Porous material, method for producing the same, current collector, secondary battery, and device

Abstract

This application provides a porous material, its preparation method, a current collector, a secondary battery, and an apparatus thereof. The porous material has pores of a first pore size and pores of a second pore size; the second pore size is in the range of nanometers (m), where 10 < m < 400; the first pore size is in the range of micrometers (n), where 0.5 ≤ n ≤ 20; the apparent volume of the porous material is V, the total pore volume of the pores with the second pore size is V2, and the total pore volume of the pores with the first pore size is V1. The porous material satisfies the following relationships: (V1 + V2) / V = 20%–90%; V2 / V = 15%–70%; and V1 / V = 5%–70%.

Description

Technical Field

[0001] This application relates to the field of metallic materials technology, and in particular to a porous material and its preparation method, a current collector, a secondary battery and device thereof. Background Technology

[0002] In recent years, with the increasingly wide application of secondary batteries, they have been widely used in energy storage power systems such as hydropower, thermal power, wind power, and solar power plants, as well as in power tools, electric bicycles, electric motorcycles, electric cars, military equipment, aerospace, and many other fields. Due to the significant development of secondary batteries, higher requirements have been placed on their energy density and cycle performance.

[0003] Lithium metal is considered an attractive high-energy lithium-ion battery anode material due to its high theoretical specific capacity (3860 mAh / g) and low electrochemical potential. However, batteries using lithium metal as the anode will encounter the following problems during cycling: lithium dendrite formation, chemical reactions with the electrolyte, and unlimited expansion of the lithium anode volume during deposition and stripping. These problems will inevitably lead to battery safety hazards and low cycle efficiency, seriously hindering the practical application of lithium metal anodes. Summary of the Invention

[0004] This application addresses the aforementioned issues and aims to provide a novel porous material, its preparation method, current collector, secondary battery, and device. The method innovatively utilizes a multiphase alloy containing αMn and γMn-M phases to obtain a porous material with a hierarchical pore size distribution. This novel porous material with a hierarchical pore size distribution is particularly suitable for applications in anode-free metal batteries (e.g., anode-free lithium metal batteries or anode-free sodium metal batteries) or batteries containing active metal / alloy anodes.

[0005] In a first aspect, this application provides a porous material having pores of a first pore size and pores of a second pore size; the first pore size is n micrometers, 0.5 ≤ n ≤ 20; the second pore size is m nanometers, 10 < m < 400; the apparent volume of the porous material is V, the total pore volume of the pores with the first pore size is V1, the total pore volume of the pores with the second pore size is V2, and the porous material satisfies the following relationships: (V1 + V2) / V = 20% ~ 90%; V2 / V = 15 ~ 70%; and V1 / V = 5 ~ 70%.

[0006] The porous material based on the above scheme exhibits an innovative multi-level pore size distribution. This novel porous material is particularly suitable for anode-free metal batteries (e.g., anode-free lithium metal batteries or anode-free sodium metal batteries) or batteries containing active metal / alloy anodes. The inner walls of pores with a first pore size (hereinafter referred to as macropores) can serve as a substrate for active material deposition; furthermore, macropores also provide electrolyte wetting channels. The inner walls of pores with a second pore size (hereinafter referred to as micropores) can also serve as a substrate for active material deposition. Micropores increase the specific surface area of ​​the material, thereby enabling the porous material to load more active material; furthermore, micropores also serve as templates for active material deposition. Specifically, due to the limitation of the pore size, the active material deposited in the pore has a nanoscale size. The nanoscale active material has a high ionic conductivity due to its small size, which can improve the overall ionic conductivity of the electrode, thereby improving the rate performance of the battery, and ultimately improving the overall capacity, cycle stability and rate performance of the battery. In addition, another function of the pore is to limit the volume expansion of the active material and prevent it from pulverizing and failing.

[0007] In some embodiments, the total specific surface area of ​​the porous material is S, the specific surface area of ​​the pores with the first pore diameter is S1, and the specific surface area of ​​the pores with the second pore diameter is S2; wherein S1 / S = 7-32%; and S2 / S = 68-93%. The porous material based on the above scheme has novel pore specific surface area distribution characteristics.

[0008] In some embodiments, the second pore size is in nanometers (m), where 20 < m < 200. Porous materials based on the above scheme exhibit innovative pore size distribution characteristics.

[0009] In some embodiments, the first pore size is n micrometers, where 0.5 ≤ n ≤ 10. Porous materials based on the above scheme exhibit innovative pore size distribution characteristics.

[0010] In some embodiments, the porous material is a metallic element or alloy containing element M, wherein element M is selected from copper, aluminum, or a combination thereof. Porous materials based on the above schemes have innovative compositions.

[0011] In a second aspect, this application discloses a method for preparing a porous material, comprising:

[0012] A multiphase alloy is provided, the multiphase alloy containing an αMn phase and a γMn-M phase, wherein the M element is selected from copper, aluminum, or a combination thereof;

[0013] At least some Mn elements are removed from the αMn phase and at least some Mn elements are removed from the γMn-M phase by dealloying.

[0014] The porous material has pores with a first pore size and pores with a second pore size; the first pore size is n micrometers, 0.5≤n≤20; the second pore size is m nanometers, 10<m<400; the apparent volume of the porous material is V, the total pore volume of the pores with the second pore size is V2, the total pore volume of the pores with the first pore size is V1, and the porous material has one or more of the following characteristics: (1) (V1+V2) / V=20%~90%; (2) V2 / V=15~70%; (3) V1 / V=5~70%.

[0015] The above method innovatively performs dealloying treatment on multiphase alloys with unique microstructures, resulting in porous materials with innovative pore distribution characteristics.

[0016] In some embodiments, at least 90 at.%, for example, 95 at.%, of the Mn element is removed from the αMn phase using a dealloying method, based on the total Mn element in the αMn phase. Based on this, the resulting porous material exhibits innovative pore distribution characteristics.

[0017] In some embodiments, at least 90 at.%, for example, 95 at.%, of the Mn element is removed from the γMn-M phase using a dealloying method, based on the total Mn element in the γMn-M phase. Based on this, the resulting porous material exhibits innovative pore distribution characteristics.

[0018] In some embodiments, based on the total amount of M element in the multiphase alloy, the dealloying method removes less than 10 at.%, for example, less than 5 at.%. Based on this, the resulting porous material exhibits innovative pore distribution characteristics.

[0019] In some embodiments, the Mn content in the αMn phase is >99 at.%. Based on this, the obtained porous material has innovative pore distribution characteristics.

[0020] In some embodiments, the Mn content in the γMn-M phase is 40-80 at.%, for example, 40-50 at.%, 50-60 at.%, 60-70 at.%, or 70-80 at.%. Based on this, the obtained porous material has innovative pore distribution characteristics.

[0021] In some embodiments, the γMn-M phase is a solid solution. Based on this, the obtained porous material has innovative pore distribution characteristics.

[0022] In some embodiments, the αMn phase content in the multiphase alloy is 22–70 vol%, for example, 25–30%, 30–40 vol%, 40–50 vol%, 50–60 vol%, or 60–70 vol%. Based on this, the obtained porous material has innovative pore distribution characteristics.

[0023] In some embodiments, the content of the γMn-M phase in the multiphase alloy is 30–78 vol%, for example, 30–40 vol%, 40–50 vol%, 50–60 vol%, or 60–70 vol%. Based on this, the obtained porous material has innovative pore distribution characteristics.

[0024] In some embodiments, the average size of the αMn phase in the metallographic photographs of the multiphase alloy is 0.5–10 micrometers. Here, the average size can be understood as the average diameter of an equal-area circle of the αMn phase.

[0025] In some embodiments, the average size of the γMn-M phase in the metallographic photographs of the multiphase alloy is 0.5 to 10 micrometers. Here, the average size can be understood as the average diameter of an equal-area circle of the γMn-M phase.

[0026] In some embodiments, the αMn phase (which appears bright white in the metallographic structure) in the metallographic photographs of the multiphase alloy has an average size of 0.5–10 micrometers. Based on this, the obtained porous material has innovative pore distribution characteristics.

[0027] In some embodiments, in the metallographic photographs of the multiphase alloy, the γMn-M phase (which appears blackish-gray in the metallographic structure) has an average size of a micrometer × b micrometers, where a = 0.89–5 (e.g., 1–2, 1–2, 3–4, 4–5) and b = 0.89–1.75 (e.g., 1–1.5). Based on this, the obtained porous material has innovative pore distribution characteristics.

[0028] In some embodiments, the αMn phase and the γMn-M phase are uniformly dispersed in the multiphase alloy. Based on this, the obtained porous material exhibits innovative pore distribution characteristics.

[0029] In some embodiments, the multiphase alloy contains Mn and M, wherein the Mn content is 60%-90 at.%, for example 70-80% at.%, and the M content is 10-40 at.%, for example 20-30 at.%, with M selected from copper, aluminum, or combinations thereof. Based on this, the obtained porous material exhibits innovative pore distribution characteristics.

[0030] In some embodiments, the dealloying method is selected from chemical etching, electrochemical etching, or a combination thereof. Based on this, the obtained porous material exhibits innovative pore distribution characteristics.

[0031] In some embodiments, the method for preparing porous materials further includes a step of preparing multiphase alloys, specifically including:

[0032] An alloy precursor is provided, the alloy precursor containing elements M and Mn, wherein the element M is selected from copper, aluminum, or a combination thereof.

[0033] The alloy precursor is subjected to a first heat treatment to obtain a first product, wherein the first product contains a γMn-M phase;

[0034] The product from the previous step is subjected to a second heat treatment to obtain a second product containing αMn and γMn-M phases. Based on this, the obtained porous material exhibits innovative pore distribution characteristics. The first product containing the γMn-M phase exhibits excellent room temperature plasticity. Processing the first product using plastic forming methods such as forging, rolling, and drawing can yield processed products of different shapes and sizes. These processed products maintain shape and dimensional stability during subsequent heat treatment and dealloying processes.

[0035] In some embodiments, the temperature of the first heat treatment is 700-865°C, for example 700-730°C, 730-760°C, 760-790°C, 790-820°C, or 820-850°C. Based on this, the obtained porous material has innovative pore distribution characteristics.

[0036] In some embodiments, the first heat treatment time is 0.16 hours or more, for example, 1-2 hours. Based on this, the obtained porous material has innovative pore distribution characteristics.

[0037] In some embodiments, the first heat treatment is followed by cooling at a rate of 20–1000 °C / s, for example, water cooling. Based on this, the obtained porous material exhibits innovative pore distribution characteristics.

[0038] In some embodiments, the content of the γMn-M phase in the first product is 95-100 vol%. The first product containing the γMn-M phase has good plasticity and can be processed into processed products of different shapes and sizes by plastic processing methods (forging, rolling, drawing, etc.).

[0039] In some embodiments, the method further includes a plastic processing operation on the first product prior to the second heat treatment.

[0040] In some embodiments, the temperature of the second heat treatment is 500-700°C, for example 550-600°C or 600-650°C. Based on this, the obtained porous material has innovative pore distribution characteristics.

[0041] In some embodiments, the second heat treatment lasts for 1 to 4 hours, for example, 2 to 3 hours. Based on this, the obtained porous material exhibits innovative pore distribution characteristics.

[0042] In some embodiments, the second treatment is followed by cooling at a rate of 20–1000 °C / s, for example, water cooling. Based on this, the obtained porous material exhibits innovative pore distribution characteristics.

[0043] In some embodiments, the content of the αMn phase in the second product is 22-70 vol%, for example 25-30%, 30-40 vol%, 40-50 vol%, 50-60 vol%, or 60-70 vol%, and the content of the γMn-M phase is 30-78 vol%, for example 30-40 vol%, 40-50 vol%, 50-60 vol%, or 60-70 vol%.

[0044] In some embodiments, the alloy precursor is an ingot. Based on this, the method for preparing porous materials has a lower cost. Furthermore, it is possible to prepare porous materials with a larger volume using this approach.

[0045] In some embodiments, the porous material obtained by the method has pores of a first pore size and pores of a second pore size; the second pore size is m nanometers, 10 < m < 400, for example 20 < m < 200; the first pore size is n micrometers, 0.5 ≤ n ≤ 20, for example 0.5 ≤ n ≤ 10. Based on this, the obtained porous material has innovative pore distribution characteristics.

[0046] In some embodiments, the total specific surface area of ​​the porous material obtained by the method is S, the specific surface area of ​​the pores with the first pore diameter is S1, and the specific surface area of ​​the pores with the second pore diameter is S2; wherein S1 / S = 7-32%; and S2 / S = 68-93%. Based on this, the obtained porous material has innovative pore distribution characteristics.

[0047] In some embodiments, this application provides a porous material prepared by the method described in any of the above-mentioned embodiments.

[0048] In some embodiments, this application provides a current collector comprising the porous material described in any of the above embodiments.

[0049] In some embodiments, this application provides a secondary battery including the current collector described in any of the above claims.

[0050] In some embodiments, this application provides an apparatus including a secondary battery as described in any of the preceding claims, the secondary battery providing electrical energy to the apparatus.

[0051] Beneficial effects

[0052] According to the Mn-Cu binary alloy phase diagram, Mn-Cu binary alloys (Mn content 90-60 at.%) exhibit a γ-Mn single-phase structure in the temperature range of 700-865℃, and an α / γ dual-phase structure in the temperature range of 500-700℃. Therefore, the Mn-Cu alloys prepared by smelting can be first annealed at high temperatures (700-865℃) to obtain a γ single-phase alloy with excellent plasticity, thus preparing precursor alloys of different shapes. Subsequently, low-temperature aging treatment (500-700℃) is performed to form an α / γ dual-phase structure, which is used to prepare the final porous material.

[0053] One or more embodiments of this application have one or more of the following beneficial effects:

[0054] (1) The method for preparing porous materials has a low cost.

[0055] (2) The method of preparing porous materials can obtain large-sized porous materials, and the product after dealloying can maintain the shape and size of the parent material.

[0056] (3) In the method of preparing porous materials, the first product containing the γMn-M phase has good plasticity and can be processed into processed products of different shapes and sizes by plastic processing methods (forging, rolling, drawing, etc.). Subsequent second heat treatment and dealloying operations on the processed products will not change the shape and size of the processed products.

[0057] (4) The method for preparing porous materials allows for flexible adjustment of the pore size and ratio of pores with a second pore size and pores with a first pore size in the porous material. For example, by adjusting the temperature and time of the second heat treatment, the content and size of the αMn phase in the second product can be controlled, thereby controlling the content and pore size of pores with a first pore size in the porous material. As another example, by adjusting the dealloying corrosion temperature, the content and pore size of pores with a second pore size in the porous material can be controlled.

[0058] (5) Figures 2-5 Scanning electron microscope images of the porous materials of the embodiments shown and Figure 8The diagram shows a porous material. The porous material of this application has pores of a first pore size and pores of a second pore size. The inner wall of the pores with the first pore size (hereinafter referred to as macropores) can serve as a substrate for active material deposition; furthermore, macropores also provide electrolyte wetting channels. The inner wall of the pores with the second pore size (hereinafter referred to as micropores) can also serve as a substrate for active material deposition. Micropores increase the specific surface area of ​​the material, thereby allowing the porous material to hold more active material; furthermore, micropores also serve as templates for active material deposition. Specifically, due to the limitation of micropore size, the active material deposited in the micropores has a nanoscale size. Nanoscale active materials, due to their small size, have higher ionic conductivity, which can improve the overall ionic conductivity of the electrode, thereby improving the rate performance of the battery, and ultimately improving the overall battery capacity, cycle stability, and rate performance; furthermore, micropores also limit the volume expansion of the active material, preventing its pulverization and failure. Attached Figure Description

[0059] Figure 1 (a) is the XRD diffraction pattern of the Mn-Cu alloy after the first heat treatment in some embodiments; Figure 1 (b) is the XRD diffraction pattern of the Mn-Cu alloy after the second heat treatment in some embodiments;

[0060] Figure 2 These are scanning electron microscope images of porous copper prepared in Example 1, where (a) is at low magnification and (b) is at high magnification.

[0061] Figure 3 Here are scanning electron microscope images of the porous copper prepared in Example 2;

[0062] Figure 4 Here is a scanning electron microscope image of the porous copper prepared in Example 3;

[0063] Figure 5 These are scanning electron microscope (SEM) images of porous copper prepared in Example 4, where (a) is at low magnification and (b) is at high magnification.

[0064] Figure 6 These are scanning electron microscope (SEM) images of porous copper prepared in a comparative manner, where (a) is at low magnification and (b) is at high magnification.

[0065] Figure 7 This is the phase diagram of Cu-Mn alloy.

[0066] Figure 8 This is a schematic diagram of the porous structure of porous materials according to some embodiments of this application.

[0067] Figure 9 This is an overall view and an exploded view of a secondary battery according to one embodiment of this application.

[0068] Figure 10 This is a schematic diagram of a battery module according to one embodiment of this application.

[0069] Figure 11 This is a schematic diagram of a battery pack according to one embodiment of this application.

[0070] Figure 12 yes Figure 11 An exploded view of a battery pack according to one embodiment of this application is shown.

[0071] Figure 13 This is a schematic diagram of a device that uses a secondary battery as a power source according to one embodiment of this application.

[0072] Explanation of reference numerals in the attached figures:

[0073] Battery pack 1; upper housing 2; lower housing 3; battery module 4; secondary battery 5; housing 51; electrode assembly 52; top cover assembly 53; three-dimensional porous skeleton 600; hole 601 with a first aperture; hole 602 with a second aperture. Detailed Implementation

[0074] The following detailed description, with appropriate reference to the accompanying drawings, discloses embodiments of the porous materials, preparation methods, current collectors, secondary batteries, and devices of this application. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided for the purpose of enabling those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0075] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0076] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0077] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0078] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0079] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0080] Unless otherwise specified, the term "or" is inclusive in this application. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, the condition "A or B" is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0081] Porous materials

[0082] In some embodiments, this application provides a porous material having pores of a first pore size and pores of a second pore size; the first pore size is n micrometers, 0.5 ≤ n ≤ 20; the second pore size is m nanometers, 10 < m < 400; the apparent volume of the porous material is V, the total pore volume of the pores with the first pore size is V1, the total pore volume of the pores with the second pore size is V2, and the porous material satisfies the following relationships: (V1 + V2) / V = 20% ~ 90%; V2 / V = 15 ~ 70%; and V1 / V = 5 ~ 70%. The porous material based on the above scheme has an innovative multi-level pore size distribution characteristic.

[0083] The porous material based on the above scheme exhibits an innovative multi-level pore size distribution. This novel porous material is particularly suitable for anode-free metal batteries (e.g., anode-free lithium metal batteries or anode-free sodium metal batteries) or metal or alloy anode batteries. The inner wall of the pores with the first pore size (hereinafter referred to as macropores) can serve as a substrate for active material deposition; in addition, macropores also provide electrolyte wetting channels. The inner wall of the pores with the second pore size (hereinafter referred to as micropores) can also serve as a substrate for active material deposition. Micropores increase the specific surface area of ​​the material, thereby enabling the porous material to load more active material; in addition, micropores also serve as templates for active material deposition. Specifically, due to the limitation of micropore size, the active material deposited in the micropores has a nanoscale size. Nanoscale active materials have high ionic conductivity due to their small size, which can improve the overall ionic conductivity of the electrode, thereby improving the rate performance of the battery, and ultimately improving the overall battery capacity, cycle stability, and rate performance; in addition, micropores also limit the volume expansion of the active material, preventing its pulverization and failure.

[0084] In some implementations, the value of (V1+V2) / V is 20-30%, 30-40%, 40-50%, 50-60%, 60-70%, 70-80%, or 80-90%.

[0085] In some implementations, the value of V2 / V is 20-30%, 30-40%, 40-50%, 50-60%, or 60-70%.

[0086] In some embodiments, the total specific surface area of ​​the porous material is S, the specific surface area of ​​the pores with the first pore diameter is S1, and the specific surface area of ​​the pores with the second pore diameter is S2; wherein S1 / S = 7-32%; and S2 / S = 68-93%. The porous material based on the above scheme has a pore specific surface area distribution characteristic.

[0087] In some implementations, the value of S1 / S is 10-15%, 15-20%, 20-25%, or 25-30%.

[0088] In some implementations, the value of S1 / S is 70-75%, 75-80%, 80-85%, or 85-90%.

[0089] In some embodiments, the second pore size is in nanometers (m), where 20 < m < 200. Porous materials based on the above scheme exhibit innovative pore size distribution characteristics.

[0090] In some embodiments, the second pore size is m nanometers, where m is 10-50, 50-100, 100-150, 150-200, 200-250, 250-300, 300-350, or 350-400.

[0091] In some embodiments, the first pore size is n micrometers, where 0.5 ≤ n ≤ 10. Porous materials based on the above scheme exhibit innovative pore size distribution characteristics.

[0092] In some embodiments, the first pore size is n micrometers, where n is 0.5-1, 1-5, 5-10, 10-15, or 15-20.

[0093] In some embodiments, the porous material is a metallic element or alloy containing element M, wherein element M is selected from copper, aluminum, or a combination thereof. Porous materials based on the above schemes have innovative compositions.

[0094] In some embodiments, the porous material is prepared using a dealloying method.

[0095] In some embodiments, the porous material is gas-permeable and / or liquid-permeable.

[0096] In a second aspect, this application discloses a method for preparing a porous material, comprising:

[0097] A multiphase alloy is provided, the multiphase alloy containing an αMn phase and a γMn-M phase, wherein the M element is selected from copper, aluminum, or a combination thereof;

[0098] At least some Mn elements are removed from the αMn phase and at least some Mn elements are removed from the γMn-M phase by dealloying.

[0099] The porous material has pores with a first pore size and pores with a second pore size; the first pore size is n micrometers, 0.5≤n≤20; the second pore size is m nanometers, 10<m<400; the apparent volume of the porous material is V, the total pore volume of the pores with the second pore size is V2, the total pore volume of the pores with the first pore size is V1, and the porous material has one or more of the following characteristics: (1) (V1+V2) / V=20%~90%; (2) V2 / V=15~70%; (3) V1 / V=5~70%.

[0100] The above method innovatively performs dealloying treatment on multiphase alloys with unique microstructures, resulting in porous materials with innovative pore distribution characteristics.

[0101] According to the Mn-Cu binary alloy phase diagram, Mn-Cu binary alloys (Mn content 90-60 at.%) exhibit a γ single-phase structure in the temperature range of 700-865℃, and an α / γ dual-phase structure in the temperature range of 500-700℃. Therefore, the Mn-Cu alloys prepared by smelting can be first annealed at high temperature (700-865℃) to obtain a γ single-phase alloy with excellent plasticity, thus preparing precursor alloys of different shapes. Subsequently, low-temperature aging treatment (500-700℃) is performed to form an α / γ dual-phase structure, which is used to prepare the final porous material.

[0102] One or more embodiments of this application have one or more of the following beneficial effects:

[0103] (1) The method for preparing porous materials has a low cost.

[0104] (2) The method of preparing porous materials can obtain large-sized porous materials.

[0105] (3) In the method of preparing porous materials, the first product containing the γMn-M phase has good plasticity and can be processed into processed products of different shapes and sizes by plastic processing methods (forging, rolling, drawing, etc.). Subsequent second heat treatment and dealloying operations on the processed products will not change the shape and size of the processed products.

[0106] (4) The method for preparing porous materials allows for flexible adjustment of the pore size and ratio of pores with a second pore size and pores with a first pore size in the porous material. For example, by adjusting the temperature and time of the second heat treatment, the content and size of the αMn phase in the second product can be controlled, thereby controlling the content and pore size of pores with a first pore size in the porous material. As another example, by adjusting the dealloying corrosion temperature, the content and pore size of pores with a second pore size in the porous material can be controlled.

[0107] In some embodiments, at least 90 at.% of the Mn element in the αMn phase is removed from the αMn phase using a dealloying method, based on the total Mn element in the αMn phase. Based on this, the resulting porous material exhibits innovative pore distribution characteristics.

[0108] In some embodiments, at least 90 at.% of the Mn element in the γMn-M phase is removed from the γMn-M phase using a dealloying method, based on the total Mn element in the γMn-M phase. Based on this, the resulting porous material exhibits innovative pore distribution characteristics.

[0109] In some embodiments, based on the total amount of M element in the multiphase alloy, the dealloying method removes less than 10 at.% of the M element. Based on this, the resulting porous material exhibits innovative pore distribution characteristics.

[0110] In some embodiments, the Mn content in the αMn phase is >99 at.%. Based on this, the obtained porous material has innovative pore distribution characteristics.

[0111] In some embodiments, the Mn content in the γMn-M phase is 40-80 at.%. Based on this, the obtained porous material has innovative pore distribution characteristics.

[0112] In some embodiments, the γMn-M phase is a solid solution. Based on this, the obtained porous material has innovative pore distribution characteristics.

[0113] In some embodiments, the αMn phase content in the multiphase alloy is 22–70 vol%. Based on this, the obtained porous material has innovative pore distribution characteristics.

[0114] In some embodiments, the content of the γMn-M phase in the multiphase alloy is 30–78 vol%. Based on this, the obtained porous material has innovative pore distribution characteristics.

[0115] In some embodiments, the average size of the αMn phase in the metallographic photographs of the multiphase alloy is 0.5–10 micrometers. Here, the average size can be understood as the average diameter of an equal-area circle of the αMn phase.

[0116] In some embodiments, the average size of the γMn-M phase in the metallographic photographs of the multiphase alloy is 0.5 to 10 micrometers. Here, the average size can be understood as the average diameter of an equal-area circle of the γMn-M phase.

[0117] In some embodiments, the αMn phase appears bright white in the metallographic structure of the multiphase alloy, with an average size of 0.5–10 micrometers. Based on this, the obtained porous material has innovative pore distribution characteristics.

[0118] In some embodiments, in the metallographic photographs of the multiphase alloy, the γMn-M phase appears blackish-gray in the metallographic structure, with an average size of a×b, where a = 0.89–5 μm and b = 0.89–1.75 μm. Based on this, the obtained porous material has innovative pore distribution characteristics.

[0119] In some implementations, the term "metallographic photograph" refers to a microscopic photograph that reflects the microstructure of a metal, particularly its phase distribution. Metallographic photographs can be obtained using an optical microscope or an electron microscope.

[0120] In some embodiments, the αMn phase and the γMn-M phase are uniformly dispersed in the multiphase alloy. Based on this, the obtained porous material exhibits innovative pore distribution characteristics.

[0121] In some embodiments, the multiphase alloy contains Mn and M, wherein the Mn content is 60%-90 at.% and the M content is 10-40 at.%, and the M element is selected from copper, aluminum, or a combination thereof. Based on this, the obtained porous material exhibits innovative pore distribution characteristics.

[0122] In some implementations, the dealloying process is based on the difference in standard electrochemical potentials of the precursor components, selectively removing relatively reactive elements from the system, while the remaining metal atoms connect with each other to obtain a porous material.

[0123] In some embodiments, the dealloying method is selected from chemical etching, electrochemical etching, or a combination thereof. Based on this, the obtained porous material exhibits innovative pore distribution characteristics.

[0124] In some embodiments, the method for preparing porous materials further includes a step of preparing multiphase alloys, specifically including:

[0125] An alloy precursor is provided, the alloy precursor containing elements M and Mn, wherein the element M is selected from copper, aluminum, or a combination thereof.

[0126] The alloy precursor is subjected to a first heat treatment to obtain a first product, wherein the first product contains a γMn-M phase;

[0127] The product from the previous step is subjected to a second heat treatment to obtain a second product containing αMn and γMn-M phases. Based on this, the obtained porous material exhibits innovative pore distribution characteristics. The first product containing the γMn-M phase exhibits excellent room temperature plasticity. Processing the first product using plastic forming methods such as forging, rolling, and drawing can yield processed products of different shapes and sizes. These processed products maintain shape and dimensional stability during subsequent heat treatment and dealloying processes.

[0128] In some embodiments, the temperature of the first heat treatment is 700-865°C. Based on this, the obtained porous material has innovative pore distribution characteristics.

[0129] In some embodiments, the first heat treatment time is 0.16 hours or more, for example, 1-2 hours. Based on this, the obtained porous material has innovative pore distribution characteristics.

[0130] In some embodiments, the first heat treatment is followed by cooling at a rate of 20–1000 °C / s, for example, water cooling. Based on this, the obtained porous material exhibits innovative pore distribution characteristics.

[0131] In some embodiments, the first heat treatment is configured to obtain a first product with a γMn-M phase content of 95–100 vol%.

[0132] In some embodiments, the content of the γMn-M phase in the first product is 95–100 vol%.

[0133] In some embodiments, the method further includes a plastic processing operation on the first product prior to the second heat treatment.

[0134] In some embodiments, the temperature of the second heat treatment is 500-700°C. Based on this, the obtained porous material has innovative pore distribution characteristics.

[0135] In some embodiments, the second heat treatment lasts for 1 to 4 hours, for example, 2 to 3 hours. Based on this, the obtained porous material has innovative pore distribution characteristics.

[0136] In some embodiments, the second treatment is followed by cooling at a rate of 20–1000 °C / s. Based on this, the obtained porous material exhibits innovative pore distribution characteristics.

[0137] In some embodiments, the second heat treatment is configured to convert a portion of the γMn-M phase in the first product into the αMn phase.

[0138] In some embodiments, the content of the αMn phase in the second product is 22-70 vol%, for example, 22-30 vol%, 30-40 vol%, 40-50 vol%, 50-60 vol%, or 60-70 vol%, and the content of the γMn-M phase is 30-78 vol%, for example, 30-40 vol%, 40-50 vol%, 50-60 vol%, or 60-78 vol%.

[0139] In some embodiments, the alloy precursor is an ingot (e.g., a smelted ingot). Based on this, the method for preparing porous materials has a lower cost. Furthermore, it is possible to prepare porous materials with a larger volume using this approach.

[0140] In some embodiments, the porous material obtained by the method has pores of a first pore size and pores of a second pore size; the second pore size is m nanometers, 10 < m < 400, for example 20 < m < 200; the first pore size is n micrometers, 0.5 ≤ n ≤ 20, for example 0.5 ≤ n ≤ 10. Based on this, the obtained porous material has innovative pore distribution characteristics.

[0141] In some embodiments, the apparent volume of the porous material obtained by the method is V, the total pore volume of the pores with the second pore diameter is V2, the total pore volume of the pores with the first pore diameter is V1, and the porous material has one or more of the following characteristics: (1) (V1+V2) / V = 20%~90%; (2) V2 / V = 15%~70%; (3) V1 / V = 5%~70%. Based on this, the obtained porous material has innovative pore distribution characteristics.

[0142] In some embodiments, the total specific surface area of ​​the porous material obtained by the method is S, the specific surface area of ​​the pores with the first pore diameter is S1, and the specific surface area of ​​the pores with the second pore diameter is S2; wherein S1 / S = 7-32%; and S2 / S = 68-93%. Based on this, the obtained porous material has innovative pore distribution characteristics.

[0143] In some implementations, the porous material has a dimension of not less than 10 mm in each direction, for example, not less than 5 mm, or for example, not less than 2 mm.

[0144] In some embodiments, this application provides a porous material prepared by the method described in any of the above-mentioned embodiments.

[0145] In some embodiments, this application provides a current collector comprising the porous material described in any of the above embodiments.

[0146] In some embodiments, this application provides a secondary battery including the current collector described in any of the above claims.

[0147] In some embodiments, this application provides an apparatus including a secondary battery as described in any of the preceding claims, the secondary battery providing electrical energy to the apparatus.

[0148] In some embodiments, αMn is an allotrope of manganese having a cbcc structure.

[0149] In some embodiments, γMn is an allotrope of manganese having an fcc structure.

[0150] In some embodiments, the γMn-M phase is a solid solution phase formed by element M dissolving in γMn.

[0151] For example, the γMn-Cu phase is a solid solution phase formed by the element Cu dissolving in γMn.

[0152] In some embodiments, a solid solution is a single-phase crystalline solid formed by dissolving one or more solute components into a crystalline solvent while maintaining the lattice type of the solvent.

[0153] [Rechargeable Battery]

[0154] Secondary batteries, also known as rechargeable batteries or storage batteries, are batteries that can be recharged after being discharged to activate the active materials and continue to be used.

[0155] Typically, a secondary battery consists of a positive electrode, a negative electrode, a separator, and an electrolyte. During charging and discharging, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, primarily prevents short circuits while allowing active ions to pass through. The electrolyte, also positioned between the positive and negative electrodes, mainly serves to conduct active ions.

[0156] [Positive electrode plate]

[0157] A positive electrode typically includes a positive current collector and a positive electrode film layer disposed on at least one surface of the positive current collector, the positive electrode film layer including a positive active material. A surface treatment composition may be disposed between the positive current collector and the positive electrode film layer.

[0158] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive electrode film layer is disposed on either or both of the two opposite surfaces of the positive current collector.

[0159] In some embodiments, the positive electrode current collector may contain the porous material described in any of the above claims. The positive electrode current collector may also be a composite current collector, for example, formed by combining the porous material described in any of the above claims with a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0160] In some embodiments, the positive electrode active material may be a known battery positive electrode active material. As an example, the positive electrode active material may include at least one of the following materials: lithium phosphates with an olivine structure, lithium transition metal oxides, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium transition metal oxides include, but are not limited to, lithium cobalt oxides (such as LiCoO2), lithium nickel oxides (such as LiNiO2), lithium manganese oxides (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, and lithium nickel cobalt manganese oxides (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM523), LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM211), LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM811), lithium nickel cobalt aluminum oxide (such as LiNi) 0.85 Co 0.15 Al 0.05 At least one of O2 and its modified compounds. Examples of lithium phosphates with an olivine structure include, but are not limited to, lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium manganese iron phosphate, and lithium manganese iron phosphate and carbon composites.

[0161] In some embodiments, the positive electrode film layer may optionally include a surface treatment. As an example, the surface treatment may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resin.

[0162] In some embodiments, the positive electrode film may optionally include a conductive agent. As an example, the conductive agent may include at least one selected from superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0163] In some embodiments, the positive electrode sheet can be prepared by dispersing the above-mentioned components for preparing the positive electrode sheet, such as positive active material, conductive agent, surface treatment and any other components, in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry; coating the positive electrode slurry onto the positive electrode current collector, and then obtaining the positive electrode sheet after drying, cold pressing and other processes.

[0164] [Negative electrode current collector and negative electrode plate]

[0165] The porous material of this application can be directly used as a current collector (or electrode) on the negative electrode side of an anode-free metal battery (such as anode-free lithium metal battery or anode-free sodium metal battery).

[0166] In lithium-free anode batteries, all active lithium ions are initially stored in the cathode material. During the initial charging process, lithium ions are extracted from the cathode, migrate to the anode, and are directly electroplated in situ onto the bare current collector, forming a lithium metal anode. Subsequently, during discharge, the active lithium ions are stripped from the in-situ formed lithium metal anode and embedded into the cathode. Lithium-free anode batteries are small in size and have a high energy density.

[0167] The porous material of this application can also be used as a current collector on the negative electrode side of a battery containing an active metal / alloy negative electrode.

[0168] In some implementations, the active metal / alloy is, for example, lithium metal or a lithium alloy.

[0169] In some embodiments, the negative electrode of the lithium metal battery uses the porous material of this application as the negative electrode current collector, and a lithium metal layer is deposited on the outer surface and / or inside the pores of the porous material.

[0170] As used herein, the term "lithium alloy" is intended to refer to a substance capable of forming an alloy with lithium through charging and capable of reversibly adsorbing and releasing lithium. Examples of substances capable of forming alloys with lithium include metallic elements such as tin (Sn), silicon (Si), zinc (Zn), aluminum (Al), magnesium (Mg), indium (In), cadmium (Cd), lead (Pb), bismuth (Bi), and antimony (Sb), as well as their compounds and alloys (including alloys of lithium with these metallic elements). One or more of these substances can be suitably used through appropriate selection.

[0171] In some embodiments, other active metals / alloys besides lithium metal or lithium alloys include elements such as tin (Sn), silicon (Si), zinc (Zn), aluminum (Al), magnesium (Mg), indium (In), cadmium (Cd), lead (Pb), bismuth (Bi), and antimony (Sb), as well as their compounds and alloys (including alloys of lithium with these metal elements).

[0172] In some implementations, active metals / alloys can be deposited on the surface and inside the pores of porous materials using methods such as electrodeposition, vapor deposition (e.g., physical / chemical vapor deposition), and magnetron sputtering, thereby obtaining the battery negative electrode.

[0173] [Electrolytes]

[0174] The electrolyte acts as a conductor of ions between the positive and negative electrodes. This application does not impose specific restrictions on the type of electrolyte; it can be selected according to requirements. For example, the electrolyte can be liquid, gel, or entirely solid.

[0175] In some embodiments, the electrolyte is liquid and includes an electrolyte salt and a solvent.

[0176] In some embodiments, the electrolyte salt may be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0177] In some embodiments, the solvent may be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone.

[0178] In some embodiments, the electrolyte may optionally include additives. As examples, additives may include negative electrode film-forming additives, positive electrode film-forming additives, and may also include additives that can improve certain battery performance, such as additives that improve battery overcharge performance, additives that improve battery high-temperature or low-temperature performance, etc.

[0179] [Isolation membrane]

[0180] In some embodiments, the secondary battery also includes a separator. This application does not impose any particular limitation on the type of separator; any known porous separator with good chemical and mechanical stability can be selected.

[0181] In some embodiments, the material of the separator can be selected from at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation.

[0182] In some implementations, the positive electrode, negative electrode, and separator can be fabricated into an electrode assembly using a winding or stacking process.

[0183] In some embodiments, the secondary battery may include an outer packaging. This outer packaging may be used to encapsulate the aforementioned electrode assembly and electrolyte.

[0184] In some embodiments, the outer packaging of the secondary battery can be a hard shell, such as a hard plastic shell, an aluminum shell, or a steel shell. The outer packaging of the secondary battery can also be a soft pack, such as a pouch. The material of the soft pack can be plastic; examples of plastics include polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0185] This application does not impose any particular limitation on the shape of the secondary battery; it can be cylindrical, square, or any other arbitrary shape. For example, Figure 9 This is an overall and exploded view of a square-structured secondary battery 5, used as an example.

[0186] In some implementations, refer to Figure 9 The outer packaging may include a housing 51 and a cover 53. The housing 51 may include a base plate and side plates connected to the base plate, the base plate and side plates forming a receiving cavity. The housing 51 has an opening communicating with the receiving cavity, and the cover 53 can be placed over the opening to close the receiving cavity. A positive electrode, a negative electrode, and a separator can be formed into an electrode assembly 52 using a winding or stacking process. The electrode assembly 52 is encapsulated within the receiving cavity. Electrolyte is immersed in the electrode assembly 52. ​​The secondary battery 5 may contain one or more electrode assemblies 52, which can be selected by those skilled in the art according to specific practical needs.

[0187] In some implementations, the secondary batteries can be assembled into a battery module, and the number of secondary batteries contained in the battery module can be one or more, the specific number of which can be selected by those skilled in the art according to the application and capacity of the battery module.

[0188] Figure 10 This is battery module 4, used as an example. (See reference...) Figure 10 In battery module 4, multiple secondary batteries 5 can be arranged sequentially along the length of battery module 4. Of course, they can also be arranged in any other manner. Furthermore, these multiple secondary batteries 5 can be fixed in place using fasteners.

[0189] Optionally, the battery module 4 may also include a housing with a receiving space in which a plurality of secondary batteries 5 are received.

[0190] In some embodiments, the battery modules described above can also be assembled into a battery pack, and the number of battery modules contained in the battery pack can be one or more, the specific number of which can be selected by those skilled in the art according to the application and capacity of the battery pack.

[0191] Figure 11 and Figure 12 This is battery pack 1 as an example. (See reference...) Figure 11 and Figure 12 The battery pack 1 may include a battery box and multiple battery modules 4 disposed within the battery box. The battery box includes an upper body 2 and a lower body 3, with the upper body 2 covering the lower body 3 to form a closed space for accommodating the battery modules 4. The multiple battery modules 4 can be arranged in any manner within the battery box.

[0192] In addition, this application also provides an apparatus comprising at least one of the secondary battery, battery module, or battery pack provided in this application. The secondary battery, battery module, or battery pack can be used as a power source for the apparatus or as an energy storage unit for the apparatus. The apparatus may include, but is not limited to, mobile devices (e.g., mobile phones, laptops, etc.), electric vehicles (e.g., pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.

[0193] As the device, a secondary battery, battery module, or battery pack can be selected according to its usage requirements.

[0194] Figure 13 This is an example device. The device could be a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. To meet the device's requirements for high power and high energy density in its secondary batteries, a battery pack or battery module can be used.

[0195] Example 1:

[0196] (1) Pure copper and pure manganese (purity ≥ 99.9%) are provided in a ratio of Mn:Cu = 80:20 (at.%), and Mn is prepared by vacuum induction melting. 80 Cu 20 (at.%) alloy button ingot, size A 2mm × 2mm × 4mm Mn-Cu alloy sample was cut from the core of a button ingot.

[0197] (2) The above Mn-Cu alloy sample was subjected to a first heat treatment to obtain a single-phase alloy composed of the γMn-Cu phase (hereinafter referred to as γ single-phase alloy). The first heat treatment temperature was 750℃, the heat treatment time was 10 minutes, and the cooling method was water cooling. The XRD characterization results are as follows: Figure 1 As shown in Figure (a), the diffraction peaks of the γMn-Cu phase can be observed in the figure.

[0198] (3) The Mn-Cu alloy after the first heat treatment was subjected to a second heat treatment to obtain a two-phase alloy composed of αMn phase and γMn-Cu phase (hereinafter referred to as α / γ two-phase alloy). The second heat treatment temperature was 650℃, the heat treatment time was 1 hour, and the cooling method was water cooling. The XRD characterization results are as follows: Figure 1 As shown in Figure (b), diffraction peaks of the αMn phase and the γMn-Cu phase can be observed in the figure.

[0199] (4) The Mn-Cu alloy after the second heat treatment was used as an alloy precursor and placed in a sufficient amount of 0.1 mol / L HCl aqueous solution for free corrosion dealloying at a temperature of 60℃. Dealloying was completed when no obvious bubbles escaped, yielding porous copper with a multi-level porous structure, maintaining a bulk morphology of 2 mm × 2 mm × 4 mm. Figure 2 As shown in the scanning electron microscope (SEM) images, porous copper has pores with a first pore size (hereinafter referred to as macropores) and pores with a second pore size (hereinafter referred to as micropores). Fifty to one hundred macropores and fifty to one hundred micropores were selected from the SEM images, and the pore sizes of the macropores and micropores were measured, with average values ​​calculated for each. The results show that the average pore size of the porous copper macropores is 1.4 micrometers, and the average pore size of the micropores is 80 nanometers.

[0200] Example 2:

[0201] (1) Pure copper and pure manganese (purity ≥ 99.9%) are provided in a ratio of Mn:Cu = 80:20 (at.%), and Mn is prepared by vacuum induction melting. 80 Cu 20 (at.%) alloy button ingot, size A 2mm × 2mm × 4mm Mn-Cu alloy sample was cut from the core of a button ingot.

[0202] (2) The above Mn-Cu alloy sample was subjected to a first heat treatment to obtain a γ single-phase alloy. The first heat treatment temperature was 750℃, the heat treatment time was 10 minutes, and the cooling method was water cooling.

[0203] (3) The Mn-Cu alloy after the first heat treatment is subjected to a second heat treatment to obtain an α / γ dual-phase alloy. The second heat treatment temperature is 650℃, the heat treatment time is 4 hours, and the cooling method is water cooling.

[0204] (4) The Mn-Cu alloy after the second heat treatment was used as an alloy precursor and placed in a sufficient amount of 0.01 mol / L HCl + 1 mol / L KCl aqueous solution for electrochemical dealloying using a constant potential method. The potential was -0.6 V (the reference electrode was an Ag / AgCl electrode, and the counter electrode was pure Cu), and the temperature was 60 °C. The process was continued until the current decreased to 10 μA / mm. 2 The dealloying process is now complete, yielding porous copper with a multi-level porous structure, maintaining a bulk morphology of 2mm × 2mm × 4mm. (Example:) Figure 3 As shown in the scanning electron microscope (SEM) images, porous copper has pores with a first pore size (hereinafter referred to as macropores) and pores with a second pore size (hereinafter referred to as micropores). Fifty to one hundred macropores and fifty to one hundred micropores were selected from the SEM images, and the pore sizes of the macropores and micropores were measured, with average values ​​calculated for each. The results show that the average pore size of the porous copper macropores is 2.7 micrometers, and the average pore size of the micropores is 80 nanometers.

[0205] Example 3:

[0206] (1) Pure copper and pure manganese (purity ≥ 99.9%) are provided in a ratio of Mn:Cu = 65:35 (at.%), and Mn is prepared by vacuum induction melting. 65 Cu 35 (at.%) alloy button ingot, size A 2mm × 2mm × 4mm Mn-Cu alloy sample was cut from the core of a button ingot.

[0207] (2) The above Mn-Cu alloy sample was subjected to a first heat treatment to obtain a γ single-phase alloy. The first heat treatment temperature was 850℃, the heat treatment time was 10 minutes, and the cooling method was water cooling.

[0208] (3) The Mn-Cu alloy after the first heat treatment is subjected to a second heat treatment to obtain an α / γ dual-phase alloy. The second heat treatment temperature is 670℃, the heat treatment time is 1 hour, and the cooling method is water cooling.

[0209] (4) The Mn-Cu alloy after the second heat treatment was used as an alloy precursor and placed in a sufficient amount of 0.1 mol / L HCl aqueous solution for free corrosion dealloying at a temperature of 20℃. Dealloying was completed when no obvious bubbles escaped, yielding porous copper with a multi-level porous structure, maintaining a bulk morphology of 2 mm × 2 mm × 4 mm. Figure 4As shown in the scanning electron microscope (SEM) images, porous copper has pores with a first pore size (hereinafter referred to as macropores) and pores with a second pore size (hereinafter referred to as micropores). Fifty to one hundred macropores and fifty to one hundred micropores were selected from the SEM images, and the pore sizes of the macropores and micropores were measured, with average values ​​calculated for each. The results show that the average pore size of the porous copper macropores is 0.8 micrometers, and the average pore size of the micropores is 25 nanometers.

[0210] Example 4:

[0211] (1) Pure copper and pure manganese (purity ≥ 99.9%) are provided in a ratio of Mn:Cu = 90:10 (at.%), and Mn is prepared by vacuum induction melting. 90 Cu 10 (at.%) alloy button ingot, size A 2mm × 2mm × 4mm Mn-Cu alloy sample was cut from the core of a button ingot.

[0212] (2) The above Mn-Cu alloy sample was subjected to a first heat treatment to obtain a γ single-phase alloy. The first heat treatment temperature was 850℃, the heat treatment time was 10 minutes, and the cooling method was water cooling.

[0213] (3) The Mn-Cu alloy after the first heat treatment is subjected to a second heat treatment to obtain an α / γ dual-phase alloy. The second heat treatment temperature is 670℃, the heat treatment time is 1 hour, and the cooling method is water cooling.

[0214] (4) The Mn-Cu alloy after the second heat treatment was used as an alloy precursor and placed in a sufficient amount of 0.1 mol / L ascorbic acid aqueous solution for free corrosion dealloying at a temperature of 20℃. Once no obvious bubbles escaped, the dealloying was complete, yielding porous copper with a multi-level porous structure. The porous copper maintained a bulk morphology of 2 mm × 2 mm × 4 mm. Figure 5 The scanning electron microscope (SEM) images shown depict porous copper with pores of a first diameter (hereinafter referred to as macropores) and pores of a second diameter (hereinafter referred to as micropores). Fifty to one hundred macropores and fifty to one hundred micropores were selected from the SEM images, and the pore diameters of both were measured and averaged. The results show that the average pore diameter of the macropores in the porous copper is 1.2 micrometers, and the average pore diameter of the micropores is 20 nanometers.

[0215] Comparative example:

[0216] (1) Pure copper and pure manganese (purity ≥ 99.9%) are provided in a ratio of Mn:Cu = 80:20 (at.%), and Mn is prepared by vacuum induction melting. 80 Cu 20 (at.%) alloy button ingot, size A 2mm × 2mm × 4mm Mn-Cu alloy sample was cut from the core of a button ingot.

[0217] (2) The above Mn-Cu alloy sample was heat-treated to obtain a γ single-phase alloy. The heat treatment temperature was 750℃, the heat treatment time was 10 minutes, and the cooling method was water cooling.

[0218] (3) The heat-treated Mn-Cu alloy was used as an alloy precursor and placed in a sufficient amount of 0.1 mol / L HCl aqueous solution for free corrosion dealloying at a temperature of 60℃. Dealloying was completed when no obvious bubbles escaped, yielding porous copper, such as... Figure 6 As shown in (a), porous copper has only one pore size, namely small pores with an average pore size of 80 nanometers. Figure 6 As shown in (b), porous copper cannot form a bulk and has a large number of internal cracks.

[0219] Structural and performance analysis

[0220] 1. Based on the original alloy composition and heat treatment process of Examples 1-4 and the comparative examples, and in combination with... Figure 7 The Cu-Mn alloy phase diagram shown can reasonably deduce the phase composition, phase composition and phase size of the alloy precursor, as detailed in Table 1.

[0221] Table 1. Phase composition, phase composition, and phase size of alloy precursors

[0222]

[0223] 2. Based on the original alloy composition and heat treatment process of Examples 1-4 and the comparative examples, and in conjunction with... Figure 7 The Cu-Mn alloy phase diagram shown can be reasonably derived from the following formulas: the percentage of the total pore volume of macropores in porous copper to the apparent volume of porous copper (V1 / V), the percentage of the total pore volume of micropores in porous copper to the apparent volume of porous copper (V2 / V), and the percentage of the total pore volume of macropores and micropores to the apparent volume of porous copper ((V1+V2) / V). The results are detailed in Table 2. Considering that the Mn-Cu alloy underwent sufficient dealloying during the dealloying process, it can be reasonably inferred that all manganese in the Mn-Cu alloy was removed. After all manganese in the αMn phase of the Mn-Cu alloy was removed, the αMn phase disappeared, and a pore structure with the first pore size (hereinafter referred to as macropores) was formed correspondingly at the position of the αMn phase. After the manganese element is removed from the γMn-Cu phase of the Mn-Cu alloy, the manganese metal in the γMn-Cu phase disappears, but the copper metal is retained, correspondingly forming a pore structure with a second pore size (hereinafter referred to as a micropore) on the γMn-Cu phase. The above-mentioned macropore structure and micropore structure together constitute the hierarchical porous structure of porous copper.

[0224] Figure 8 A partial schematic diagram of a porous material is shown. The porous material has a three-dimensional porous framework 600. The framework of the three-dimensional porous framework 600 has macropore structures between its components, and these macropore structures have pores 601 with a first pore diameter. The surface of the framework of the three-dimensional porous framework 600 has micropore structures, and these micropore structures have pores 602 with a second pore diameter.

[0225] Let V be the apparent volume of porous copper. The volume ratio of macropores (V1 / V) and micropores (V2 / V) can be calculated using the following formula:

[0226]

[0227]

[0228] x represents the Mn content (at.%) in the alloy precursor;

[0229] x γ The Mn content (at.%) in the γMn-Cu phase;

[0230] 1.045 is the atomic volume ratio of Mn:Cu.

[0231] Table 2

[0232] x <![CDATA[x γ ]]> <![CDATA[V1 / V]]> <![CDATA[V2 / V]]> <![CDATA[(V1+V2) / V]]> Example 1 0.80 0.60 0.504 0.303 80％ Example 2 0.80 0.60 0.504 0.303 80％ Example 3 0.65 0.55 0.226 0.434 65％ Example 4 0.90 0.68 0.690 0.213 90％ Comparative Example 0.80 0.80 - 0.803 -

[0233] In addition, the total specific surface area of ​​porous copper is S (unit: m²). 2 / g), where the specific surface area of ​​macropores is S1 and the specific surface area of ​​micropores is S2. The values ​​of S1 / S and S2 / S can be calculated based on V1 / V and V2 / V, respectively. The specific surface areas of macropores (S1) and micropores (S2) are obtained using the calculation formulas and methods provided in Celal Soyarslan, et al., Acta Materialia, (2018), 149, 326. The total specific surface area S = S1 + S2. The relevant results are shown in Table 3 below.

[0234] The formula for calculating the specific surface area S1 of a macropore is as follows:

[0235]

[0236] C1 is an empirical constant, and its value is taken from Table 3 below;

[0237] Ψ1 is the macropore volume fraction V1 / V, and its value is taken from Table 2 above;

[0238] L1 is the average diameter of the ribs that form the three-dimensional framework of the macroporous structure;

[0239] ρ CuThe density of copper is 8.9 g / cm³. 3 ;

[0240] p represents the atomic percentage of manganese in the alloy;

[0241] V is 1cm 3 .

[0242] The formula for calculating the specific surface area S2 of the orifice is as follows:

[0243]

[0244] C2 is an empirical constant, and its value is taken from Table 2 below;

[0245] Ψ2 is the orifice volume fraction V2 / V, and its value is taken from Table 2 above;

[0246] L2 is the average diameter of the ribs that form the three-dimensional skeleton of the small hole structure;

[0247] ρ Cu The density of copper is 8.9 g / cm³. 3 ;

[0248] p represents the atomic percentage of manganese in the alloy;

[0249] V is 1cm 3 .

[0250] Table 3

[0251] Mn atomic percentage p <![CDATA[Average edge diameter L1 (μm) of macropores]]> <![CDATA[Macropore constant C1]]> <![CDATA[Macropore specific surface area S1 (m 2 / g)]]> <![CDATA[S1 / S]]> Example 1 0.80 1.14 2.84 0.981 0.14 Example 2 0.80 1 2.84 1.072 0.16 Example 3 0.65 1.75 1.99 0.144 0.07 Example 4 0.90 0.89 2.48 2.708 0.32 p <![CDATA[Average edge diameter L2 of small holes (μm)]]> <![CDATA[Small hole constant C2]]> <![CDATA[Specific surface area S2 of small pores (m 2 / g)]]> <![CDATA[S2 / S]]> Example 1 0.80 0.1 2.48 4.255 0.86 Example 2 0.80 0.1 2.48 4.255 0.84 Example 3 0.65 0.08 2.75 1.082 0.93 Example 4 0.90 0.07 1.99 4.695 0.68

[0252] The experimental data above confirm that the porous material prepared using the method described in this application has indeed been successfully prepared. The method for preparing porous materials has advantages such as low cost, ability to prepare large-size products, and flexible adjustment of pore size and distribution. The porous material of this application possesses an innovative porous structure.

[0253] The porous material of this application has pores with a first pore size and pores with a second pore size. The inner wall of the pore with the first pore size (hereinafter referred to as macropore) can serve as a substrate for active material deposition; in addition, another function of macropore is to provide electrolyte wetting channels. The inner wall of the pore with the second pore size (hereinafter referred to as micropore) can serve as a substrate for active material deposition. Micropore increases the specific surface area of ​​the material, thereby enabling the porous material to load more active material; in addition, another function of micropore is to serve as a template for active material deposition. Specifically, due to the limitation of micropore size, the active material deposited in the micropore has a nanoscale size. Nanoscale active material has a high ionic conductivity due to its small size, which can improve the overall ionic conductivity of the electrode, thereby improving the rate performance of the battery, and ultimately improving the overall battery capacity, cycle stability and rate performance; in addition, another function of micropore is to limit the volume expansion of the active material and prevent its pulverization and failure.

[0254] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A porous material having pores of a first pore diameter and pores of a second pore diameter; The first aperture is n micrometers, where 0.5 ≤ n ≤ 20; The second pore size is in nanometers (m), where 10 < m < 400; The apparent volume of the porous material is V, the total pore volume of the pores with the first pore diameter is V1, and the total pore volume of the pores with the second pore diameter is V2. The porous material satisfies the following relationship: (V1+V2) / V = 20%~90%; V2 / V = 15~70%; and V1 / V ​​= 5~70%; The porous material is a metallic element or alloy containing element M, wherein element M is selected from copper. The raw materials for the porous material are copper and manganese metals.

2. The porous material of claim 1, wherein, The total surface area ratio of the porous material is S, the specific surface area of ​​the first pore diameter is S1, and the specific surface area of ​​the second pore diameter is S2. Wherein, S1 / S = 7~32%; Among them, S2 / S = 68~93%.

3. The porous material according to any one of claims 1 to 2, having one or more of the following characteristics: (1) The second pore size is m nanometers, 20 < m < 200; (2) The first aperture is n micrometers, 0.5≤n≤10.

4. A method for preparing a porous material, comprising: A multiphase alloy is provided, the multiphase alloy being composed of an αMn phase and a γMn-M phase, wherein the M element is selected from copper; At least some Mn elements are removed from the αMn phase and at least some Mn elements are removed from the γMn-M phase by dealloying. The porous material has pores with a first pore diameter and pores with a second pore diameter; The first aperture is n micrometers, where 0.5 ≤ n ≤ 20; The second pore size is in nanometers (m), where 10 < m < 400; The apparent volume of the porous material is V, the total pore volume of the pores with the first pore diameter is V1, and the total pore volume of the pores with the second pore diameter is V2. The porous material satisfies the following relationship: (V1+V2) / V = 20%~90%; V2 / V = 15~70%; and V1 / V ​​= 5~70%.

5. The method of claim 4, wherein One or more of the following: (1) Based on all Mn elements in the αMn phase, remove more than 90 at.% of Mn elements from the αMn phase by dealloying. (2) Based on all Mn elements in the γMn-M phase, remove more than 90 at.% of Mn elements from the γMn-M phase by dealloying. (3) Based on all M elements in the multiphase alloy, the amount of M elements removed by the dealloying method is less than 10 at.%.

6. The method of claim 4, wherein One or more of the following: (1) The content of Mn element in the αMn phase is > 99 at.%; (2) The content of Mn element in the γMn-M phase is 40-80 at.%.

7. The method according to claim 4, wherein the γMn-M phase is a solid solution.

8. The method according to claim 4, characterized in that One or more of the following: (1) The content of αMn phase in the multiphase alloy is 22~70 vol% (2) The content of γMn-M phase in the multiphase alloy is 30~78 vol%.

9. The method according to claim 4, characterized in that... One or more of the following: (1) In the metallographic photographs of the multiphase alloy, the average size of the αMn phase is 0.5~10 micrometers; (2) In the metallographic photograph of the multiphase alloy, the average size of the γMn-M phase is 0.5~5 micrometers.

10. The method according to claim 4, wherein the αMn phase and the γMn-M phase are uniformly dispersed in the multiphase alloy.

11. The method according to claim 4, wherein the elements in the multiphase alloy are composed of Mn and M, wherein the content of Mn is 60%-90 at.% and the content of M is 10-40 at.% and M is selected from copper.

12. The method according to claim 4, wherein the dealloying method is selected from chemical corrosion, electrochemical corrosion, or a combination thereof.

13. The method according to claim 4, further comprising the step of preparing a multiphase alloy, specifically including: An alloy precursor is provided, wherein the alloy precursor is composed of elements M and Mn, wherein the element M is selected from copper. The alloy precursor is subjected to a first heat treatment to obtain a first product, wherein the first product contains a γMn-M phase; The product from the previous step is subjected to a second heat treatment to obtain a second product, which is composed of an αMn phase and a γMn-M phase.

14. The method according to claim 13, wherein it has one or more of the following features: (1) The temperature of the first heat treatment is 700-865°C; (2) The duration of the first heat treatment is 0.16 hours or more; (3) After the first heat treatment, cooling is performed at a cooling rate of 20~1000°C / s; (4) The content of γMn-M phase in the first product is 95~100 vol% (5) The method further includes a plastic processing operation on the first product before performing the second heat treatment.

15. The method according to claim 13, wherein it has one or more of the following features: (1) The temperature of the second heat treatment is 500-700°C; (2) The second heat treatment time is 1 to 4 hours; (3) After the second heat treatment, cooling is performed at a cooling rate of 20~1000°C / s; (4) The content of αMn phase in the second product is 22~70 vol%, and the content of γMn-M phase is 30~78 vol%.

16. The method according to claim 13, wherein, The alloy precursor is an ingot.

17. The method according to any one of claims 4 to 16, wherein, The total surface area ratio of the porous material obtained by the method is S, the specific surface area of ​​the first pore diameter is S1, and the specific surface area of ​​the second pore diameter is S2. Wherein, S1 / S = 7~32%; Among them, S2 / S = 68~93%.

18. A porous material prepared by the method described in any one of claims 4 to 17.

19. A current collector comprising the porous material according to any one of claims 1-3 and 18.

20. A secondary battery comprising the current collector as described in claim 19.

21. The secondary battery according to claim 20, wherein, The secondary battery is a metal battery without a negative electrode.

22. The secondary battery according to claim 20 or 21, wherein, The negative electrode active material of the secondary battery contains a metal or alloy.

23. An apparatus comprising a secondary battery as described in any one of claims 20 to 22, wherein the secondary battery provides electrical energy to the apparatus.

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