Additive for lithium ion rechageable battery cells

Patent metadata

Field	Value
Publication number	US-8945774-B2
Application number	US-201113265464-A
Country	US
Kind code	B2
Filing date	Jun 7, 2011
Priority date	Jun 7, 2010
Publication date	Feb 3, 2015
Grant date	Feb 3, 2015

Abstract

The present invention claims the addition of vinylene carbonate (VC) and optionally also fluoroethylene carbonate to the electrolyte of lithium ion cells having a structural silicon composite anode, i.e. an anode containing fibers or particles of silicon. The additive significantly improves the cycling performance of the cells. A VC content in the range 3.5-8 wt % based on the weight of the electrolyte has been found to be optimum.

First claim

The invention claimed is:

1. A lithium ion rechargeable battery cell comprising:
a porous anode comprising structured electroactive material-containing particles that are structured to provide space between or within the particles for the expansion of the electroactive material during lithiation;
a cathode comprising an active material capable of incorporating lithium and also of liberating lithium electrochemically; and
an electrolyte;

wherein the electrolyte comprises both a cyclic carbonate including a vinyl group and a fluorinated cyclic carbonate, wherein the total amount of the cyclic carbonate including a vinyl group and the fluorinated cyclic carbonate together is in the range 3.5 wt % to 70 wt % based on the total weight of the electrolyte solution.

2. A lithium ion rechargeable battery cell according to claim 1 , where the structured electroactive material-containing particles comprise one or more of Si, Sn, Ge, and Ga.

3. A lithium ion rechargeable battery cell as claimed in claim 1 wherein the structured electroactive material-containing particles are fibres selected from the group comprising tin-containing fibres, germanium-containing fibres, gallium containing fibres and silicon-containing fibres with a diameter of 10-500 nm and length of 1-150 μm, such fibres optionally being provided in the form of a scaffold or felt comprising such fibres.

4. A lithium ion rechargeable battery cell as claimed in claim 1 , wherein the structured electroactive material-containing particles are fibres selected from the group comprising tin-containing fibres, gallium containing fibres and silicon-containing fibres with a diameter of 50-250 nm and length of 1-80 μm, such fibres optionally being provided in the form of a scaffold or felt comprising such fibres.

5. A lithium ion rechargeable battery cell as claimed in claim 1 , wherein the structured electroactive material-containing particles are tubes selected from the group comprising tin-containing tubes, germanium-containing tubes, gallium containing tubes and silicon-containing tubes with a wall thickness of ≧10 nm and length of ≧1 μm.

6. A lithium ion rechargeable battery cell as claimed in claim 1 , wherein the structured electroactive material-containing particles are ribbons selected from the group comprising tin-containing ribbons, gallium containing ribbons and silicon-containing ribbons with a thickness of 50-200 nm, a width of 500 nm to 1 μm and a length of ≧1 μm or felts comprising such ribbons.

7. A lithium ion rechargeable battery cell as claimed in claim 1 , wherein the structured electroactive material-containing particles are flakes selected from the group comprising tin containing flakes, gallium containing flakes and silicon-containing flakes with a thickness of 50-200 nm and the two other dimensions in the range of 1-20 μm.

8. A lithium ion rechargeable battery cell as claimed in claim 1 , wherein the structured electroactive material-containing particles are silicon-containing pillared particles consisting of a silicon-based particle core of diameter 5-25 μm with an array of silicon pillars attached thereto, the pillars having diameter of no more than 1000 nm and a length of 1-5 μm.

9. A lithium ion rechargeable battery cell as claimed in claim 1 , wherein the structured electroactive material-containing particles are silicon-containing porous particles, each particle having a network of voids or pores extending therethrough.

10. A lithium ion rechargeable battery cell as claimed in claim 9 wherein at least some of the walls between adjacent pores have a thickness of ≧10 nm and extend over a length of ≧100 nm, and wherein the diameter of the porous particle is 1-30 μm.

11. A lithium ion rechargeable battery cell as claimed in claim 1 , wherein the structured electroactive material-containing particles are carbon coated.

12. A lithium ion rechargeable battery cell as claimed in claim 1 , wherein the electroactive material-containing particles comprise silicon with a purity of 90-99.990% by weight.

13. A lithium ion rechargeable battery cell as claimed in claim 1 , wherein substantially all the active material in the anode comprises silicon.

14. A lithium ion rechargeable battery cell according to claim 1 , wherein the electrolyte comprises 1-8 wt % of a cyclic carbonate including a vinyl group based on the total weight of the electrolyte.

15. A lithium ion rechargeable battery cell according to claim 14 , wherein the electrolyte comprises at least 3 wt % of a fluorinated cyclic carbonate based on the total weight of the electrolyte.

16. A lithium ion rechargeable battery cell according to claim 1 , wherein the electrolyte comprises at least 2%, 3%, 5%, 10% or 15% by weight of a cyclic carbonate including a vinyl group.

17. A lithium ion rechargeable battery cell according to claim 1 , wherein the electrolyte comprises 3.5 to 8% by weight of a cyclic carbonate including a vinyl group.

18. A lithium ion rechargeable battery cell according to claim 1 , wherein the electrolyte comprises at least 10% by weight of a fluorinated cyclic carbonate.

19. A lithium ion rechargeable battery cell according to claim 1 , wherein the electrolyte comprises at least 15% by weight of a fluorinated cyclic carbonate.

20. A lithium ion rechargeable battery cell according to claim 1 , wherein the electrolyte comprises at least 30% by weight of a fluorinated cyclic carbonate.

21. A lithium ion rechargeable battery cell according to claim 1 , wherein the electrolyte comprises no more than 50% by weight of a fluorinated cyclic carbonate.

22. A lithium ion rechargeable battery cell according to claim 1 , wherein the cyclic carbonate including a vinyl group is vinylene carbonate.

23. A lithium ion rechargeable battery cell according to claim 1 , wherein the fluorinated cyclic carbonate is fluoroethylene carbonate, difluoroethylene carbonate or a mixture thereof.

24. A lithium ion rechargeable battery cell as claimed in claim 1 , wherein the electrolyte initially includes 0.05 to 0.25 wt % dissolved CO 2 .

25. A lithium ion rechargeable battery cell according to claim 1 , wherein the electrolyte includes a cyclic carbonate including a vinyl group, a fluorinated cyclic carbonate and dissolved CO 2 .

26. A lithium ion rechargeable battery cell according to claim 1 wherein the cyclic carbonate including a vinyl group is vinylene carbonate and the fluorinated cyclic carbonate is fluoroethylene carbonate, difluoroethylene carbonate or a mixture thereof.

27. A lithium ion rechargeable battery cell according to claim 1 , wherein the electrolyte solution further comprises a C 1-8 chain carbonate.

28. A lithium ion rechargeable battery cell according to claim 27 , wherein the C 1-8 chain carbonate is selected from one or more of dimethylcarbonate, diethyl carbonate, and ethyl methyl carbonate.

29. A lithium ion rechargeable battery cell according to claim 27 , wherein the ratio of the cyclic carbonate (including a cyclic carbonate including a vinyl group and/or a fluorinated cyclic carbonate) to the C 1-8 chain carbonate is in the range 30:70 to 50:50.

30. A lithium ion rechargeable battery cell according to claim 1 , wherein the electrolyte solution further comprises a cyclic carbonate other than a cyclic carbonate including a vinyl group or a fluorinated cyclic carbonate.

Assignees

• Coowar Fazlil
• Abdelsalam Mamdouh Elsayed
• Lain Michael Jonathan
• Nexeon Ltd

Inventors

• Coowar Fazlil
• Abdelsalam Mamdouh Elsayed
• Lain Michael Jonathan

Classifications

• H01M10/44

  Methods for charging or discharging (circuits for charging H02J7/00) · CPC title

• H01M10/0566

  Liquid materials · CPC title

• H01M10/0568

  characterised by the solutes · CPC title

• H01M4/387

  Tin or alloys based on tin · CPC title

• H01M10/0567

  characterised by the additives · CPC title