Method for producing a homogenous particulate material composition

Abstract

A method is provided for producing a homogenous particulate material composition, including at least one particulate material M, at least one additive Z, and at least one binding agent B, the method including providing at least one particulate material M, at least one additive Z, and at least one binding agent B; producing a homogenous mixture G1 from the at least one particulate material M and the at least one additive Z in a gravity mixer; producing a mixture G2 from the mixture G1 and the at least one binding agent B, with the introduction of shear forces; and removing dispersed gases from the mixture G2.

Claims

1. A method for producing a homogenous particulate material composition, including at least one particulate material M, at least one additive Z, and at least one binding agent B, the method comprising: a) providing at least one particulate material M, at least one additive Z, and at least one binding agent B; b) producing a homogenous mixture G1 from the at least one particulate material M and the at least one additive Z in a gravity mixer; c) producing a mixture G2 from the mixture G1 and the at least one binding agent B, with the introduction of shear forces; and d) removing dispersed gases from the mixture G2.

2. The method as recited in claim 1, wherein the mixture G2 includes a fibrillated binding agent B.

3. The method as recited in claim 1, wherein a jet mill is used to produce the mixture G2 in order to introduce shear forces necessary for the fibrillation of the binding agent B into the mixture.

4. The method as recited in claim 1, wherein the dispersed gases is removed from the mixture G2 in step d) under reduced pressure, in particular in a downdraft vaporizer.

5. The method as recited in claim 1, wherein the particulate material M is mixed, in method step b), with only a portion of the additive Z, a quantity of the additive Z being selected such that the additive Z occupies at most 50% of the surface of the particulate material M.

6. The method as recited in claim 5, wherein a remaining portion of the additive Z is first being mixed, in a further method step b), with at least the binding agent B to form a mixture G3 that subsequently replaces the pure binding agent B in the step c).

7. The method as recited in claim 1, wherein the particulate material composition is used in an electrode active material.

8. The method as recited in claim 1, wherein the particulate material composition is used in an electrode active material, and wherein the electrode active material is used in a free-standing electrode active material foil.

9. The method as recited in claim 8, wherein the free-standing electrode active material foil is used to produce an electrode for an electrochemical energy storage system, an electrolyzer, or a fuel cell.

Description

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

(1) A composition made up of 90 wt % LiMn2O4 particles (average particle size: 10 m), 5 wt % carbon nanotubes, and 5 wt % PVDF particles (average particle size: 50 m), relative to the overall weight of the composition, is produced. For this purpose, the components are first weighed separately from one another.

(2) Half of the carbon nanotubes (i.e., 2.5 wt %, relative to the overall weight of the composition) is briefly mixed, in a gravity mixer, with all of the LiMn.sub.2O.sub.4 particles (90 wt %, relative to the overall weight of the composition), in order in this way to form a mixture G1. The mixing duration is less than 10 minutes.

(3) Parallel thereto, or at a different time, the remaining portion of the carbon nanotubes (i.e. 2.5 wt %, relative to the overall weight of the composition) is mixed with half the PVDF particles (i.e., 2.5 wt %, relative to the overall weight of the composition), also in a gravity mixer, in order in this way to form a mixture G3. The mixing duration is less than 10 minutes.

(4) Subsequently, the obtained mixture G1, the obtained mixture G3, and the remaining PVDF particles (i.e. 2.5 wt % relative to the overall weight of the composition) are mixed in a jet mill, with input of a high degree of kinetic energy, over a time period of less than 20 minutes, preferably less than 15 minutes, in particular less than 10 minutes, e.g. 5 minutes. A pastelike mixture G2 is obtained.

(5) Mixture G2 is now freed of dispersed gas at reduced pressure, e.g. 0.5 bar. Subsequently, the material composition obtained in this way can be processed, using a calendar, to form a free-standing electrode active material foil. This foil can be cut to the desired size. The foils obtained in this way are placed on at least one surface of a current collector, and are compressed and applied using rollers. Preferably, free-standing electrode material foils are applied on at least two surfaces of the current collector. This step can also take place at high temperature, e.g. >100 C., in particular >150 C. The electrode produced in this way is combined, together with a second electrode and a separator situated between the electrodes, in a suitable housing made of metal (e.g. aluminum) or plastic, to form a cell, the electrodes each being connected to terminals via which a flow of current can take place. The housing is filled with electrolyte, so that the electrolytes surrounds and penetrates the electrodes and the separator. The cells produced in this way can be connected to one another in series or in parallel. Depending on the choice of the second electrode, in this way a lithium-ion battery or a hybrid supercapacitor can be provided as an electrochemical energy storage system.

(6) The present invention is not limited to the exemplary embodiments described here and the aspects emphasized therein. Rather, in accordance with the present invention, a large number of modifications are possible that are within the competence of those skilled in the art.