# US 2013/0157133 A1 · Process for Producing Defect-Free Lithium Metal Phosphate Electrode Materials

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- Number: US 2013/0157133 A1
- Document ID: US20130157133A1
- Status: Published application
- Kind: A1
- Application number: 13/676,916
- Filed: 2012-11-14
- Published: 2013-06-20
- Earliest claimed: 2011-11-17
- Assignees: Brookhaven Science Associates, LLC
- Inventors: Jiajun Chen; Jason Graetz
- Web page: https://patentgrep.com/patent/US20130157133A1

## CPC

- H01M 4/485: of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy (H01M4/505, H01M4/525 take precedence)
- C01B 25/45: containing plural metal, or metal and ammonium
- H01M 4/5825: {Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines}
- H01M 4/136: Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
- Y02E 60/10: Energy storage using 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

## Abstract

A method of synthesizing defect-free phospho-olivine materials is disclosed. The method is based on direct hydrothermal synthesis of phospho-olivine compound(s) and subsequent lattice reordering at or near the transition temperature to eliminate lattice defects or on one-pot in situ hydrothermal synthesis of phospho-olivine compound(s), where the cation ordering occurs during dwell time after rapid synthesis to eliminate lattice defects. The disclosed methods produce defect-free phospho-olivine compound(s) having a crystal lattice with a Pnma space group. In order to determine the exact transition temperature for complete removal of single- or mixed-transition metals from lithium sites or to monitor the crystal growth and removal of single- or mixed-transition metals from lithium sites during the hydrothermal synthesis, the method encompasses a procedure for determining and monitoring defects in the phospho-olivine phases using X-ray diffraction.

## Claims

### Claim 1

A method of synthesizing a defect-free phospho-olivine, comprising:
providing an aqueous solutions of Li+, Mn+, and PO43− in a reactor, wherein Mn+ is one or more single or a mixed transition metal selected from the group consisting of Fe2+, Fe3+, Mn2+, Co2+, Ni2+, Mg2+, and Zn2+;
heating the solution in the reactor to about 100° C. to 350° C. under elevated pressure of 100-3000 psi for about 1 to 16 hours to produce a phospho-olivine crystal lattice having a formula
LixMPO4
where 0<x≦1, with varying degree of defects due to a presence of M-type metal in lithium sites of the phospho-olivine structure;
recovering the produced phospho-olivine as a powder; and
heating the phospho-olivine powder to a transition temperature in an inert or reducing atmosphere, thereby forming a defect-free phospho-olivine structure.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the defect-free phospho-olivine structure has less than about 2% defects.

### Claim 3 (depends on 2)

The method according to claim 2, wherein the defect-free phospho-olivine structure has less than about 0.5% defects.

### Claim 4 (depends on 1)

The method according to claim 1, wherein the phospho olivine crystal lattice has a Pnma space group.

### Claim 5 (depends on 1)

The method according to claim 1, further comprising determining the transition temperature for defect elimination in the phospho-olivine crystal lattice by in situ X-ray diffraction.

### Claim 6 (depends on 1)

The method according to claim 1, further comprising adding a reducing agent to the aqueous solution of Li+, Mn+, and PO43− to minimize Mn+ oxidation.

### Claim 7 (depends on 6)

The method according to claim 6, wherein the reducing agent is selected from the group consisting of L-ascorbic acid, sucrose, hydrazine, citric acid, and a combination thereof.

### Claim 8 (depends on 1)

The method according to claim 1, wherein the reactor is an autoclave.

### Claim 9 (depends on 8)

The method according to claim 8, wherein the autoclave is a Parr reactor.

### Claim 10 (depends on 1)

The method according to claim 1, wherein Li+ is selected from the group consisting of LiOH, Li2SO4, LiH2PO4 and Li2CO3, PO43− is selected from the group consisting of H3PO4 and NH4H2PO4, Fe2+ is selected from the group consisting of FeSO4.7H2O, FeCl2.4H2O, FeC2O4, and FeCl2, Fe3+ is Fe(NO3)3, Mn2+ is selected from the group consisting of MnSO4.H2O, Mn(NO3)2, and MnCl2, Co2+ is selected from the group consisting of CoSO4.7H2O, CoCl2.6H2O, and Co(NO3)2, Ni2+ is selected from the group consisting of NiSO4, Ni(NO3)2 and NiCl2, Mg2+ is selected from the group consisting of MgSO4, Mg(NO3)2, and MgCl2, and Zn2+ is selected from the group consisting of ZnSO4, Zn(NO3)2, and ZnCl2.

### Claim 11 (depends on 1)

The method according to claim 1, wherein the transition temperature for defect elimination of the lithium iron phospho-olivine powder (LiFePO4) is about 450° C. to about 500° C.

### Claim 12

A method of manufacturing a defect-free phospho olivine based lithium insertion-type electrode, comprising:
providing an aqueous solutions of Li+, Mn+, and PO43− in a reactor, wherein Mn+ is one or more single or a mixed transition metal selected from the group consisting of Fe2+, Fe3+, Mn2+, Co2+, Ni2+, Mg2+, and Zn2+;
heating the solution in the reactor to about 150° C. to 220° C. under elevated pressure 100-3000 psi for about 3 to 10 hours to produce a phospho-olivine having a formula LiMxPO4 where 0<x≦1, with varying degree of defects due to a presence of M metal in lithium sites of the phospho-olivine structure;
recovering the produced phospho-olivine as a powder;
heating the phospho-olivine powder to a transition temperature in an inert or reducing atmosphere, thereby forming a defect-free phospho-olivine structure, and
mixing the defect-free phospho-olivine with a conducting additive to produce the defect-free phospho olivine based lithium insertion-type electrode.

### Claim 13 (depends on 12)

The method according to claim 12, further comprising determining the transition temperature for defect elimination in the phospho-olivine crystal lattice by in situ X-ray diffraction.

### Claim 14 (depends on 12)

The method according to claim 12, further comprising adding a binder to the combination of the defect-free phospho-olivine and the conducting additive.

### Claim 15 (depends on 14)

The method according to claim 14, wherein the conducting additive is a conducting carbon.

### Claim 16

A defect-free phospho-olivine composition prepared by a process, comprising: providing an aqueous solutions of Li+, Mn+, and PO43− in a reactor, wherein Mn+ is one or more single or a mixed transition metal selected from the group consisting of Fe2+, Fe3+ Mn2+, Co2+, Ni2+, Mg2+, and Zn2+;
heating the solution in the reactor to about 150 to 220° C. under elevated pressure 100-3000 psi for about 3 to 10 hours to produce a phospho-olivine having a formula LiMxPO4 where 0<x≦1, with varying degree of defects due to a presence of M metal in lithium sites of the phospho-olivine structure;
recovering the produced phospho-olivine as a powder; and
heating the phospho-olivine powder to a transition temperature in an inert or reducing atmosphere, thereby forming the defect-free phospho-olivine structure.

### Claim 17 (depends on 16)

The defect-free phospho-olivine composition according to claim 16, wherein the defect-free phospho-olivine structure has less than about 2% defects.

### Claim 18 (depends on 17)

The defect-free phospho-olivine composition according to claim 17, wherein the defect-free phospho-olivine structure has less than about 0.5% defects.

### Claim 19 (depends on 16)

The defect-free phospho-olivine composition according to claim 16, where the phospho-olivine forms a crystal lattice having a Pnma space group.

### Claim 20 (depends on 16)

The defect-free phospho-olivine composition according to claim 16, wherein the transition temperature for defect elimination in the phospho-olivine crystal lattice is determined by in situ x-ray diffraction.

### Claim 21 (depends on 16)

A lithium insertion-type electrode comprising the defect-free phospho-olivine according to claim 16, a conducting additive and a binder.

### Claim 22 (depends on 21)

A battery comprising the lithium insertion-type electrode of claim 21, a negative electrode and an electrolyte.

### Claim 23

A method of synthesizing a defect-free phospho-olivine composition, comprising:
providing a slurry of Li+, Mn+, and PO43− in a one-pot in-situ reactor, wherein Mn+ is one or more single or a mixed transition metal selected from the group consisting of Fe2+, Fe3+, Mn2+, Co2+, Ni2+, Mg2+, and Zn2+;
heating the slurry in the reactor to about a first reaction temperature where a phospho-olivine crystal lattice having a formula LixMPO4 where 0<x≦1, with varying degree of defects due to a presence of M-type metal in lithium sites forms under autogenous pressure;
heating the formed phospho-olivine crystal lattice in the reactor to about a second reaction temperature, which defines the onset of cation ordering;
holding the second reaction temperature until a desired defect concentration is reached; and
recovering the produced defect-free phospho-olivine.

### Claim 24 (depends on 23)

The method according to claim 23, further comprising determining the first reaction temperature for crystal growth in the phospho-olivine crystal lattice and the second reaction temperature for defect elimination in the phospho-olivine crystal lattice by in situ X-ray diffraction.

### Claim 25 (depends on 24)

The method according to claim 24, wherein the crystal growth in the phospho-olivine crystal lattice is determined based on characteristic Bragg peaks detected by the in situ X-ray diffraction.

### Claim 26 (depends on 24)

The method according to claim 24, wherein the onset of cation ordering in the phospho-olivine crystal lattice is determined based lattice parameters detected by the in situ X-ray diffraction.

### Claim 27 (depends on 24)

The method according to claim 24, wherein the first reaction temperature is about 105° C. to about 210° C.

### Claim 28 (depends on 24)

The method according to claim 24, wherein the second reaction temperature is about 155° C. to about 210° C.

### Claim 29 (depends on 24)

The method according to claim 24, wherein the first reaction temperature and the second reaction temperature are the same or similar.

### Claim 30 (depends on 24)

The method according to claim 24, further comprising adding a reducing agent to the aqueous solution of Li+, Mn+, and PO43− to minimize Mn+ oxidation.

### Claim 31 (depends on 30)

The method according to claim 30, wherein the reducing agent is selected from the group consisting of L-ascorbic acid, sucrose, hydrazine, citric acid, and a combination thereof.

### Claim 32 (depends on 23)

The method according to claim 23, wherein Li+ is selected from the group consisting of LiOH, Li2SO4, LiH2PO4 and Li2CO3, PO43− is selected from the group consisting of H3PO4 and NH4H2PO4, Fe2+ is selected from the group consisting of FeSO4.7H2O, FeCl2.4H2O, FeC2O4, and FeCl2, Fe3+ is Fe(NO3)3, Mn2+ is selected from the group consisting of MnSO4.H2O, Mn(NO3)2, and MnCl2, Co2+ is selected from the group consisting of CoSO4.7H2O, CoCl2.6H2O, and Co(NO3)2, Ni2+ is selected from the group consisting of NiSO4, Ni(NO3)2 and NiCl2, Mg2+ is selected from the group consisting of MgSO4, Mg(NO3)2, and MgCl2, and Zn2+ is selected from the group consisting of ZnSO4, Zn(NO3)2, and ZnCl2.

### Claim 33 (depends on 24)

A method according to claim 24, wherein the method further comprises
monitoring the slurry in the reactor by in situ x-ray diffraction during the heating of the slurry to determine the first reaction temperature; and
monitoring an onset of cation ordering in the formed phospho-olivine crystal lattice by in situ x-ray diffraction to determine the second reaction temperature.

### Claim 34 (depends on 23)

A method of manufacturing a defect-free phospho-olivine based lithium insertion-type electrode, comprising:
mixing the defect-free phospho-olivine prepared according to claim 23 with a conducting additive to produce the defect-free phospho olivine based lithium insertion-type electrode.

### Claim 35 (depends on 34)

The method according to claim 34, further comprising adding a binder to the combination of the defect-free phospho-olivine and the conducting additive.

### Claim 36 (depends on 35)

The method according to claim 35, wherein the conducting additive is a conducting carbon.

### Claim 37

A defect-free phospho-olivine composition prepared by a process, comprising:
providing a slurry of Li+, Mn+, and PO43− in a one-pot in-situ reactor, wherein Mn+ is one or more single or a mixed transition metal selected from the group consisting of Fe2+, Fe3+, Mn2+, Co2+, Ni2+, Mg2+, and Zn2+;
heating the slurry in the reactor under autogenous pressure;
monitoring the slurry in the reactor by in situ x-ray diffraction to determine a first temperature where a phospho-olivine crystal lattice having a formula LixMPO4 where 0<x≦1 forms;
heating the formed phospho-olivine crystal lattice in the reactor;
monitoring the formed phospho-olivine crystal lattice in the reactor by in situ x-ray diffraction to determine an onset of cation ordering;
holding the temperature until a desired defect concentration is reached; and
recovering a defect-free phospho-olivine.

### Claim 38 (depends on 37)

A lithium insertion-type positive electrode comprising the defect-free phospho-olivine according to claim 37, a conducting additive and a binder.

### Claim 39 (depends on 38)

A battery comprising the lithium insertion-type electrode of claim 38, a negative electrode and an electrolyte.