CN116864646A - Composite silicon negative electrode material, preparation method thereof and lithium ion battery - Google Patents
Composite silicon negative electrode material, preparation method thereof and lithium ion battery Download PDFInfo
- Publication number
- CN116864646A CN116864646A CN202310935864.1A CN202310935864A CN116864646A CN 116864646 A CN116864646 A CN 116864646A CN 202310935864 A CN202310935864 A CN 202310935864A CN 116864646 A CN116864646 A CN 116864646A
- Authority
- CN
- China
- Prior art keywords
- silicon
- inorganic filler
- composite
- lithium
- anode material
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 title claims abstract description 67
- 239000002131 composite material Substances 0.000 title claims abstract description 54
- 229910052710 silicon Inorganic materials 0.000 title claims abstract description 47
- 239000010703 silicon Substances 0.000 title claims abstract description 47
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 title claims abstract description 19
- 229910001416 lithium ion Inorganic materials 0.000 title claims abstract description 19
- 239000007773 negative electrode material Substances 0.000 title claims abstract description 16
- 238000002360 preparation method Methods 0.000 title claims abstract description 14
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 100
- 229910052814 silicon oxide Inorganic materials 0.000 claims abstract description 57
- 239000011256 inorganic filler Substances 0.000 claims abstract description 53
- 229910003475 inorganic filler Inorganic materials 0.000 claims abstract description 53
- 239000010405 anode material Substances 0.000 claims abstract description 37
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 35
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 29
- 239000011247 coating layer Substances 0.000 claims abstract description 29
- PAZHGORSDKKUPI-UHFFFAOYSA-N lithium metasilicate Chemical compound [Li+].[Li+].[O-][Si]([O-])=O PAZHGORSDKKUPI-UHFFFAOYSA-N 0.000 claims abstract description 25
- 229910052912 lithium silicate Inorganic materials 0.000 claims abstract description 25
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims description 38
- 229910052744 lithium Inorganic materials 0.000 claims description 37
- 238000010438 heat treatment Methods 0.000 claims description 27
- 239000000843 powder Substances 0.000 claims description 22
- 238000002156 mixing Methods 0.000 claims description 21
- 239000011863 silicon-based powder Substances 0.000 claims description 20
- 150000001335 aliphatic alkanes Chemical class 0.000 claims description 18
- 150000001336 alkenes Chemical class 0.000 claims description 18
- 238000006138 lithiation reaction Methods 0.000 claims description 18
- 239000000377 silicon dioxide Substances 0.000 claims description 18
- 238000001816 cooling Methods 0.000 claims description 16
- 238000006243 chemical reaction Methods 0.000 claims description 15
- -1 silica compound Chemical class 0.000 claims description 14
- OBNDGIHQAIXEAO-UHFFFAOYSA-N [O].[Si] Chemical compound [O].[Si] OBNDGIHQAIXEAO-UHFFFAOYSA-N 0.000 claims description 12
- 239000002245 particle Substances 0.000 claims description 11
- 239000011248 coating agent Substances 0.000 claims description 10
- 238000000576 coating method Methods 0.000 claims description 10
- 238000000197 pyrolysis Methods 0.000 claims description 9
- 238000000034 method Methods 0.000 claims description 7
- 239000000203 mixture Substances 0.000 claims description 7
- 235000012239 silicon dioxide Nutrition 0.000 claims description 7
- 239000000835 fiber Substances 0.000 claims description 6
- 229910004283 SiO 4 Inorganic materials 0.000 claims description 4
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 4
- LIVNPJMFVYWSIS-UHFFFAOYSA-N silicon monoxide Chemical compound [Si-]#[O+] LIVNPJMFVYWSIS-UHFFFAOYSA-N 0.000 claims description 4
- TVEXGJYMHHTVKP-UHFFFAOYSA-N 6-oxabicyclo[3.2.1]oct-3-en-7-one Chemical compound C1C2C(=O)OC1C=CC2 TVEXGJYMHHTVKP-UHFFFAOYSA-N 0.000 claims description 3
- 229920000049 Carbon (fiber) Polymers 0.000 claims description 3
- 239000006229 carbon black Substances 0.000 claims description 3
- 239000004917 carbon fiber Substances 0.000 claims description 3
- 239000000919 ceramic Substances 0.000 claims description 3
- 229910021389 graphene Inorganic materials 0.000 claims description 3
- 239000002048 multi walled nanotube Substances 0.000 claims description 3
- 239000002109 single walled nanotube Substances 0.000 claims description 3
- 239000000463 material Substances 0.000 abstract description 18
- 230000014759 maintenance of location Effects 0.000 abstract description 6
- 239000000872 buffer Substances 0.000 abstract description 4
- 230000000977 initiatory effect Effects 0.000 abstract description 4
- 150000002500 ions Chemical class 0.000 abstract description 3
- 230000000052 comparative effect Effects 0.000 description 14
- 239000002210 silicon-based material Substances 0.000 description 11
- 102220043159 rs587780996 Human genes 0.000 description 7
- 238000007599 discharging Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- JRZJOMJEPLMPRA-UHFFFAOYSA-N olefin Natural products CCCCCCCC=C JRZJOMJEPLMPRA-UHFFFAOYSA-N 0.000 description 3
- 230000001105 regulatory effect Effects 0.000 description 3
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 2
- 239000002041 carbon nanotube Substances 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 239000011267 electrode slurry Substances 0.000 description 2
- 239000003792 electrolyte Substances 0.000 description 2
- 230000005764 inhibitory process Effects 0.000 description 2
- 239000011244 liquid electrolyte Substances 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 238000001878 scanning electron micrograph Methods 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 238000010374 somatic cell nuclear transfer Methods 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 239000011800 void material Substances 0.000 description 2
- OTMSDBZUPAUEDD-UHFFFAOYSA-N Ethane Chemical compound CC OTMSDBZUPAUEDD-UHFFFAOYSA-N 0.000 description 1
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 1
- 239000005977 Ethylene Substances 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 230000003139 buffering effect Effects 0.000 description 1
- 229910021393 carbon nanotube Inorganic materials 0.000 description 1
- 239000010406 cathode material Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000006258 conductive agent Substances 0.000 description 1
- 239000011258 core-shell material Substances 0.000 description 1
- 150000001924 cycloalkanes Chemical class 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 239000008367 deionised water Substances 0.000 description 1
- 229910021641 deionized water Inorganic materials 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 239000007772 electrode material Substances 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 239000007770 graphite material Substances 0.000 description 1
- 229910021385 hard carbon Inorganic materials 0.000 description 1
- 230000002687 intercalation Effects 0.000 description 1
- 238000009830 intercalation Methods 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 229920001296 polysiloxane Polymers 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 239000007774 positive electrode material Substances 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 230000036632 reaction speed Effects 0.000 description 1
- 239000011856 silicon-based particle Substances 0.000 description 1
- 229910021384 soft carbon Inorganic materials 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 239000013589 supplement Substances 0.000 description 1
- 239000002562 thickening agent Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/362—Composites
- H01M4/366—Composites as layered products
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
- H01M4/5825—Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/624—Electric conductive fillers
- H01M4/625—Carbon or graphite
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
- H01M2004/027—Negative electrodes
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Composite Materials (AREA)
- Inorganic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Crystallography & Structural Chemistry (AREA)
- Materials Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Silicon Compounds (AREA)
- Battery Electrode And Active Subsutance (AREA)
Abstract
The invention discloses a composite silicon anode material and a preparation method thereof, and a lithium ion battery, wherein the composite silicon anode material comprises lithium silicate, inorganic filler and silicon oxide; and a carbon coating layer coated on the material. The coating layer provides strong structural protection and has higher ion conductivity; the lithium silicate improves the first coulombic efficiency and the cycle performance of the material; the inorganic filler provides a certain internal gap, and buffers the volume expansion, thereby improving the circulation performance; the composite silicon anode material has the characteristics of high initial efficiency and low expansion, and has good cycle performance. Simple preparation and easy industrialization. As the negative electrode material of the lithium ion battery, the lithium ion battery has higher initial effect, better capacity retention rate and smaller expansion of the pole piece after circulation.
Description
Technical Field
The invention belongs to the technical field of lithium ion battery materials, and particularly relates to a composite silicon anode material, a preparation method thereof and a lithium ion battery.
Background
Along with the continuous popularization of new energy automobiles, people put forth higher and higher demands on the energy density of lithium ion batteries, and the cathode material is taken as an important component part of the lithium ion batteries and has important influence on the specific energy and the cycle performance of the batteries; the current general negative electrode material is a graphite material, the capacity is close to the limit (the theoretical capacity is 372 mAh/g), and the subsequent high energy density requirement is difficult to meet.
The silicon-based material is considered as the most potential high-energy-density anode material of the next generation because of higher specific capacity (up to 4200mA.h/g), lower lithium intercalation site, large storage in crust and environmental friendliness. However, the silicon material belongs to a semiconductor, has poor conductivity and large expansion, can reach 300-400%, and seriously affects the performance of the silicon material; in addition, the first coulombic efficiency of the silicon material is low, so that the energy density of the battery is not expected to be exerted, and the industrialized application of the material is affected.
Disclosure of Invention
In order to overcome the defects of the prior art, the first aim of the invention is to provide a composite silicon anode material which has the characteristics of high initial efficiency and low expansion and has good cycle performance.
The second object of the present invention is to provide a method for preparing a composite silicon anode material, which is easy to industrialize.
The third purpose of the invention is to provide a lithium ion battery which has higher initial efficiency, better capacity retention rate and smaller expansion of pole pieces after circulation.
The first object of the invention can be achieved by adopting the following technical scheme:
a composite silicon negative electrode material comprises a composite material composed of a silicon oxygen compound, lithium silicate and an inorganic filler, and a carbon coating layer coated outside the composite material.
Further, the mass percentage of the lithium silicate is 2-50%, and the mass percentage of the inorganic filler is 1-50%; the carbon coating layer contains 0.5-3% by mass percent of silicon oxide and the balance of silicon oxide.
Further, the silicon oxide is SiOx,0.95 < x < 1.05.
Further, the lithium silicate is Li 2 SiO 3 、Li 4 SiO 4 、Li 2 Si 2 O 5 Or Li (lithium) 6 Si 2 O 7 One or more of the above.
Further, the inorganic filler is one or a combination of more than two of carbon black, super P, graphene, single-wall carbon nano tube, multi-wall carbon nano tube, carbon fiber, ceramic particle or porous carbon.
Further, the thickness of the carbon coating layer is 10nm-5 μm; preferably 50nm to 500nm.
Further, the inorganic filler is particles and/or fibers, and the D50 of the particles is 1nm-10 μm, preferably 5nm-100nm.
Further, the fibers have an aspect ratio value of 1 to 100, preferably 5 to 20.
The second object of the invention can be achieved by adopting the following technical scheme:
the preparation method of the composite silicon anode material comprises the following steps:
(1) Uniformly mixing silica powder, silicon dioxide powder and inorganic filler, and performing heat treatment to obtain a silica compound containing the inorganic filler;
(2) Carbon-coating a silica compound containing an inorganic filler;
(3) And mixing the silicon oxygen compound coated by carbon and containing the inorganic filler with a lithium source, and performing lithiation reaction to obtain the composite silicon anode material.
Further, in the step (1), the particle size of the silicon powder and the silicon dioxide powder is 1nm-50um; preferably 1um to 20um; the mass ratio of the silicon powder to the silicon dioxide powder is 10:1-1:10.
Further, in the step (3), the lithium source is lithium powder, and the addition mass of the lithium powder is 1% -20% of the total mass of the silicon powder and the silicon dioxide, and preferably 2% -10%.
Further, the heat treatment conditions in the step (1) are as follows: reacting for 2-3h at 900-1200 ℃ and then vacuum cooling.
Further, the carbon-coated condition in the step (2) is that the siloxane compound containing the inorganic filler and alkane and/or alkene are subjected to pyrolysis reaction for 1-2 hours at the temperature of 800-1100 ℃.
Further, the lithiation reaction conditions in step (3) are: reacting for 2-3h at 800-1100 ℃.
Further, steps (1) - (3) are performed at a vacuum level of 0.05Pa or less; heating to the target temperature at a rate of 5-15 ℃/min.
The third object of the invention can be achieved by adopting the following technical scheme:
a lithium ion battery comprises the composite silicon anode material prepared by any one of the above or the preparation method of any one of the above.
Compared with the prior art, the invention has the beneficial effects that:
1. the invention relates to a composite silicon anode material, which comprises lithium silicate, inorganic filler and silicon oxide; and a carbon coating layer coated on the material. The coating layer provides strong structural protection and has higher ion conductivity; the lithium silicate improves the first coulombic efficiency and the cycle performance of the material; the inorganic filler provides a certain internal gap, and buffers the volume expansion, thereby improving the circulation performance; the composite silicon anode material has the characteristics of high initial efficiency and low expansion, and has good cycle performance.
2. The preparation method of the composite silicon anode material can form lithium silicate, combines the lithium silicate with inorganic filler and silicon oxide, and forms the composite silicon anode material after coating, and the preparation method is simple and easy to industrialize.
3. The lithium ion battery has higher initial effect, better capacity retention rate and smaller expansion of the pole piece after circulation.
Drawings
FIG. 1 is a block diagram of a composite silicon negative electrode material of the present invention;
wherein: 1. a carbon coating layer; 2. an inorganic filler; 3. a silicone compound; 4. lithium silicate;
fig. 2 is an SEM image of the composite silicon negative electrode material of the present invention.
Detailed Description
The technical scheme of the present invention will be clearly and completely described in the following in connection with specific embodiments. It will be apparent that the described embodiments are merely some, but not all, embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Silicon material is a potential high energy density negative electrode material, which belongs to a semiconductor, so that the conductivity is poor, and the silicon material expands, so that the performance is influenced; in addition, the silicon material is used as a negative electrode material, the ratio of the capacity released after the lithium ion battery is fully charged for the first time to the capacity fully charged for the first time is low, and the value of the released capacity is always lower than the charged capacity, so that the conversion efficiency is low; this results in less than expected battery energy density performance, affecting the industrial application of the materials. The invention provides a composite silicon anode material, which solves the problems of large silicon particle expansion and low initial effect.
A composite silicon negative electrode material comprises a composite material composed of a silicon oxygen compound, lithium silicate and an inorganic filler, and a carbon coating layer coated outside the composite material.
The composite silicon anode material is similar to a core-shell structure, as shown in figure 1, wherein the core is a composite material formed by a silicon oxygen compound, lithium silicate and an inorganic filler, and the lithium silicate can improve the first coulombic efficiency and the cycle performance of the material; the inorganic filler may provide some internal void, and the inorganic filler material expands in volume, thereby improving cycle performance. The shell is a carbon coating layer which can be hard carbon or soft carbon, and the carbon coating layer can avoid the direct contact between a composite material formed by a silicon oxygen compound, lithium silicate and an inorganic filler and the outside or electrolyte, so that the stability of the anode material is improved.
As one embodiment, the mass percentage of the lithium silicate is 2-50%, and the mass percentage of the inorganic filler is 1-50%; the carbon coating layer contains 0.5-3% by mass percent of silicon oxide and the balance of silicon oxide.
As one embodiment, the silicon oxide is SiOx,0.95 < x < 1.05.SiOx,0.95 < x < 1.05 is Si nanocrystalline with SiO 2 The mixed one is in a sub-oxidation state and has certain electrochemical performance.
As one embodiment, the lithium silicate is Li 2 SiO 3 、Li 4 SiO 4 、Li 2 Si 2 O 5 Or Li (lithium) 6 Si 2 O 7 One or more of the above. The lithium silicate can improve the conductivity of the pole piece material and supplement the consumption of effective lithium in the battery, and the multiplying power performance and the stability of the raw battery.
As one embodiment, the inorganic filler is one or a combination of two or more of carbon black, super P, graphene, single-walled carbon nanotubes, multi-walled carbon nanotubes, carbon fibers, ceramic particles, and porous carbon. The inorganic filler is a porous material, can provide a certain internal gap, and can buffer and expand when the silicon material expands, so that the integral structure of the material is changed little, the cycle performance is improved, and the stability of the performance and the extension of the service life are facilitated.
As one embodiment thereof, the carbon coating layer has a thickness of 10nm to 5 μm; preferably 50nm to 500nm.
As one embodiment thereof, the inorganic filler is particles and/or fibers, the D50 of the particles being 1nm to 10 μm, preferably 5nm to 100nm.
As one embodiment, the fibers have an aspect ratio value of 1 to 100, preferably 5 to 20.
The invention also provides a preparation method of the composite silicon anode material, which comprises the following steps:
(1) Uniformly mixing silica powder, silicon dioxide powder and inorganic filler, and performing heat treatment to obtain a silica compound containing the inorganic filler;
(2) Carbon-coating a silica compound containing an inorganic filler;
(3) And mixing the silicon oxygen compound coated by carbon and containing the inorganic filler with a lithium source, and performing lithiation reaction to obtain the composite silicon anode material.
Silicon powder and silicon dioxide can form silicon oxide SiOx in a sub-oxidation state through heat treatment, x is more than 0.95 and less than 1.05, the silicon oxide SiOx is mixed with inorganic filler for heat treatment, and the inorganic filler is uniformly dispersed in the formed silicon oxide to play a role in buffering the silicon oxide. After carbon coating, adding a lithium source, and enabling lithium atoms with small atom diameters to contact with silicon oxide through the carbon coating layer to generate lithiation reaction with the silicon oxide to generate Li 2 SiO 3 、Li 4 SiO 4 、Li 2 Si 2 O 5 Or Li (lithium) 6 Si 2 O 7 Is incorporated into the material, increases conductivity and reduces the consumption of available lithium in the battery. And the formed lithium silicate inhibits the expansion of silicon oxide, reducing the volume effect of the battery.
In one embodiment, in the step (1), the particle size of the silicon powder and the silicon dioxide powder is 1nm-50um; preferably 1um to 20um; the mass ratio of the silicon powder to the silicon dioxide powder is 10:1-1:10.
In one embodiment, in the step (3), the lithium source is lithium powder, and the addition mass of the lithium powder is 1% -20% of the total mass of the silicon powder and the silicon dioxide, and preferably 2% -10%.
As one embodiment, the conditions of the heat treatment in the step (1) are: reacting for 2-3h at 900-1200 ℃ and then vacuum cooling. In the embodiment, the heat treatment is performed in a vacuum furnace, and after the silicon powder, the silicon dioxide powder and the inorganic filler are uniformly mixed, the vacuum furnace is heated to a target temperature for reaction; preferably, the temperature is raised at a rate of 5-15 ℃/min during heating; further preferably, the temperature is raised at a rate of 10℃per minute during heating.
As one embodiment, the carbon-coated condition of step (2) is that the siloxane compound containing the inorganic filler is pyrolyzed with alkane and/or alkene at a temperature of 800 ℃ to 1100 ℃ for 1 to 2 hours. In this embodiment, the alkane is one or a combination of two or more of a chain alkane and/or a cyclic alkane, and the alkene is one or a combination of two or more of a chain alkene and/or a cyclic alkene. Wherein the mixture is mixed with the siloxane compound containing the inorganic filler at one time with alkane and/or alkene or is introduced into a reactor in which the siloxane compound containing the inorganic filler is placed in the form of an introduced gas. Preferably, the carbon coating is performed in a CVD furnace, alkane or alkene organic matters are introduced into a reactor containing a silicon oxygen compound containing inorganic filler, and the CVD furnace is heated to a target temperature for reaction; preferably, the temperature is raised at a rate of 5-15 ℃/min during heating; further preferably, the temperature is raised at a rate of 10℃per minute during heating.
As one embodiment, the alkane is a C1-C4 alkane; preferably, the alkane is methane and/or ethane; the olefin is C1-C4 olefin; preferably, the olefin is ethylene.
As one embodiment, the lithiation reaction conditions in step (3) are: reacting for 2h at 800-1100 ℃.
In this embodiment, the lithiation reaction is performed in a CVD furnace; heating the CVD furnace to a target temperature for reaction; preferably, the temperature is raised at a rate of 5-15 ℃/min during heating; further preferably, the temperature is raised at a rate of 10℃per minute during heating.
As one embodiment, steps (1) - (3) are performed at a vacuum level of 0.05Pa or less; heating at a rate of 5-15 deg.C/min; preferably, the temperature is raised to the target temperature at a rate of 10deg.C/min.
As one of the embodiments of this invention,
after evenly mixing silicon powder, silicon dioxide powder and inorganic filler, reacting for 2-3 hours at the temperature of 900-1200 ℃ under the vacuum degree of below 0.05Pa to obtain a silica compound containing the inorganic filler;
mixing a silica compound containing an inorganic filler with alkane and/or alkene, and carrying out pyrolysis reaction for 1-2h at the temperature of 800-1100 ℃ under the vacuum degree of below 0.05Pa to carry out carbon coating;
and mixing the silicon-oxygen compound coated by carbon and containing the inorganic filler with a lithium source, and carrying out lithiation reaction for 2-3 hours at the vacuum degree of below 0.05Pa and the temperature of 800-1100 ℃ to obtain the composite silicon anode material.
The invention also provides a lithium ion battery, which comprises the composite silicon anode material prepared by any one of the above or the preparation method of any one of the above.
Specific examples are described below.
Example 1
Uniformly mixing 300g of D50=10um silicon powder and 300g of silicon dioxide powder with 5% of Super P powder, adding into a vacuum furnace for heating treatment, adjusting the vacuum degree of the vacuum furnace to be below 0.05Pa, then raising the vacuum degree to 1050 ℃ at the speed of 10 ℃/min, reacting for 2h, and vacuum cooling to obtain a silicon oxide SiOx containing Super, wherein x is more than 0.95 and less than 1.05;
adding the obtained Super-containing silicon oxide into a CVD furnace, adjusting the vacuum degree to be below 0.05Pa, introducing alkane or alkene organic matters, then raising the temperature to 950 ℃ at the speed of 10 ℃/min, and carrying out pyrolysis reaction for 1h to form a 1um coating layer on the SiOx surface;
uniformly mixing the SiOx with the coating layer and 3% lithium powder, adding the mixture into a CVD furnace, adjusting the vacuum degree to be below 0.05Pa, then raising the temperature to 950 ℃ at the speed of 10 ℃/min, carrying out lithiation reaction for 2 hours, and carrying out vacuum cooling to obtain the composite silicon anode material. The SEM image is shown in fig. 2.
Example 2
Uniformly mixing 30g of silicon powder 300 with D50=20um and 30g of silicon dioxide powder with 10% of CNT powder, adding into a vacuum furnace for heating treatment, adjusting the vacuum degree of the vacuum furnace to be below 0.05Pa, then raising the vacuum degree to 900 ℃ at the speed of 10 ℃/min, reacting for 3 hours, and vacuum cooling to obtain a silicon oxide SiOx containing CNT, wherein x is more than 0.95 and less than 1.05;
adding a silicon oxygen compound containing CNTs into a CVD furnace, adjusting the vacuum degree to be below 0.05Pa, introducing alkane or alkene organic matters, then raising the temperature to 800 ℃ at the speed of 10 ℃/min, and carrying out pyrolysis reaction for 2 hours to form a 1um coating layer on the SiOx surface.
Uniformly mixing the SiOx with the coating layer and 3% lithium powder, adding the mixture into a CVD furnace, adjusting the vacuum degree to be below 0.05Pa, then raising the temperature to 1100 ℃ at a speed of 5 ℃/min, carrying out lithiation reaction for about 3 hours, and carrying out vacuum cooling to obtain the composite silicon anode material.
Example 3
30g of D50=50um silicon powder, 300g of silicon dioxide powder and 1% of Al 2 O 3 Mixing the powder, heating in a vacuum furnace with vacuum degree of below 0.05Pa, heating to 1200deg.C at a rate of 10deg.C/min, reacting for 2.5 hr, and vacuum cooling to obtain Al-containing powder 2 O 3 0.95 < x < 1.05;
will contain Al 2 O 3 Adding the silicon oxide SiOx into a CVD furnace, regulating the vacuum degree to be below 0.05Pa, introducing alkane or alkene organic matters, then raising the temperature to 1100 ℃ at the speed of 10 ℃/min, and carrying out pyrolysis reaction for 1.5h to form a 1um coating layer on the SiOx surface.
Uniformly mixing the SiOx with the coating layer and 3% lithium powder, adding the mixture into a CVD furnace, adjusting the vacuum degree to be below 0.05Pa, then raising the temperature to 800 ℃ at the speed of 15 ℃/min, carrying out lithiation reaction for about 2.5 hours, and carrying out vacuum cooling to obtain the composite silicon anode material.
Examples 4 to 7
The other steps and process parameters were the same as in example 1, except that the content of the added lithium powder was 1%, 5%, 10% and 20%, respectively.
Example 8
The other steps are the same as in example 1, except that 2.5% of particulate Super P and 2.5% of fibrous carbon nanotube SCNT are mixed with the added inorganic filler.
Comparative example 1
Uniformly mixing 300g of D50=10um silicon powder and 300g of silicon dioxide powder with 5% of Super P powder, adding into a vacuum furnace for heating treatment, adjusting the vacuum degree of the vacuum furnace to be below 0.05Pa, then raising the vacuum degree to 1050 ℃ at the speed of 10 ℃/min, reacting for 2h, and vacuum cooling to obtain a silicon oxide SiOx containing Super, wherein x is more than 0.95 and less than 1.05;
adding a Super silicon oxide SiOx into a CVD furnace, regulating the vacuum degree to be below 0.05Pa, introducing alkane or alkene organic matters, then raising the temperature to 90 ℃ at the speed of 10 ℃/min, and carrying out pyrolysis reaction for 1h to form a 1um coating layer on the SiOx surface to obtain the material.
Comparative example 2
Uniformly mixing 300g of D50=10um silicon powder and 300g of silicon dioxide powder respectively, adding into a vacuum furnace for heating treatment, adjusting the vacuum degree of the vacuum furnace to be below 0.05Pa, then raising the vacuum degree to 1050 ℃ at the speed of 10 ℃/min, reacting for 2h, and vacuum cooling to obtain a silicon oxide SiOx, wherein x is more than 0.95 and less than 1.05;
adding a silicon oxide SiOx into a CVD furnace, adjusting the vacuum degree to be below 0.05Pa, introducing alkane or alkene organic matters, then raising the temperature to 950 ℃ at a speed of 10 ℃/min for pyrolysis reaction for 1h, and forming a 1um coating layer on the SiOx surface;
uniformly mixing the SiOx with the coating layer and 3% lithium powder, adding the mixture into a CVD furnace, adjusting the vacuum degree to be below 0.05Pa, then raising the temperature to 950 ℃ at the speed of 10 ℃/min, carrying out lithiation reaction for about 2 hours, and carrying out vacuum cooling to obtain the silicon material containing lithium silicate.
Comparative example 3
Uniformly mixing 300g of D50=10um silicon powder and 300g of silicon dioxide powder respectively, adding into a vacuum furnace for heating treatment, adjusting the vacuum degree of the vacuum furnace to be below 0.05Pa, then raising the vacuum degree to 1050 ℃ at the speed of 10 ℃/min, reacting for 2h, and vacuum cooling to obtain a silicon oxide SiOx, wherein x is more than 0.95 and less than 1.05;
adding a silicon oxide SiOx into a CVD furnace, regulating the vacuum degree to be below 0.05Pa, introducing alkane or alkene organic matters, then raising the temperature to 900 ℃ at the speed of 10 ℃/min, and carrying out pyrolysis reaction for 1h to form a 1um coating layer on the SiOx surface to obtain the material.
Comparative example 4
Uniformly mixing 300g of D50=10um silicon powder and 300g of silicon dioxide powder with 5% of Super P powder, adding into a vacuum furnace for heating treatment, adjusting the vacuum degree of the vacuum furnace to be below 0.05Pa, then raising the vacuum degree to 1050 ℃ at the speed of 10 ℃/min, reacting for 2h, and vacuum cooling to obtain a silicon oxide SiOx containing Super, wherein x is more than 0.95 and less than 1.05;
uniformly mixing the obtained Super-containing silicon oxide and 3% lithium powder, adding the mixture into a CVD furnace, adjusting the vacuum degree to be below 0.05Pa, then increasing the temperature to 950 ℃ at the speed of 10 ℃/min, carrying out lithiation reaction for 2 hours, introducing alkane or alkene organic matters after vacuum cooling, then increasing the temperature to 950 ℃ at the speed of 10 ℃/min, carrying out reaction for 2 hours, and carrying out vacuum cooling to obtain the silicon material containing lithium silicate.
Comparative example 5
The other steps and process parameters were the same as in example 1, except that the content of the added lithium powder was 30%.
The electrode materials obtained in comparative examples 1 to 5 and examples 1 to 8 were assembled into a battery cell, and electrochemical performance test was performed:
firstly, 96.0wt% of the materials obtained in comparative examples 1-5 and examples 1-8, 1.5wt% of a binder SBR, 1.5wt% of a thickener CMC-Na, 1.0wt% of a conductive agent Super P and a certain amount of deionized water are added into a planetary stirring tank, and stirred for 8 hours at a stirring speed of revolution 35Hz and dispersion 1500Hz, so that the materials are fully mixed to prepare negative electrode slurry with discharge viscosity of 2000-6000mPa.s;
and (3) coating the negative electrode slurry on the surface of a current collector with the thickness of 6 mu m, and drying for 8 hours in a vacuum (-0.1 MPa.) drying oven at 90 ℃ to obtain the negative electrode plate.
The positive electrode active material of the selected positive electrode plate is lithium cobaltate, the diaphragm is a conventional substrate diaphragm for a lithium battery, and the electrolyte is a liquid electrolyte for lithium ion battery business; and preparing the prepared negative plate, positive plate and diaphragm into a lithium ion battery by adopting a winding process and matching with liquid electrolyte. Charging and discharging the lithium ion battery at 0.1C to obtain primary charging and discharging efficiency, and circulating for 500 weeks under the condition of 1C/charging and discharging to obtain capacity retention rate and pole piece expansion data; the results are shown in Table 1.
Table 1 lithium battery negative electrode material battery test results
The test results in table 1 show that the composite silicon anode material provided by the invention has more excellent battery performance, higher initial efficiency, better capacity retention rate and smaller expansion of the pole piece after circulation compared with the comparative example. It can be seen from examples 1,4 to 7 and comparative example 5 that by adjusting the doping amount of lithium, a silicon anode material having higher initial efficiency can be obtained. Comparative example 5 when the lithium content is too high, the internal silicon grain size grows up, resulting in an increase in expansion and deterioration in cycle performance; therefore, a doping amount of lithium of 1% -20% is suitable.
It can be seen from examples 1-3 and example 8 that by adjusting different buffers, a silicon anode material with better expansion can be obtained, wherein example 8 performs better, has better initial effect under the condition of lower lithium doping, and maintains higher capacity retention rate and lower pole piece expansion rate, because granular SP and fibrous SCNT can play the role of combining dotted lines, the conductive network is better, and the expansion inhibition capability is stronger.
Comparative example 1, which is not lithium doped, consumes a large amount of active lithium for the first charge and discharge, so the first effect is lower; comparative example 2 has no inorganic filler, has poor expansion inhibition capability, and has larger expansion of the pole piece after circulation and poor circulation performance; comparative example 3 exhibited the lowest first effect and worst pole piece expansion properties.
The comparative example 4 is subjected to lithiation and then coating, so that the lithiation reaction speed is difficult to control; the invention is characterized by coating and lithiation, which can effectively control the speed of lithiation reaction, make the reaction more complete and the distribution of the obtained product more uniform. In summary, the invention provides a composite silicon anode material, a preparation method thereof and a lithium ion battery, wherein the composite silicon anode material comprises a composite material composed of a silicon oxygen compound, lithium silicate and an inorganic filler, and a carbon coating layer coated outside the composite material. The coating layer can provide strong structural protection and has higher ion conductivity; the lithium silicate can improve the first coulombic efficiency and the cycle performance of the material; the inorganic filler may provide some internal void, cushioning material volume expansion, and thus improve cycle performance. The silicon material provided by the invention is simple to prepare and easy to industrialize.
The above embodiments are only preferred embodiments of the present invention, and the scope of the present invention is not limited thereto, but any insubstantial changes and substitutions made by those skilled in the art on the basis of the present invention are intended to be within the scope of the present invention as claimed.
Claims (10)
1. The composite silicon negative electrode material is characterized by comprising a composite material formed by a silicon oxygen compound, lithium silicate and an inorganic filler, and a carbon coating layer coated outside the composite material.
2. A composite silicon negative electrode material according to claim 1, wherein,
the mass percentage of the lithium silicate is 2-50%, and the mass percentage of the inorganic filler is 1-50%; the carbon coating layer contains 0.5-3% by mass percent of silicon oxide and the balance of silicon oxide.
3. A composite silicon negative electrode material according to claim 1, wherein,
the silicon oxide is SiOx, x is more than 0.95 and less than 1.05;
the lithium silicate is Li 2 SiO 3 、Li 4 SiO 4 、Li 2 Si 2 O 5 Or Li (lithium) 6 Si 2 O 7 One or more of the above-mentioned compositions;
the inorganic filler is one or a combination of more than two of carbon black, super P, graphene, single-wall carbon nano tube, multi-wall carbon nano tube, carbon fiber, ceramic particle or porous carbon.
4. A composite silicon negative electrode material according to claim 1, wherein,
the thickness of the carbon coating layer is 10nm-5 mu m; preferably 50nm to 500nm.
5. A composite silicon negative electrode material according to claim 1, wherein,
the inorganic filler is particles and/or fibers, and the D50 of the particles is 1nm-10 mu m, preferably 5nm-100nm;
the aspect ratio of the fibers is 1 to 100, preferably 5 to 20.
6. The preparation method of the composite silicon anode material is characterized by comprising the following steps of:
(1) Uniformly mixing silica powder, silicon dioxide and inorganic filler, and then performing heat treatment to obtain a silica compound containing the inorganic filler;
(2) Carbon-coating a silica compound containing an inorganic filler;
(3) And mixing the silicon oxygen compound coated by carbon and containing the inorganic filler with a lithium source, and performing lithiation reaction to obtain the composite silicon anode material.
7. The method for preparing a composite silicon anode material according to claim 6, wherein,
in the step (1), the grain diameters of the silicon powder and the silicon dioxide are 1nm-50um; preferably 1um to 20um; the mass ratio of the silicon powder to the silicon dioxide is 10:1-1:10; the mass ratio of the silicon powder to the inorganic filler is 50:1-1:5;
in the step (3), the lithium source is lithium powder, and the adding mass of the lithium powder is 1% -20% of the total mass of the silicon powder and the silicon dioxide; preferably 2% -10%.
8. The method for preparing a composite silicon anode material according to claim 6, wherein,
the heat treatment conditions in the step (1) are as follows: reacting for 2-3h at 900-1200 ℃ and then vacuum cooling;
the carbon-coated condition in the step (2) is that a siloxane compound containing inorganic filler and alkane and/or alkene are subjected to pyrolysis reaction for 1-2h at the temperature of 800-1100 ℃;
the lithiation reaction conditions in step (3) are: reacting for 2-3h at 800-1100 ℃.
9. The method for preparing a composite silicon anode material according to any one of claims 6 to 8, characterized in that,
steps (1) - (3) are performed at a vacuum level of 0.05Pa or less; heating to the target temperature at a rate of 5-15 ℃/min.
10. A lithium ion battery, characterized by comprising the composite silicon anode material according to any one of claims 1 to 5 or the composite silicon anode material prepared by the preparation method of the composite silicon anode material according to any one of claims 6 to 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310935864.1A CN116864646A (en) | 2023-07-27 | 2023-07-27 | Composite silicon negative electrode material, preparation method thereof and lithium ion battery |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310935864.1A CN116864646A (en) | 2023-07-27 | 2023-07-27 | Composite silicon negative electrode material, preparation method thereof and lithium ion battery |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116864646A true CN116864646A (en) | 2023-10-10 |
Family
ID=88223424
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310935864.1A Pending CN116864646A (en) | 2023-07-27 | 2023-07-27 | Composite silicon negative electrode material, preparation method thereof and lithium ion battery |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116864646A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117446805A (en) * | 2023-10-25 | 2024-01-26 | 广东凯金新能源科技股份有限公司 | Preparation method of carbon-coated silicon material and carbon-coated silicon material |
-
2023
- 2023-07-27 CN CN202310935864.1A patent/CN116864646A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117446805A (en) * | 2023-10-25 | 2024-01-26 | 广东凯金新能源科技股份有限公司 | Preparation method of carbon-coated silicon material and carbon-coated silicon material |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109004203B (en) | Silicon-carbon composite negative electrode material and preparation method thereof | |
| CN108428876B (en) | High-performance silicon/carbon nano composite negative electrode material and preparation method thereof | |
| WO2021128603A1 (en) | Modified silicon monoxide material for use in negative electrode of lithium-ion battery and preparation method therefor | |
| CN112886015B (en) | Three-dimensional carbon-silicon composite material | |
| CN109817949B (en) | Silicon or oxide @ titanium dioxide @ carbon core-shell structure composite particle thereof and preparation | |
| CN107994217B (en) | Preparation method of double-coated silicon-based composite material and lithium ion battery | |
| CN108493421B (en) | Preparation method of tin-silicon-based graphene ball cathode material for lithium ion battery | |
| CN109585801B (en) | Carbon nanotube filled silicon/hollow carbon composite negative electrode material and preparation method thereof | |
| CN107658452B (en) | Silicon/carbon nanotube/silicon oxycarbide composite material and preparation method and application thereof | |
| JP2010501970A (en) | Silicon / carbon composite cathode material for lithium ion battery and method for producing the same | |
| CN112510185A (en) | Silicon-carbon composite negative electrode material and manufacturing method thereof | |
| CN112768671A (en) | Preparation method of silicon-carbon composite negative electrode material and negative electrode material prepared by preparation method | |
| Dong et al. | Exploring the practical applications of silicon anodes: a review of silicon-based composites for lithium-ion batteries | |
| CN112374482B (en) | Silicon-oxygen-fluorine-carbon negative electrode material of lithium ion battery prepared by mechanochemical method | |
| CN108281627A (en) | A kind of lithium ion battery germanium carbon compound cathode materials and preparation method thereof | |
| CN116053452A (en) | Silicon-based anode material, preparation method thereof, battery and terminal | |
| CN116864646A (en) | Composite silicon negative electrode material, preparation method thereof and lithium ion battery | |
| CN115207330A (en) | Lithium-containing silicon-oxygen negative electrode material and manufacturing method thereof | |
| WO2023005987A1 (en) | Two-element lithium supplementing additive, preparation method therefor, and use thereof | |
| CN112952048A (en) | Silicon-carbon composite negative electrode material, preparation method thereof, electrode and secondary battery | |
| TWI805421B (en) | Particles of silicon-carbon composite material and method of manufacturing the same | |
| CN115863574A (en) | Negative electrode material, negative plate comprising negative electrode material and battery | |
| CN112310386B (en) | Silicon oxide/carbon lithium ion battery cathode material with hollow structure and preparation method and application thereof | |
| CN114976024A (en) | Silicon-based material and preparation method and application thereof | |
| CN113745519A (en) | Silicon-based negative electrode material with artificial SEI film and preparation method and application thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |