Electroactive material

Patent metadata

Field	Value
Publication number	US-9647263-B2
Application number	US-201113820234-A
Country	US
Kind code	B2
Filing date	Sep 2, 2011
Priority date	Sep 3, 2010
Publication date	May 9, 2017
Grant date	May 9, 2017

Abstract

A composition for use in a lithium ion battery includes a plurality of elongate elements and a plurality of particles. The elongate elements and particles each include a metal or semi-metal selected from one or more of the group including silicon, tin, germanium, aluminum or mixtures thereof. The composition may include additional ingredients such as a binder, a conductive material and a further electro-active material, such as graphite. The compositions can be used for the fabrication of electrodes, preferably anodes in the manufacture of lithium ion batteries and optionally batteries based on magnesium ions or sodium ions. The composition is able to intercalate and release lithium during the charging and discharging cycles respectively of a battery into which it has been incorporated. Methods of fabricating the composition and electrodes including the composition are included as well as electrodes thus prepared and devices including such electrodes.

First claim

The invention claimed is:

1. A composition comprising a plurality of electroactive elongate elements and a plurality of electroactive particles, the elongate elements and particles each comprising a metal or semi-metal selected from one or more of the group consisting of silicon, tin, and germanium or mixtures thereof, characterized in that
a. the elongate elements are selected from one or more of the group consisting of fibers, tubes, ribbons and flakes and
b. the particles are selected from one or more of the group consisting of pillared particles, porous particles and porous particle fragments; and

wherein the composition has a density in the range 0.3 g/cm 3 to 0.9 g/cm 3 and wherein the diameter of said plurality of particles is between the diameter of the elongate elements and three times the diameter of the elongate elements.

2. A composition comprising a plurality of electroactive elongate elements and a plurality of electroactive particles, the elongate elements and particles each comprising a metal or semi-metal selected from one or more of the group consisting of silicon, tin and germanium or mixtures thereof, characterized in that
a. the elongate elements comprise pillars which extend outward from a particle core; and
b. the particles are selected from one or more of the group consisting of porous particles, porous particle fragments and particles with an average diameter of 80 nm to 15 μm; wherein the composition has a density in the range 0.3 g/cm 3 to 0.9 g/cm 3 and

wherein the diameter of said plurality of particles is between the diameter of the elongate elements and three times the diameter of the elongate elements.

3. The composition according to claim 1 , wherein the particles are selected from one or more of:
a. porous particles comprising a random or ordered network of linear, branched or layered elongate elements having one or more discrete or interconnected void spaces or channels defined there between;
b. pillared particles have an overall diameter in the range 20 to 30 μm;
c. pillared particles having a principle diameter in the range 5 to 15 μm;
d. pillared particles having a principle diameter in the range 15 to 25 μm;
e. pillared particles having a principle diameter in the range 25 to 35 μm, and
f. pillared particles have a pillar length of up to 10 μm.

4. The composition according to claim 1 , wherein the elongate elements are selected from one or more of:
a. elongate elements having a diameter of at least 50 nm;
b. fibres having a diameter in the range 100 to 500 nm;
c. ribbons having a thickness in the range 0.08 μm to 1 μm, a width in the range 240 nm to 300 nm, a length in the range 0.8 μm to 20 μm and an aspect ratio in the range 10:1 to 200:1;
d. flakes having a thickness in the range 80 nm to 100 nm, a width in the range 0.8 μm to 10 μm, a length in the range 0.8 μm to 20 μm and an aspect ratio in the range 10:1 to 200:1; and
e. tubes having a wall thickness in the range 0.08 μm to 2 μm, an outer wall diameter of between 2.5 and 100 times larger than the wall thickness and a length of between 10 and 500 times as large as the wall thickness.

5. The composition according to claim 1 , wherein:
a. the volume of the elongate elements is more than that of the particles; and
b. the diameter of the particle is less than twice the length of the elongate element.

6. The composition according to claim 1 , wherein the metal or semi-metal is a silicon comprising material selected from substantially pure silicon, silicon alloy and a material selected from silicon oxide, silicon nitride and silicon boride or mixtures thereof wherein optionally at least some of the elongate elements or particles comprise silicon with a purity in the range 90% to 99.95%.

7. The composition according to claim 1 , which comprises 50 to 90% by weight of an electroactive material.

8. The composition according to claim 1 , wherein the electroactive material comprises 40 to 100% by weight silicon comprising elongate elements, silicon comprising particles and further silicon comprising components.

9. A method of manufacturing the composition according to claim 2 , comprising the steps of mixing
a. a plurality of metal or semi-metal comprising electroactive elongate elements comprising pillars which extend outward from a particle core; with
b. a plurality of metal or semi-metal comprising electroactive particles selected from one or more of the group consisting of porous particles, porous particle fragments and particles with an average diameter of 80 nm to 15 μm.

10. An electrode comprising a current collector and the composition according to claim 1 .

11. A battery comprising a cathode, an anode comprising the composition according to claim 1 and an electrolyte.

12. A device employing a battery according to claim 11 .

13. The composition of claim 7 , additionally comprising one or more components selected from a binder, a conductive material.

14. The composition of claim 7 , additionally comprising a non-silicon comprising electroactive material.

15. The method of claim 9 additionally comprising the step of combining the elongate elements and particles according to paragraphs (a) and (b) with a binder or with one or more components selected from the group consisting of a conductive material, a viscosity adjuster, a filler, a cross-linking accelerator, a coupling agent and an adhesive accelerator.

16. The method of claim 9 additionally comprising the step of combining the elongate elements and particles according to paragraphs (a) and (b) with a binder or with one or more components selected from the group consisting of a conductive material, a viscosity adjuster, a filler, a cross-linking accelerator, a coupling agent and an adhesive accelerator.

17. The method of claim 9 wherein the particles according to paragraphs (a) and (b) comprise silicon.

18. The method of claim 9 wherein the particles according to paragraphs (a) and (b) comprise silicon.

19. The composition of claim 1 , additionally comprising a binder, wherein said composition is a homogeneous composite electrode material.

20. The composition according to claim 1 wherein a volume ratio of the electroactive particles to the electroactive elongate elements is in the range 2:1 to 0.5:1.

21. The composition according to claim 20 wherein the volume ratio is between the electroactive particles and electroactive elongate elements comprising fibres.

22. Use of the composition according to claim 19 , in the manufacture of a secondary battery, wherein said manufacture comprises the steps of:
applying said homogeneous composite electrode material as a coating to a substrate or a current collector to form a composite electrode layer; and
using said composite electrode layer as an anode in a secondary battery.

Assignees

• Green Mino
• Nexeon Ltd

Inventors

• Green Mino

Classifications

• H01M4/134 Primary

  Electrodes based on metals, Si or alloys · CPC title

• Y02E60/122

  Cross-Sectional Technologies · mapped topic

• H01M4/1395

  of electrodes based on metals, Si or alloys · CPC title

• H01M4/0404

  by coating on electrode collectors · CPC title

• H01M4/623

  fluorinated polymers · CPC title