Processes for preparing lithium transition metal phosphate cathode materials

Patent metadata

Field	Value
Publication number	US-2024421286-A1
Application number	US-202318697712-A
Country	US
Kind code	A1
Filing date	Mar 30, 2023
Priority date	Apr 1, 2022
Publication date	Dec 19, 2024
Grant date	—

Abstract

The present disclosure is directed to methods of forming lithium transition metal phosphate and fluorophosphate materials in a conductive carbon matrix. The disclosed methods are advantageous in utilizing inexpensive reactants, can mitigate formation of impurities during the synthesis, providing a more homogenous product, and may provide cathode materials with enhanced tap density relative to prior lithium transition metal phosphates. The lithium transition metal phosphate and fluorophosphate materials prepared by the disclosed methods are intimately mixed with carbon within a continuous, three-dimensional conductive carbon matrix. The materials prepared according to the disclosed methods are suitable for use in environments involving electrochemical reactions, for example as cathode materials within a lithium-ion battery.

First claim

1 - 32 . (canceled)

33 . A method of preparing a lithium transition metal phosphate cathode material within a conductive carbon matrix, the method comprising:
combining a group of precursors for synthesizing the lithium transition metal phosphate cathode material, wherein at least a first precursor of the group comprises a solid phase having a first density greater than 1 gram (g)/cubic centimeter (cc), and at least a second precursor of the group comprises a liquid phase having a second density, wherein the second density is less than the first density; providing one or more carbon precursors in a fluid state, the one or more carbon precursors configured to form a solid organogel in the presence of a gelation initiator, the solid organogel configured to form a conductive carbon matrix upon pyrolysis; mixing the group of precursors with the one or more carbon precursors to form a precursor mixture; adding the gelation initiator to the precursor mixture; allowing the one or more carbon precursor to undergo gelation to form a solid organogel; and pyrolyzing the solid organogel to form the lithium transition metal phosphate cathode material within the conductive carbon matrix.

34 . The method of claim 33 , wherein the solid organogel forms within 5 seconds to 15 minutes after addition of the gelation initiator.

35 . The method of claim 33 , wherein the solid organogel comprises a porous network of interconnected solid phase polymer structures.

36 . The method of claim 35 , wherein the porous network maintains contact between the first precursor of the group and the second precursor of the group.

37 . The method of claim 36 , wherein the contact is maintained to a temperature of at least about 300° C.

38 . The method of claim 33 , wherein:
the first precursor comprises iron; the second precursor comprises a lithium source and phosphoric acid; and the lithium transition metal phosphate cathode material is lithium iron phosphate.

39 . The method of claim 38 , wherein the iron is present in the form of an iron (II) salt, an iron (III) salt, iron (II) oxide (FeO), iron (III) oxide (Fe 2 O 3 ), a mixed iron oxide (Fe 3 O 4 ), or a combination thereof.

40 . The method of claim 33 , wherein the solid organogel comprises a phloroglucinol-furfural polymer or a resorcinol-furfural polymer, the one or more carbon precursors are phloroglucinol or resorcinol and furfural, and the gelation initiator is an amine base or an acid.

41 . The method of claim 33 , wherein the solid organogel comprises a polyurethane polymer, the one or more carbon precursors comprise a polyol and an isocyanate, and the gelation initiator comprises an alkylamine.

42 . The method of claim 33 , wherein the organogel comprises a polyamic acid polymer and the gelation initiator comprises acetic anhydride, acetic acid, or a combination thereof.

43 . The method of claim 33 , wherein the group of precursors includes a precursor having microwave susceptibility and the pyrolyzing is performed by applying microwave radiation.

44 . The method of claim 43 , wherein the precursor having microwave susceptibility comprises one or more of carbon, magnetite, and maghemite.

45 . The method of claim 44 , comprising nanoparticles of one or more of magnetite and maghemite having a particle size of from 20 nm to 100 nm.

46 . The method of claim 33 , wherein:
the first precursor comprises manganese, vanadium, or both; the second precursor comprises a lithium source and phosphoric acid; and the lithium transition metal phosphate cathode material is lithium manganese phosphate or lithium vanadium phosphate.

47 . The method of claim 33 , further comprising drying the lithium transition metal phosphate cathode material by applying microwave radiation.

48 . The method of claim 33 , wherein the solid phase having the first density greater than 1 gram comprises a ferromagnetic iron compound, a ferrimagnetic iron compound, or both.

49 . The method of claim 48 , wherein the ferromagnetic iron compound, the ferrimagnetic iron compound, or both are synthesized by a method comprising:
oxidizing an iron-containing anode in an electrochemical cell with a porous carbon substrate, an oxygen cathode, and an electrolyte in contact with both the iron-containing anode and the porous carbon substrate; wherein the oxidizing produces particles of the ferromagnetic iron compound, the ferrimagnetic iron compound, or both, having a particle size of from 20 nm to 100 nm.

50 . The method of claim 49 , further comprising removing the particles by magnetic filtration.

51 . The method of claim 49 , further comprising drying the particles by applying microwave radiation.

52 . The method of claim 49 , wherein operation of the electrochemical cell and formation of the ferromagnetic iron compound, the ferrimagnetic iron compound, or both is at a temperature between 15° C. and 35° C.

53 . A composition comprising a nanoparticle comprising olivine lithium iron phosphate and integral with a conductive carbon matrix, the conductive carbon matrix comprising a carbonized organogel polymer matrix, wherein the nanoparticle has a particle size from 20 nm to 1000 nm and a nitrogen sorption BET surface area from 10 meters 2 (m 2 )/gram (g) to 65 m 2 /g, wherein the particle size is a diameter or one or more of a width, length, and/or depth.

Assignees

• Aspen Aerogels Inc

Inventors

• Yaghoobnejad Asl Hooman
• Begag Redouane
• Soni Rushi
• Leventis Nicholas

Classifications

• H01M2004/021

  Physical characteristics, e.g. porosity, surface area · CPC title

• H01M10/0525

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

• H01M4/625

  Carbon or graphite · CPC title

• H01M4/364 Primary

  as mixtures · CPC title

• H01M4/136

  Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy · CPC title