Method of producing a battery anode active material comprising a porous host structure and silicon residing in the host pores
A method of producing multiple particulates having pores containing Si therein, comprising: (a) providing a porous conductive host structure having from 5% to 99.9% of pores; (b) introducing a halogen gas that chemically reacts with Si at a first temperature to form a silicon halide, wherein the silicon halide is selected from SiF 4 , SiCl 4 , SiI 4 , SiBr 4 , and/or SiX a Z b , wherein X and Z are each a halogen element and a=1-3, b=1-3, and a+b=4; (c) vaporizing the silicon halide to form a vapor phase and directing the silicon halide vapor into pores of the host and facilitating the silicon halide to decompose into a halogen gas product and solid Si particles or coating deposited at a second temperature in the pores to form a Si-infiltrated porous host structure; and (d) optionally breaking and reducing said Si-infiltrated host structure into smaller porous particles.
1 . A method of producing a solid powder mass of multiple porous particulates having pores containing silicon (Si) therein for use as an anode active material of a lithium-ion or sodium-ion battery, said method comprising:
(a) providing a porous conductive host structure having a volume fraction of pores from 5% to 99.9%, wherein the porous host structure is selected from a carbonaceous, graphitic, graphene, or metallic material in a bulk form or in a form of multiple porous particles;
(b) introducing a reactant gas or vapor of a halogen that chemically reacts with a Si source disposed in a reaction chamber at a first temperature to form a silicon halide with or without using a catalyst, wherein the halogen is selected from F, Cl, I, Br, or a combination thereof and the silicon halide is selected from SiF 4 , SiCl 4 , SiI, SiBr 4 , SiX a Z b , or a combination thereof wherein X and Z are each a halogen element and a=1-3, b=1-3, and a+b=4 and wherein the Si source is selected from Si or a Si-rich compound containing no less than 60% by weight of Si in the compound; and
(c) vaporizing said silicon halide to form a vapor phase and, immediately or at a later time, directing said silicon halide vapor phase into pores of said porous host structure and facilitating said silicon halide to decompose, at a second temperature, into a halogen gas product and solid Si particles or coating deposited in said pores to form a Si-infiltrated or Si-impregnated porous host structure.
2 . The method of claim 1 , further including breaking and reducing said Si-infiltrated or Si-impregnated porous host structure into smaller porous particles, having a diameter from 50 nm to 100 μm, to obtain the solid powder mass of multiple porous particulates containing Si therein.
3 . The method of claim 1 , wherein said halogen gas product is collected into a container or reused as a reactant gas or vapor of a halogen that chemically reacts with additional Si to produce additional solid powder mass.
4 . The method of claim 1 , wherein the method further meets at least one of the following conditions: (i) step (b) comprises further utilizing a catalyst to accelerate a chemical reaction and/or lower the required reaction temperature; (ii) step (c) comprises introducing an inert gas to mix with said vapor phase to facilitate the transport and diffusion of said silicon halide vapor phase into pores of said porous host structure; (iii) step (c) comprises subjecting the vapor phase to a second temperature that induces decomposition of the silicon halide into Si and/or facilitating Si vapor to deposit as a solid coating or particles in the pores of the porous conductive host structure; and (iv) the Si-rich compound comprises silicon and a metal selected from the group consisting of alkali metals, alkali earth metals, transition metals, rare earth metals, and low meting point metals.
5 . The method of claim 4 , wherein the catalyst comprises a metal, a metal alloy, a metal oxide, a metal salt, a metal hydride, a metal-containing compound, or a combination thereof, wherein the metal is selected from a group of elements consisting of noble metal elements, alkaline and alkaline earth metal elements, transition metal elements, rare earth metal elements, low melting point metal elements, and combinations thereof.
6 . The method of claim 1 , wherein the Si source disposed in the reaction chamber is in a form of one or multiple particles, fibers, rods, plates, discs, tubes, wafer, or a combination thereof.
7 . The method of claim 1 , wherein the first temperature is from 20° C. to 1,500° C. and the second temperature is the same as or different from the first temperature.
8 . The method of claim 1 , wherein the first temperature is from 300° C. to 1,200° C. and the second temperature is greater than 250° C.
9 . The method of claim 1 , wherein said porous graphene structure comprises pore walls comprising graphene sheets selected from pristine graphene, graphene fluoride, graphene chloride, graphene bromide, graphene iodide, nitrogenated graphene, hydrogenated graphene, doped graphene, chemically functionalized graphene, graphene oxide, reduced graphene oxide, or a combination thereof.
10 . The method of claim 1 , wherein said porous carbonaceous or graphitic particles comprise particles of activated carbon, soft carbon, hard carbon, activated natural graphite, activated artificial graphite, exfoliated graphite worms, expanded graphite flakes, meso-phase carbon, needle coke, or a combination thereof.
11 . The method of claim 1 , further comprising a procedure of encapsulating or coating the porous particulates with a thin protecting layer having a thickness from 0.5 nm to 2 μm, wherein the protecting lay comprises carbon, graphene, electron-conducting polymer, lithium ion-conducting polymer, or a combination thereof.
12 . The method of claim 1 , further comprising a procedure of prelithiating the Si coating or particles deposited in the pores of the multiple particulates, wherein said Si coating or particles are prelithiated to contain an amount of lithium from 1% to 100% of a maximum lithium content contained in said Si, or the prelithiated Si particles or coating is selected from Li x Si, wherein numerical x is from 0.01 to 4.4.
13 . The method of claim 12 , further comprising a procedure of encapsulating or coating the prelithiated multiple particulates with a thin protecting layer having a thickness from 0.5 nm to 2 μm.
14 . The method of claim 13 , wherein said protecting layer comprises a carbon material, graphene, a polymer, or a lithium- or sodium-containing species chemically bonded to said particulates and said lithium- or sodium-containing species is selected from Li 2 CO 3 , Li 2 C 2 O 4 , LiOH, LiCl, LiI, LiBr, ROCO 2 Li, HCOLi, ROLi, (ROCO 2 Li) 2 , (CH 2 OCO 2 Li) 2 , Li 2 S, Li x SO y , Li 4 B, Na 4 B, Na 2 CO 3 , Na 2 O, Na 2 C 2 O 4 , NaOH, NaX, ROCO 2 Na, HCONa, RONa, (ROCO 2 Na) 2 , (CH 2 OCO 2 Na) 2 , Na 2 S, Na x SO y , a combination thereof, a combination thereof with Li 2 O or LiF, or a combination of Li 2 O and LiF, wherein X=F, Cl, I, or Br, R=a hydrocarbon group, x=0-1, y=1-4.
15 . The method of claim 14 , wherein said protecting layer comprises a thin layer of a high-elasticity polymer having a fully recoverable tensile strain from 5% to 1,000%, and a lithium ion conductivity from 10 −7 S/cm to 5×10 −2 S/cm at room temperature.
16 . The method of claim 12 , wherein said step of prelithiating includes a procedure selected from chemical prelithiation, electrochemical lithiation, solution lithiation, physical lithiation, or a combination thereof.
17 . The method of claim 1 , further comprising a step of forming said multiple porous particulates, along with a binder, into an anode electrode.
18 . The method of claim 17 , wherein said forming step further includes a conductive additive.
19 . The method of claim 17 , further comprising a step of combining said anode electrode with a cathode, and an electrolyte to form a battery cell.
20 . A method of producing a Si-coated or Si-infiltrated host structure, said method comprising (a) providing a solid or porous current collector; (b) introducing a reactant gas or vapor of a halogen that chemically reacts with a Si source disposed in a reaction chamber at a first temperature to form a silicon halide with or without using a catalyst, wherein the halogen is selected from F, Cl, I, Br, or a combination thereof and the silicon halide is selected from SiF 4 , SiCl 4 , SiI 4 , SiBr 4 , SiX a Z b , or a combination thereof wherein X and Z are each a halogen element and a=1-3, b=1-3, and a+b=4; and wherein the Si source is selected from Si or a Si-rich compound containing no less than 60% by weight of Si in the compound; (c) vaporizing said silicon halide to form a vapor phase and directing said silicon halide vapor phase into pores or onto surfaces of said current collector and facilitating said silicon halide to decompose into solid Si particles or coating deposited at a second temperature on said current collector surface or inside pores of the current collector to form a Si-coated or Si-infiltrated current collector.