Method of producing graphene-carbon hybrid foam-protected anode active material coating for lithium-ion batteries
Provided is method of producing a porous anode material structure for a lithium-ion battery, the method comprising (A) providing an integral 3D graphene-carbon hybrid foam comprising multiple pores, having a pore volume Vp, and pore walls; and (B) impregnating or infiltrating the pores with a fluid for forming a coating of an anode active material, having a coating volume Vc, deposited on or bonded to surfaces of the pore walls; wherein the pore walls contain single-layer or few-layer graphene sheets chemically bonded by a carbon material having a carbon material-to-graphene weight ratio from 1/200 to 1/2, and wherein the volume ratio Vp/Vc is from 0.1/1.0 to 10/1.0.
1. A method of producing a porous anode material structure for a lithium-ion battery, said method comprising (A) providing an integral 3D graphene-carbon hybrid foam comprising multiple pores, having a pore volume Vp, and pore walls; and (B) impregnating or infiltrating said pores with a fluid for forming a coating of an anode active material, having a coating volume Vc, coated on or bonded to surfaces of said pore walls; wherein said pore walls contain single-layer or few-layer graphene sheets chemically bonded by a carbon material having a carbon material-to-graphene weight ratio from 1/200 to 1/2, and wherein the volume ratio Vp/Vc is from 0.1/1.0 to 10/1.0, wherein said porous anode material structure is in a porous particulate form having a diameter from 5 μm to 50 μm, wherein said anode active material coating is selected from the group consisting of: (a) lithium-containing composites; (b) lithium titanate, lithium manganate, lithium aluminate, lithium-containing titanium oxide, lithium transition metal oxide; (c) prelithiated versions thereof; (d) particles of Li, Li alloy, or surface-stabilized Li having at least 60% by weight of lithium element therein; and (e) combinations thereof.
2. The method of claim 1 , wherein said integral 3D graphene-carbon hybrid foam is produced by conducting a process including:
(a) mixing multiple particles of a graphitic material and multiple particles of a solid polymer carrier material to form a mixture in an impacting chamber of an energy impacting apparatus;
(b) operating said energy impacting apparatus with a frequency and an intensity for a length of time sufficient for peeling off graphene sheets from said graphitic material and transferring said graphene sheets to surfaces of said solid polymer carrier material particles to produce graphene-coated polymer particles inside said impacting chamber;
(c) recovering said graphene-coated polymer particles from said impacting chamber and consolidating said graphene-coated or graphene-embedded polymer particles into a desired shape of graphene-polymer composite structure; and
(d) pyrolyzing said shape of graphene-polymer composite structure to thermally convert said polymer into pores and carbon or graphite that bonds said graphene sheets to form said integral 3D graphene-carbon hybrid foam.
3. The method of claim 2 , wherein a plurality of impacting balls or media are added to the impacting chamber of said energy impacting apparatus.
4. The method of claim 3 , wherein step (c) includes operating a magnet to separate the impacting balls or media from the graphene-coated or graphene-embedded polymer particles.
5. The method of claim 2 , wherein said solid polymer material particles include plastic or rubber beads, pellets, spheres, wires, fibers, filaments, discs, ribbons, or rods, having a diameter or thickness from 10 nm to 10 mm.
6. The method of claim 5 , wherein said diameter or thickness is from 100 nm to 1 mm.
7. The method of claim 2 , wherein said solid polymer is selected from solid particles of a thermoplastic, thermoset resin, rubber, semi-penetrating network polymer, penetrating network polymer, natural polymer, or a combination thereof.
8. The method of claim 2 , wherein said solid polymer is partially removed by melting, etching, or dissolving in a solvent prior to step (d).
9. The method of claim 2 , wherein said graphitic material is selected from natural graphite, synthetic graphite, highly oriented pyrolytic graphite, graphite fiber, graphitic nanofiber, graphite fluoride, oxidized graphite, chemically modified graphite, exfoliated graphite, recompressed exfoliated graphite, expanded graphite, mesocarbon microbead, or a combination thereof.
10. The method of claim 2 , wherein the energy impacting apparatus is a vibratory ball mill, planetary ball mill, high energy mill, basket mill, agitator ball mill, cryo ball mill, micro ball mill, tumbler ball mill, attritor, continuous ball mill, stirred ball mill, pressurized ball mill, freezer mill, vibratory sieve, bead mill, nanobead mill, ultrasonic homogenizer mill, centrifugal planetary mixer, vacuum ball mill, or resonant acoustic mixer.
11. The method of claim 2 , wherein said graphitic material contains a non-intercalated and non-oxidized graphitic material that has never been previously exposed to a chemical or oxidation treatment prior to said mixing step.
12. The method of claim 2 , wherein said solid polymer contains a high carbon-yield polymer selected from phenolic resin, poly furfuryl alcohol, polyacrylonitrile, polyimide, polyamide, polyoxadiazole, polybenzoxazole, polybenzobisoxazole, polythiazole, polybenzothiazole, polybenzobisthiazole, poly (p-phenylene vinylene), polybenzimidazole, polybenzobisimidazole, a copolymer thereof, a polymer blend thereof, or a combination thereof.
13. The method of claim 2 , wherein said solid polymer contains a low carbon-yield polymer selected from polyethylene, polypropylene, polybutylene, polyvinyl chloride, polycarbonate, acrylonitrile-butadiene (ABS), polyester, polyvinyl alcohol, poly vinylidiene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyphenylene oxide (PPO), poly methyl methacrylate (PMMA), a copolymer thereof, a polymer blend thereof, or a combination thereof.
14. The method of claim 2 , wherein said step of pyrolyzing includes carbonizing said polymer at a temperature from 200° C. to 2,500° C. to obtain graphene-carbon foam, or carbonizing said polymer at a temperature from 200° C. to 2,500° C. to obtain graphene-carbon foam and then graphitizing said graphene-carbon foam from 2,500° C. to 3,200° C. to obtain graphitized graphene-carbon foam.
15. The method of claim 2 , wherein said consolidating step includes melting said polymer particles to form a polymer melt mixture with graphene sheets dispersed therein, forming said polymer melt mixture into a desired shape and solidifying said shape into a graphene-polymer composite structure.
16. The method of claim 2 , wherein said consolidating step includes dissolving said polymer particles in a solvent to form a polymer solution mixture with graphene sheets dispersed therein, forming said polymer solution mixture into a desired shape, and removing said solvent to solidify said shape into said graphene-polymer composite structure.
17. The method of claim 2 , wherein said consolidating step includes forming said graphene-coated polymer particles into a composite shape selected from a rod, sheet, film, fiber, powder, ingot, or block form.
18. The method of claim 2 , wherein said consolidating step includes compacting said graphene-coated polymer particles in a porous green compact having macroscopic pores and then infiltrate or impregnate said pores with an additional carbon source material selected from a petroleum pitch, coal tar pitch, an aromatic organic material, a monomer, an organic polymer, or a combination thereof.
19. The method of claim 18 , wherein said organic polymer contains a high carbon-yield polymer selected from phenolic resin, poly furfuryl alcohol, polyacrylonitrile, polyimide, polyamide, polyoxadiazole, polybenzoxazole, polybenzobisoxazole, polythiazole, polybenzothiazole, polybenzobisthiazole, poly (p-phenylene vinylene), polybenzimidazole, polybenzobisimidazole, a copolymer thereof, a polymer blend thereof, or a combination thereof.
20. The method of claim 2 , wherein said consolidating step includes forming a mass of said graphene-coated or graphene-embedded polymer particles into a compacted object.
21. The method of claim 20 , wherein said compacted object is in a form selected from a rod, sheet, film, fiber, powder, ingot, or block.
22. The method of claim 1 , further comprising a step of introducing a conducting polymer or carbon into said pores wherein said conducting polymer or carbon is deposited onto a surface of said coating of anode active material, providing protection thereto.
23. The method of claim 1 , wherein said coating of anode active material is further coated with a layer of carbon or conducting polymer.