Ag-c type composite material and use thereof for preparing solid-state battery negative electrode material

Abstract

The application belongs to the technical field of secondary batteries, and particularly relates to a transition metal-based inorganic filler regulated Ag-C composite material, and further discloses a preparation method thereof and an application of the preparation method in preparing a solid-state battery negative material. The Ag-C composite material containing the transition metal-based filler is prepared by in-situ synthesis of Ag, C and a layered metal filler containing a transition metal element, to form the transition metal filler regulated Ag-C composite material, which can effectively improve uniform deposition of lithium on a current collector, so that a lithium-free anode solid-state battery is verified at a high rate, and safety and rate capability of the solid-state battery in long cycle are improved.

Description

Technical Field

[0001] This invention belongs to the field of secondary battery technology, specifically relating to an Ag-C type composite material regulated by transition metal-based inorganic fillers, and further disclosing its preparation method and its use in preparing solid-state battery anode materials. Background Technology

[0002] Lithium-ion batteries, as a new type of energy storage device, have received widespread attention and application in many fields due to their advantages such as high energy density, long cycle life, high operating voltage, abundant resources, low price, and environmental friendliness. They not only dominate the field of automotive power batteries, but are also widely used in many high-tech fields such as mobile communications, satellites, and high-end electronic devices.

[0003] However, current mainstream lithium-ion batteries achieve high energy density by using organic liquid electrolytes and special additives to increase battery voltage, which may cause serious safety issues. With the development of new energy power battery technology, traditional liquid batteries are increasingly unable to meet consumer demands, and lithium battery technology is trending towards higher safety and higher energy density requirements. Currently, the development of high-energy-density all-solid-state batteries is accelerating the development of electric vehicles and large-scale energy storage systems such as power grids. Therefore, developing high-energy-density and high-safety all-solid-state batteries (ASSLBs) has become a future trend in the industry.

[0004] Solid electrolytes are a key factor in the development of high-energy-density solid-state batteries. Currently, sulfide solid electrolytes are widely used in solid-state batteries due to their superior conductivity. However, in practical applications, it has been found that this battery system suffers from unavoidable problems such as lithium dendrite growth, low coulombic efficiency, and volume expansion during operation, leading to low battery safety and cycle life. To reduce or avoid these application defects, developing a novel lithium-free anode material to improve the energy density during battery cycling is of positive significance for optimizing the performance of solid-state batteries. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to provide an Ag-C type composite material based on transition metal-based inorganic filler, wherein the composite material has a larger specific surface area for Ag nanoparticle attachment, and the synergistic effect of LDH and C is beneficial to improving the agglomeration phenomenon of carbon materials, making the Ag nanoparticles more uniformly distributed and more conducive to lithium ion transport.

[0006] The second technical problem to be solved by the present invention is to provide a method for preparing the above-mentioned Ag-C type composite material;

[0007] The third technical problem to be solved by the present invention is to provide the use of the above-mentioned Ag-C type composite material in the preparation of solid-state battery anode material, wherein the Ag-C type composite material helps to improve the safety and rate performance of solid-state batteries during long cycles.

[0008] To solve the above-mentioned technical problems, the present invention provides a method for preparing Ag-C type composite materials, comprising the following steps:

[0009] (1) Take C source material and transition metal-based inorganic filler and add them to the first solvent to mix and set aside;

[0010] (2) Take Ag source material and mix it with the second solvent for later use;

[0011] (3) Mix the solutions obtained in steps (1) and (2) above, collect the reactants, and obtain the desired Ag-C type composite material.

[0012] Specifically, in the preparation method of the Ag-C type composite material, in step (1), the transition metal-based inorganic filler includes a transition metal-based morphological filler.

[0013] Preferably, the transition metal-based inorganic filler is a transition metal-based layered bimetallic hydroxide M. 2+ M 3+ -LDH, where

[0014] M 2+ Selected from Ni 2+ Co 2+ V 2+ Ti 2+ Cr 2+ Fe 2+ Mn 2+ Cu 2+ Zn 2+ Cd 2+ Mg 2+ Ca 2+ 、Sr 2+ Pb 2+ Or Ba 2+ One or more of the following;

[0015] M 3+ Selected from Al 3+ Ga 3+ In 3+ Fe 3+ Cr 3+ or Co 3+ One or more of them.

[0016] Preferably, in the transition metal-based inorganic filler, M 2+ M 3+The mass ratio is (5-40):(1-10).

[0017] Preferably, the layered bimetallic hydroxide M 2+ M 3+ -LDH has a specific surface area of ​​10-120 m². 2 / g, with a particle size of 0.5-1.5μm.

[0018] Specifically, in the preparation method of the Ag-C type composite material, in step (1), the C source material includes amorphous carbon material and / or crystalline carbon or other materials.

[0019] Preferably, the amorphous carbon material includes one or a mixture of several of the following: carbon black, carbon fiber, acetylene black, activated carbon, sugar char, bone char, or glassy carbon.

[0020] The crystalline carbon material includes one or a mixture of several of graphite, acetylene black, graphene, carbon nanotubes, or modified carbon nanotubes.

[0021] Specifically, in the preparation method of the Ag-C type composite material, in step (1), the mass ratio of the C source material and the transition metal-based inorganic filler is (0.5-30):(0.1-20).

[0022] Specifically, in step (1), the mixing temperature is -5 to 120°C, and the mixing time is 0.5 to 12 hours.

[0023] Specifically, in the preparation method of the Ag-C type composite material, in step (2), the Ag source material is selected from Ag a Y b A mixture of one or more of the following: Y is selected from one or more of O, Cl, Br, SO4, NO3, CO3, S, OH, NH4 or I, 1≤a≤3, 0.5≤b≤1.5.

[0024] Preferably, in step (2), the mixing temperature is -5 to 30°C.

[0025] Specifically, in the preparation method of the Ag-C type composite material, the first solvent and the second solvent are independently selected from one or a mixture of several of the following: water, ethanol, sodium borohydride, sodium citrate, glycerol, polyvinylpyrrolidone, polyethylene glycol, chitosan, sodium hypophosphite, triamine citrate, sodium thiosulfate, glucose, glyoxal, or hydrazine sulfate.

[0026] Specifically, in the preparation method of the Ag-C type composite material, in step (3), the mass ratio of the Ag source material to the C source material is (0.5-10):(0.1-20).

[0027] Preferably, step (3) further includes a step of diluting the obtained mixed solution by a ratio of 10-80 v / v%.

[0028] Preferably, step (3) further includes a step of ultrasonically dispersing the obtained mixed solution, wherein the ultrasonic time is preferably 10-120 min.

[0029] Preferably, step (3) further includes the steps of filtration, washing, and drying (preferably drying at 40-150°C for 4-48 hours) of the obtained mixed solution.

[0030] Preferably, in step (3), the mixing temperature is -5 to 120°C and the mixing time is 0.5 to 24 hours.

[0031] The present invention also discloses the Ag-C type composite material prepared by the method.

[0032] The present invention also discloses the use of the Ag-C type composite material in the preparation of lithium-ion solid-state battery anode materials, anode sheets, and lithium-ion solid-state batteries.

[0033] The present invention also discloses a lithium-ion solid-state battery anode material, anode sheet, and lithium-ion solid-state battery prepared from the Ag-C type composite material.

[0034] The Ag-C composite material containing transition metal-based fillers of this invention is synthesized in situ by combining Ag, C, and layered metal fillers containing transition metal elements to form an Ag-C composite material regulated by transition metal fillers. In this Ag-C composite material, the layered inorganic filler possesses a large specific surface area at the nanoscale, providing more attachment sites for Ag nanoparticle deposition. The synergistic effect of the inorganic filler and C material not only acts as a protective layer and framework but also mitigates the tendency of C material to aggregate, thus facilitating lithium-ion transport and deposition during battery cycling. Simultaneously, the presence of transition metal elements imparts a certain level of electrical conductivity, effectively improving the material's electrochemical performance.

[0035] The Ag-C type composite material containing transition metal-based filler described in this invention can effectively improve the uniform deposition of lithium on the current collector, enabling the lithium-free anode solid-state battery to be verified at a high rate cycle, thereby improving the safety and rate performance of solid-state batteries during long cycles.

[0036] The Ag-C type composite material containing transition metal-based fillers described in this invention can achieve a larger specific surface area for Ag nanoparticle attachment by optimizing the transition metal elements in the LDH material. The synergistic effect of LDH and C helps to improve the agglomeration phenomenon of carbon materials, resulting in a more uniform distribution of Ag nanoparticles, which is more conducive to lithium ion transport.

[0037] The Ag-C type composite material containing transition metal-based fillers of the present invention combines Ag and C with layered metal fillers containing transition metal elements through in-situ synthesis, which also saves the material preparation cost to a certain extent and has high industrial application value. Detailed Implementation

[0038] Example 1

[0039] The method for preparing the composite material described in this embodiment includes the following steps:

[0040] (1) The carbon black material (denoted as C1) and NiCoAl-LDH material were mixed and fully dissolved in deionized water. The mixture was magnetically stirred at 4°C for 2 hours to obtain the C / LDH solvent, which was then set aside. In this embodiment, the mass ratio of Ni:Co:Al in the NiCoAl-LDH material was 1:2:1, and the specific surface area was 87 m². 2 / g;

[0041] (2) Dissolve AgNO3 in a solvent containing sodium borohydride and deionized water at 5℃, wherein the mass ratio of AgNO3 to sodium borohydride is controlled to be 1:2, to obtain an Ag-containing solution for later use; wherein, sodium borohydride is a reducing agent of silver nitrate, and can reduce silver nitrate to silver element in subsequent reactions;

[0042] (3) The Ag-containing solution was slowly added dropwise to the C / LDH solution and mixed. The Ag:C mass ratio in the solution was controlled to be 1:3. The reaction was carried out at 5°C. The resulting slurry was stirred under magnetic stirring for 8 hours and diluted with deionized water at a ratio of 50%. It was then ultrasonically dispersed for 0.5 hours and filtered and washed in a glass container. The final product was dried at 80°C for 12 hours to obtain the Ag-Cl / LDH composite material.

[0043] Example 2

[0044] The preparation method of the composite material described in this embodiment is the same as that in Embodiment 1. The only difference is that the selection of the C source material is different. In this embodiment, the C2 material listed in Table 1 below, namely carbon nanofibers (diameter 30-180nm, length 2-30μm), is selected as the C source material to prepare the Ag-C2 / LDH composite material.

[0045] Example 3

[0046] The preparation method of the composite material described in this embodiment is the same as that in Embodiment 1. The only difference is that the selection of the C source material is different. In this embodiment, the C3 material listed in Table 1 below, namely carbon nanotubes (diameter 5-15nm, length 15-80μm), is selected as the C source material to prepare the Ag-C3 / LDH composite material.

[0047] Example 4

[0048] The preparation method of the composite material described in this embodiment is the same as that in Embodiment 1, except that the Ag source material is Ag. a Y b Depending on the choice, this embodiment selects AgBr as the Ag source material to prepare the Ag2-Cl / LDH composite material.

[0049] Example 5

[0050] The preparation method of the composite material described in this embodiment is the same as that in Embodiment 1, except that the mass ratio of C:LDH is different. In this embodiment, the mass ratio (1:5) listed in Table 1 is selected to prepare the Ag-Cl / LDH composite material.

[0051] Example 6

[0052] The preparation method of the composite material described in this embodiment is the same as that in Embodiment 1, except that the mass ratio of C:LDH is different. In this embodiment, the mass ratio (2:1) listed in Table 1 is selected to prepare the Ag-Cl / LDH composite material.

[0053] Example 7

[0054] The preparation method of the composite material described in this embodiment is the same as that in Example 1, except that the reaction solvent is different. In this embodiment, the solvent system (glycerol + polyvinylpyrrolidone) listed in Table 1 is selected for the reaction. The amount of glycerol added is not specifically limited, and the mass ratio of AgNO3 to polyvinylpyrrolidone is controlled to be 1:2 to prepare the Ag-Cl / LDH composite material. In this embodiment, glycerol is equivalent to the water added in Example 1, and polyvinylpyrrolidone is equivalent to the use of sodium borohydride, which can be added in step (2).

[0055] Example 8

[0056] The preparation method of the composite material described in this embodiment is the same as that in Embodiment 1, except that the reaction solvent is different. In this embodiment, the solvent system (water + sodium citrate) listed in Table 1 is selected for the reaction. The amount of water added is not specifically limited, and the mass ratio of AgNO3 to sodium citrate is controlled to be 1:2 to prepare the Ag-Cl / LDH composite material. In this embodiment, sodium citrate is equivalent to sodium borohydride and can be added in step (2).

[0057] Example 9

[0058] The preparation method of the composite material described in this embodiment is the same as that in Example 1, except that the reaction solvent is different. In this embodiment, the solvent system (glycerol + polyethylene glycol) listed in Table 1 is selected for the reaction. The amount of glycerol added is not specifically limited, and the mass ratio of AgNO3 to polyethylene glycol is controlled to be 1:2 to prepare the Ag-Cl / LDH composite material. In this embodiment, glycerol is equivalent to the water added in Example 1, and polyethylene glycol is equivalent to the use of sodium borohydride, which can be added in step (2).

[0059] Example 10

[0060] The preparation method of the composite material described in this embodiment is the same as that in Embodiment 1, except that the mass ratio of Ag:C is different. In this embodiment, the mass ratio (1:1) listed in Table 1 is selected to prepare the Ag-Cl / LDH composite material.

[0061] Example 11

[0062] The preparation method of the composite material described in this embodiment is the same as that in Embodiment 1, except that the Ag:C mass ratio is different. In this embodiment, the mass ratio listed in Table 1 (1.5:0.8) is selected to prepare the Ag-Cl / LDH composite material.

[0063] Example 12

[0064] The preparation method of the composite material described in this embodiment is the same as that in Embodiment 1, except that the mass ratio of Ag:C is different. In this embodiment, the mass ratio listed in Table 1 (0.1:10) is selected to prepare the Ag-Cl / LDH composite material.

[0065] Example 13

[0066] The preparation method of the composite material described in this embodiment is the same as that in Embodiment 1, except that the Ag:C mass ratio is different. In this embodiment, the mass ratio listed in Table 1 (1:10) is selected to prepare the Ag-Cl / LDH composite material.

[0067] Example 14

[0068] The preparation method of the composite material described in this embodiment is the same as that in Embodiment 1, except that the type of metal element in the LDH material is different. In this embodiment, NiAl-LDH listed in Table 1 is selected as the raw material, wherein the Ni:Al mass ratio is 3:1 and the specific surface area is 69m². 2 / g, to prepare the Ag-C1 / LDH composite material.

[0069] Example 15

[0070] The preparation method of the composite material described in this embodiment is the same as that in Embodiment 1, except that the type of metal element in the LDH material is different. In this embodiment, ZnAl-LDH listed in Table 1 is selected as the raw material, wherein the Zn:Al mass ratio is 3:1 and the specific surface area is 64m². 2 / g, to prepare the Ag-C1 / LDH composite material.

[0071] Example 16

[0072] The preparation method of the composite material described in this embodiment is the same as that in Embodiment 1, except that the type of metal element in the LDH material is different. In this embodiment, CuCoAl-LDH listed in Table 1 is selected as the raw material, wherein the mass ratio of Cu:Co:Al is 1:2:1 and the specific surface area is 79m². 2 / g, to prepare the Ag-C1 / LDH composite material.

[0073] Comparative Example 1

[0074] The preparation method of the composite material described in this embodiment is the same as that in Embodiment 1, except that Ag is not added. a Y b Materials were used to obtain the desired composite C / LDH material.

[0075] Comparative Example 2

[0076] The preparation method of the composite material described in this embodiment is the same as that in Embodiment 1, except that the LDH material is not added to obtain the desired composite Ag-C material.

[0077] Comparative Example 3

[0078] The preparation method of the composite material described in this embodiment is the same as that in Embodiment 1, except that the C source material is not added to obtain the desired composite Ag / LDH material.

[0079] Comparative Example 4

[0080] The preparation method of the composite material described in this embodiment is the same as that in Embodiment 1, except that NiCo alloy material is added instead of LDH, wherein the mass ratio of Ni to Co in the alloy material is 1:3, and the desired composite Ag-Cl / NiCo alloy composite material is obtained.

[0081] Experimental Example

[0082] The composite materials prepared in Examples 1-16 and Comparative Examples 1-4 were subjected to mold battery cycle tests to obtain battery cycle and rate performance data. The specific operation process is as follows: the composite material powder was pressed into a sheet and attached to the current collector, then combined with the sulfide electrolyte and ternary positive electrode sheet, pressed into a sheet, and assembled onto the mold battery. The metal salt of the current collector was then tested at 60°C. The test results are shown in Table 1.

[0083] Table 1 Electrochemical performance of composite polymer electrolyte membrane materials

[0084]

[0085]

[0086] As can be seen from the data in the table above, combined with the performance of the composite materials in Examples 1-16, the test results of the Ag-C / LDH material mold battery described in this invention show that the battery has good application performance. Especially when using AgNO3, Cl, and LDH-NiCoAl, with a C:LDH ratio of 1:1 and an Ag:C ratio of 1:3, and using deionized water and sodium borohydride as reagents, the prepared Ag-Cl / LDH... -NiCoAl The highest discharge capacity was observed at a 0.3C rate. Combined with the performance of the composite materials in Comparative Examples 1-4, it can be seen that AgNO3, Cl, and LDH in the composite material described in this invention can form a certain synergistic effect, which is beneficial for achieving the optimal discharge capacity of the mold battery.

[0087] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing Ag-C type composite material for the negative electrode of lithium-ion solid-state batteries, characterized in that, Includes the following steps: (1) Take C source material and transition metal-based inorganic filler and add them to the first solvent to mix and set aside; The transition metal-based inorganic filler includes transition metal-based substrate filler; The transition metal-based inorganic filler is a layered bimetallic hydroxide M. 2+ M 3+ -LDH, where M 2+ Selected from Ni 2+ Co 2+ V 2+ Ti 2+ Cr 2+ Fe 2+ Mn 2+ Cu 2+ Zn 2+ Cd 2+ Mg 2+ Ca 2+ 、Sr 2+ Pb 2+ Or Ba 2+ One or more of the following; M 3+ Selected from Al 3+ Ga 3+ In 3+ Fe 3+ Cr 3+ or Co 3+ One or more of the following; (2) Take Ag source material and mix it with the second solvent for later use; The second solvent also includes at least one of sodium borohydride, sodium citrate, polyvinylpyrrolidone, polyethylene glycol, chitosan, sodium hypophosphite, glucose, and glyoxal; (3) Mix the solutions obtained in steps (1) and (2) above, collect the reactants, and obtain the desired Ag-C type composite material; The Ag-C type composite material is an Ag-C / LDH composite material.

2. The method for preparing the Ag-C type composite material for the negative electrode of a lithium-ion solid-state battery according to claim 1, characterized in that, In the transition metal-based inorganic filler, M 2+ M 3+ The mass ratio is (5-40):(1-10).

3. The method for preparing the Ag-C type composite material for the negative electrode of a lithium-ion solid-state battery according to claim 1, characterized in that, The layered bimetallic hydroxide M 2+ M 3+ -LDH has a specific surface area of ​​10-120 m². 2 / g, with a particle size of 0.5-1.5μm.

4. The method for preparing the Ag-C type composite material for the negative electrode of a lithium-ion solid-state battery according to claim 1, characterized in that, In step (1), the C source material includes amorphous carbon material and / or crystalline carbon material.

5. The method for preparing the Ag-C type composite material for the negative electrode of a lithium-ion solid-state battery according to claim 4, characterized in that, The amorphous carbon material includes one or a mixture of several of the following: carbon black, carbon fiber, acetylene black, activated carbon, sugar char, bone char, or glassy carbon. The crystalline carbon material includes one or a mixture of several of graphite, acetylene black, graphene, carbon nanotubes, or modified carbon nanotubes.

6. The method for preparing the Ag-C type composite material for the negative electrode of a lithium-ion solid-state battery according to claim 1, characterized in that, In step (1), the mass ratio of the C source material to the transition metal-based inorganic filler is (0.5-30):(0.1-20).

7. The method for preparing the Ag-C type composite material for the negative electrode of a lithium-ion solid-state battery according to claim 6, characterized in that, In step (1), the mixing temperature is -5~120℃ and the mixing time is 0.5-12h.

8. The method for preparing the Ag-C type composite material for the negative electrode of a lithium-ion solid-state battery according to claim 1, characterized in that, In step (2), the Ag source material is selected from Ag. a Y b A mixture of one or more of the following: Y is selected from one or more of O, Cl, Br, SO4, NO3, CO3, S, OH, NH4 or I, 1≤a≤3, 0.5≤b≤1.

5.

9. The method for preparing the Ag-C type composite material for the negative electrode of a lithium-ion solid-state battery according to claim 8, characterized in that, In step (2), the mixing temperature is -5~30℃.

10. The method for preparing the Ag-C type composite material for the negative electrode of a lithium-ion solid-state battery according to any one of claims 1-9, characterized in that, In step (3), the mass ratio of the Ag source material to the C source material is (0.5-10):(0.1-20).

11. The method for preparing the Ag-C type composite material for the negative electrode of a lithium-ion solid-state battery according to claim 10, characterized in that, Step (3) further includes a step of diluting the obtained mixed solution by a ratio of 10-80 v / v%.

12. The method for preparing the Ag-C type composite material for the negative electrode of a lithium-ion solid-state battery according to claim 10, characterized in that, Step (3) further includes the step of ultrasonically dispersing the resulting mixed solution.

13. The method for preparing the Ag-C type composite material for the negative electrode of a lithium-ion solid-state battery according to claim 10, characterized in that, Step (3) further includes the steps of filtration, washing and drying of the obtained mixed solution.

14. The method for preparing the Ag-C type composite material for the negative electrode of a lithium-ion solid-state battery according to claim 10, characterized in that, In step (3), the mixing temperature is -5~120℃ and the mixing time is 0.5-24h.

15. An Ag-C type composite material for anode of lithium-ion solid-state batteries prepared by the method according to any one of claims 1-14.

16. The use of the Ag-C type composite material for lithium-ion solid-state battery anode as described in claim 15 for preparing lithium-ion solid-state battery anode material, anode sheet, and lithium-ion solid-state battery.

17. A lithium-ion solid-state battery anode material, anode sheet, and lithium-ion solid-state battery prepared from the Ag-C type composite material for lithium-ion solid-state battery anode as described in claim 15.

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