of at least about 10 −6 S/cm.
7. The method of claim 6 , wherein the electrode material is mixed until the electrode material has an electronic conductivity of at least about 10 −5 S/cm.
8. The method of claim 7 , wherein the electrode material is mixed until the electrode material has an electronic conductivity of at least about 10 −4 S/cm.
9. The method of claim 8 , wherein the electrode material is mixed until the electrode material has an electronic conductivity of at least about 10 −3 S/cm.
10. The method of claim 9 , wherein the electrode material is mixed until the electrode material has an electronic conductivity of at least about 10 −2 S/cm.
11. The method of claim 1 , further comprising:
mixing the electrode material until the electrode material has an apparent viscosity of less than about 100,000 Pa-s at an apparent shear rate of 1,000 s −1 .
12. The method of claim 11 , wherein the electrode material is mixed until the electrode has an apparent viscosity of less than about 10,000 Pa-s at an apparent shear rate of 1,000 s −1 .
13. The method of claim 12 , wherein the suspension is mixed until the suspension has an apparent viscosity of less than about 1,000 Pa-s at an apparent shear rate of 1,000 s −1 .
14. The method of claim 1 , wherein the quantity of the active material is about 20% to about 75% by volume of the electrode material.
15. The method of claim 14 , wherein the quantity of the active material is about 40% to about 75% by volume of the electrode material.
16. The method of claim 15 , wherein the quantity of the active material is about 60% to about 75% by volume of the electrode material.
17. The method of claim 1 , wherein the quantity of the electrolyte is about 25% to about 70% by volume of the electrode material.
18. The method of claim 17 , wherein the quantity of the electrolyte is about 30% to about 50% by volume of the electrode material.
19. The method of claim 18 , wherein the quantity of the electrolyte is about 20% to about 40% by volume of the electrode material.
20. The method of claim 1 , wherein the quantity of the conductive material is about 0.5% to about 25% by volume of the electrode material.
21. The method of claim 20 , wherein the quantity of the conductive material is about 1% to about 6% by volume of the electrode material.
22. The method of claim 1 , wherein the mixing index is evaluated with a sample volume that is a cube of a formed semi-solid electrode thickness±10%.
23. The method of claim 1 , wherein the mixing index is evaluated with a sample volume of 0.12 mm 3 ±10%.
24. The method of claim 1 , wherein the controlling includes decreasing the temperature of the electrode material during mixing.
25. The method of claim 24 , wherein the controlling includes decreasing the temperature of the electrode material to lower than 10 degrees Celsius during mixing.
26. A method of preparing a semi-solid electrode, the method comprising:
combining a quantity of an active material with a quantity of an electrolyte and a conductive additive to form an electrode material;
mixing the electrode material to form a stable suspension having a mixing index of at least about 0.80 and an electronic conductivity of at least about 10 −6 S/cm; and
controlling a temperature of the electrode material during mixing to control rate of evaporation of the electrolyte therefrom.
27. The method of claim 26 , wherein the quantity of the active material is about 20% to about 75% by volume of the stable suspension, the quantity of the conductive additive is about 0.5% to about 25% by volume of the stable suspension, and the quantity of the electrolyte is about 25% to about 70% by volume of the stable suspension.
28. The method of claim 27 , wherein the mixing supplies a specific mixing energy of about 90 J/g to about 150 J/g to the electrode material.
29. The method of claim 26 , wherein the mixing supplies a specific mixing energy of at least about 90 J/g to the electrode material.
30. The method of claim 29 , wherein the mixing supplies a specific mixing energy of at least about 100 J/g to the electrode material.
31. The method of claim 30 , wherein the mixing supplies a specific mixing energy of about 100 J/g to about 120 J/g to the electrode material.
32. A method of preparing a semi-solid electrode, the method comprising:
combining an active material, an electrolyte, and a conductive additive in a vessel of a mixer;
mixing the active material, the electrolyte, and the conductive additive in the mixer to form an electrode material suspension having a mixing index of at least about 0.80; and
forming the electrode material into a semi-solid electrode,
wherein the mixing imparts a specific mixing energy to the active material, the electrolyte, and the conductive additive so as to control evaporation of the electrolyte therefrom.
33. The method of claim 32 , wherein the vessel of the mixer is cooled to a temperature of lower than 10 degrees Celsius during mixing.
34. The method of claim 32 , wherein the mixer is a high shear mixer.
35. The method of claim 32 , wherein the mixer is a planetary mixer.
36. The method of claim 32 , wherein the mixer is a centrifugal planetary mixer.
37. The method of claim 32 , wherein the mixer is a sigma mixer.
38. The method of claim 32 , wherein the mixer is a CAM mixer.
39. The method of claim 32 , wherein the mixer is a roller mixer.