Alloy, preparation method and application thereof, porous material, current collector, secondary battery and device

Abstract

The invention provides a Mn-M binary multiphase alloy which comprises 39 wt% < = Mn < = 78 wt%, and the balance metal M, wherein the standard electrode potential of the metal M is higher than that of the Mn, and an alpha Mn phase, a gamma M-Mn phase and a gamma 'Mn-M phase are distributed in the binary metal multiphase alloy. In addition, the invention also relates to a preparation method of the Mn-M binary multiphase alloy, application of the Mn-M binary multiphase alloy in preparation of a porous material, and a current collector, a secondary battery and an electric device comprising the porous material.

Description

Technical Field

[0001] The present application relates to the technical field of metal materials, and in particular to a Mn-M binary multiphase alloy and a preparation method and use thereof, a porous material, a current collector, a secondary battery and an electrical device. Background Art

[0002] Porous metal materials are a new type of multifunctional materials that have emerged in recent years with the rapid development of material preparation and mechanical processing technology. Their inherent structural characteristics can achieve diversified functions and are widely used in electrode materials, automobiles, catalysis, heat exchange and other fields. Currently, common porous metal materials are mainly prepared by dealloying the precursor alloy. However, due to the distribution of the precursor alloy itself, the resulting material inevitably has intrinsic defects such as grain boundaries and dislocations. Therefore, it is still a considerable challenge to obtain porous materials, especially porous materials with multi-level pore size distribution, through dealloying.

[0003] Therefore, there is a need to continuously develop new precursor materials in order to obtain improved porous materials with multi-level pore size distribution. Summary of the invention

[0004] The present application is made in view of the above-mentioned problems, and its purpose is to provide a new Mn-M binary multiphase alloy, in which αMn phase, γM-Mn phase and γ'Mn-M phase are distributed. Through the coexistence of α phase, γ phase and γ' phase, the multiphase alloy of the present application can form a porous material with different levels of pore size after dealloying corrosion. Moreover, the pore size of the porous material can be effectively and relatively easily controlled by controlling the content and size of α phase, γ phase and γ' phase.

[0005] In the first aspect, the present application provides a Mn-M binary metal multiphase alloy, which includes: 39wt%≤Mn≤78wt%, optionally, 68wt%≤Mn≤78wt%, and the rest includes metal M and inevitable impurities; wherein the standard electrode potential of the metal M is higher than the standard electrode potential of Mn, and the binary metal multiphase alloy is distributed with αMn phase, γM-Mn phase and γ'Mn-M phase. In the multiphase alloy of the present application, the standard electrode potential of the metal M is higher than the standard electrode potential of Mn, so that during the dealloying process of the Mn-M alloy, Mn is corroded and M is left, and finally a porous metal M material is formed. At the same time, by setting the Mn content between 39wt% and 78wt%, optionally between 68wt% and 78wt%, it is possible to maintain a moderate corrosion rate during the dealloying corrosion process, and to make the obtained porous structure have a porosity as high as possible while maintaining the pore continuity of the porous material. In addition, the binary alloy of the present application contains αMn phase, γM-Mn phase and γ'Mn-M phase, and the sizes of the three phases differ by an order of magnitude, thereby endowing the alloy with the ability to form a porous material with a multi-level pore size distribution through dealloying.

[0006] In any embodiment, the metal M is selected from one of Cu, Cr, Co, Sn, and Ni, and is optionally Cu. The binary alloys formed by these metals M and Mn are dealloyed to obtain corresponding porous Cu materials, porous Cr materials, porous Co materials, porous Sn materials, and porous Ni materials with multi-level pore size distribution. These porous materials can be widely used in fields such as energy, environment, and biomedicine.

[0007] In any embodiment, the multiphase alloy includes quasi-equiaxed grains, and optionally the quasi-equiaxed grains have an average size of 5 μm to 30 μm, optionally 10 μm to 25 μm. The grains in the multiphase alloy and the size of the grains affect the mechanical properties and processing properties of the alloy. Through the quasi-equiaxed grains within this range, the multiphase alloy of the present application will have a suitable degree of plasticity and hardness, making it easy to process.

[0008] In any embodiment, the grains of the multiphase alloy have grain boundaries with discontinuous distribution of metal Mn and metal M. The discontinuous distribution of Mn and metal M in the grain boundaries effectively forms a continuous skeleton of metal M after corrosion, obtaining a porous metal M material with a relatively regular pore size distribution.

[0009] In any embodiment, the αMn phase accounts for 4.6wt% to 65.6wt% of the multiphase alloy, and optionally, the content of Mn element in the αMn phase is >99wt%. After the Mn element in the αMn phase is completely or at least substantially completely removed by the dealloying process, the αMn phase will basically disappear, and a pore structure with a first pore size (hereinafter referred to as macropores) is correspondingly formed at the position of the αMn phase. The αMn phase within the scope of the present application can form a moderate proportion of macropores in the porous material.

[0010] In any embodiment, the γM-Mn phase and the γ'Mn-M phase account for 34.4wt% to 95.3wt% of the multiphase alloy in total, and optionally, the content of M element in the γM-Mn phase is 35wt% to 100wt%, and the content of Mn element in the γ'Mn-M phase is 62wt% to 72wt%. The γM-Mn phase is a M-rich phase, and when it is subsequently corroded by a dealloying method, only the Mn element contained therein is removed, while the M metal contained therein is retained, thereby increasing the strength of the ridge after corrosion. The γ'Mn-M alloy is a Mn-rich phase, and when it is subsequently corroded by a dealloying method, after the Mn element in the γ'Mn-M phase is removed, the Mn metal in the phase disappears, while the M metal is retained, and a pore structure with a second aperture (hereinafter referred to as a small pore) is correspondingly formed at the Mn in the γ'Mn-M phase.

[0011] In a second aspect, the present application provides a method for preparing a Mn-M binary metal multiphase alloy, comprising:

[0012] Smelting Mn and metal M in a weight ratio of (39-78):(22-61), optionally (68-78):(22-32), to obtain a Mn-M binary alloy, wherein the standard electrode potential of the metal M is higher than the standard electrode potential of Mn;

[0013] performing a first heat treatment on the obtained Mn-M binary alloy to obtain a first product including a γMn-M solid solution;

[0014] performing a second heat treatment on the first product to crystallize the first product to obtain a second product;

[0015] performing a third heat treatment on the second product to obtain a third product including a γM-Mn phase and a γ'Mn-M phase; and

[0016] The third product is subjected to a fourth heat treatment to obtain a binary multiphase alloy including an αMn phase, a γM-Mn phase and a γ′Mn-M phase.

[0017] Through the preparation method of the present application, a Mn—M binary multiphase alloy including an αMn phase, a γM-Mn phase and a γ′Mn-M phase can be specifically prepared.

[0018] In any embodiment, the method includes one or more of the following features: the first heat treatment is a homogenization heat treatment; the temperature of the first heat treatment is 720°C to 900°C; the time of the first heat treatment is 12h to 24h; and the alloy is plastically processed after the first heat treatment. The above-mentioned first heat treatment can reduce the dendrite segregation formed during the casting process, and the dendrite segregation will cause Mn and metal M to exist in irregular segregation, which is not conducive to obtaining regular pores.

[0019] In any embodiment, the method further includes one or more of the following features: the second heat treatment is a recrystallization treatment; the temperature of the second heat treatment is 720°C to 800°C; the time of the second heat treatment is 0.5h to 6h. Through the above-mentioned second heat treatment, equiaxed alloy grains are obtained. By performing the second heat treatment, that is, through recrystallization, the material no longer forms a rolling orientation along the rolling direction, so that uniformly distributed pores are generated along the length direction after dealloying corrosion, and no strip corrosion pits or pores parallel to the length direction will appear.

[0020] In any embodiment, the method further includes one or more of the following features: the third heat treatment is a spinodal decomposition treatment; the temperature of the third heat treatment is 400°C to 500°C; the time of the third heat treatment is 0.5h to 4h. Through the third heat treatment, the second product will undergo phase decomposition to obtain a third product including a γM-Mn phase and a γ'Mn-M phase. The M-rich γ phase can improve the strength of the edge diameter after dealloying.

[0021] In any embodiment, the method further includes one or more of the following features: the fourth heat treatment is a phase separation treatment; the temperature of the fourth heat treatment is 600°C to 680°C; the time of the fourth heat treatment is 1h to 6h. Through the above-mentioned fourth heat treatment, the αMn phase can be precipitated, and by adjusting the temperature and time of the treatment, the proportion and size of the αMn phase can be adjusted, thereby achieving the regulation of the proportion and pore size of the pores with the first pore size in the porous material. For example, when the fourth heat treatment temperature is lower, the proportion of the αMn phase is higher.

[0022] In a third aspect, the present application provides a use of the multiphase alloy of the first aspect and the multiphase alloy prepared in the second aspect in preparing a porous material. Optionally, the porous material is used as a current collector in a battery.

[0023] In a fourth aspect, the present application provides a porous material, which is obtained by dealloying the multiphase alloy of the first aspect of the present application and the multiphase alloy prepared in the second aspect during the preparation of the porous material, wherein the porous material has pores of a first pore size and a second pore size, the first pore size is n microns, wherein 0.5≤n≤10, optionally 2≤n≤5, and the second pore size is m nanometers, wherein 20<m<200, optionally, 40<m<70.

[0024] In a fifth aspect, the present application provides a current collector comprising the porous material described in the fourth aspect.

[0025] In a sixth aspect, the present application provides a secondary battery, comprising the current collector described in the fifth aspect.

[0026] In a seventh aspect, the present application provides an electrical device, comprising the secondary battery described in the sixth aspect.

[0027] In the present application, by setting the content of Mn metal in the alloy to 39wt%-78wt%, when the porous structure is obtained by the dealloying method, a higher porosity is obtained as much as possible while maintaining the stability of the porous skeleton, and the corrosion rate will not be too fast or too slow to affect the pore continuity of the porous material. In addition, by distributing needle-shaped α phase and γ phase (M-rich phase) and γ' phase (Mn-rich phase) inside the alloy grains, a porous material with different pore distributions (such as micron and nanometer pore sizes) can be obtained by the dealloying method. In addition, by controlling the ratio and size of the α phase and the γ phase (M-rich phase) and the γ' phase (Mn-rich phase), the pore size and ratio of the pores with the first pore size and the pores with the second pore size in the porous material can be flexibly adjusted. For example, by adjusting the temperature and time of the fourth heat treatment, the ratio and size of the αMn phase in the alloy can be adjusted, and then the ratio and pore size of the pores with the first pore size in the porous material can be adjusted. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1A This is a metallographic photograph of the binary multiphase alloy prepared in Example 3.

[0029] Figure 1B This is a backscattered photograph of the binary multiphase alloy prepared in Example 3.

[0030] Figure 2 This is the XRD pattern of the binary multiphase alloy prepared in Example 3.

[0031] Figure 3A and Figure 3B This is a scanning electron microscope photograph of the binary multiphase alloy of Example 3 after dealloying.

[0032] Figure 4 This is a photo of the precursor prepared in Comparative Example 1.

[0033] Figure 5 This is a scanned photo of the alloy of Example 1 after dealloying as a precursor.

[0034] Figure 6 It is the phase diagram of Mn-Cu binary alloy.

[0035] Figure 7 is a schematic diagram of a secondary battery according to one embodiment of the present application.

[0036] Figure 8 yes Figure 7 An exploded view of a secondary battery according to an embodiment of the present application is shown.

[0037] Fig. 9 is a schematic diagram of a battery module according to an embodiment of the present application.

[0038] Fig.10 It is a schematic diagram of a battery pack according to one embodiment of the present application.

[0039] Fig.11 yes Fig.10 An exploded view of a battery pack according to an embodiment of the present application is shown.

[0040] Fig.12 FIG. 1 is a schematic diagram of an electric device using a secondary battery according to an embodiment of the present application as a power source.

[0041] Description of reference numerals:

[0042] 1 battery pack; 2 upper box; 3 lower box; 4 battery module; 5 secondary battery; 51 shell; 52 electrode assembly; 53 top cover assembly DETAILED DESCRIPTION

[0043] Hereinafter, the embodiments of the multiphase alloy of the present application, its preparation method and use, porous materials, current collectors, secondary batteries and devices are specifically disclosed with appropriate reference to the accompanying drawings. However, there are cases where unnecessary detailed descriptions are omitted. For example, there are cases where detailed descriptions of well-known matters and repeated descriptions of actually the same structures are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art. In addition, the drawings and the following descriptions are provided for those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0044] "Scope" disclosed in the present application is limited in the form of lower limit and upper limit, and a given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of a special range. The scope limited in this way can be including end values ​​or not including end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a scope. For example, if the scope of 60-120 and 80-110 is listed for a specific parameter, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range values ​​1 and 2 are listed, and if the maximum range values ​​3, 4 and 5 are listed, the following scope can be all expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In the present application, unless otherwise specified, the numerical range "ab" represents the abbreviation of any real number combination between a and b, wherein a and b are real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0045] Unless otherwise indicated, the following terms used in the specification and claims have the following meanings.

[0046] The "standard electrode potential" mentioned herein refers to the equilibrium potential measured when the temperature is 25°C and the effective concentration of the metal ion is 1 mol / L (i.e., the activity is 1), which reflects the redox ability of the substance. The standard electrode potential of Mn is -1.18V. Metals with a standard electrode potential higher than that of Mn refer to metals with a standard electrode potential more positive than -1.18V, such as Co (-0.277V), Ni (-0.25V), Sn (+0.15V), Cu (+0.337V), and Cr (+1.64V). The standard electrode potentials of each metal are well known in the art and will not be described in detail here. The difference in the standard electrode potential between Mn and metal M enables the removal of most or even complete removal of the Mn element from the αMn, γM-Mn phase, and γ'Mn-M phase when preparing porous materials by dealloying. And very little or no M element is removed.

[0047] The "αMn phase" mentioned herein refers to an allotrope of Mn having a body-centered cubic (bcc) structure.

[0048] "γM" referred to herein refers to an allotrope of M having a face-centered cubic (fcc) structure.

[0049] "γMn" referred to herein refers to an allotrope of Mn having a face-centered cubic (fcc) structure.

[0050] The "γM-Mn phase" mentioned herein refers to a solid solution phase formed by Mn dissolving in γM. In some embodiments, the content of M element in the γM-Mn phase is 35 wt% to 100 wt%.

[0051] The "γ'Mn-M phase" mentioned herein refers to a solid solution phase formed by M dissolving in γMn. In some embodiments, the content of Mn element in the γ'Mn-M phase is 60 wt% to 74 wt%.

[0052] The "solid solution" mentioned herein refers to a single-phase crystalline solid formed by one or more solute components dissolving into a crystalline solvent while maintaining the lattice type of the solvent.

[0053] The "quasi-equiaxed grains" mentioned herein have grains with small differences in size in each direction.

[0054] The "dealloying method" mentioned herein refers to selectively removing relatively active metal atoms in the system based on the difference in standard electrochemical potential between metals in the system, and the remaining metal atoms are interconnected to obtain a porous material. For example, the dealloying method includes chemical corrosion, electrochemical corrosion, or a combination thereof, but is not limited thereto.

[0055] The "metallographic photograph" mentioned in this article refers to a microscopic photograph that can reflect the metal microstructure, especially the phase distribution. The metallographic photograph can be obtained by taking an optical microscope or an electron microscope.

[0056] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0057] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0058] If there is no special explanation, all steps of the present application can be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), which means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0059] As mentioned above, porous metal materials are a combination of structural materials and functional materials. They integrate multiple properties such as electrical properties, permeability, damping properties, and flow properties, and have unparalleled superiority in application over traditional materials. At present, the demand and requirements for porous materials with multi-level pore size distribution are increasing, so the preparation of such porous materials has also attracted more and more attention. Previously, common porous metal materials were mainly prepared by dealloying. However, due to the uneven composition of the precursor alloy, the material inevitably has inherent defects such as grain boundaries and dislocations, resulting in the acquisition of porous materials with multi-level pore size distribution after dealloying. There are still considerable challenges. Therefore, there is still a need to develop new precursor materials to be able to prepare improved porous materials with multi-level pore size distribution.

[0060] The present application provides a Mn-M binary multiphase alloy material with an improved structure, especially a Mn-Cu alloy material, by changing the composition and phase state of the precursor alloy material. The present invention and preferred embodiments are described in more detail below.

[0061] [Mn-M binary multiphase alloy]

[0062] The "Mn-M binary multiphase alloy" mentioned herein refers to an alloy including Mn and metal M, having two or more metal phases at room temperature. The "metal phase" mentioned herein includes, for example, α phase, β phase and γ phase, but is not limited thereto.

[0063] In some embodiments, the present application provides a Mn-M binary multiphase alloy, the multiphase alloy comprising: 39wt%≤Mn≤78wt%, optionally, 68wt%≤Mn≤78wt%, and the rest comprising metal M; wherein the standard electrode potential of the metal M is higher than the standard electrode potential of Mn, and the binary metal multiphase alloy is distributed with αMn phase, γM-Mn phase and γ'Mn-M phase. It should be understood that the binary multiphase alloy of the present application also contains inevitable impurities. Here, as inevitable impurities, although Mg, Al, Si, Ag, Ca, S, O, C, Be, N, H, B, Zr, rare earths, etc. can be listed, the total amount of these inevitable impurities is preferably less than 0.1wt%. Wherein, the weight percentage involved in the present application, i.e., wt%, is determined by atomic fluorescence spectrometry known in the art.

[0064] In the present application, by 39wt%≤Mn≤78wt%, optionally, 68wt%≤Mn≤78wt%, when the porous structure is obtained by the dealloying method, a higher porosity can be obtained as much as possible while maintaining the stability of the porous skeleton, and the corrosion rate will not be too fast or too slow to affect the pore continuity performance of the porous material. By the simultaneous existence of αMn phase, γM-Mn phase and γ'Mn-M phase in the alloy, since there is an order of magnitude difference in size between the three, when the porous material is subsequently prepared, the α phase will form pores with a pore size of 0.5μm to 10μm after dealloying corrosion, and the γ phase and γ' phase will form pores of 20nm to 200nm, thereby forming a porous material with a multi-level pore size distribution.

[0065] In some embodiments, the metal M may be selected from one of Cu, Cr, Co, Sn, and Ni. In some embodiments, the metal M is Cu. For example, the alloys formed by these metal elements and Mn are obtained after dealloying to obtain corresponding materials with multi-level pore size distribution such as porous Cu materials, porous Cr materials, porous Co materials, porous Sn materials, and porous Ni materials. These metal porous materials are widely used in fields such as energy, environment, and biomedicine. Specifically, porous Cu materials and porous Ni are used as current collectors in batteries, and porous Sn is used in the field of catalysis.

[0066] In some embodiments, the multiphase alloy includes quasi-equiaxed grains. In practice, after the material is rolled into a foil, a rolling orientation is formed along the rolling direction, and the rolling orientation causes uneven pore distribution along the length direction after corrosion, and strip corrosion pits or pores parallel to the length direction appear. Quasi-equiaxed grains avoid the pores only facing the rolling direction after corrosion, so that strip corrosion pits or pores parallel to the length direction will not appear in subsequent corrosion.

[0067] In some embodiments, the multiphase alloy of the present application includes quasi-equiaxed grains with an average size of 5 μm to 30 μm, optionally 10 μm to 25 μm. The grain size is obtained by placing the sample under a metallographic microscope to obtain a metallographic structure, counting the sizes of 50 grains, and then taking the average value. The grains in the multiphase alloy and the size of the grains affect the mechanical properties and processing properties of the alloy. Through the quasi-equiaxed grains within this range, the multiphase alloy of the present application will have a suitable degree of plasticity and hardness, making it easy to process.

[0068] In some embodiments, the grains of the multiphase alloy have grain boundaries with discontinuous distribution of metal Mn and metal M. The discontinuous distribution of Mn and metal M in the grain boundaries effectively forms a continuous skeleton of metal M after corrosion, and obtains a porous metal M material with a relatively regular pore size distribution, so that the porous structure will not collapse during corrosion due to the presence of the continuous grain boundaries of Mn, and the porous material will not be free of pores in local areas due to the presence of the continuous grain boundaries of metal M.

[0069] In some embodiments, the αMn phase accounts for 4.6wt% to 65.6wt% of the multiphase alloy. After the Mn element in the αMn phase is completely or at least substantially completely removed, the αMn phase disappears completely or substantially completely, and a pore structure with a first pore size (hereinafter referred to as macropores) is correspondingly formed at the position of the αMn phase. The αMn phase within the scope of the present application can form a moderate proportion of macropores.

[0070] In some embodiments, the content of Mn element in the αMn phase is >99wt%, such as 99.1wt%, 99.2wt%, 99.3wt%, 99.4wt%, 99.5wt%, 99.6wt%, 99.7wt%, 99.8wt%, 99.9wt%. Advantageously, based on the total Mn elements in the αMn phase, at least 89wt%, such as 95wt%, such as 99wt% or more of the Mn elements are removed from the αMn phase by a dealloying method. Thus, the porous material obtained subsequently has a first pore size, the first pore size is n microns, wherein 0.5≤n≤10, for example, optionally the value of n is 0.5-1, 1-5, 5-10, 2-8 or 2-7, and optionally 2≤n≤5.

[0071] In some embodiments, the γM-Mn phase and the γ'Mn-M phase account for 34.4wt% to 95.3wt% of the multiphase alloy. In some embodiments, the content of M element in the γM-Mn phase is 35wt% to 100wt%. The γM-Mn phase is an M-rich phase, and when it is subsequently corroded by a dealloying method, only the Mn element contained therein is removed, while the M metal contained therein is retained, thereby increasing the strength of the edge diameter after corrosion.

[0072] In some embodiments, the content of Mn element in the γ'Mn-M phase is 60wt% to 72wt%. The γ'Mn-M alloy is a Mn-rich phase. When the Mn element in the γ'Mn-M phase is subsequently corroded by the dealloying method, the Mn metal in the phase disappears after the Mn element in the γ'Mn-M phase is removed, while the M metal is retained, and a pore (hereinafter referred to as a small pore) structure with a second pore size is correspondingly formed at the Mn in the γ'Mn-M phase. Advantageously, based on all the Mn elements in the γ'Mn-M phase, the dealloying method is used to remove at least 89wt%, for example, more than 94wt% of the Mn element from the γ'Mn-M phase. Based on this, the obtained porous material has a second pore size, and the second pore size is m nanometers, for example, 20<m<200. Optionally, the value of m is 20-50, 50-100, 100-150 or 150-200, and optionally, 40<m<70. Thus, together with the macropores formed after the αMn phase is corroded, a porous material with multi-level pore size distribution is formed.

[0073] [Preparation method]

[0074] In an embodiment of the present application, a method for preparing a Mn—M binary multiphase alloy is provided.

[0075] The method comprises:

[0076] Smelting Mn and metal M in a weight ratio of (39-78):(22-61), optionally (68-78):(22-32), to obtain a Mn-M binary alloy, wherein the standard electrode potential of the metal M is higher than the standard electrode potential of Mn;

[0077] performing a first heat treatment on the obtained Mn-M binary alloy to obtain a first product including a γMn-M solid solution;

[0078] performing a second heat treatment on the first product to crystallize the first product to obtain a second product;

[0079] performing a third heat treatment on the second product to obtain a third product including a γM-Mn phase and a γ'Mn-M phase; and

[0080] The third product is subjected to a fourth heat treatment to obtain a binary multiphase alloy including an αMn phase, a γM-Mn phase and a γ′Mn-M phase.

[0081] In some embodiments, the first heat treatment is a homogenization heat treatment. The dendrite segregation formed during the casting process can be reduced by the homogenization heat treatment, because the dendrite segregation will cause Mn and metal M to exist in irregular segregation, which is not conducive to obtaining regular pores.

[0082] In some embodiments, the temperature of the first heat treatment is 720°C to 900°C, optionally 850°C to 900°C, for example 900°C), and the treatment time is 12h to 24h, optionally 20h to 24h, for example 24h.

[0083] In some embodiments, the homogenization heat treatment should make the content of Mn-M solid solution in the first product 95-100 vol%, for example, 96 vol%, 99 vol%, 98 vol%, 99 vol%, 99.5 vol%, based on the total volume of the first product. The "volume percentage" involved in this article is obtained by calculating the phase diagram. That is, substantially all alloys have been converted into the form of Mn-M solid solution. The first product containing the γMn-M phase has excellent room temperature plasticity. The first product can be processed by plastic processing methods such as forging, rolling, and drawing to obtain processed products of different shapes and sizes. The processed product can maintain the stability of shape and size during the subsequent heat treatment and dealloying process.

[0084] In some embodiments, between the first heat treatment and the second heat treatment, the method includes: plastic processing (forging, rolling, drawing, etc.) the obtained Mn-M binary alloy into processed products of different shapes and sizes. For example, in some embodiments, the first product is rolled to obtain a foil with a thickness of 0.05 mm to 1 mm, but is not limited thereto.

[0085] In some embodiments, the second heat treatment is a recrystallization treatment. The recrystallization treatment obtains equiaxed alloy grains. Without recrystallization, the material will form a rolling orientation along the rolling direction after being rolled into a foil. The rolling orientation will cause uneven pore distribution along the length direction after corrosion, resulting in strip corrosion pits or pores parallel to the length direction.

[0086] In some embodiments, the temperature of the second heat treatment is 720°C to 800°C, optionally 720°C to 750°C, such as 750°C, and the treatment time is 0.5h to 6h, optionally 0.5h to 1h, such as 1h.

[0087] In some embodiments, the third heat treatment is a spinodal decomposition treatment. The uniform M-Mn phase is decomposed by spinodal decomposition to obtain a third product including a γM-Mn phase and a γ'Mn-M phase. The M-rich γ phase can improve the strength of the edge diameter after dealloying.

[0088] In some embodiments, the temperature of the third heat treatment is 400°C to 500°C, optionally 400°C to 450°C, for example 450°C; the treatment time is 0.5h to 4h, optionally 1h to 2h, for example 1.5h.

[0089] In some embodiments, the fourth heat treatment is a phase separation treatment. Through the fourth treatment step, an αMn phase is precipitated from the M-rich γ phase and the Mn-rich γ' phase, thereby obtaining a binary multiphase alloy including an αMn phase, a γM-Mn phase and a γ'Mn-M phase.

[0090] In some embodiments, the temperature of the fourth heat treatment is 600°C to 680°C, optionally 650°C to 680°C, for example 650°C; the time of the fourth heat treatment is 1h to 6h, optionally 4h to 6h, for example 4h. In some embodiments, by controlling and adjusting the temperature and time of the fourth heat treatment, the proportion and size of the precipitated αMn phase can be regulated, thereby regulating the proportion and pore size of the pores with the first pore size in the porous material. For example, the lower the fourth heat treatment temperature, the higher the proportion of the αMn phase.

[0091] In some specific embodiments, the method for preparing a Mn-M binary multiphase alloy of the present application comprises:

[0092] (1) preparing pure Mn and pure M (purity required to be ≥99.9%) in a weight ratio of (39-78):(22-61), optionally (68-78):(22-32), and preparing a Mn-M binary alloy by vacuum induction melting, wherein the standard electrode potential of the metal M is higher than the standard electrode potential of Mn;

[0093] (2) forging and homogenizing the Mn-M binary alloy obtained in the first step to obtain a first product including a γMn-M solid solution, wherein the forging pressure is 20 tons to 2000 tons, the homogenizing heat treatment temperature is 720° C. to 900° C., and the treatment time is 12 h to 24 h;

[0094] (3) rolling the first product to obtain a foil with a thickness of 0.05 mm to 1 mm;

[0095] (4) performing a recrystallization treatment on the foil to obtain a second product, wherein the treatment temperature is 720° C. to 800° C. and the treatment time is 0.5 h to 6 h;

[0096] (5) subjecting the second product to a spinodal decomposition treatment to obtain a third product, wherein the treatment temperature is 400° C. to 500° C., and the treatment time is 0.5 h to 4 h; and

[0097] (6) The third product is subjected to a phase separation treatment to obtain the Mn—M binary multiphase alloy of the present application, the treatment temperature being 600° C. to 680° C. and the treatment time being 1 h to 6 h.

[0098] Taking Mn-Cu as an example, Figure 6As shown in the binary alloy phase diagram, the Mn-Cu binary alloy (Mn content 39wt% to 78wt%) is a γ-Mn single-phase structure in the temperature range of 720℃ to 900℃, and an α / γ dual-phase structure in the temperature range of 500℃ to 700℃. Therefore, the smelted Mn-Cu alloy can be first annealed at a high temperature (700℃ to 865℃) to obtain a γ single-phase alloy with excellent plastic processing ability, and to prepare precursor alloys of different shapes. Subsequently, a low-temperature (600℃ to 680℃) aging treatment is performed to form an α / γ dual-phase structure for the subsequent preparation of the final porous material.

[0099] [Application of alloy]

[0100] In some embodiments, the present application provides the use of a Mn-M binary multiphase alloy in preparing a porous material. Optionally, the porous material is used as a current collector, a catalyst, an adsorbent, a carrier, a molecular sieve, and the like.

[0101] [Porous materials]

[0102] In some embodiments, the present application provides a porous material obtained by dealloying the Mn-M binary metal multiphase alloy of the present application, wherein the porous material has pores of a first pore size and a second pore size, the first pore size is n microns, wherein 0.5≤n≤10, optionally 2≤n≤5, and the second pore size is m nanometers, wherein 20<m<200, optionally, 40<m<70.

[0103] In some embodiments, the porous material is gas permeable and / or liquid permeable.

[0104] In some embodiments, the dealloying method is selected from chemical corrosion, electrochemical corrosion, or a combination thereof, wherein the dealloying process is mainly based on the difference in standard electrode potential of the precursor components, and relatively active elements in the system are selectively removed, while the remaining metal atoms are interconnected to obtain a porous material.

[0105] The porous material obtained in the present application has a multi-level pore size distribution characteristic (such as nanopores and micropores). The porous material is particularly suitable for use in anode-free metal batteries (such as anode-free lithium metal batteries or anode-free sodium metal batteries) or metal or alloy anode batteries, but is not limited thereto. For example, the inner wall of a hole with a first pore size (hereinafter referred to as a macropore) can be used as a substrate for the deposition of active substances; in addition, another function of the macropore is to provide an electrolyte infiltration channel. The inner wall of a hole with a second pore size (hereinafter referred to as a small pore) can be used as a substrate for the deposition of active substances. The small pores increase the specific surface area of ​​the material, so that the porous material can load more active substances; in addition, another function of the small pores is to serve as a template for the deposition of active substances. Specifically, limited by the size of the pores, the active materials deposited in the pores have nanoscale sizes. Nanoscale active materials have higher 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 battery's capacity, cycle stability and rate performance as a whole. In addition, another function of the pores is to limit the volume expansion of the active material to prevent it from pulverizing and failing.

[0106] In addition, the secondary battery and the electric device of the present application will be described below with reference to the drawings as appropriate.

[0107] [Secondary battery]

[0108] In one embodiment of the present application, a secondary battery is provided.

[0109] The term "secondary battery" mentioned herein refers to a battery cell, a battery module or a battery pack, which are described below.

[0110] Generally, a secondary battery cell includes a positive electrode sheet, a negative electrode sheet, an electrolyte and a separator. During the battery charging and discharging process, active ions are embedded and released back and forth between the positive electrode sheet and the negative electrode sheet. The electrolyte plays the role of conducting ions between the positive electrode sheet and the negative electrode sheet. The separator is set between the positive electrode sheet and the negative electrode sheet, mainly to prevent the positive and negative electrodes from short-circuiting, while allowing ions to pass through.

[0111] [Positive electrode]

[0112] The positive electrode sheet includes a positive electrode current collector and a positive electrode film layer disposed on at least one surface of the positive electrode current collector, wherein the positive electrode film layer includes a positive electrode active material.

[0113] As an example, the positive electrode current collector has two surfaces opposite to each other in its thickness direction, and the positive electrode film layer is disposed on any one or both of the two opposite surfaces of the positive electrode current collector.

[0114] In some embodiments, the positive electrode current collector may include the porous material described above in the present application. The positive electrode current collector may also be a composite current collector, for example, it may be formed by compounding the porous material described above in the present application with a polymer material substrate (such as polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0115] In some embodiments, when the battery cell is a lithium-ion battery, the positive electrode active material may adopt a positive electrode active material for lithium-ion batteries that is well known in the art. As an example, the positive electrode active material may include at least one of the following materials: a lithium-containing phosphate with an olivine structure, a lithium transition metal oxide, and their respective modified compounds. However, the present application is not limited to these materials, and other traditional materials that can be used as positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. Among them, examples of lithium transition metal oxides may include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3Mn 1 / 3 O2 (also referred to as NCM 333 )、LiNi 0.5 Co 0.2 Mn 0.3 O2 (also referred to as NCM 523 )、LiNi 0.5 Co 0.25 Mn 0.25 O2 (also referred to as NCM 211 )、LiNi 0.6 Co 0.2 Mn 0.2 O2 (also referred to as NCM 622 )、LiNi 0.8 Co 0.1 Mn 0.1 O2 (also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05 O2) and its modified compounds, etc. Examples of lithium-containing phosphates with an olivine structure may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon.

[0116] When the battery cell is a sodium ion battery, the positive electrode active material may include at least one of a sodium transition metal oxide, a polyanionic compound and a Prussian blue compound. However, the present application is not limited to these materials, and other conventionally known materials that can be used as positive electrode active materials for sodium ion batteries may also be used.

[0117] As an optional technical solution of the present application, in the sodium transition metal oxide, the transition metal may be at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr and Ce. The sodium transition metal oxide is, for example, Na x MO2, wherein M is one or more of Ti, V, Mn, Co, Ni, Fe, Cr and Cu, 0 <x≤1。

[0118] As an optional technical solution of the present application, the polyanionic compound can be a compound having sodium ions, transition metal ions and tetrahedral (YO4) n- A class of compounds with anionic units. The transition metal can be at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr and Ce; Y can be at least one of P, S and Si; n represents (YO4) n- valence state.

[0119] Polyanionic compounds can also be those with sodium ions, transition metal ions, tetrahedral (YO4) n- A class of compounds containing anion units and halogen anions. The transition metal may be at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr and Ce; Y may be at least one of P, S and Si, and n represents (Y04) n- valence state; the halogen may be at least one of F, Cl and Br.

[0120] Polyanionic compounds can also be sodium ions, tetrahedral (YO4) n- Anion unit, polyhedral unit (ZO y ) m+ and an optional halogen anion. Y can be at least one of P, S and Si, and n represents (YO4) n- Valence state: Z represents a transition metal, which can be at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr and Ce, and m represents (ZO y ) m+ valence state; the halogen may be at least one of F, Cl and Br.

[0121] Polyanionic compounds include NaFePO4, Na3V2(PO4)3, NaM'PO4F (M' is one or more of V, Fe, Mn and Ni) and Na3(VO y )2(PO4)2F 3-2y At least one of (0≤y≤1).

[0122] The Prussian blue compound may be a compound having sodium ions, transition metal ions and cyanide ions (CN-). The transition metal may be at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr and Ce. The Prussian blue compound may be, for example, Na a Me b Me' c (CN)6, wherein Me and Me' are each independently at least one of Ni, Cu, Fe, Mn, Co and Zn, 0 <a≤2,0<b<1,0<c<1。

[0123] The battery will be accompanied by Li deintercalation and consumption during the charge and discharge process, and the molar content of Li is different when the battery is discharged to different states. In the list of positive electrode materials in this application, the molar content of Li is the initial state of the material, that is, the state before feeding. The positive electrode material is used in the battery system, and the molar content of Li will change after charge and discharge cycles.

[0124] In the list of positive electrode materials in this application, the molar content of O is only a theoretical value. The release of oxygen from the lattice will cause the molar content of oxygen to change, and the actual molar content of O will fluctuate.

[0125] In some embodiments, the positive electrode film layer may further optionally include a binder. As an example, the binder may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorine-containing acrylate resin.

[0126] In some embodiments, the positive electrode film layer may further include a conductive agent, which may include, for example, at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0127] In some embodiments, the positive electrode sheet can be prepared in the following manner: the components for preparing the positive electrode sheet, such as the positive electrode active material, the conductive agent, the binder and any other components are dispersed in a solvent (such as N-methylpyrrolidone) to form a positive electrode slurry; the positive electrode slurry is coated on the positive electrode collector, and after drying, cold pressing and other processes, the positive electrode sheet can be obtained.

[0128] [Negative electrode current collector and negative electrode sheet]

[0129] The porous material of the present application can be directly used as anode-side current collector (or electrode) of an anode-free metal battery (eg, an anode-free lithium metal battery or an anode-free sodium metal battery).

[0130] In anode-free lithium batteries, all active lithium ions are initially stored in the positive electrode material. During the initial charging process, lithium ions are extracted from the positive electrode, moved to the negative electrode, and directly plated on the negative electrode bare current collector in situ to form a lithium metal negative electrode. Subsequently, during the discharge process, the active lithium ions are stripped from the in-situ formed lithium metal negative electrode and embedded in the positive electrode. Lithium-free negative electrode batteries are small in size and have a large energy density.

[0131] The porous material of the present application can also be used as a negative electrode side current collector of a battery containing an active metal / alloy negative electrode.

[0132] In some embodiments, the active metal / alloy is, for example, lithium metal or a lithium alloy.

[0133] In some embodiments, the negative electrode sheet of the lithium metal battery uses the porous material of the present 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.

[0134] The term "lithium alloy" used herein is intended to mean a substance that can form an alloy with lithium by charging and can reversibly adsorb and release lithium. Examples of substances that can form alloys with lithium include elements of metals such as tin (Sn), silicon (Si), zinc (Zn), aluminum (Al), magnesium (Mg), indium (In), cadmium (Cd), lead (Pb), bismuth (Bi) and antimony (Sb), and their compounds and alloys thereof (including alloys of lithium with these elemental metals). One or two or more of these substances can be suitably used by appropriate selection.

[0135] In some embodiments, other active metals / alloys besides lithium metal or lithium alloys include elements of metals such as tin (Sn), silicon (Si), zinc (Zn), aluminum (Al), magnesium (Mg), indium (In), cadmium (Cd), lead (Pb), bismuth (Bi) and antimony (Sb), and their compounds and alloys thereof (including alloys of lithium with these elemental metals).

[0136] In some embodiments, the active metal / alloy can be deposited on the surface and inside the voids of the porous material by electrodeposition, vapor deposition (such as physical / chemical vapor deposition), magnetron sputtering, etc., to obtain the negative electrode of the battery.

[0137] [Electrolytes]

[0138] The electrolyte plays the role of conducting ions between the positive electrode and the negative electrode. The present application has no specific restrictions on the type of electrolyte, which can be selected according to needs. For example, the electrolyte can be liquid, gel or all-solid.

[0139] In some embodiments, the electrolyte is an electrolyte solution, which includes an electrolyte salt and a solvent.

[0140] In some embodiments, the electrolyte salt can 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 difluorooxalatoborate, lithium dioxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate.

[0141] In some embodiments, the solvent can be selected from at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, cyclopentane sulfone, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone.

[0142] In some embodiments, the electrolyte may further include additives, such as negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain battery properties, such as additives that improve battery overcharge performance, additives that improve battery high or low temperature performance, etc.

[0143] [Isolation film]

[0144] In some embodiments, the battery cell further includes a separator. The present application has no particular limitation on the type of separator, and any known porous separator with good chemical stability and mechanical stability can be selected.

[0145] In some embodiments, the material of the isolation membrane can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride. The isolation membrane can be a single-layer film or a multi-layer composite film, without particular limitation. When the isolation membrane is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation.

[0146] In some embodiments, the positive electrode sheet, the negative electrode sheet, and the separator may be formed into an electrode assembly by a winding process or a lamination process.

[0147] In some embodiments, the battery cell may include an outer packaging, which may be used to encapsulate the electrode assembly and the electrolyte.

[0148] In some embodiments, the outer packaging of the battery cell may be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc. The outer packaging of the battery cell may also be a soft package, such as a bag-type soft package. The material of the soft package may be plastic, and examples of the plastic include polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0149] The present application has no particular limitation on the shape of the battery cell, which may be cylindrical, square or any other shape. Figure 7 The battery cell 5 is a square structure as an example.

[0150] In some embodiments, reference Figure 8 , the outer packaging may include a shell 51 and a cover plate 53. Among them, the shell 51 may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plate enclose a receiving cavity. The shell 51 has an opening connected to the receiving cavity, and the cover plate 53 can be covered on the opening to close the receiving cavity. The positive electrode sheet, the negative electrode sheet and the isolation membrane can form an electrode assembly 52 through a winding process or a lamination process. The electrode assembly 52 is encapsulated in the receiving cavity. The electrolyte is infiltrated in the electrode assembly 52. ​​The number of electrode assemblies 52 contained in the battery cell 5 can be one or more, and those skilled in the art can select according to specific actual needs.

[0151] In some embodiments, battery cells may be assembled into a battery module. The number of battery cells contained in the battery module may be one or more, and the specific number may be selected by those skilled in the art according to the application and capacity of the battery module.

[0152] Fig. 9 4 is an example of a battery module. Fig. 9 In the battery module 4, the plurality of battery cells 5 may be arranged in sequence along the length direction of the battery module 4. Of course, they may also be arranged in any other manner. Further, the plurality of battery cells 5 may be fixed by fasteners.

[0153] Optionally, the battery module 4 may further include a housing having a receiving space, and the plurality of battery cells 5 are received in the receiving space.

[0154] In some embodiments, the battery modules described above may also be assembled into a battery pack. The battery pack may contain one or more battery modules, and the specific number may be selected by those skilled in the art according to the application and capacity of the battery pack.

[0155] Fig.10 and Fig.11 1 is a battery pack 1 as an example. Fig.10 and Fig.11The battery pack 1 may include a battery box and a plurality of battery modules 4 disposed in the battery box. The battery box includes an upper box body 2 and a lower box body 3. The upper box body 2 can cover the lower box body 3 and form a closed space for accommodating the battery modules 4. The plurality of battery modules 4 can be arranged in the battery box in any manner.

[0156] In addition, the present application also provides an electric device, which includes a secondary battery provided in the present application. The secondary battery can be used as a power source for the electric device, or as an energy storage unit for the electric device. The electric device may include mobile devices (such as mobile phones, laptops, etc.), electric vehicles (such as 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., but are not limited thereto.

[0157] As the electrical device, a battery cell, a battery module or a battery pack can be selected according to its usage requirements.

[0158] Fig.12 The power consumption device is taken as an example. The power consumption device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. In order to meet the high power and high energy density requirements of the power consumption device for the secondary battery, a battery pack or a battery module can be used.

[0159] As another example, the device may be a mobile phone, a tablet computer, a notebook computer, etc. The device is usually required to be light and thin, and a battery cell may be used as a power source.

[0160] Example

[0161] Hereinafter, the embodiments of the present application will be described. The embodiments described below are exemplary and are only used to explain the present application, and should not be construed as limiting the present application. If no specific techniques or conditions are indicated in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. If the manufacturer is not indicated in the reagents or instruments used, they are all conventional products that can be obtained commercially.

[0162] Preparation of binary multiphase alloys

[0163] Example 1

[0164] (1) Pure Cu and pure Mn (purity requirement ≥ 99.9%) are provided in a weight ratio of 39:61, and a Mn-Cu binary alloy is prepared by vacuum induction melting.

[0165] (2) The obtained Mn-Cu alloy was forged and subjected to homogenization heat treatment, with a forging pressure of 1000 tons, a homogenization heat treatment temperature of 900°C, and a time of 24 hours.

[0166] (3) The Mn-Cu alloy obtained in the second step is rolled to obtain a foil with a thickness of 0.23 mm.

[0167] (4) The Mn-Cu alloy obtained in the third step is recrystallized at 750°C for 1 h.

[0168] (5) The Mn-Cu alloy obtained in the fourth step was subjected to a spinodal decomposition treatment at a temperature of 450°C for 2 h.

[0169] (6) The Mn-Cu alloy obtained in the fifth step is subjected to phase separation treatment at a temperature of 600°C for 4 hours.

[0170] Example 2

[0171] (1) Pure Cu and pure Mn (purity requirement ≥ 99.9%) are provided in a weight ratio of 40:60, and a Mn-Cu binary alloy is prepared by vacuum induction melting.

[0172] (2) The Mn-Cu alloy obtained in the first step is forged and subjected to homogenization heat treatment, with a forging pressure of 1000 tons, a homogenization heat treatment temperature of 900°C, and a time of 24 hours.

[0173] (3) The Mn-Cu alloy obtained in the second step is rolled to obtain a foil with a thickness of 0.23 mm.

[0174] (4) The Mn-Cu alloy obtained in the third step is recrystallized at 750°C for 1 h.

[0175] (5) The Mn-Cu alloy obtained in the fourth step was subjected to a spinodal decomposition treatment at a temperature of 450°C for 2 h.

[0176] (6) The Mn-Cu alloy obtained in the fifth step was subjected to phase separation treatment at a temperature of 650°C for 4 h.

[0177] Example 3

[0178] (1) Pure Cu and pure Mn (purity requirement ≥ 99.9%) are provided in a weight ratio of 22:78, and a Mn-Cu binary alloy is prepared by vacuum induction melting.

[0179] (2) The Mn-Cu alloy obtained in the first step is forged and subjected to homogenization heat treatment, with a forging pressure of 1000 tons, a homogenization heat treatment temperature of 900°C, and a time of 24 hours.

[0180] (3) The Mn-Cu alloy obtained in the second step is rolled to obtain a foil with a thickness of 0.23 mm.

[0181] (4) The Mn-Cu alloy obtained in the third step is recrystallized at 750°C for 1 h.

[0182] (5) The Mn-Cu alloy obtained in the fourth step was subjected to a spinodal decomposition treatment at a temperature of 450°C for 2 h.

[0183] (6) The Mn-Cu alloy obtained in the fifth step was subjected to phase separation treatment at a temperature of 650°C for 4 h.

[0184] Example 4

[0185] (1) Pure Cu and pure Mn (purity requirement ≥ 99.9%) are provided in a weight ratio of 22:78, and a Mn-Cu binary alloy is prepared by vacuum induction melting.

[0186] (2) The Mn-Cu alloy obtained in the first step is forged and subjected to homogenization heat treatment, with a forging pressure of 1000 tons, a homogenization heat treatment temperature of 900°C, and a time of 24 hours.

[0187] (3) The Mn-Cu alloy obtained in the second step is rolled to obtain a foil with a thickness of 0.23 mm.

[0188] (4) The Mn-Cu alloy obtained in the third step is recrystallized at 750°C for 1 h.

[0189] (5) The Mn-Cu alloy obtained in the fourth step was subjected to spinodal decomposition treatment at a temperature of 400°C for 2 h.

[0190] (6) The Mn-Cu alloy obtained in the fifth step was subjected to phase separation treatment at a temperature of 650°C for 4 h.

[0191] Example 5

[0192] (1) Pure Cu and pure Mn (purity requirement ≥ 99.9%) are provided in a weight ratio of 22:78, and a Mn-Cu binary alloy is prepared by vacuum induction melting.

[0193] (2) The Mn-Cu alloy obtained in the first step is forged and subjected to homogenization heat treatment, with a forging pressure of 2000 tons, a homogenization heat treatment temperature of 900°C, and a time of 24 hours.

[0194] (3) The Mn-Cu alloy obtained in the second step is rolled to obtain a foil with a thickness of 0.23 mm.

[0195] (4) The Mn-Cu alloy obtained in the third step is recrystallized at 750°C for 1 h.

[0196] (5) The Mn-Cu alloy obtained in the fourth step was subjected to spinodal decomposition treatment at a temperature of 500°C for 2 h.

[0197] (6) The Mn-Cu alloy obtained in the fifth step was subjected to phase separation treatment at a temperature of 650°C for 4 h.

[0198] Comparative Example 1

[0199] Pure Cu and pure Mn (purity requirement ≥ 99.9%) are provided in a weight ratio of 22:78, and a Mn-Cu binary alloy sample is obtained after vacuum induction melting and forging.

[0200] Comparative Example 2

[0201] The alloy was prepared by the same process as in Example 3, except that pure Cu and pure Mn (purity required to be ≥ 99.9%) were provided in a weight ratio of 20:80.

[0202] Characterization of alloys

[0203] Morphological characterization

[0204] After each step of the above examples and comparative examples, the obtained products were observed with a metallographic microscope (model NM910-R) and characterized with an X-ray diffractometer (model D8AA25).

[0205] Through the metallographic images of Examples 1 to 5 and Comparative Example 2, it is observed that after step 4, quasi-equiaxed crystals are formed, while no crystal grains are observed in Comparative Example 1. Here, the metallographic image of Mn-Cu prepared in Example 3 is shown as an example (see Figure 1A ), backscattered photograph (see Figure 1B ); and metallographic photographs of the alloy prepared in Comparative Example 1 ( Figure 4 ).

[0206] in, Figure 1A The black lines or needles are formed after metallographic corrosion. The corroded substances are Mn elements or phases with high Mn content. The continuous grooves are formed after grain boundary corrosion.

[0207] Figure 1B The medium gray-black area is the grain boundary area and the Mn-rich area in the grain. Some areas of the grain boundary show discontinuous distribution of Mn (for example, the bright area on the grain boundary is where the Mn content is relatively low).

[0208] according to Figure 4 It can be seen that in the absence of heat treatment, the rolling morphology in the rolling direction (horizontal direction) is retained and the grain boundaries are completely destroyed.

[0209] Characterization of grain size

[0210] The alloys prepared in Examples 1 to 5 and Comparative Example 2 were ground and polished using sandpaper of 200 mesh, 600 mesh, 800 mesh, and 1200 mesh and diamond polishing paste until the metal surface showed a mirror surface. Ferric chloride was used for metallographic etching for 10 seconds, and then the alloys were cleaned and dried with alcohol and deionized water, and then placed under a metallographic microscope to obtain the metallographic structure. The sizes of 50 grains were counted, and then the average value was calculated as the grain size of the sample. The results are shown in Table 1 below.

[0211] HV Hardness

[0212] The test equipment was HVS-1000 hardness tester, and the load force was 300 g. The results are shown in Table 1 below.

[0213] Crystal phase

[0214] The test equipment is an X-ray diffractometer (model D8A A25), with a scanning angle of 30-110° and a scanning step of 0.016°. Here, the XRD pattern of the Mn-Cu alloy prepared in Example 3 is shown as an example (see Figure 2 ).from Figure 2 The diffraction peaks of αMn phase, γ'Mn-Cu phase and γCu-Mn phase can be observed.

[0215] Preparation of porous materials

[0216] The alloys obtained in Examples 1 to 5 and Comparative Examples 1 to 2 were cut into samples with a size of 2 cm×3 cm, and placed in a 0.1 mol / L hydrochloric acid etching solution for free chemical etching. When no bubbles emerged, the dealloying process was completed.

[0217] The continuity of the skeleton after dealloying was then observed by scanning electron microscopy (Zeiss Gemini360). The results are shown in Table 1. Figure 3A The scanning electron microscope photograph of the Mn-Cu alloy of Example 3 after dealloying is shown. Figure 3B Shows Figure 3A Magnified image of the edge diameter micro-area (surface scanning). Figure 5 The scanned photo of the alloy of Comparative Example 1 after dealloying as a precursor is shown.

[0218] Table 1

[0219]

[0220] like Figure 3AAs shown in the scanning electron microscope photograph, the porous copper has pores with a first pore size (hereinafter referred to as large pores) and pores with a second pore size (hereinafter referred to as small pores). 100 large pores and 100 small pores were selected from the scanning electron microscope photograph, and the pore sizes of the large pores and the small pores were measured respectively, and the average values ​​were calculated respectively. The results showed that the average pore size of the large pores of the obtained porous copper was 6.4 microns, and the average pore size of the small pores was 86 nanometers. And in the alloys prepared in other embodiments, similar results were obtained. It can be seen from the above experimental data that the porous material of the present application can be successfully prepared by the binary alloy of the present application.

[0221] In contrast, Figure 5 It is obvious from the photos that the alloy of comparative example 1 cannot obtain a continuous skeleton after corrosion, and therefore cannot obtain a porous material with regular pores. The alloy of comparative example 2 is directly powdered after corrosion, and no corresponding scanning electron microscope photos are obtained.

[0222] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and the embodiments having the same structure as the technical idea and exerting the same effect within the scope of the technical solution of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the main purpose of the present application, various modifications that can be thought of by those skilled in the art to the embodiments and other methods of combining some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A Mn-M binary multiphase alloy, characterized in that: The multiphase alloy comprises: 39wt%≤Mn≤78wt%, optionally, 68wt%≤Mn≤78wt%, The rest include metal M; wherein the standard electrode potential of the metal M is higher than the standard electrode potential of Mn, and The binary metal multiphase alloy has αMn phase, γM-Mn phase and γ'Mn-M phase distributed therein.

2. The multiphase alloy according to claim 1, wherein: The metal M is selected from one of Cu, Cr, Co, Sn and Ni, and is optionally Cu.

3. The multiphase alloy according to claim 1 or 2, wherein: The multiphase alloy comprises quasi-equiaxed grains, optionally the quasi-equiaxed grains have an average size of 5 μm to 30 μm, optionally 10 μm to 25 μm.

4. The multiphase alloy according to any one of claims 1 to 3, wherein The crystal grains of the multi-phase alloy have grain boundaries where metal Mn and metal M are discontinuously distributed.

5. The multiphase alloy according to any one of claims 1 to 4, wherein The αMn phase accounts for 4.6wt% to 65.6wt% of the multi-phase alloy, and optionally, the content of Mn element in the αMn phase is >99wt%.

6. The multiphase alloy according to any one of claims 1 to 5, wherein The γM-Mn phase and the γ′Mn-M phase together account for 34.4wt% to 95.3wt% of the multiphase alloy, and optionally, the content of M element in the γM-Mn phase is 35wt% to 100wt%, and the content of Mn element in the γ′Mn-M phase is 60wt% to 72wt%.

7. A method for preparing a Mn-M binary multiphase alloy, comprising: Smelting Mn and metal M in a weight ratio of (39-78):(22-61), optionally (68-78):(22-32), to obtain a Mn-M binary alloy, wherein the standard electrode potential of the metal M is higher than the standard electrode potential of Mn; performing a first heat treatment on the obtained Mn-M binary alloy to obtain a first product including a γMn-M solid solution; performing a second heat treatment on the first product to crystallize the first product to obtain a second product; performing a third heat treatment on the second product to obtain a third product including a γM-Mn phase and a γ'Mn-M phase; and The third product is subjected to a fourth heat treatment to obtain a binary multiphase alloy including an αMn phase, a γM-Mn phase and a γ′Mn-M phase.

8. The method according to claim 7, wherein: The method includes one or more of the following features: The first heat treatment is a homogenization heat treatment; The temperature of the first heat treatment is 720°C to 900°C; The first heat treatment time is 12h to 24h; The alloy is subjected to plastic working after the first heat treatment.

9. The method according to claim 7 or 8, wherein: The method includes one or more of the following features: The second heat treatment is a recrystallization treatment; The temperature of the second heat treatment is 720°C to 800°C; The second heat treatment time is 0.5h to 6h.

10. The method according to any one of claims 7 to 9, wherein: The method includes one or more of the following features: The third heat treatment is a spinodal decomposition treatment; The temperature of the third heat treatment is 400°C to 500°C; The third heat treatment lasts for 0.5 h to 4 h.

11. The method according to any one of claims 7 to 10, wherein: The method includes one or more of the following features: The fourth heat treatment is a phase separation treatment; The temperature of the fourth heat treatment is 600°C to 680°C; The fourth heat treatment lasts for 1 hour to 6 hours.

12. Use of the Mn-M binary multiphase alloy according to any one of claims 1 to 6 or the Mn-M binary multiphase alloy prepared by the method according to any one of claims 7 to 11 in preparing a porous material, wherein optionally, the porous material is used as a current collector.

13. A porous material, characterized in that: The porous material is obtained by dealloying the Mn-M binary multiphase alloy according to any one of claims 1 to 6 or the Mn-M binary multiphase alloy prepared by the method according to any one of claims 7 to 11, wherein the porous material has pores with a first pore size and a second pore size, the first pore size is n micrometers, wherein 0.5≤n≤10, optionally 2≤n≤5, and the second pore size is m nanometers, wherein 20<m<200, optionally, 40<m<70.

14. A current collector comprising the porous material according to claim 13.

15. A secondary battery comprising the current collector according to claim 14.

16. An electrical device comprising the secondary battery according to claim 15.

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