Structured silicon particles

Patent metadata

Field	Value
Publication number	US-10103379-B2
Application number	US-201314371822-A
Country	US
Kind code	B2
Filing date	Feb 28, 2013
Priority date	Feb 28, 2012
Publication date	Oct 16, 2018
Grant date	Oct 16, 2018

Abstract

A composite particle is provided. The particle comprises a first particle component and a second particle component in which: (a) the first particle component comprises a body portion and a surface portion, the surface portion comprising one or more structural features and one or more voids, whereby the surface portion and body portion define together a structured particle; and (b) the second component comprises a removable filler; characterized in that (i) one or both of the body portion and the surface portion comprise an active material; and (ii) the filler is contained within one or more voids comprised within the surface portion of the first component. The use of the particle in applications such as electrochemical cells, metal-ion batteries such as secondary battery applications, lithium air batteries, flow cell batteries, fuel cells, solar cells, filters, sensors, electrical and thermal capacitors, micro-fluidic devices, gas or vapor sensors, thermal or dielectric insulating devices, devices for controlling or modifying the transmission, absorption or reflectance of light or other forms of electromagnetic radiation, chromatography or wound dressings is disclosed.

First claim

The invention claimed is:

1. A composite particle comprising a first particle component and a second particle component in which:
(a) the first particle component comprises a body portion and a surface portion, the surface portion comprising one or more structural features and one or more voids, wherein the one or more structural features and the one or more voids extend between the body portion and a particle boundary of the composite particle, whereby the surface portion and body portion define together a structured porous or pillared particle; and
(b) the second particle component consists of a removable filler that is removable from the composite particle during processing;
characterised in that (i) the one or more structural features of the surface portion comprise an electroactive material comprising a member selected from the group consisting of silicon, tin, germanium, gallium, lead, zinc and aluminium; (ii) the filler is contained around the one or more structural features and within the one or more voids comprised within the surface portion of the first particle component; and (iii) the filler has a sublimation or disintegration temperature of at least 50° C. and/or is soluble in an ionic liquid or an electrolyte solution.

2. The composite particle according to claim 1 , wherein the filler is soluble in an electrolyte solution having a salt concentration of at least 0.7 M.

3. The composite particle according to claim 1 , wherein the filler is soluble in a solution comprising a member selected from the group consisting of N-methylpyrrolidone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, gamma butyro lactone, 1,2-dimethoxy ethane, 2-methyl tetrahydrofuran, dimethyl sulphoxide, 1,3-dioxolane, formamide, dimethylformamide, acetonitrile, nitromethane, methylformate, methyl acetate, phosphoric acid trimester, trimethoxy methane, sulpholane, methyl sulpholane and 1,3-dimethyl-2-imidazolidione.

4. The composite particle according to claim 1 , wherein the filler sublimes or degrades at a temperature in the range 70 to 200° C.

5. The composite particle according to claim 1 , wherein the removable filler comprises a member selected from the group consisting of o- and p-cresol, 3-nonanol, 1-methyl cyclohexanol, p-toluenenitrile, 2-methoxyphenol, 2-phenol-2-propanol, 2,3-dimethylanisole, phenol, 2,4-diemthylphenol, 3,4,4-trimethylpentanol, butanediol, oxalic acid, a surfactant and a natural wax or a synthetic wax selected from the group comprising 12-hydroxystearic acid, low molecular weight polyethylene, petroleum waxes such as paraffin wax, and microcrystalline waxes.

6. The composite particle according to claim 1 , wherein the first particle component is selected from a pillared particle, a porous particle having voids distributed there through, a porous particle fragment or a fractal, or a scaffold structure.

7. The composite particle according to claim 6 , wherein the first particle component is the pillared particle and wherein the surface portion comprises one or more pillars distributed over a body portion.

8. The composite particle according to claim 6 , wherein the first particle component is the pillared particle and wherein the voids of the surface portion comprise channels extending from the body portion to the particle boundary.

9. The composite particle according to claim 6 , wherein the first particle component is the porous particle having voids distributed there through and wherein the porous particle is a fibre, wire, thread, tube, flake, or ribbon with a minor dimension of at least 10 nm.

10. The composite particle according to claim 6 , wherein the first particle component is the porous particle having voids distributed there through and further comprising voids distributed at the surface of the particle.

11. The composite particle according to claim 1 , wherein the particle has a principal diameter in the range 0.5 to 10 μm.

12. The composite particle according to claim 1 , wherein the body portion and the surface portion are formed integrally and the active material comprising the body portion is the same as or is similar to the active material of the surface portion.

13. The composite particle according to claim 1 , wherein the active material of the body portion is different to the active material of the surface portion.

14. The composite particle according to claim 1 , wherein the active material is an electroactive material.

15. The composite particle according to claim 1 , wherein the electroactive material is silicon, a silicon alloy or an electroactive silicon compound.

16. A method of forming a composite particle according to claim 1 , the method comprising steps of mixing the first particle component with the filler in liquid form.

17. The method according to claim 16 , wherein the filler is provided in a solution comprising a solvent and wherein the solvent is removed by evaporation.

18. A composite material comprising:
a composite particle, the composite particle comprising a first particle component and a second particle component in which:
(a) the first particle component comprises a body portion and a surface portion, the surface portion comprising one or more structural features and one or more voids, wherein the one or more structural features and the one or more voids extend between the body portion and a particle boundary of the composite particle, whereby the surface portion and body portion define together a structured particle; and
(b) the second particle component comprises a removable filler;
characterised in that (i) the one or more structural features of the surface portion comprise an electroactive material comprising a member selected from the group consisting of silicon, tin, germanium, gallium, lead, zinc and aluminium; (ii) the filler is contained around the one or more structural features within one or more voids comprised within the surface portion of the first particle component; and (iii) the filler has a sublimation or disintegration temperature of at least 50° C. and/or is soluble in an ionic liquid or an electrolyte solution;
and a binder; and optionally further comprising one or more components selected from an electroactive carbon, a conductive carbon and an electroactive component.

19. A composition comprising:
a stable suspension of a composite particle, the composite particle comprising a first particle component and a second particle component in which:
(a) the first particle component comprises a body portion and a surface portion, the surface portion comprising one or more structural features and one or more voids, wherein the one or more structural features and the one or more voids extend between the body portion and a particle boundary of the composite particle, whereby the surface portion and body portion define together a structured particle; and
(b) the second particle component comprises a removable filler;
characterised in that (i) the one or more structural features of the surface portion comprise an electroactive material comprising a member selected from the group consisting of silicon, tin, germanium, gallium, lead, zinc, and aluminium; (ii) the filler is contained around the one or more structural features within one or more voids comprised within the surface portion of the first particle component; and (iii) the filler has a sublimation or disintegration temperature of at least 50° C. and/or is soluble in an ionic liquid or an electrolyte solution; and
wherein the stable suspension is in a liquid carrier; an

Assignees

• Nexeon Ltd

Inventors

• Macklin William James
• Scott Fiona
• Friend Christopher Michael

Classifications

• H01M4/136

  Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy · CPC title

• H01M4/362 Primary

  Composites · CPC title

• H01M4/386

  Silicon or alloys based on silicon · CPC title

• H01M4/134

  Electrodes based on metals, Si or alloys · CPC title

• C01P2002/84

  by UV- or VIS- data · CPC title