# US 8,541,136 B2 · Mixed metal olivine electrode materials for lithium ion batteries

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- Number: US 8,541,136 B2
- Document ID: US8541136B2
- Status: Granted
- Kind: B2
- Application number: 12/357,008
- Filed: 2009-01-21
- Published: 2009-07-23
- Granted: 2013-09-24
- Earliest claimed: 2008-01-17
- Assignees: A123 Systems, Inc.
- Applicants: Larry Beck; Anthony E. Pullen; Chuanjing Xu; Liya Wang; Phillip Sholtes
- Inventors: Larry Beck; Anthony E. Pullen; Chuanjing Xu; Liya Wang; Phillip Sholtes
- Web page: https://patentgrep.com/patent/US8541136B2

## CPC

- H01M 4/5825: {Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines}
- C01B 25/45: containing plural metal, or metal and ammonium
- H01M 10/052: Li-accumulators
- Y02E 60/10: Energy storage using batteries
- Y02T 10/70: Energy storage systems for electromobility, e.g. batteries
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

A positive electrode material is provided including an electroactive material having one or more phases comprising lithium (Li), an electroactive metal (M), and phosphate (PO4), wherein in the fully lithiated state, the overall composition has a ratio of Li:M ranging from greater than about 1.0 to about 1.3, a ratio of (PO4):M ranging from about 1.0 to about 1.132, M is one or more metals selected from the group consisting of Cr, Mn, Fe, Co, and Ni, and at least one phase includes an olivine lithium electroactive metal phosphate. In some instances, a composite cathode material including an electroactive olivine transition metal phosphate and a lithium and phosphate rich secondary phase is disclosed for use in a lithium ion battery.

## Claims

### Claim 1

A positive electrode material having an improved charge capacity at high discharge rates, the positive electrode material comprising:
an electroactive material having two or more phases comprising lithium (Li), an electroactive metal (M), and phosphate (PO4),
wherein the overall composition of the electroactive material has a ratio of Li:M ranging from greater than 1.1 to about 1.3, a ratio of (PO4):M ranging from about 1.0 to about 1.14,
the ratios Li:M and (PO4):M are as compared to a stoichiometric composition for an olivine lithium transition metal phosphate (LiMPO4),
M is one or more metals selected from the group consisting of Cr, Mn, Fe, Co, and Ni, and wherein the electroactive material comprises an olivine lithium electroactive metal phosphate phase and less than 10 wt % of a lithium-rich secondary phase or a lithium-rich and phosphate-rich secondary phase.

### Claim 2 (depends on 1)

The positive electrode material of claim 1, wherein the electroactive material further comprises one or more dopant metals (Z) selected from the group consisting of V, Nb, Ti, AI, Mg, Mn, Co, Ni, and Zr, wherein M and Z are different.

### Claim 3 (depends on 2)

The positive electrode material of claim 2, wherein
M comprises Fe,
the ratio of Li:M ranges from greater than 1.1 to about 1.15,
the ratio of (PO4):M ranges from about 1.0 to about 1.03, and
the electroactive material comprises up to 5 mol % of the one or more dopant metals.

### Claim 4 (depends on 2)

The positive electrode material of claim 2, wherein
M comprises Fe,
the ratio of Li:M ranges from greater than 1.1 to about 1.15,
the ratio of (PO4):M ranges from about 1.03 to about 1.05, and
the electroactive material comprises up to 5 mol % of the one or more dopant metals.

### Claim 5 (depends on 2)

The positive electrode material of claim 2, wherein
M comprises Fe,
the ratio of Li:M ranges from greater than 1.1 to about 1.2,
the ratio of (PO4):M ranges from about 1.05 to about 1.07, and
the electroactive material comprises up to 5 mol % of the one or more dopant metals.

### Claim 6 (depends on 2)

The positive electrode material of claim 2, wherein
M comprises Fe,
the ratio of Li:M ranges from greater than 1.1 to about 1.3,
the ratio of (PO4):M ranges from about 1.07 to about 1.14, and
the electroactive material comprises up to 5 mol % of the one or more dopant metals.

### Claim 7 (depends on 2)

The positive electrode material of claim 2, wherein the one or more dopant metals substitutes one or more of the lithium or electroactive metals in the olivine lithium electroactive metal phosphate.

### Claim 8 (depends on 2)

The positive electrode material of claim 2, wherein the olivine lithium electroactive metal phosphate has the formula (Li1−x,Zx)MPO4, x ranges from about 0.001 to about 0.05, and the ratio of (Li1−x,Zx):M in the overall composition of the electroactive material ranges from greater than 1.1 to about 1.3.

### Claim 9 (depends on 1)

The positive electrode material of claim 1, wherein the electroactive material comprises the olivine lithium electroactive metal phosphate phase and lithium-rich and phosphate rich secondary phase.

### Claim 10 (depends on 9)

The positive electrode material of claim 9, wherein the secondary phase comprises lithium phosphate or lithium pyrophosphate.

### Claim 11

A lithium secondary cell, comprising:
a positive electrode in electronic contact with a positive electrode current collector, said current collector in electrical connection with an external circuit;
a negative electrode in electronic contact with a negative electrode current collector, said current collector in electrical connection with an external circuit;
a separator positioned between and in ionic contact with the cathode and the anode; and an electrolyte in ionic contact with the positive and negative electrodes; wherein
the positive electrode comprises an electroactive material having two or more phases comprising lithium (Li), an electroactive metal (M), and phosphate (PO4), wherein the overall composition in the electroactive material has a ratio of Li:M ranging from greater than 1.1 to about 1.3, a ratio of (PO4):M ranging from about 1.0 to about 1.14, the ratios Li:M and (PO4):M are as compared to a stoichiometric composition for an olivine lithium transition metal phosphate (LiMPO4), M is one or more metals selected from the group consisting of Cr, Mn, Fe, Co, and Ni, and wherein the electroactive material comprises an olivine lithium electroactive metal phosphate phase and less than 10 wt % of a lithium-rich secondary phase or a lithium-rich and phosphate-rich secondary phase.

### Claim 12 (depends on 11)

The lithium secondary cell of claim 11, wherein the electroactive material further comprises one or more dopant metals (Z) selected from the group consisting of V, Nb, Ti, AI, Mg, Mn, Co, Ni, and Zr, wherein M and Z are different.

### Claim 13 (depends on 12)

The lithium secondary cell of claim 12, wherein the electroactive material comprises up to about 5 mol % of the one or more dopant metals.

### Claim 14 (depends on 12)

The lithium secondary cell of claim 12, wherein the one or more dopant metals substitutes one or more of the lithium or electroactive metals in the olivine lithium electroactive metal phosphate.

### Claim 15 (depends on 12)

The lithium secondary cell of claim 12, wherein the olivine lithium electroactive metal phosphate has the formula (Li1−xZx)MPO4, x ranges from about 0.001 to about 0.05, and the ratio of (Li1−xZx):M in the overall electroactive material ranges from greater than 1.1 to about 1.3.

### Claim 16 (depends on 11)

The lithium secondary cell of claim 11, wherein the electroactive material comprises the olivine lithium electroactive metal phosphate phase and lithium-rich and phosphate rich secondary phase.

### Claim 17 (depends on 11)

The lithium secondary cell of claim 11, wherein the negative electrode comprises a lithium intercalation compound or a lithium metal alloy.

### Claim 18 (depends on 11)

The lithium secondary cell of claim 11, the negative electrode comprises carbon.

### Claim 19 (depends on 18)

The lithium secondary cell of claim 18, wherein the negative electrode comprises graphitic carbon.

### Claim 20 (depends on 18)

The lithium secondary cell of claim 18, wherein the carbon is selected from the group consisting of graphite, spheroidal graphite, mesocarbon microbeads and carbon fibers.

### Claim 21 (depends on 1)

A positive electrode comprising the positive electrode material of claim 1.

### Claim 22 (depends on 21)

The positive electrode of claim 21, wherein the electroactive material further comprises one or more dopant metals (Z) selected from the group consisting of V, Nb, Ti, AI, Mg, Mn, Co, Ni, and Zr, wherein M and Z are different.

### Claim 23 (depends on 22)

The positive electrode of claim 22, wherein the electroactive material comprises up to about 5 mol % of the one or more dopant metals.

### Claim 24 (depends on 22)

The positive electrode of claim 22, wherein the one or more dopant metals substitutes one or more of the lithium or electroactive metals in the olivine lithium electroactive metal phosphate.

### Claim 25 (depends on 22)

The positive electrode of claim 22, wherein the olivine lithium electroactive metal phosphate has the formula (Li1−xZx)MPO4, x ranges from about 0.001 to about 0.05, and the ratio of (Li1−xZx):M in the overall electroactive material ranges from greater than 1.1 to about 1.3.

### Claim 26 (depends on 21)

The positive electrode of claim 21, wherein the electroactive material comprises the olivine lithium electroactive metal phosphate phase and lithium-rich and phosphate rich secondary phase.

### Claim 27 (depends on 21)

The positive electrode of claim 21, further comprising a binder and an electronically conductive material.