Electrodes for Metal-Ion Batteries

Patent metadata

Field	Value
Publication number	US-2016308205-A1
Application number	US-201415101209-A
Country	US
Kind code	A1
Filing date	Dec 3, 2014
Priority date	Dec 3, 2013
Publication date	Oct 20, 2016
Grant date	—

Abstract

A method is provided for the manufacture of an electrode for a metal-ion battery. The method comprises sintering porous silicon-containing particles at a temperature of 500 to 1200° C. and in an oxygen-free atmosphere to obtain particles of reduced BET surface area which are suitable for use as the active material of a metal ion battery when disposed onto a current collector.

First claim

1 . A method for the manufacture of an electrode for a metal-ion battery, the method comprising:
(i) sintering porous silicon-containing particles at a temperature of 500 to 1200° C. and in an oxygen-free atmosphere; and (ii) disposing the sintered silicon-containing particles from step (i) onto a current collector.

2 . A method according to claim 1 , wherein the porous silicon-containing particles are mesoporous or microporous silicon-containing particles.

3 . A method according to claim 2 , wherein the porous silicon-containing particles are mesoporous silicon-containing particles containing pores having a diameter of 30 nm or less, more preferably 20 nm or less, more preferably 10 nm or less.

4 . A method according to any one of the preceding claims, wherein the porous silicon-containing particles preferably have a BET surface area in the range of from 10 to 500 m 2 /g, preferably from 20 to 400 m 2 /g, or from 30 to 300 m 2 /g.

5 . A method according to any one of the preceding claims, wherein at least 50%, preferably at least 70% and more preferably at least 90% of the porous silicon-containing particles have a major particle dimension in the range of from 500 nm to 50 μm.

6 . A method according to any one of the preceding claims, wherein the porous silicon-containing particles have a mass median diameter (D 50 ) in the range of from 500 nm to 50 μm, more preferably in the range of from 1 to 30 μm.

7 . A method according to any one of the preceding claims, wherein the porous silicon-containing particles have a porosity in the range of from 20 to 80%, preferably from 30 to 70%, and more preferably from 30 to 60%.

8 . A method according to any one of the preceding claims, wherein the porous silicon-containing particles comprise or consist of microcrystalline or nanocrystalline silicon.

9 . A method according to any one of the preceding claims, wherein the porous silicon-containing particles comprise at least 80% silicon by weight, for example at least 85% silicon by weight, at least 90% silicon by weight, at least 95% silicon by weight, at least 98% silicon by weight or at least 99% silicon by weight. cm 10 . A method according to any one of the preceding claims, wherein the porous silicon-containing particles comprise no more than 5% by weight, preferably no more than 2% by weight, more preferably no more than 1% by weight, and most preferably no more than 0.5% by weight each of carbon and oxygen.

11 . A method according to claim 1 , comprising comprising:
(ia) reducing silica-containing particles to provide porous silicon-containing particles; (ib) sintering the porous silicon-containing particles from step (ia) at a temperature of 500 to 1200° C. and in an oxygen-free atmosphere; and (ii) disposing the sintered silicon-containing particles from step (ib) onto a current collector.

12 . A method according to claim 11 , wherein the porous silicon-containing particles are as defined in any one of claims 2 to 10 .

13 . A method according to claim 11 or claim 12 , wherein the silica-containing particles are reduced in step (ia) in the presence of magnesium or calcium, preferably magnesium.

14 . A method according to any one of claims 11 to 13 , wherein the silica-containing particles in step (ia) comprise elongate silica-containing particles, preferably having an aspect ratio of at least 3:1, more preferably having an aspect ratio of at least 5:1.

15 . A method according to any one of claims 11 to 14 , wherein the smallest dimension of the silica-containing particles in step (ia) is less than 15 μm, for example less than 10 pm, less than 3 μm, less than 2 μm, or less than 1 μm.

16 . A method according to any one of claims 11 to 15 , wherein the silica-containing particles in step (ia) have a major particle dimension in the range of from 2 to 50 μm, preferably in the range of from 5 to 30 μm.

17 . A method according to any one of claims 11 to 16 , wherein the silica-containing particles comprise or consist of amorphous silica.

18 . A method according to any one of claims 11 to 17 , wherein step (ia) comprises reducing substantially all of the silica in the silica-containing particles to silicon.

19 . A method according to any one of claims 11 to 17 , wherein step (ia) comprises reducing silica at a surface of the silica-containing particles is reduced and wherein silica at the core of the silica-containing particles is not reduced.

20 . A method according any one of claims 11 to 19 , wherein residual silica in the porous silicon-containing particles from step (ia) is removed by treatment with HF or an aqueous metal hydroxide.

21 . A method according any one of claims 11 to 20 , wherein step (ia) is conducted at a reaction temperature of no more than 750° C., preferably no more than 650° C.

22 . A method according any one of claims 11 to 21 , wherein step (ia) is conducted at a reaction temperature of at least 450° C.

23 . A method according any one of claims 11 to 22 , wherein the BET surface area of the porous silicon-containing particles from step (ia) is in the range of from 10 to 500 m 2 /g, preferably from 20 to 400 m 2 /g, or from 30 to 300 m 2 /g.

24 . A method according to any one of the preceding claims, wherein step (i) or (ib) is carried out in an inert atmosphere or in a reducing atmosphere.

25 . A method according to any one of the preceding claims, wherein the porous silicon-containing particles are pre-treated with hydrogen fluoride so as to remove a native oxide layer from the silicon surface prior to step (i) or (ib).

26 . A method according to any one of the preceding claims, wherein step (i) or (ib) is carried out at a temperature of from 600 to 1100° C., more preferably from 800 to 1100° C., more preferably from 850 to 1050° C. and most preferably from 900 to 1000° C.

27 . A method according to any one of the preceding claims, wherein step (i) or (ib) is carried out for a duration in the range of from 5 minutes to 24 hours, for example from 10 minutes to 4 hours.

28 . A method according to any one of the preceding claims, wherein the sintered silicon-containing particles from step (i) or (ib) have a BET surface area of less than 50 m 2 /g, preferably less than 40 m 2 /g, more preferably less than 30 m 2 /g, more preferably less than 20 m 2 /g, and most preferably less than 10 m 2 /g.

29 . A method according to any one of the preceding claims, wherein the sintered silicon-containing particles from step (i) or (ib) have a BET surface area of at least 0.1 m 2 /g, preferably at least 0.2 m 2 /g, at least 0.5 m 2 /g or at least 1.0 m 2 /g.

30 . A method according to any one of the preceding claims, wherein the sintering of the porous silicon-containing particles in step (i) or (ib) reduces the BET surface area of the porous silicon-containing particles by at least 10%, preferably at least 20%, more preferably at least 30%, more preferably at least 40% and most preferably at least 50%.

31 . A method according to any one of the preceding claims, wherein the BJH average pore size of the sintered silicon-containing particles is at least 40 nm.

32 . A method according to any one of the preceding claims, wherein wherein at least 50%, preferably at least 70% and more preferably at least 90% of the sintered silicon-containing particles have a

Assignees

• Nexeon Ltd

Inventors

• Canham Leigh
• Friend Christopher Michael

Classifications

• H01M4/0404

  by coating on electrode collectors · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• H01M4/0471 Primary

  involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis · CPC title

• H01M4/485

  of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy (H01M4/505, H01M4/525 take precedence) · CPC title

• H01M4/623

  fluorinated polymers · CPC title