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KR-20260066132-A - Silicon-based composite material, method for manufacturing the same, and cathode

KR20260066132AKR 20260066132 AKR20260066132 AKR 20260066132AKR-20260066132-A

Abstract

The present invention relates to a silicon-based composite material, a method for manufacturing the same, and a cathode. The silicon-based composite material comprises a porous matrix, silicon nanoparticles, and heteroatoms. The porous matrix has three-dimensional cross-pore channels with multi-stage pores, and the pore channels contain at least one silicon nanoparticle. The heteroatoms are partially coated on the surface of at least the silicon nanoparticles, and/or, the heteroatoms are spaced apart between the silicon nanoparticles. The heteroatoms separate and confine the silicon nanoparticles, thereby allowing the silicon nanoparticles to be uniformly dispersed in the three-dimensional cross-pore channels of the porous matrix. This effectively mitigates the volume effect of silicon during the charge-discharge process and prevents structural collapse of the composite material, thereby improving the cycle stability of the electrode.

Inventors

  • 천 칭화
  • 팡 빙
  • 류 루이팡

Assignees

  • 란시 지데 어드밴스드 메테리얼즈 컴퍼니 리미티드.

Dates

Publication Date
20260512
Application Date
20240327
Priority Date
20230906

Claims (14)

  1. In silicon-based composite materials, A silicon-based composite material comprising silicon-based composite particles, wherein the silicon-based composite particles comprise a porous matrix, silicon nanoparticles, and heteroatoms, wherein the porous matrix has a three-dimensional cross-pore channel having a multi-stage pore, the pore channel comprises at least one silicon nanoparticle, the heteroatom is partially coated on the surface of at least the silicon nanoparticle, and/or, the heteroatom is spaced apart between the silicon nanoparticles.
  2. In paragraph 1, The silicon-based composite material further comprises closed pores, wherein the volume of the closed pores of the silicon-based composite material is 0.01 to 0.25 cm³ /g; and/or, wherein the true density of the silicon-based composite material is 1.3 to 3.0 g/ cm³ .
  3. In paragraph 1, A silicon-based composite material characterized in that the specific surface area of the silicon-based composite material is 0.5 to 50 m² /g, preferably 0.5 to 10 m² /g, and more preferably 0.5 to 2 m² /g; and/or, the compressive specific surface area of the silicon-based composite material is 1 to 20 times the specific surface area of the silicon-based composite material, preferably 1 to 10 times, and more preferably 1 to 5 times.
  4. In paragraph 1, The silicon nanoparticles comprise a first silicon nanoparticle, a second silicon nanoparticle, and a third silicon nanoparticle, wherein the size of the first silicon nanoparticle is D1, 0.35 nm ≤ D1 ≤ 2 nm, the size of the second silicon nanoparticle is D2, 2 nm < D2 ≤ 5 nm, and the size of the third silicon nanoparticle is D3, 5 nm < D3 ≤ 10 nm; Preferably, a silicon-based composite material characterized in that, based on the mass of the silicon nanoparticles, the mass content of the first silicon nanoparticle is 60 to 100%, the mass content of the second silicon nanoparticle is 0 to 40%, and the mass content of the third silicon nanoparticle is 0 to 5%.
  5. In paragraph 1, The pore channels of the porous matrix include a first pore channel, a second pore channel, and a third pore channel, wherein the pore diameter of the first pore channel is d1 and 0.35 nm ≤ d1 ≤ 2 nm, the pore diameter of the second pore channel is d2 and 2 nm < d2 ≤ 10 nm, and the pore diameter of the third pore channel is d3 and 10 nm < d3 ≤ 50 nm; Preferably, a silicon-based composite material characterized in that the volume ratio of the first pore channel in the pore channel of the porous matrix is 30 to 95%, the volume ratio of the second pore channel in the pore channel of the porous matrix is 1 to 60%, and the volume ratio of the third pore channel in the pore channel of the porous matrix is 0 to 15%.
  6. In paragraph 1, A silicon-based composite material characterized in that the porous matrix comprises at least one of porous carbon, molecular sieve, porous metal, porous metal oxide, porous metal-organic framework, and porous organic-inorganic hybrid material framework; preferably, the specific surface area of the porous matrix is 200 to 3000 m² /g and the pore capacity is 0.2 to 3.0 cm³ /g.
  7. In paragraph 1, In the above silicon-based composite material, the mass content of the silicon element is 5 to 90%, and the mass content of the heteroatom is 0.1 to 10%; and/or, the heteroatoms are coated on the surface of the silicon nanoparticles and/or are spaced apart between a plurality of the silicon nanoparticles to form a heteroatom layer, wherein the total thickness of the heteroatom layer is 0.5 to 50 nm, preferably 0.5 to 10 nm, and more preferably 0.5 to 2 nm; and/or, a silicon-based composite material characterized in that the heteroatom comprises at least one of B, C, N, P, O, and S.
  8. In paragraph 1, A silicon-based composite material characterized in that the median particle size d V,50 of the silicon-based composite material is 5 to 20 μm and the diameter distance ( d V, 90 - d V,10 )/ d V,50 is 0.8 to 2.0; preferably, the median particle size d V,50 of the silicon-based composite material is 6 to 12 μm and the diameter distance ( d V, 90 - d V,10 )/ d V,50 is 0.8 to 1.2.
  9. In any one of paragraphs 1 through 8, The silicon-based composite material further comprises a coating layer; preferably, the material of the coating layer is one or more selected from a solid-state electrolyte, a conductive polymer, a carbonaceous material, a metal, an alloy, a metal oxide, a metal hydroxide, a metal halide, a metal sulfide, a metal phosphate, a boric acid-containing compound, a sulfuric acid-containing compound, a nitric acid-containing compound, and a polymetallic oxyphosphate; more preferably, the silicon-based composite material is characterized in that the coating layer comprises a carbonaceous material.
  10. In a method for manufacturing silicon-based composite materials, The method comprises the steps of: providing a porous matrix having three-dimensional cross-pore channels having multi-stage pores (S1); and obtaining a silicon-based composite material by contacting a silicon-containing precursor and a heteroatom-containing precursor with the porous matrix (S2). A method for manufacturing a silicon-based composite material, characterized in that the porous matrix, the pore channel, the silicon nanoparticle, and the heteroatom each have the same meaning as the porous matrix, pore channel, silicon nanoparticle, and heteroatom according to claims 1 to 9.
  11. In Paragraph 10, In the above step (S2), the silicon-containing precursor comprises at least one of monosilane, disilane, trisilane, halogensilane, polysilane, silole and its derivatives, silafluorene and its derivatives; and/or, the heteroatom-containing precursor comprises at least one of an oxygen-containing precursor, a carbon-containing precursor, a nitrogen-containing precursor, a phosphorus-containing precursor, a sulfur-containing precursor, or a boron-containing precursor; and/or, the temperature at which the silicon-containing precursor and the heteroatom-containing precursor contact the porous matrix is 150 to 1000°C and the time is 0.1 to 100h; preferably, the temperature at which the silicon-containing precursor and the heteroatom-containing precursor contact the porous matrix is 200 to 700°C; and/or, a method of contacting the silicon-containing precursor and the heteroatom-containing precursor with the porous matrix comprises: a method in which the silicon-containing precursor and the heteroatom-containing precursor are in alternating contact with the porous matrix; or a method in which the silicon-containing precursor and the heteroatom-containing precursor are in simultaneous contact with the porous matrix; or a method in which a mixed gas comprising the silicon-containing precursor and the silicon-containing precursor and the heteroatom-containing precursor is in alternating contact with the porous matrix, wherein, preferably, the silicon-containing precursor is in continuous contact with the porous matrix and the heteroatom-containing precursor is intermittently introduced during this process, a method for manufacturing a silicon-based composite material.
  12. In Paragraph 10, A method for manufacturing a silicon-based composite material, further comprising a step (S3) of obtaining a silicon-based composite material having a coating layer on its surface by coating the composite material obtained in step (S2) after step (S2), wherein the coating layer has the same meaning as the coating layer according to claim 9.
  13. A cathode characterized by comprising a negative electrode active material comprising a silicon-based composite material according to any one of claims 1 to 9 or a silicon-based composite material obtained by a method for manufacturing a silicon-based composite material according to any one of claims 10 to 12.
  14. In the case of batteries, A battery comprising a positive electrode, a negative electrode, a separator, and an electrolyte, wherein the negative electrode comprises a negative electrode active material, and the negative electrode active material comprises a silicon-based negative electrode material containing sub-nano micropores according to any one of claims 1 to 9, and/or the silicon-based negative electrode material containing sub-nano micropores manufactured by a method for manufacturing a silicon-based composite material according to any one of claims 10 to 12.

Description

Silicon-based composite material, method for manufacturing the same, and cathode [Cross-reference of related applications] The present application claims priority to a Chinese patent application filed with the National Intellectual Property Administration of China on September 6, 2023, with application number “202311148345.7” and application title “Silicon-based composite material and method for manufacturing the same and cathode”, the entire contents of which are incorporated by reference into the present application. [Technology Field] The present application relates to the field of battery material technology, specifically to a silicon-based composite material, a method for manufacturing the same, and a negative electrode. Silicon is an alloyed lithium insertion material with a theoretical lithium insertion capacity of 4200 mAh/g. It is abundant, safe, and non-toxic, and is currently the lithium-ion battery anode material with the highest potential to realize industrial applications by replacing traditional carbon materials. Silicon-based materials have two problems as lithium-ion battery anode materials. First, silicon has poor conductivity, which can be resolved through various methods such as carbon carriers, carbon blending, and carbon coating; second, silicon undergoes massive volume expansion/contraction during the lithium insertion/lithium extraction process, which destroys the electrode structure, reduces battery capacity, and lowers cycle efficiency. In recent years, volume expansion of silicon-based composite materials, such as silicon-oxygen and silicon-carbon cathodes, has been significantly reduced by optimizing silicon particle size and distribution and controlling the structure of the cathode material; however, these improvements are still far from sufficient for practical applications. Therefore, how to further reduce the volume expansion of silicon-based composite materials during the charge-discharge process and improve cycle life is an important task that needs to be urgently addressed. The drawings in the specification, which constitute part of this application, are intended to provide further understanding of this application, and exemplary embodiments and descriptions of this application are used to interpret this application and do not constitute an inappropriate limitation of this application. The drawings are as follows. Figure 1 shows a schematic diagram of the cross-sectional structure of a silicon-based composite material provided in the present application. Figure 2 shows a schematic diagram of the structure of a porous matrix of a silicon-based composite material provided in the present application. Figure 3 shows the pore size distribution of the porous matrix of Example 1. Figure 4 shows the XRD pattern of the silicon-based composite material obtained in Example 1. Figure 5 shows the dQ/dV curve obtained according to the lithium deliquency curve of the first cycle in the constant current charge/discharge curve of the silicon-based composite material lithium electronic battery obtained in Example 1. Figure 6 shows the dQ/dV curve obtained according to the lithium deliquency curve of the first cycle in the constant current charge/discharge curve of the silicon-based composite material obtained in Comparative Example 1. It should be noted that the embodiments and features of the embodiments of this application may be combined with one another unless contradictory. The present application will be described in detail below in conjunction with the embodiments. As analyzed in the background art of this application, silicon in the prior art exhibits significant volume expansion during the charge-discharge process when used as a negative electrode material for lithium-ion batteries. To address this issue, CN108475779B discloses a novel material with very long-lasting lithium insertion and a method for manufacturing the same. This comprises a composite of a porous carbon scaffold and silicon, wherein the porous scaffold material may be a carbon material containing micropores, mesopores, and/or macropores, and the pore channels are subsequently filled with silicon. Silicon is deposited onto the pore channel structure of the porous scaffold material to form a composite. This composite exhibits a remarkably long-lasting lithium insertion capability. When manufactured into a battery cell, it possesses excellent cycle life. The above invention can reduce the expansion of the silicon anode material itself to some extent by forming uniformly dispersed nano-silicon particles through the deposition of silicon within the pore channels of a porous carbon material using a chemical vapor deposition method. The improvement of electrochemical performance is highly correlated with the size and distribution of the deposited silicon particles and the physicochemical properties of the scaffold material. Compared to graphite anodes, silicon materials deposited by the above technology still undergo sign