US-12626910-B2 - Composite silicon material and preparation method therefor, negative electrode plate, secondary battery, and electrical apparatus

US12626910B2US 12626910 B2US12626910 B2US 12626910B2US-12626910-B2

Abstract

The composite silicon material includes an inner core and a silicon-containing cladding layer cladded on the outer side of the inner core. The inner core comprises a silicon-carbon material, the silicon-carbon material includes a porous conductive material and a first silicon-based material, the outer surface of the porous conductive material has pores, and at least a portion of the first silicon-based material is distributed in the pores. The silicon-containing cladding layer contains an ion-conducting material and a second silicon-based material. The second silicon-based material is dispersed in the ion-conducting material. At least a portion of the first silicon-based material is embedded in the pores of the porous conductive material, which can effectively alleviate the problem of silicon expansion; meanwhile, the ion-conducting material can increase the ion transmission path, thereby effectively alleviating the problem of poor dynamic performance caused by the small number of ion transmission paths of the silicon-carbon material.

Inventors

Kai Wu
Zhipeng Cheng
Dongyang Shi
Ning Chen
Zhi Liu
Yaqian Deng
Yuzhen Wang

Assignees

CONTEMPORARY AMPEREX TECHNOLOGY CO., LIMITED

Dates

Publication Date: 20260512
Application Date: 20250820
Priority Date: 20230906

Claims (19)

1 . A composite silicon material, comprising: an inner core, the inner core comprising a silicon-carbon material, the silicon-carbon material comprising a porous conductive material and a first silicon-based material, the porous conductive material having pores on its outer surface, and at least a portion of the first silicon-based material being distributed in the pores; a silicon-containing cladding layer cladded on the outer side of the inner core, the silicon-containing cladding layer comprising an ion-conducting material and a second silicon-based material, and the second silicon-based material being dispersed in the ion-conducting material; and a first carbon cladding layer, wherein the first carbon cladding layer is located between the inner core and the silicon-containing cladding layer.
2 . The composite silicon material according to claim 1 , wherein the silicon-containing cladding layer has at least one of the following characteristics: (1) the silicon-containing cladding layer has a thickness of 5 nm to 100 nm; (2) the ion-conducting material comprises one or more of hard carbon, soft carbon, graphite, transition metal nitride, silicon-based alloy, tin-based alloy and lithium metal; (3) the ion-conducting material and the second silicon-based material are compounded into silicon oxide; (4) the volume average particle size Dv50 of the second silicon-based material is 2 nm to 20 nm; (5) the second silicon-based material comprises one or more of elemental silicon and silicon-tin alloy; and (6) the shape of the second silicon-based material comprises one or more of the following: granular, linear, spherical, quasi-spherical, and sheet-like.
3 . The composite silicon material according to claim 2 , wherein the thickness of the silicon-containing cladding layer is 30 nm to 60 nm.
4 . The composite silicon material according to claim 2 , wherein the molar ratio of oxygen element to silicon element contained in the silicon oxide is denoted as x, and 0<x≤0.6.
5 . The composite silicon material according to claim 2 , wherein the volume average particle size Dv50 of the second silicon-based material is 2 nm to 9 nm.
6 . The composite silicon material according to claim 1 , wherein the silicon-carbon material has at least one of the following characteristics: (1) the mass percentage of silicon element in the silicon-carbon material is 3% to 25%; (2) the pore size of the pores is 2 nm to 50 nm; (3) the stacking height of the first silicon-based material in the pores is 1 nm to 35 nm; (4) the shape of the silicon-carbon material comprises one or more of granular, spherical and quasi-spherical; (5) the first silicon-based material comprises one or more of elemental silicon and silicon-tin alloy; (6) the shape of the first silicon-based material comprises one or more of the following: granular, linear, spherical, quasi-spherical, and sheet-like; and (7) the porous conductive material comprises porous carbon.
7 . The composite silicon material according to claim 6 , wherein the mass percentage of silicon element in the silicon-carbon material is 8% to 10%.
8 . The composite silicon material according to claim 6 , wherein the pore size of the pores is 15 nm to 35 nm.
9 . The composite silicon material according to claim 8 , wherein the stacking height of the first silicon-based material in the pores is 15 nm to 25 nm.
10 . The composite silicon material according to claim 1 , wherein at least 3% of the first silicon-based material is embedded in the pores.
11 . The composite silicon material according to claim 10 , wherein all the first silicon-based material is embedded in the pores.
12 . The composite silicon material according to claim 1 , wherein the first carbon cladding layer has at least one of the following characteristics: (1) the first carbon cladding layer has a thickness of 10 nm to 30 nm; and (2) the material of the first carbon cladding layer comprises amorphous carbon.
13 . The composite silicon material according to claim 1 , wherein the composite silicon material further comprises a second carbon cladding layer, and the second carbon cladding layer is cladded on the outer side of the silicon-containing cladding layer.
14 . The composite silicon material according to claim 13 , wherein the second carbon cladding layer has at least one of the following characteristics: (1) the second carbon cladding layer has a thickness of 10 nm to 30 nm; and (2) the material of the second carbon cladding layer comprises amorphous carbon.
15 . The composite silicon material according to claim 1 , wherein the shape of the composite silicon material comprises one or more of granular, spherical and quasi-spherical.
16 . The composite silicon material according to claim 15 , wherein the volume average particle size Dv50 of the composite silicon material is 3 μm to 22 μm.
17 . The composite silicon material according to claim 16 , wherein the volume average particle size Dv50 of the composite silicon material is 5 μm to 10 μm.
18 . A secondary battery, comprising the composite silicon material according to claim 1 .
19 . An electrical apparatus, comprising the secondary battery according to claim 18 .

Description

CROSS REFERENCE TO RELATED APPLICATIONS The present application is a continuation of International application PCT/CN2024/089331 filed on Apr. 23, 2024 that claims priority from Chinese patent application No. 202311146150.9 filed on Sep. 6, 2023. The content of these applications is incorporated into the present application by reference in its entirety. TECHNICAL FIELD The present application relates to the technical field of secondary batteries, and in particular to a composite silicon material and a preparation method therefor, a negative electrode plate, a secondary battery, and an electrical apparatus. BACKGROUND Secondary batteries are widely used in various consumer electronic products and electric vehicles due to their outstanding characteristics of light weight, no pollution, memoryless effect and the like. With the continuous development of new energy industry, increasingly high requirements have been put forward for the energy density of secondary batteries. Silicon-based negative electrode materials are widely used in secondary batteries due to their high capacity. However, due to the high expansion characteristics of silicon and its poor conductivity, while silicon-based negative electrode materials improve the energy density of secondary batteries, they also cause expansion and poor dynamics in secondary batteries, limiting the further development of battery technology. SUMMARY OF THE INVENTION Based on this, it is necessary to provide a composite silicon material and a preparation method therefor, a negative electrode plate, a secondary battery and an electrical apparatus to alleviate the expansion of secondary batteries and improve the dynamic performance of secondary batteries. To achieve the aforementioned objective, a first aspect of the present application provides a composite silicon material, which includes: an inner core, the inner core comprising a silicon-carbon material, the silicon-carbon material comprising a porous conductive material and a first silicon-based material, the porous conductive material having pores on its outer surface, and at least a portion of the first silicon-based material being distributed in the pores; anda silicon-containing cladding layer cladded on the outer side of the inner core, the silicon-containing cladding layer comprising an ion-conducting material and a second silicon-based material, and the second silicon-based material being dispersed in the ion-conducting material. The composite silicon material of the present application includes a silicon-carbon material and a silicon-containing cladding layer. The silicon-carbon material includes a porous conductive material with pores on the outer surface and a first silicon-based material. At least a portion of the first silicon-based material is embedded in the pores of the porous conductive material, which can effectively alleviate the problem of silicon expansion. At the same time, the silicon-containing cladding layer contains an ion-conducting material, which can increase the ion transmission path, thereby effectively alleviating the problem of poor dynamic performance caused by the small number of ion transmission paths of the silicon-carbon material. In some embodiments, the silicon-containing cladding layer has at least one of the following characteristics: (1) the silicon-containing cladding layer has a thickness of 5 nm to 100 nm;(2) the ion-conducting material comprises one or more of hard carbon, soft carbon, graphite, transition metal nitride, silicon-based alloy, tin-based alloy and lithium metal;(3) the ion-conducting material and the second silicon-based material are compounded into silicon oxide;(4) the volume average particle size Dv50 of the second silicon-based material is 2 nm to 20 nm;(5) the second silicon-based material comprises one or more of elemental silicon and silicon-tin alloy; and(6) the shape of the second silicon-based material comprises one or more of the following: granular, linear, spherical, quasi-spherical, and sheet-like. In some embodiments, the thickness of the silicon-containing cladding layer is 30 nm to 60 nm. In some embodiments, the molar ratio of oxygen element to silicon element contained in the silicon oxide is denoted as x, 0<x<2. In some embodiments, 0<x≤0.6. In some embodiments, the volume average particle size Dv50 of the second silicon-based material is 2 nm to 9 nm. In some embodiments, the silicon-carbon material has at least one of the following characteristics: (1) the mass percentage of silicon element in the silicon-carbon material is 3% to 25%;(2) the pore size of the pores is 2 nm to 50 nm;(3) the stacking height of the first silicon-based material in the pores is 1 nm to 35 nm;(4) the shape of the silicon-carbon material comprises one or more of granular, spherical and quasi-spherical;(5) the first silicon-based material comprises one or more of elemental silicon and silicon-tin alloy;(6) the shape of the first silicon-based material comprise