Aluminum borate coated lithium ion cathode materials

Patent metadata

Field	Value
Publication number	US-2017012284-A1
Application number	US-201615206080-A
Country	US
Kind code	A1
Filing date	Jul 8, 2016
Priority date	Jul 10, 2015
Publication date	Jan 12, 2017
Grant date	—

Abstract

Composite cathode materials are provided herein. Disclosed composite cathode materials include those comprising an aluminum borate coating. Systems making use of the cathode active materials are also described, such as electrochemical cells and electrodes for use in electrochemical cells. Methods for making and using the composite cathode materials are also disclosed.

First claim

1 . A composite cathode material comprising:
a cathode active material; and a metal borate compound coating the cathode active material.

2 . The composite cathode material of claim 1 , wherein the cathode active material comprises lithium and one or more of nickel, magnesium, aluminum, and cobalt.

3 . The composite cathode material of claim 1 , wherein the cathode active material comprises crystalline particles having cross-sectional dimensions selected from the range of 50 nm to 500 nm.

4 . The composite cathode material of claim 1 , wherein the cathode active material comprises agglomerates of crystalline particles, wherein the agglomerates have cross sectional dimensions selected from the range of 1 μm to 20 μm.

5 . The composite cathode material of claim 1 , wherein the metal borate compound comprises AlBO 3 .

6 . The composite cathode material of claim 1 , wherein the metal borate compound has a thickness selected from the range of 0.5 nm to 20 nm.

7 . The composite cathode material of claim 1 , wherein the metal borate compound is formed by a precipitation reaction between metal cations and borate anions.

8 . The composite cathode material of claim 1 , wherein a coating of the metal borate compound is formed depositing a thin film over a layer of the cathode active material.

9 . The composite cathode material of claim 1 , wherein the metal borate compound provides a protective barrier against oxidative degradation of an electrolyte in contact with the composite cathode material when the cathode active material is charged using a voltage greater than 4.2 V.

10 . The composite cathode material of claim 1 , wherein the coating comprises a percentage of the composite cathode material, by weight, of between 1% and 3%.

11 . The composite cathode material of claim 1 , provided in the form of an electrode comprising an aggregate of a plurality of particles of the cathode active material each coated with the metal borate compound

12 . A method of making a composite cathode material, comprising:
forming a reaction mixture by adding a cathode active material, a cation precursor, and an anion precursor to a solvent thereby initiating a precipitation reaction between the cation precursor and the anion precursor to form the composite cathode material, wherein the composite cathode material comprises the cathode active material and a metal borate coating on the cathode active material, wherein:
the cation precursor comprises a metal salt, and
the anion precursor comprises borate anions.

13 . The method of claim 12 , wherein forming the reaction mixture comprises:
adding the cathode active material to the solvent to form suspended cathode active material in the solvent; adding the cation precursor to the solvent, thereby forming a solution containing metal cations and suspended cathode active material; and adding the anion precursor to the solution.

14 . The method of claim 13 , wherein adding the anion precursor to the solution comprises adding the anion precursor to the solution drop-wise while continuously stirring the solution.

15 . The method of claim 12 , further comprising:
forming the composite cathode material into an electrode.

16 . The method of claim 15 , further comprising:
assembling an electrochemical cell using the electrode, wherein the electrochemical cell comprises:
a cathode comprising the electrode;
an anode;
a separator positioned between the anode and the cathode; and
an electrolyte positioned between the anode and the cathode and in contact with the separator.

17 . The method of claim 16 , further comprising charging the electrochemical cell by applying a charging voltage between the cathode and the anode, wherein the charging voltage is greater than 4.2 V.

18 . The method of claim 15 , wherein forming the composite cathode material into an electrode comprises:
applying a slurry comprising the composite cathode material to a current collector; and drying the slurry, thereby forming the electrode.

19 . (canceled)

20 . An electrochemical cell comprising:
an anode; a cathode; a separator positioned between the anode and the cathode; and an electrolyte positioned between the anode and the cathode and in contact with the separator; wherein the cathode comprises:
a cathode active material; and
a metal borate coating over the cathode active material.

21 . The electrochemical cell of claim 20 , wherein a voltage difference between the anode and the cathode is greater than 4.2 V.

22 .- 23 . (canceled)

Assignees

• California Inst Of Techn

Inventors

• Bugga Ratnakumar V
• Seu Candace S

Classifications

• H01M4/525

  of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy · CPC title

• H01M4/628

  Inhibitors, e.g. gassing inhibitors, corrosion inhibitors · CPC title

• H01M10/0525

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

• H01M4/366 Primary

  as layered products · CPC title

• H01M4/505

  of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy · CPC title