A silicon negative electrode material with high specific capacity, ultra-low expansion, high initial efficiency and excellent cycle performance, and a preparation method and application thereof
By depositing a mixed layer and a doped layer of metallic copper and silicon oxide on copper foil, the problems of low conductivity and large volume expansion of silicon oxide anode materials are solved, realizing a silicon anode material with high specific capacity, ultra-low expansion, high initial efficiency, and excellent cycle performance, thus improving the performance of lithium-ion batteries.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HUZHOU CHENENTROPY NANOTECHNOLOGY CO LTD
- Filing Date
- 2026-03-20
- Publication Date
- 2026-06-19
AI Technical Summary
Existing silicon oxide anode materials in lithium-ion batteries suffer from problems such as low conductivity, low initial coulombic efficiency, large volume expansion, and poor cycle performance, making it difficult to meet the requirements of practical applications.
Using a roll of copper foil as a carrier, a mixed layer and doped layer of metallic copper, silicon and silicon oxide are deposited by magnetron sputtering to control the lithium-ion diffusion path, improve electronic conductivity, and limit volume expansion, thus preparing a silicon anode material with high specific capacity, ultra-low expansion, high first-efficiency and excellent cycle performance.
It significantly improves the initial coulombic efficiency and cycle performance of the material, enhances electronic conductivity, reduces volume expansion, and improves the energy density and lifespan of lithium-ion batteries.
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Figure CN122246051A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of anode material technology, and in particular to a silicon anode material with high specific capacity, ultra-low expansion, high initial efficiency, and excellent cycle life, as well as its preparation method and application. Background Technology
[0002] The primary anode material in commercially available lithium-ion batteries is graphite, but its low theoretical capacity (372 mAh / g) limits further improvements in energy density. Pure silicon anodes, on the other hand, have a theoretical specific capacity of 4200 mAh / g, more than 10 times that of graphite anodes (372 mAh / g), and a potential plateau of ~0.4 V vs Li / Li + It is suitable and is considered one of the most promising anode materials for next-generation lithium-ion batteries.
[0003] Currently, there are two main types of silicon anode materials: one is a composite material of elemental silicon and its carbon counterpart; the other is a composite material of silicon oxides and their carbon counterparts. Elemental silicon anode materials have a significant capacity advantage, approximately 10 times the theoretical capacity of currently available commercial graphite anode materials. However, elemental silicon suffers from severe lattice expansion during lithium insertion / extraction, with a volume expansion rate exceeding 300%. This leads to the pulverization of the active material, and even loss of electrical contact with the current collector. Repeated damage and repair of the SEI film irreversibly consumes a limited number of lithium ions, resulting in a severe decline in cycle life.
[0004] In comparison, the theoretical capacity of silicon oxide compounds is approximately 1700 mAh / g. Although its capacity is lower than that of elemental silicon anode materials, it has significant advantages in expansion rate and cycle stability, making it easier to achieve industrial applications compared to elemental silicon. The volume expansion rate of silicon oxide compounds during lithium insertion / extraction is only 150%. This is because silicon oxide compounds generate inert Li₂O and Li₄SiO₄ during the initial lithium insertion, which effectively mitigates the volume effect, thus resulting in better cycle performance. Although the cycle performance of silicon oxide compounds is improved compared to elemental silicon, its initial coulombic efficiency, conductivity, rate performance, and cycle performance still fall short of the requirements for practical applications.
[0005] Currently, the main solution to the problem of low conductivity of silicon oxides is to coat them with amorphous carbon. The conductive carbon coating can not only solve the problem of low conductivity of silicon oxides themselves, but also improve the initial coulombic efficiency of the material. However, because the strength and toughness of the carbon coating cannot withstand the repeated volume expansion and contraction of silicon during charging and discharging, after multiple cycles, material structure damage, electrode cracking, and even powder shedding will still occur. Therefore, the cycle performance still cannot fully meet the service life requirements.
[0006] Therefore, developing a novel silicon anode material with high specific capacity, ultra-low expansion, high initial efficiency, and excellent cycle life is of great research significance and economic value. Summary of the Invention
[0007] The purpose of this invention is to address the aforementioned shortcomings of the prior art by proposing a silicon anode material with high specific capacity, ultra-low expansion, high initial efficiency, and excellent cycle life, as well as its preparation method and application.
[0008] The first objective of this invention is to provide a silicon anode material with high specific capacity, ultra-low expansion, high first-efficiency and excellent cycle performance, comprising a copper foil and a mixed layer comprising metallic copper and silicon deposited by magnetron sputtering on the front and back sides of the copper foil, wherein a doped layer comprising silicon oxide and metallic copper is also deposited by magnetron sputtering on the mixed layer on the front and back sides.
[0009] Furthermore, the thickness of the hybrid layer is 1-10 μm, and when the hybrid layer is composed of copper and silicon, the mass ratio of copper to silicon is 1:1. Specifically, the copper layer is 0.5-5 μm thick, and the silicon layer is 0.5-5 μm thick. Furthermore, the mixed layer also includes silicon oxides; the mass ratio of silicon, silicon oxides and metallic copper is 1:2:2-2.5.
[0010] Furthermore, the doped layer also includes silicon; the mass ratio of silicon, silicon oxide and metallic copper is 1:2:2-2.5.
[0011] Furthermore, when the doped layer is a silicon oxide compound and metallic copper, the mass ratio of silicon oxide compound to metallic copper is 1:2-2.5.
[0012] Furthermore, the thickness of the doped layer is 0.5-5 μm; the thickness of the copper foil is 3-10 μm.
[0013] Furthermore, the silicon oxide is a mixture of SiO and SiO2.
[0014] Furthermore, the mass ratio of SiO to SiO2 is 1:1.
[0015] A second objective of this invention is to provide a method for preparing a silicon anode material as described above, comprising the following steps: S1: Place the entire roll of copper foil into a vacuum winding plating equipment, and after vacuuming, use plasma cleaning to clean the surface of the copper foil. S2: A hybrid layer is deposited on the cleaned copper foil surface using magnetron sputtering; S3: Copper foil with a mixed layer deposited by magnetron sputtering; S4: After the magnetron sputtering deposition of the doped layer reaches the predetermined thickness, the entire roll is taken out and divided into appropriate sizes, which is a new type of silicon anode material with high specific capacity, ultra-low expansion, high first efficiency and excellent cycle performance.
[0016] A third objective of this invention is to provide an application of the silicon anode material with high specific capacity, ultra-low expansion, high initial efficiency, and excellent cycle performance as described above, for use as a lithium-ion battery anode material.
[0017] This invention abandons the traditional method of coating amorphous carbon with silicon oxide compounds, followed by homogenization, coating, drying, and rolling to obtain silicon-containing negative electrode sheets. Instead, this invention uses a roll of copper foil as the negative electrode carrier, and first deposits a mixed layer comprising metallic copper and silicon, or metallic copper, silicon, and silicon oxide compounds, in a vacuum system via magnetron sputtering. Then, a doped layer comprising silicon oxide compounds and metallic copper, or silicon, silicon oxide compounds, and metallic copper is deposited.
[0018] By controlling the silicon and silicon oxide film layers to the micrometer level, the lithium-ion diffusion path is significantly shortened, improving the rate performance of the material. Then, a micrometer-scale copper layer is used to prevent the initial coulombic efficiency from dropping drastically due to the reduction in the size of the silicon and silicon oxide film layers, and to effectively improve electronic conductivity, thus solving the problem of low intrinsic conductivity of silicon oxides. At the same time, a micrometer-scale copper foil is used as a carrier to fabricate a micrometer-thick doped layer including silicon oxides and copper by magnetron sputtering. The thickness is controllable, which helps to limit volume expansion, thereby improving the cycling performance of the material.
[0019] The method provided by this invention is simple in process and has excellent performance, and has broad prospects for application in lithium-ion battery anode materials. Attached Figure Description
[0020] Figure 1 A schematic diagram of the principle of a magnetron sputtering coating device for producing novel silicon anode materials; Figure 2 for Figure 1 A schematic diagram illustrating the principle of magnetron sputtering coating on a substrate surface using a single rotating magnetron sputtering target. 1. Vacuum coating chamber; 2. Unwinding chamber; 3. Rewinding chamber; 4. Partition; 5. First vacuum lock; 6. Second vacuum lock; 7. First moving door; 8. Second moving door; 9. Unwinding roller; 10. Unwinding tracking oscillating roller; 11. Unwinding tension roller; 12. Heater; 13. Ion source; 14. Rewinding tension roller; 15. Rewinding tracking oscillating roller; 16. Rewinding roller; 17. Coating roller; 18. Magnetron sputtering target; 19. Curved stretching roller; 20. Tension detection roller; 21. Gas pipeline; 22. Copper foil substrate; 23. Cooling partition; 24. Magnetic lines of force; 25. Plasma. Detailed Implementation
[0021] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.
[0022] Example 1 This embodiment provides a novel silicon anode material with high specific capacity, ultra-low expansion, high initial efficiency, and excellent cycle life, which is prepared by the following method.
[0023] S1. Place a roll of copper foil, 6 micrometers thick, into the... Figure 1 In the magnetron sputtering coating apparatus shown, the vacuum was evacuated to 0.005 Pa, the current of ion source 13 was set to 4 A, and the argon flow rate was 200 sccm.
[0024] S2. The cleaned copper foil surface enters the magnetron sputtering deposition area. Near the first coating roller, there are four copper targets with a current of 30A and four silicon targets with a current of 60A (copper and silicon targets are arranged alternately, copper target silicon target copper target silicon target copper target silicon target copper target silicon target copper target silicon target copper target silicon target). Argon gas is introduced at 200 sccm to deposit a 2-micron mixed layer of metallic copper and silicon (the mass ratio of metallic copper to silicon is 1:1) on the front side of the copper foil.
[0025] Near the second coating roller, there are four copper targets with a current of 30A and four silicon targets with a current of 60A (copper and silicon targets are arranged alternately, copper target silicon target copper target silicon target copper target silicon target copper target silicon target copper target silicon target copper target silicon target). Argon gas is introduced at 200 sccm to deposit a 2-micron mixed layer of metallic copper and silicon (the mass ratio of metallic copper to silicon is 1:1) on the back of the aluminum foil.
[0026] S3, depositing a copper foil with a mixed layer, entering the magnetron sputtering deposition region for silicon oxide and metallic copper doped layers. Near the third coating roller, the magnetron sputtering targets are set with four copper targets at 10A and four silicon targets at 40A (copper and silicon targets (silicon oxide) are arranged alternately, copper target silicon target copper target silicon target copper target silicon target copper target silicon target copper target silicon target copper target silicon target). Argon gas is introduced at 200 sccm and oxygen gas at 200 sccm. A 1-micron doped layer of silicon oxide (SiO and SiO2 mass ratio of 1:1) and metallic copper is deposited on the front side of the copper foil, wherein the mass ratio of silicon oxide to metallic copper is 1:2.1.
[0027] Near the fourth coating roller, the magnetron sputtering targets are set with four copper targets at 10A and four silicon targets at 40A (copper and silicon targets are arranged alternately, copper-silicon-copper-silicon-copper-silicon-copper-silicon-copper-silicon-silicon-copper-silicon). Argon gas is introduced at 200 sccm and oxygen gas at 200 sccm. A 1-micron doped layer of silicon oxide and metallic copper is deposited on the back of the copper foil. The mass ratio of silicon oxide to metallic copper is 1:2.1.
[0028] S4. After magnetron sputtering deposition is completed, the entire roll is removed and cut into appropriate sizes.
[0029] Example 2 This embodiment provides a novel silicon anode material with high specific capacity, ultra-low expansion, high initial efficiency, and excellent cycle life, which is prepared by the following method.
[0030] S1. Place a roll of copper foil, 6 micrometers thick, into the... Figure 1 In the magnetron sputtering coating apparatus shown, the vacuum was evacuated to 0.005 Pa, the current of ion source 13 was set to 4 A, and the argon flow rate was 200 sccm.
[0031] S2. The cleaned copper foil surface enters the magnetron sputtering deposition area. Near the first coating roller, there are four copper targets with a current of 40A and four silicon targets with a current of 80A (copper and silicon targets are arranged alternately, copper target silicon target copper target silicon target copper target silicon target copper target silicon target copper target silicon target copper target silicon target). Argon gas is introduced at 200 sccm to deposit a 3-micron mixed layer of metallic copper and silicon (the mass ratio of metallic copper to silicon is 1:1) on the front side of the copper foil.
[0032] Near the second coating roller, there are four copper targets with a current of 40A and four silicon targets with a current of 80A (copper and silicon targets are arranged alternately, copper target silicon target copper target silicon target copper target silicon target copper target silicon target copper target silicon target copper target silicon target). Argon gas is introduced at 200 sccm to deposit a 3-micron mixed layer of metallic copper and silicon (the mass ratio of metallic copper to silicon is 1:1) on the back of the copper foil.
[0033] S3. The copper foil after the deposition of the mixed layer enters the magnetron sputtering deposition area for silicon oxide and metallic copper doping. Near the third coating roller, the magnetron sputtering targets are set with four copper targets at 15A and four silicon targets at 45A (copper and silicon targets are arranged alternately, copper-silicon-copper-silicon-copper-silicon-copper-silicon-copper-silicon-silicon). Argon gas is introduced at 200 sccm and oxygen gas at 200 sccm. A 1.5-micron doped layer of silicon oxide (SiO and SiO2 mass ratio of 1:1) and metallic copper is deposited on the front side of the copper foil. The mass ratio of silicon oxide to metallic copper is 1:2.5.
[0034] Near the fourth coating roller, the magnetron sputtering targets are set with four copper targets at a current of 15A and four silicon targets at a current of 45A (copper and silicon targets are arranged alternately, copper-silicon-copper-silicon-copper-silicon-copper-silicon-copper-silicon-silicon). Argon gas is introduced at 200 sccm and oxygen gas at 200 sccm. A 1.5-micron doped layer of silicon oxide (SiO and SiO2 mass ratio of 1:1) and metallic copper is deposited on the back of the copper foil. The mass ratio of silicon oxide to metallic copper is 1:2.5.
[0035] S4. After magnetron sputtering deposition is completed, the entire roll is removed and cut into appropriate sizes.
[0036] Example 3 This embodiment provides a novel silicon anode material with high specific capacity, ultra-low expansion, high initial efficiency, and excellent cycle life, which is prepared by the following method.
[0037] S1. Place a roll of copper foil, 6 micrometers thick, into the... Figure 1 In the magnetron sputtering coating apparatus shown, the vacuum was evacuated to 0.005 Pa, the current of ion source 13 was set to 4 A, and the argon flow rate was 200 sccm.
[0038] S2. The cleaned copper foil surface enters the magnetron sputtering deposition area. By using a low volume of oxygen, magnetron sputtering of the silicon target will not completely generate silicon oxides, and pure silicon will be deposited on the surface of the copper foil.
[0039] Near the first coating roller, four copper targets were set to a current of 20A, and four silicon targets were set to a current of 60A (copper and silicon targets were arranged alternately). Argon gas was introduced at 200 sccm, and oxygen at 80 sccm (using the low oxygen level, the magnetron sputtering silicon targets would not completely generate silicon oxides, thus allowing pure silicon to be deposited on the copper foil surface). A 2-micrometer mixed layer of silicon, silicon oxides (SiO and SiO2 in a 1:1 mass ratio), and metallic copper was deposited on the front side of the copper foil. The mass ratio of silicon, silicon oxides, and metallic copper was 1:2:2.5.
[0040] Near the second coating roller, the magnetron sputtering targets are set with four copper targets at 20A and four silicon targets at 60A (copper and silicon targets are arranged alternately, copper-silicon-copper-silicon-copper-silicon-copper-silicon-copper-silicon-silicon-copper-silicon). Argon gas is introduced at 200 sccm and oxygen at 80 sccm. A 2-micrometer layer of silicon, silicon oxide (SiO and SiO2 in a 1:1 mass ratio), and metallic copper doped layer is deposited on the back of the copper foil. The mass ratio of silicon, silicon oxide, and metallic copper is 1:2:2.5.
[0041] S3. After depositing the copper foil with metallic copper and silicon oxide layers, continue to deposit silicon oxide and metallic copper doped layers.
[0042] Near the third coating roller, the magnetron sputtering targets are set with four copper targets at 20A and four silicon targets at 60A (copper and silicon targets are arranged alternately, copper-silicon-copper-silicon-copper-silicon-copper-silicon-copper-silicon-silicon-copper-silicon). Argon gas is introduced at 200 sccm and oxygen at 80 sccm. A 2-micrometer doped layer of silicon, silicon oxide (SiO and SiO2 in a 1:1 mass ratio), and metallic copper is deposited on the front side of the copper foil. The mass ratio of silicon, silicon oxide, and metallic copper is 1:2:2.5.
[0043] Near the fourth coating roller, the magnetron sputtering targets are set with four copper targets at 20A and four silicon targets at 60A (copper and silicon targets are arranged alternately, copper-silicon-copper-silicon-copper-silicon-copper-silicon-copper-silicon-silicon-copper-silicon). Argon gas is introduced at 200 sccm and oxygen at 80 sccm. A 2-micron layer of silicon, silicon oxide (SiO and SiO2 in a 1:1 mass ratio), and metallic copper doping is deposited on the back of the copper foil. The mass ratio of silicon, silicon oxide, and metallic copper is 1:2:2.5.
[0044] S4. After magnetron sputtering deposition is completed, the entire roll is removed and cut into appropriate sizes.
[0045] Example 4 This embodiment provides a novel silicon anode material with high specific capacity, ultra-low expansion, high initial efficiency, and excellent cycle life, which is prepared by the following method.
[0046] S1. Place a roll of copper foil, 6 micrometers thick, into the... Figure 1 In the magnetron sputtering coating apparatus shown, the vacuum was evacuated to 0.005 Pa, the current of ion source 13 was set to 4 A, and the argon flow rate was 200 sccm.
[0047] S2. The cleaned copper foil surface enters the magnetron sputtering deposition area. By using a low volume of oxygen, magnetron sputtering of the silicon target will not completely generate silicon oxides, and pure silicon will be deposited on the surface of the copper foil.
[0048] Near the first coating roller, the magnetron sputtering targets are set with four copper targets at 15A and four silicon targets at 50A (copper and silicon targets are arranged alternately, copper target silicon target copper target silicon target copper target silicon target copper target silicon target copper target silicon target copper target silicon target). Argon gas is introduced at 200 sccm and oxygen at 80 sccm. A 1.6-micron mixed layer of silicon, silicon oxide (SiO and SiO2 in a 1:1 mass ratio), and metallic copper is deposited on the front side of the copper foil. The mass ratio of silicon, silicon oxide, and metallic copper is 1:2:2.3.
[0049] Near the second coating roller, the magnetron sputtering targets are set with four copper targets at 15A and four silicon targets at 50A (copper and silicon targets are arranged alternately, copper target silicon target copper target silicon target copper target silicon target copper target silicon target copper target silicon target copper target silicon target). Argon gas is introduced at 200 sccm and oxygen at 80 sccm. A 1.6-micron mixed layer of silicon oxide compound (SiO and SiO2 mass ratio of 1:1) and metallic copper is deposited on the back of the copper foil. The mass ratio of silicon, silicon oxide compound and metallic copper is 1:2:2.3.
[0050] S3. After depositing the copper foil with metallic copper and silicon oxide layers, continue to deposit silicon oxide and metallic copper doped layers.
[0051] Near the third coating roller, the magnetron sputtering targets are set with four copper targets at 15A and four silicon targets at 50A (copper and silicon targets are arranged alternately, copper target silicon target copper target silicon target copper target silicon target copper target silicon target copper target silicon target copper target silicon target). Argon gas is introduced at 200 sccm and oxygen at 80 sccm. A 1.6-micron doped layer of silicon, silicon oxide (SiO and SiO2 in a 1:1 mass ratio), and metallic copper is deposited on the front side of the copper foil. The mass ratio of silicon, silicon oxide, and metallic copper is 1:2:2.3.
[0052] Near the fourth coating roller, the magnetron sputtering targets are set with four copper targets at a current of 15A and four silicon targets at a current of 50A (copper and silicon targets are arranged alternately, copper-silicon-copper-silicon-copper-silicon-copper-silicon-copper-silicon-silicon-copper-silicon). Argon gas is introduced at 200 sccm and oxygen at 80 sccm. A 1.6-micron doped layer of silicon, silicon oxide (SiO and SiO2 in a 1:1 mass ratio), and metallic copper is deposited on the back of the copper foil. The mass ratio of silicon, silicon oxide, and metallic copper is 1:2:2.3.
[0053] S5. After magnetron sputtering deposition is completed, the entire roll is removed and cut into appropriate sizes.
[0054] Example 5 This embodiment provides a novel silicon anode material with high specific capacity, ultra-low expansion, high initial efficiency, and excellent cycle life, which is prepared by the following method.
[0055] S1. Place a roll of copper foil, 6 micrometers thick, into the... Figure 1 In the magnetron sputtering coating apparatus shown, the vacuum was evacuated to 0.005 Pa, the current of ion source 13 was set to 4 A, and the argon flow rate was 200 sccm.
[0056] S2. The cleaned copper foil surface enters the magnetron sputtering deposition area. Near the first coating roller, there are four copper targets with a current of 40A and four silicon targets with a current of 80A (copper and silicon targets are arranged alternately, copper target silicon target copper target silicon target copper target silicon target copper target silicon target copper target silicon target copper target silicon target). Argon gas is introduced at 200 sccm to deposit a 3-micron mixed layer of metallic copper and silicon (the mass ratio of metallic copper to silicon is 1:1) on the front side of the copper foil.
[0057] Near the second coating roller, there are four copper targets with a current of 40A and four silicon targets with a current of 80A (copper and silicon targets are arranged alternately, copper target silicon target copper target silicon target copper target silicon target copper target silicon target copper target silicon target copper target silicon target). Argon gas is introduced at 200 sccm to deposit a 3-micron mixed layer of metallic copper and silicon (the mass ratio of metallic copper to silicon is 1:1) on the back of the copper foil.
[0058] S3. After depositing a copper foil containing a mixture of metallic copper and silicon, a mixed layer of silicon, silicon oxide, and metallic copper is further deposited. Utilizing a low volume of oxygen, the magnetron sputtering silicon target does not completely generate silicon oxide, resulting in pure silicon being deposited on the copper foil surface.
[0059] Near the third coating roller, the magnetron sputtering targets are set with four copper targets at 15A and four silicon targets at 50A (copper and silicon targets are arranged alternately, copper target silicon target copper target silicon target copper target silicon target copper target silicon target copper target silicon target copper target silicon target). Argon gas is introduced at 200 sccm and oxygen at 80 sccm. A 1.6-micron doped layer of silicon, silicon oxide (SiO and SiO2 in a 1:1 mass ratio), and metallic copper is deposited on the front side of the copper foil. The mass ratio of silicon, silicon oxide, and metallic copper is 1:2:2.3.
[0060] Near the fourth coating roller, the magnetron sputtering targets are set with four copper targets at a current of 15A and four silicon targets at a current of 50A (copper and silicon targets are arranged alternately, copper-silicon-copper-silicon-copper-silicon-copper-silicon-copper-silicon-silicon-copper-silicon). Argon gas is introduced at 200 sccm and oxygen at 80 sccm. A 1.6-micron doped layer of silicon, silicon oxide (SiO and SiO2 in a 1:1 mass ratio), and metallic copper is deposited on the back of the copper foil. The mass ratio of silicon, silicon oxide, and metallic copper is 1:2:2.3.
[0061] S5. After magnetron sputtering deposition is completed, the entire roll is removed and cut into appropriate sizes.
[0062] The deposition parameters for the embodiments are shown in Table 1: Table 1
[0063] Comparative Example 1 Ten parts of silicon-oxygen composite material, 85 parts of artificial graphite, 2.5 parts of conductive additive, and 2.5 parts of binder are homogenized, coated, dried, and rolled in an aqueous system to obtain a silicon-oxygen compound-containing negative electrode sheet.
[0064] Electrochemical performance of novel silicon anode materials: The negative electrode materials prepared in Examples 1-5 were used as the counter electrode, a polypropylene microporous membrane (Celgard 2400) as the separator, and a 1 mol / L LiPF6 solution (DC:DEC:EMC = 1:1:1) as the electrolyte to assemble a Type 2016 lithium-ion battery.
[0065] Battery charge / discharge: Charge / discharge range 0.01~1.5V; 0.1C charge / discharge for the first cycle, 0.2C charge / discharge for the second to sixth cycles, 0.5C charge / discharge for the seventh to eleventh cycles, 1C charge / discharge for the twelfth to sixteenth cycles, and 0.2C charge / discharge for the 17th to 116th cycles. 0.2C capacity retention = (reversible capacity at the 116th cycle / reversible capacity at the 17th cycle) * 100%. Test results are shown in Table 2.
[0066] Table 2
[0067] As shown in Table 1, the novel anode materials provided in each embodiment of the present invention have high initial coulombic efficiency, and each embodiment also has good rate performance and cycle performance.
[0068] For any points not covered above, existing technologies shall apply.
[0069] Although specific embodiments of the present invention have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of the invention. Those skilled in the art can make various modifications or additions to the described specific embodiments or use similar methods to replace them, without departing from the direction of the invention or exceeding the scope defined by the appended claims. Those skilled in the art should understand that any modifications, equivalent substitutions, improvements, etc., made to the above embodiments based on the technical essence of the present invention should be included within the protection scope of the present invention.
Claims
1. A silicon anode material with high specific capacity, ultra-low expansion, high initial efficiency, and excellent cycle life, characterized in that, The mixture includes copper foil and a mixed layer of metallic copper and silicon deposited on the front and back sides of the copper foil by magnetron sputtering. The mixed layer on the front and back sides is also magnetron sputtered with doped layers including silicon oxide and metallic copper.
2. The silicon anode material as described in claim 1, characterized in that, The thickness of the hybrid layer is 1-10 μm, and when the hybrid layer is composed of copper and silicon, the mass ratio of copper to silicon is 1:
1.
3. The silicon anode material as described in claim 1, characterized in that, The hybrid layer also includes silicon oxides; the mass ratio of silicon, silicon oxides and metallic copper is 1:2:2-2.
5.
4. The silicon anode material as described in claim 1 or 3, characterized in that, The doped layer also includes silicon; the mass ratio of silicon, silicon oxide and metallic copper is 1:2:2-2.
5.
5. The silicon anode material as described in claim 1, characterized in that, When the doped layer is a silicon oxide compound and metallic copper, the mass ratio of silicon oxide compound to metallic copper is 1:2-2.
5.
6. The silicon anode material as described in claim 1, characterized in that, The thickness of the doped layer is 0.5-5 μm; the thickness of the copper foil is 3-10 μm.
7. The silicon anode material as described in claim 1, characterized in that, Silicon oxides are a mixture of SiO and SiO2.
8. The silicon anode material as described in claim 7, characterized in that, The mass ratio of SiO to SiO2 is 1:
1.
9. A method for preparing a silicon anode material as described in any one of claims 1-8, characterized in that, Includes the following steps: S1: Place the entire roll of copper foil into a vacuum winding plating equipment, and after vacuuming, use plasma cleaning to clean the surface of the copper foil. S2: A hybrid layer is deposited on the cleaned copper foil surface using magnetron sputtering; S3: Copper foil with a mixed layer deposited by magnetron sputtering; S4: After the magnetron sputtering deposition of the doped layer reaches the predetermined thickness, the entire roll is taken out and divided into appropriate sizes, which is a new type of silicon anode material with high specific capacity, ultra-low expansion, high first efficiency and excellent cycle performance.
10. The application of the silicon anode material with high specific capacity, ultra-low expansion, high first-efficiency, and excellent cycle performance as described in any one of claims 1-8, characterized in that, Used as a negative electrode material for lithium-ion batteries.