Preparation method of multi-component mixed ion conductor

Abstract

The invention belongs to the technical field of electrochemical energy storage, and particularly relates to a preparation method of a multi-component mixed ion conductor, which comprises the following steps: selecting fluosilicate particles and lithium metal foil, and repeatedly folding and rolling to manufacture the multi-component mixed ion conductor, a battery pole piece with a certain thickness is manufactured through a multi-component mixed ion conductor according to actual requirements, and the battery is manufactured through the battery pole piece. The multi-component mixed ion conductor electrode material with the bicontinuous conductive path is prepared, the bicontinuous conductive path penetrating through an electrode body phase and an interface is established, and rapid electron transmission and uniform ion flux distribution of the electrode body phase and the surface are guaranteed. Meanwhile, the electrode can reduce Li < + > migration energy barriers, uniformize lithium metal deposition and inhibit volume expansion. When the multi-component mixed ion conductor electrode material is applied to the lithium metal battery, the long cycle life and the cycle safety and stability of the battery are successfully improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrochemical energy storage, and in particular relates to a method for preparing a multi-component mixed ion conductor. Background Art

[0002] Against the backdrop of rapid global socio-economic development and energy consumption upgrades, the shrinking fossil energy reserves and ecological environmental pressures have driven the clean energy substitution strategy to become a global consensus. At the same time, the development of the electric vehicle industry and mobile smart terminals has placed stringent requirements on the energy density and cycle life of secondary energy storage batteries. Current commercial lithium-ion batteries are limited by the inherent characteristics of the graphite negative electrode based on the ion insertion / extraction mechanism (theoretical capacity 372mAh g -1 ), its energy density is close to the theoretical limit. Lithium metal anode has become the core research object of new energy storage system due to its outstanding electrochemical properties, with the lowest reduction potential (-3.04V vs standard hydrogen electrode) and 3860mAh g -1 To break through the energy storage limit of traditional lithium-ion batteries, the energy storage field focuses on key technologies such as lithium metal anode interface regulation and dendrite suppression, and promotes the practical application of high-capacity energy storage devices through materials engineering and structural optimization.

[0003] However, the dynamic deposition of lithium metal lacks three-dimensional skeleton constraints, leading to uncontrolled lithium growth during deposition and dissolution, triggering two major failure mechanisms. First, the volume expansion of the localized deposited layer, up to 300%, causes stress concentration, resulting in the rupture of the brittle solid electrolyte layer (SEI). Second, the fresh lithium surface exposed by the SEI rupture continuously consumes electrolyte active components, forming a thick and uneven SEI layer. This process exacerbates the spatial non-uniformity of the interfacial and bulk ion fluxes and electron transport networks, causing further uneven deposition, resulting in lithium dendrites and dead lithium, accelerating capacity decay and increasing safety risks. Current research aims to improve performance by constructing composite anodes (Adv. Mater. 2023, 35, 2302872), preparing solid-state electrolytes (Angew. Chem. Int. Ed. 2025, e202501411), and designing artificial SEI layers (Adv. Mater. 2023, 35, 2209404), but the problem remains unresolved. To inhibit dendrite growth and volume expansion and achieve stable deposition during the cycle, it is necessary to construct a double continuous conductive network while ensuring rapid electron transport between the electrode bulk and surface and uniform ion flux distribution. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for preparing a multi-component mixed ion conductor. The technical solution includes a dual optimization mechanism: on the one hand, the prepared multi-component mixed ion conductors LiF and Li3N exhibit low Li +migration energy barrier, good ionic conductivity, and the ability to quickly and uniformly transport Li + , thereby promoting the uniform deposition of lithium metal. On the other hand, the in-situ formed Li-Si alloy framework in the composite negative electrode not only has improved ionic conductivity, but also has good structural stability, which can provide a good deposition site and alleviate the volume expansion of the deposited layer. Therefore, the prepared multi-component mixed ion conductor negative electrode material can establish a double continuous conductive path through the electrode body and the interface, reducing Li + The migration energy barrier, uniform lithium metal deposition, and suppressed volume expansion. The application of this multi-component mixed ion conductor electrode material in lithium metal batteries can successfully improve the battery's long cycle life and cycle safety and stability.

[0005] The technical solutions adopted by the present invention are as follows:

[0006] A method for preparing a multi-component mixed ion conductor comprises the following steps:

[0007] Step 1: Weigh fluorosilicate particles and lithium metal foil in a mass ratio of 1:97 to 105;

[0008] Step 2: Repeatedly folding and rolling the fluorosilicate particles and lithium metal foil to produce a multi-component mixed ion conductor;

[0009] Step 3: Make battery electrodes by using multi-component mixed ion conductors;

[0010] Step 4: Prepare a battery using the battery electrodes prepared in step 3.

[0011] Furthermore, the material of the fluorosilicate particles is any one of (NH4)2SiF6, Na2SiF6 and K2SiF6.

[0012] Furthermore, the method for preparing the multi-component mixed ion conductor comprises the following steps:

[0013] Step A1: Weigh 0.01 g of (NH4)2SiF6;

[0014] Step A2: Weigh 1 g of lithium metal foil;

[0015] Step A3: placing the (NH4)2SiF6 obtained in step A1 on the surface of the lithium metal foil obtained in step A2, folding the lithium metal foil, and wrapping the fluorosilicate inside the lithium metal foil to prepare Li@(NH4)2SiF6;

[0016] Step A4: Roll-pressing the Li@(NH4)2SiF6 prepared in step A3 to promote an in-situ reaction between the two to obtain a multi-component mixed ion conductor;

[0017] Step A5: repeatedly folding and rolling the multi-component mixed ion conductor obtained in step A4 to in situ generate a uniform LiF, Li3N, and Li-Si alloy mixed conductor;

[0018] Step A6: Control the roller spacing of the roller press to prepare a multi-component mixed ion conductor with a thickness of 50 μm, and then use the multi-component mixed ion conductor to prepare a lithium metal composite negative electrode.

[0019] Furthermore, the method for preparing the multi-component mixed ion conductor comprises the following steps:

[0020] Step B1: Weigh 0.01 g of Na2SiF6;

[0021] Step B2: Weigh 1 g of lithium metal foil;

[0022] Step B3: After placing the Na2SiF6 weighed in step B1 on the surface of the lithium metal foil weighed in step B2, folding the lithium metal foil and wrapping the fluorosilicate inside the lithium metal foil to prepare Li@Na2SiF6;

[0023] Step B4: Roll-pressing the Li@Na2SiF6 prepared in step B3 to promote an in-situ reaction between the two to obtain a multi-component mixed ion conductor;

[0024] Step B5: repeatedly folding and rolling the multi-component mixed ion conductor obtained in step B4 to in-situ generate a uniform LiF and Li-Si alloy mixed conductor;

[0025] Step B6: Control the roller spacing of the roller press to prepare a multi-component mixed ion conductor with a thickness of 50 μm, and then use the multi-component mixed ion conductor to make a lithium metal composite negative electrode.

[0026] Furthermore, the method for preparing the multi-component mixed ion conductor comprises the following steps:

[0027] Step C1: Weigh 0.01 g of K2SiF6;

[0028] Step C2: Weigh 1 g of lithium metal foil;

[0029] Step C3: placing the K2SiF6 weighed in step C1 on the surface of the lithium metal foil weighed in step C2, folding the lithium metal foil, and wrapping the fluorosilicate inside the lithium metal foil to prepare Li@K2SiF6;

[0030] Step C4: Roll-pressing the Li@K2SiF6 prepared in step C3 to promote an in-situ reaction between the two to obtain a multi-component mixed ion conductor;

[0031] Step C5: repeatedly folding and rolling the multi-component mixed ion conductor obtained in step C4 to in-situ generate a uniform LiF and Li-Si alloy mixed conductor;

[0032] Step C6: Controlling the roller spacing of the roller press to prepare a multi-component mixed ion conductor with a thickness of 50 μm, and then preparing a lithium metal composite negative electrode using the multi-component mixed ion conductor.

[0033] A lithium metal composite negative electrode is prepared by adopting a multi-component mixed ion conductor preparation method.

[0034] A lithium metal battery comprises a lithium metal composite negative electrode.

[0035] The technical effects achieved by the present invention are:

[0036] The invention discloses a method for preparing a multi-component mixed ion conductor to prepare a multi-component mixed ion conductor electrode material with a double continuous conductive path by repeated folding and rolling, thereby establishing a double continuous conductive path that runs through the electrode body and the interface, ensuring rapid electron transmission and uniform ion flux distribution between the electrode body and the surface, and reducing Li + The migration energy barrier, uniform lithium metal deposition, and suppressed volume expansion. This composite anode material is used in lithium metal batteries and has successfully improved the battery's long cycle life and cycle safety and stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is the XRD pattern of the multi-component ion mixed conductor of the present invention;

[0038] Figure 2 is a cross-sectional SEM image of the multi-component ion mixed conductor of the present invention;

[0039] Figure 3 The symmetrical battery of the present invention is 1mA cm -2 -1mAh cm -2 Cycling performance under . DETAILED DESCRIPTION

[0040] In order to make the purpose and advantages of the present invention more clearly understood, the present invention is described in detail below with reference to the following examples. It should be understood that the following text is only used to describe one or more specific embodiments of the present invention and does not strictly limit the scope of protection of the present invention.

[0041] like Figure 1-Figure 3 As shown, a method for preparing a multi-component mixed ion conductor comprises the following steps:

[0042] Step 1: Select / weigh a certain mass of fluorosilicate particles and lithium metal foil of certain specifications (thickness, size);

[0043] The mass ratio of the fluorosilicate particles to the lithium metal foil is preferably 1:97-105, preferably 1:100, that is, the mass of the fluorosilicate particles is 0.01 g, and the mass of the lithium metal foil is 1 g.

[0044] Step 2: Repeatedly folding and rolling the fluorosilicate particles and lithium metal foil at room temperature until the fluorosilicate particles and lithium metal are evenly mixed and fully reacted to produce a multi-component mixed ion conductor;

[0045] Step 3: According to actual needs, a battery electrode of a certain thickness is made by using a multi-component mixed ion conductor;

[0046] Step 4: Complete the subsequent battery assembly and prepare a battery using the battery electrodes prepared in step 3.

[0047] Lithium metal is used as the main processing body, and after the introduction of fluorosilicate particles, only repeated folding and rolling operations are performed. The simple preparation process can realize large-scale production; repeated folding and rolling operations can ensure that the fluorosilicate particles are evenly distributed on the surface and inside the bulk of the lithium metal, and a uniform multi-component mixed ion conductor is generated in situ. By using multi-component mixed ion conductors to make battery electrodes, it is possible to start from the ionic and electronic conductivity of the lithium metal electrode body and fundamentally change the ionic and electronic conductivity of the lithium metal electrode. It can effectively suppress the dendrite growth and volume expansion problems of the negative electrode during the cycle process. The prepared multi-component mixed ion conductor electrode can improve the long cycle life and cycle safety and stability of the battery.

[0048] The material of the fluorosilicate particles may be any one of (NH4)2SiF6, Na2SiF6 and K2SiF6. Please refer to the following embodiments for details.

[0049] Example 1:

[0050] A preparation method of a multi-component mixed ion conductor comprises the following steps:

[0051] Step A1: Weigh 0.01 g of (NH4)2SiF6.

[0052] Step A2: Weigh 1 g of lithium metal foil.

[0053] Step A3: After placing the (NH4)2SiF6 weighed in step A1 on the surface of the lithium metal foil weighed in step A2, fold the lithium metal foil, and wrap the fluorosilicate inside the lithium metal foil to prepare Li@(NH4)2SiF6.

[0054] Step A4: Roll-press the Li@(NH4)2SiF6 prepared in step A3 to promote an in-situ reaction between the two to obtain a multi-component mixed ion conductor.

[0055] Step A5: repeatedly folding and rolling the multi-component mixed ion conductor obtained in step A4.

[0056] The repeated folding and rolling operations can ensure that the (NH4)2SiF6 particles are evenly distributed on the surface and inside the bulk of the lithium metal, and a uniform LiF, LI3N, and Li-Si alloy mixed conductor is generated in situ.

[0057] Step A6: Control the roller spacing of the roller press to prepare a multi-component mixed ion conductor with a thickness of 50 μm, and then use the multi-component mixed ion conductor to prepare a lithium metal composite negative electrode.

[0058] Example 2:

[0059] A method for preparing a multi-component mixed ion conductor comprises the following steps:

[0060] Step B1: Weigh 0.01 g of Na2SiF6.

[0061] Step B2: Weigh 1 g of lithium metal foil.

[0062] Step B3: After placing the Na2SiF6 weighed in step B1 on the surface of the lithium metal foil weighed in step B2, fold the lithium metal foil and wrap the fluorosilicate inside the lithium metal foil to prepare Li@Na2SiF6.

[0063] Step B4: Roll-press the Li@Na2SiF6 prepared in step B3 to promote an in-situ reaction between the two to obtain a multi-component mixed ion conductor.

[0064] Step B5: repeatedly folding and rolling the multi-component mixed ion conductor obtained in step B4.

[0065] Repeated folding and rolling operations on the multi-component mixed ion conductor in step B5 can ensure that the Na2SiF6 particles are evenly distributed on the surface and inside the bulk of the lithium metal, thereby generating a uniform LiF and Li-Si alloy mixed conductor in situ.

[0066] Step B6: Control the roller spacing of the roller press to prepare a multi-component mixed ion conductor with a thickness of 50 μm, and then use the multi-component mixed ion conductor to make a lithium metal composite negative electrode.

[0067] Example 3:

[0068] A preparation method of a multi-component mixed ion conductor comprises the following steps:

[0069] Step C1: Weigh 0.01 g of K2SiF6.

[0070] Step C2: Weigh 1 g of lithium metal foil.

[0071] Step C3: After placing the K2SiF6 weighed in step C1 on the surface of the lithium metal foil weighed in step C2, fold the lithium metal foil, and wrap the fluorosilicate inside the lithium metal foil to prepare Li@K2SiF6.

[0072] Step C4: Roll-press the Li@K2SiF6 prepared in step C3 to promote an in-situ reaction between the two to obtain a multi-component mixed ion conductor.

[0073] Step C5: repeatedly folding and rolling the multi-component mixed ion conductor obtained in step C4.

[0074] The repeated folding and rolling operations can ensure that the K2SiF6 particles are evenly distributed on the surface and inside the bulk of the lithium metal, thereby generating a uniform LiF and Li-Si alloy mixed conductor in situ.

[0075] Step C6: Controlling the roller spacing of the roller press to prepare a multi-component mixed ion conductor with a thickness of 50 μm, and then preparing a lithium metal composite negative electrode using the multi-component mixed ion conductor.

[0076] In summary, this technical solution prepares a multi-component mixed ion conductor electrode material with a double continuous conductive path by repeated folding and rolling, establishes a double continuous conductive path running through the electrode body and the interface, ensures rapid electron transmission and uniform ion flux distribution between the electrode body and the surface, and reduces Li + The migration energy barrier, uniform lithium metal deposition, and suppressed volume expansion. This composite anode material is used in lithium metal batteries and has successfully improved the battery's long cycle life and cycle safety and stability.

[0077] The foregoing is merely a preferred embodiment of the present invention. It should be noted that those skilled in the art may make various improvements and modifications without departing from the principles of the present invention, and such improvements and modifications are also within the scope of protection of the present invention. Structures, devices, and operating methods not specifically described or explained herein shall, unless otherwise specified or limited, be implemented in accordance with conventional means in the art.

Claims

1. A method for preparing a multi-component mixed ion conductor, characterized in that: The following steps are involved: Step 1: Weigh fluorosilicate particles and lithium metal foil in a mass ratio of 1:97 to 105; Step 2: Repeatedly fold and roll the fluorosilicate particles and lithium metal foil to produce a multi-component mixed ion conductor.

2. The method for preparing a multi-component mixed ion conductor according to claim 1, wherein: The mass ratio of the fluorosilicate particles to the lithium metal foil is 1:

100.

3. The method for preparing a multi-component mixed ion conductor according to claim 1, wherein: The following steps are also included: Step 3: Make battery electrodes using multi-component mixed ion conductors.

4. The method for preparing a multi-component mixed ion conductor according to claim 3, wherein: The following steps are also included: Step 4: Prepare a battery using the battery electrodes prepared in step 3.

5. The method for preparing a multi-component mixed ion conductor according to claim 4, characterized in that: The material of the fluorosilicate particles is any one of (NH4)2SiF6, Na2SiF6 and K2SiF6.

6. The method for preparing a multi-component mixed ion conductor according to claim 5, characterized in that: The following steps are involved: Step A1: Weigh 0.01 g of (NH4)2SiF6; Step A2: Weigh 1 g of lithium metal foil; Step A3: placing the (NH4)2SiF6 obtained in step A1 on the surface of the lithium metal foil obtained in step A2, folding the lithium metal foil, and wrapping the fluorosilicate inside the lithium metal foil to prepare Li@(NH4)2SiF6; Step A4: Roll-pressing the Li@(NH4)2SiF6 prepared in step A3 to promote an in-situ reaction between the two to obtain a multi-component mixed ion conductor; Step A5: repeatedly folding and rolling the multi-component mixed ion conductor obtained in step A4 to in situ generate a uniform LiF, Li3N, and Li-Si alloy mixed conductor; Step A6: Control the roller spacing of the roller press to prepare a multi-component mixed ion conductor with a thickness of 50 μm, and then use the multi-component mixed ion conductor to prepare a lithium metal composite negative electrode.

7. The method for preparing a multi-component mixed ion conductor according to claim 5, characterized in that: The following steps are involved: Step B1: Weigh 0.01 g of Na2SiF6; Step B2: Weigh 1 g of lithium metal foil; Step B3: After placing the Na2SiF6 weighed in step B1 on the surface of the lithium metal foil weighed in step B2, folding the lithium metal foil and wrapping the fluorosilicate inside the lithium metal foil to prepare Li@Na2SiF6; Step B4: Roll-pressing the Li@Na2SiF6 prepared in step B3 to promote an in-situ reaction between the two to obtain a multi-component mixed ion conductor; Step B5: repeatedly folding and rolling the multi-component mixed ion conductor obtained in step B4 to in-situ generate a uniform LiF and Li-Si alloy mixed conductor; Step B6: Control the roller spacing of the roller press to prepare a multi-component mixed ion conductor with a thickness of 50 μm, and then use the multi-component mixed ion conductor to make a lithium metal composite negative electrode.

8. The method for preparing a multi-component mixed ion conductor according to claim 5, characterized in that: The following steps are involved: Step C1: Weigh 0.01 g of K2SiF6; Step C2: Weigh 1 g of lithium metal foil; Step C3: placing the K2SiF6 weighed in step C1 on the surface of the lithium metal foil weighed in step C2, folding the lithium metal foil, and wrapping the fluorosilicate inside the lithium metal foil to prepare Li@K2SiF6; Step C4: Roll-pressing the Li@K2SiF6 prepared in step C3 to promote an in-situ reaction between the two to obtain a multi-component mixed ion conductor; Step C5: repeatedly folding and rolling the multi-component mixed ion conductor obtained in step C4 to in-situ generate a uniform LiF and Li-Si alloy mixed conductor; Step C6: Controlling the roller spacing of the roller press to prepare a multi-component mixed ion conductor with a thickness of 50 μm, and then preparing a lithium metal composite negative electrode using the multi-component mixed ion conductor.

9. A lithium metal composite negative electrode, characterized in that: The lithium metal composite negative electrode is prepared by using a multi-component mixed ion conductor preparation method according to any one of claims 3 to 8.

10. A lithium metal battery, characterized in that: The lithium metal battery comprises the lithium metal composite negative electrode according to claim 9.

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