Additive for positive electrode material, positive electrode material and lithium-ion battery comprising the same, and method thereof

Patent metadata

Field	Value
Publication number	US-2017133684-A1
Application number	US-201515129987-A
Country	US
Kind code	A1
Filing date	Apr 28, 2015
Priority date	Apr 28, 2014
Publication date	May 11, 2017
Grant date	—

Abstract

An additive for a positive electrode material includes an internal component and an external component. The internal component contains a silane coupling agent modified inorganic lithium salt. The external component is formed on a surface of the internal component and contains a polymer with a low melting point. The internal component and the external component form a core-shell structure together, and the shell has a porosity of 0.01% to 20%. A positive electrode material and a lithium-ion battery including the additive, and method of preparing the lithium-ion battery are also provided.

First claim

1 . An additive for a positive electrode material, comprising:
an internal component comprising a silane coupling agent modified inorganic lithium salt; an external component formed on a surface of the internal component and comprising a polymer, the internal component and the external component forming a core-shell structure together, and the shell having a porosity of 0.01% to 20%.

2 . The additive according to claim 1 , wherein the silane coupling agent modified inorganic lithium salt comprises an inorganic lithium salt and a silane coupling agent to modify the inorganic lithium salt.

3 . The additive according to claim 1 , wherein the internal component has an average particle diameter of 30 nm to 25 μm.

4 . The additive according to claim 1 , wherein the shell has a thickness of 5 nm to 5 μm.

5 . The additive according to claim 1 , wherein the additive has an average particle diameter of 50 nm to 26 μm.

6 . The additive according to claim 1 , wherein the polymer has a melting point of 60° C. to 140° C.

7 . The additive according to claim 1 , wherein the polymer has an average molecular weight of 50 to 10000.

8 . The additive according to claim 1 , wherein the polymer comprises low-density polyethylene.

9 . The additive according to claim 8 , wherein the low-density polyethylene has an average molecular weight of 200 to 10000.

10 . The additive according to claim 9 , wherein the low-density polyethylene has an average molecular weight of 500 to 6000.

11 . The additive according to claim 2 , wherein the silane coupling agent modified inorganic lithium salt is at least one selected from the group consisting of:
LiFe x Mn y M z PO 4 , where 0≦x≦1, 0≦y≦1, 0≦z≦1, x+y+z=1, and M is at least one selected from the group consisting of Al, Mg, Ga, Ti, Cr, Cu, Zn and Mo; Li 3 V 2 (PO 4 ) 3 ; LiNi 0.5-x Mn 1.5-y M x+y O 4 , where −0.1≦x≦0.5, 0≦y≦1.5, and M is at least one selected from the group consisting of Li, Co, Fe, Al, Mg, Ca, Ti, Mo, Cr, Cu and Zn; LiVPO 4 F; Li 1+x L 1-y-z M y N z O 2 , where L, M, N are independently selected from the group consisting of Li, Co, Mn, Ni, Fe, Al, Mg, Ga, Ti, Cr, Cu, Zn, Mo, F, I, S and B, −0.1≦x≦0.2, 0≦y≦1, 0≦z≦1, 0≦y+z≦1.0; Li 2 CuO 2 ; and Li 5 FeO 4 .

12 . The additive according to claim 1 , wherein based on the total weight of the additive, the amount of the polymer is 0.01 wt % to 40 wt %, and the amount of the silane coupling agent modified inorganic lithium salt is 60 wt % to 99.98 wt %.

13 . A method of preparing an additive for a positive electrode material, comprising the steps of:
providing an internal component comprising a silane coupling agent modified inorganic lithium salt; and mixing the silane coupling agent modified inorganic lithium salt, a polymer and a volatile organic solvent together to form a system, and heating the system until the organic solvent volatilizes completely to form an external component, such that the external component is formed on a surface of the internal component, the internal component and the external component form a core-shell structure together, and the shell has a porosity of 0.01% to 20%.

14 . The method according to claim 13 , wherein the step of providing an internal component comprises modifying an inorganic lithium salt with a silane coupling agent to obtain the silane coupling agent modified inorganic lithium salt.

15 . The method according to claim 13 , further comprising drying the core-shell structure.

16 . The method according to claim 14 , wherein in the step of providing an internal component, the ratio between the inorganic lithium salt and the silane coupling agent is 100:0.01 to 100:15.

17 . The method according to claim 13 , wherein in the step of mixing, a weight ratio of the silane coupling agent modified inorganic lithium salt to the polymer to the volatile organic solvent is 100:0.01:100 to 100:40:1000.

18 . The method according to claim 13 , wherein the volatile organic solvent comprises decalin or diphenyl ether.

19 . A positive electrode material for a lithium-ion battery, comprising:
a positive electrode active material; a conductive agent; a binding agent; and an additive according to claim 1 .

20 . The positive electrode material according to claim 19 , wherein the positive electrode active material comprises a low-voltage material with a charging voltage below 4.4 V.

21 - 29 . (canceled)

Assignees

• Byd Co Ltd

Inventors

• Han Xiaoyan
• Li Shicai
• Zhang Zhongchun

Classifications

• C01G53/50

  of the type (MnO2)n-, e.g. Li(NixMn1-x)O2 or Li(MyNixMn1-x-y)O2 · CPC title

• C08K9/06

  with silicon-containing compounds · CPC title

• H01M10/0525

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

• C01B25/45

  containing plural metal, or metal and ammonium · CPC title

• C08K3/32

  Phosphorus-containing compounds · CPC title