A metal electrode with a rare earth alloy protective layer and its preparation method and application

Abstract

The present application relates to the technical field of energy storage materials, and in particular to a metal electrode with a rare earth alloy protective layer, and a preparation method and application thereof; the metal electrode comprises a metal electrode material and a rare earth alloy protective layer wrapped on the surface of the metal electrode material, wherein the thickness of the rare earth alloy protective layer is 5nm to 10μm; the method comprises: polishing the metal electrode material and the rare earth metal respectively; under preset temperature and preset pressure conditions, physically contacting the polished metal electrode material and the rare earth metal to realize in-situ generation of a rare earth alloy protective layer on the surface of the metal electrode to obtain a metal electrode; by covering the surface of the metal electrode with a rare earth alloy protective layer and limiting the thickness of the rare earth total protective layer, the purpose of improving the rate performance of the metal electrode while solving the problem of dendrite growth of the metal electrode is achieved.

Description

Technical Field

[0001] The present application relates to the technical field of energy storage materials, and in particular to a metal electrode with a rare earth alloy protective layer, a preparation method thereof, and an application thereof. Background Art

[0002] The development of advanced energy storage technology is crucial to meet the needs of portable electronic products, electric vehicles, fixed grid storage, etc., and metal (lithium, sodium, magnesium, potassium, aluminum and zinc, etc.) ion secondary batteries are vigorously developed as an important type of energy storage device due to their advantages of high energy density, environmental protection and low self-discharge rate. In addition, the development and application of key battery materials (including positive electrode, negative electrode, electrolyte, conductive agent, binder, etc.) have an important driving role in the development of battery devices. However, the negative electrode of metal ion secondary batteries is mainly carbon materials, such as graphite, soft carbon, hard carbon, etc., and the actual energy density of metal ion secondary batteries with carbon materials as negative electrodes has gradually approached the theoretical limit value, which has caused the development of these metal ion secondary batteries to enter a period of stagflation.

[0003] Therefore, in order to better meet the demand for energy density of energy storage batteries for future industrial products, it is urgent to develop or apply negative electrode materials with higher theoretical capacity. Compared with carbon material negative electrodes, metal negative electrodes (such as lithium, sodium, potassium, aluminum and zinc, etc.) have become ideal negative electrode materials for the next generation of secondary batteries due to their extremely high theoretical capacity and low standard electrode potential; currently, metal-based secondary batteries mainly include metal-oxide batteries, metal-sulfur batteries and metal-air batteries. Due to their extremely high theoretical energy density, they are considered to be an important development direction in the future energy storage field. However, using pure metals (such as lithium, sodium, potassium, aluminum and zinc, etc.) as negative electrode materials faces serious dendrite growth problems, which can easily lead to adverse factors such as interface film rupture, electrolyte drying, dead lithium formation and diaphragm puncture, resulting in rapid battery failure and hindering its commercial application.

[0004] Although there are currently a variety of solutions to the dendrite growth problem of pure metal as negative electrode materials, among which covering a layer of alloy protective layer on the metal electrode is the mainstream, although the alloy protective layer at this stage has a significant protective effect on improving the performance of the metal negative electrode, the rate performance of the alloy protective layer is poor, which easily causes the rate performance loss of the metal electrode. Therefore, how to provide a metal electrode with a high rate performance and an alloy protective layer is a technical problem that needs to be solved urgently. Summary of the invention

[0005] The present application provides a metal electrode with a rare earth alloy protective layer and a preparation method and application thereof, so as to solve the technical problem in the prior art of low rate performance of the alloy protective layer in the process of dendrite growth of the metal electrode.

[0006] In a first aspect, the present application provides a metal electrode with a rare earth alloy protective layer, wherein the metal electrode comprises a metal electrode material and a rare earth alloy protective layer wrapped on the surface of the metal electrode material, wherein the thickness of the rare earth alloy protective layer is 5 nm to 10 μm.

[0007] Optionally, the raw material of the metal electrode material includes any one of lithium, sodium, potassium, zinc, aluminum, lithium alloy, sodium alloy, potassium alloy, zinc alloy and aluminum alloy.

[0008] Optionally, the rare earth metal in the rare earth alloy protective layer includes at least one of scandium, yttrium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium.

[0009] In a second aspect, the present application further provides a method for preparing the metal electrode according to the first aspect, the method comprising:

[0010] polishing the metal electrode material and the rare earth metal respectively;

[0011] Under the conditions of preset temperature and preset pressure, the polished metal electrode material and the rare earth metal are brought into physical contact to realize in-situ generation of a rare earth alloy protective layer on the surface of the metal electrode, thereby obtaining a metal electrode.

[0012] Optionally, the preset temperature is 25° C. to 100° C.; and / or,

[0013] The preset pressure is 0.1 MPa to 20 MPa.

[0014] Optionally, the physical contact time is 0.5 min to 30 min.

[0015] Optionally, the metal electrode material and the rare earth metal are in the shape of sheets and / or foils respectively.

[0016] Optionally, the physical contact includes physical contact in the form of single-sided contact between the metal electrode material and the rare earth metal.

[0017] Optionally, the area of ​​the metal electrode material is ≤ the area of ​​the rare earth metal.

[0018] In a third aspect, the present application also provides an application of the metal electrode described in the first aspect in an energy storage battery.

[0019] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0020] A metal electrode with a rare earth alloy protective layer provided in an embodiment of the present application covers the surface of the metal electrode with a rare earth alloy protective layer, limits the thickness of the rare earth total protective layer, and utilizes the rare earth alloy protective layer as an ion dynamics accelerator. On the one hand, the lithium affinity of the rare earth metal elements in the rare earth alloy protective layer can be utilized to ensure that the rare earth alloy layer has a lower diffusion barrier, thereby promoting the rapid diffusion and lateral redistribution of metal atoms on the electrode surface, thereby avoiding the dendrite growth of the metal electrode. On the other hand, the interstitial migration energy barrier of the metal ions in the metal electrode in the rare earth metal of the rare earth alloy protective layer is lower, which helps to promote the rapid passage of the metal ions through the interface layer, giving the metal electrode excellent rate performance, thereby achieving the purpose of improving the rate performance of the metal electrode under the premise of solving the dendrite growth of the metal electrode. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0022] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0023] Figure 1 A schematic flow chart of a method for preparing a metal electrode having a rare earth alloy protective layer provided in an embodiment of the present application;

[0024] Figure 2 A diagram showing the rate performance of a lithium iron phosphate / lithium full battery with and without protection of a metal lithium electrode provided in an embodiment of the present application;

[0025] Figure 3 A diagram showing the electrochemical performance of a symmetrical battery with and without protection of a metallic sodium electrode provided in an embodiment of the present application;

[0026] Figure 4 A diagram showing the electrochemical cycle stability of a symmetrical battery with and without protected lithium metal electrodes provided in an embodiment of the present application. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0028] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0029] The creative thinking of this application is:

[0030] There are currently a variety of solutions to the dendrite growth problem of pure metals as negative electrode materials, including: (1) developing high-concentration electrolytes or introducing new additives. However, the actual application cost of high-concentration electrolytes is high, and the effect of additives will become ineffective as they are quickly consumed;

[0031] (2) The three-dimensional skeleton design effectively alleviates the volume expansion effect of metal electrodes, but in practical applications, it faces problems such as difficult welding of the tabs, easy penetration of the skeleton through the diaphragm, and low volume energy density;

[0032] (3) Construction of interface protective layer, which has the dual effect of inhibiting dendrite growth and interface reaction. In addition to polymer (PVDF, PDMS, etc.), inorganic (Al2O3, LiF, etc.) and organic-inorganic mixed protective layer (LiCl / PVDF-HFP, FeF2 / PVDF, etc.), alloy protective layer is also an efficient and stable interface protective layer; for example: Professor Liu Wei's research group at the School of Materials Science and Engineering of Shanghai University of Science and Technology introduced a nano-tin protective layer on the surface of the lithium negative electrode through thermal evaporation technology to form a lithium-tin alloy protective layer, which effectively stabilized the lithium metal negative electrode and inhibited the growth of lithium dendrites; or the modified lithium negative electrode was used in lithium-sulfur batteries, which significantly enhanced the battery cycle stability (Energy Storage Materials, 2020, 24, 329-335; and the use of liquid mercury to treat the metal electrode to form an amalgam alloy protective layer can effectively reduce the damage to the metal electrode structure caused by volume expansion during the cycle, and in the process of metal ion extraction, a reversible phase change occurs, inhibiting the growth of metal dendrites, and ultimately giving the metal negative electrode a long cycle life.

[0033] Although the alloy protective layer of the above method has a significant protective effect on improving the performance of the metal negative electrode, the rate performance of the alloy protective layer is poor, which will cause the rate performance of the metal electrode to be lost. Therefore, how to provide a metal electrode with an alloy protective layer with high rate performance is a technical problem that needs to be solved urgently.

[0034] An embodiment of the present application provides a metal electrode with a rare earth alloy protective layer, wherein the metal electrode comprises a metal electrode material and a rare earth alloy protective layer wrapped on the surface of the metal electrode material, wherein the thickness of the rare earth alloy protective layer is 5 nm to 10 μm.

[0035] In the embodiment of the present application, the positive effect of limiting the thickness of the rare earth alloy protective layer to 5nm to 10μm is that within this thickness range, the rare earth alloy protective layer protects the metal electrode, ensures that the rare earth alloy layer has a low diffusion barrier, avoids the dendrite growth of the metal electrode, and also makes the interstitial migration energy barrier of the metal ions in the rare earth alloy protective layer lower, thereby giving the metal electrode excellent rate performance, thereby achieving the purpose of improving the rate performance of the metal electrode while solving the dendrite growth of the metal electrode.

[0036] In some optional embodiments, the raw material of the metal electrode material includes any one of lithium, sodium, potassium, zinc, aluminum, lithium alloy, sodium alloy, potassium alloy, zinc alloy and aluminum alloy.

[0037] In the embodiments of the present application, the positive effect of limiting the specific raw materials of the metal electrode is that most of the metal electrode materials can be covered within the limited range, thereby improving the applicability of the metal electrode of the present application.

[0038] In some optional embodiments, the rare earth metal in the rare earth alloy protective layer includes at least one of scandium, yttrium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium.

[0039] In the embodiments of the present application, the specific types of rare earth metals in the rare earth alloy protective layer are limited to cover most of the existing rare earth metal elements, thereby broadening the scope of application of the metal electrode of the present application.

[0040] like Figure 1 As shown, based on a general inventive concept, the present application also provides a method for preparing the metal electrode described in the first aspect, the method comprising:

[0041] S1. polishing the metal electrode material and the rare earth metal respectively;

[0042] S2. Under preset temperature and preset pressure conditions, the polished metal electrode material and the rare earth metal are brought into physical contact to achieve in-situ generation of a rare earth alloy protective layer on the surface of the metal electrode to obtain a metal electrode.

[0043] In the embodiment of the present application, the metal electrode material and the rare earth metal are first polished so that the surface oxide layer of the metal electrode material and the rare earth metal falls off, thereby facilitating the in-situ formation of a rare earth alloy protective layer to wrap the metal electrode of the metal electrode material in the subsequent physical contact stage, thereby achieving the purpose of improving the rate performance of the metal electrode while solving the problem of metal electrode dendrite growth.

[0044] Polishing refers to the removal of oxide layers and impurities on the surface of metal electrodes and rare earth metals by mechanical polishing, chemical polishing, electrolytic polishing, ultrasonic polishing and fluid polishing, which can facilitate the in-situ reaction in the subsequent physical contact stage to form a rare earth alloy protective layer.

[0045] This method is a method for preparing the above-mentioned metal electrode. The specific composition and structure of the metal electrode can refer to the above-mentioned embodiment. Since this method adopts part or all of the technical solutions of the above-mentioned embodiment, it at least has all the beneficial effects brought by the technical solutions of the above-mentioned embodiment, which will not be described one by one here.

[0046] In some optional embodiments, the preset temperature is 25° C. to 100° C.; and / or,

[0047] The preset pressure is 0.1 MPa to 20 MPa.

[0048] In the embodiment of the present application, the positive effect of limiting the preset temperature to 25°C to 100°C is that within this temperature range, the in-situ reaction of the metal electrode material and the rare earth metal can be promoted, thereby ensuring the reaction efficiency of the in-situ generation.

[0049] The positive effect of limiting the preset pressure to 0.1MPa to 20MPa is that within this pressure range, the physical contact between the metal electrode material and the rare earth metal can be sufficient, so that a uniform rare earth alloy protective layer is formed on the surface of the metal electrode material, thereby achieving the purpose of improving the rate performance of the metal electrode while solving the problem of metal electrode dendrite growth.

[0050] In some optional embodiments, the physical contact time is 0.5 min to 30 min.

[0051] In the embodiment of the present application, the positive effect of limiting the physical contact time to 0.5 min to 30 min is that within this time range, sufficient time can be ensured for the in-situ reaction between the metal electrode material and the rare earth metal, thereby ensuring the thickness and uniform distribution of the rare earth alloy protective layer.

[0052] In some optional embodiments, the metal electrode material and the rare earth metal are in the shape of sheets and / or foils respectively.

[0053] In the embodiments of the present application, the positive effect of limiting the shapes of the metal electrode material and the rare earth metal is that the sheet and foil have the largest area during the physical contact stage, thereby ensuring that a rare earth alloy protective layer of sufficient thickness is formed in a shorter time.

[0054] In some optional embodiments, the physical contact includes physical contact in the form of single-sided contact between the metal electrode material and the rare earth metal.

[0055] In the embodiments of the present application, the specific contact mode of physical contact is limited to ensure that a rare earth alloy protective layer of sufficient thickness is formed in a relatively short period of time.

[0056] In some optional embodiments, the area of ​​the metal electrode material is ≤ the area of ​​the rare earth metal.

[0057] In the embodiment of the present application, the area of ​​the metal electrode material is limited to ≤ the area of ​​the rare earth metal, which can ensure that the rare earth metal fully wraps the metal electrode, thereby forming a rare earth alloy protective layer of sufficient range and sufficient thickness on the metal electrode material.

[0058] Based on a general inventive concept, the present application also provides an application of the metal electrode in an energy storage battery.

[0059] This application is realized based on the above-mentioned metal electrode. The specific composition and structure of the metal electrode can refer to the above-mentioned embodiment. Since this application adopts part or all of the technical solutions of the above-mentioned embodiment, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiment, which will not be described one by one here.

[0060] The present application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are intended only to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods for which specific conditions are not specified in the following examples are usually measured according to national standards. If there is no corresponding national standard, then the conditions recommended by the manufacturer are followed.

[0061] Example 1

[0062] A method for preparing a metal electrode having a rare earth alloy protective layer, specifically comprising:

[0063] (1) Mechanically polishing a metal lithium electrode and a rare earth metal lanthanum in an inert gas atmosphere;

[0064] (2) After the polished metal lithium electrode is physically contacted with the rare earth metal lanthanum for 1 minute at room temperature 25°C and a pressure of 0.2 MPa, a lanthanum-lithium alloy protective layer is in situ generated on the surface of the metal lithium electrode, thereby obtaining a metal electrode with a rare earth alloy protective layer.

[0065] Example 2

[0066] Comparing Example 2 with Example 1, the difference between Example 2 and Example 1 is:

[0067] (1) Under an inert gas atmosphere, a metallic sodium electrode and a rare earth metal are subjected to cerium ultrasonic polishing;

[0068] (2) At room temperature (25°C) and a pressure of 0.1 MPa, the polished metal sodium electrode was physically contacted with the rare earth metal cerium for 5 minutes, and a cerium-sodium alloy protective layer was in situ generated on the surface of the metal sodium electrode, thereby obtaining a metal electrode with a rare earth alloy protective layer.

[0069] Example 3

[0070] Comparing Example 3 with Example 1, the difference between Example 3 and Example 1 is:

[0071] (1) Mechanically polishing a metal potassium electrode and a rare earth metal yttrium in an inert gas atmosphere;

[0072] (2) At room temperature (25°C) and a pressure of 0.3 MPa, the polished potassium metal electrode was brought into direct physical contact with the rare earth metal yttrium for 10 minutes, and a potassium yttrium alloy protective layer was in situ generated on the surface of the sodium metal electrode, thereby obtaining a metal electrode with a rare earth alloy protective layer.

[0073] Example 4

[0074] Comparing Example 4 with Example 1, the difference between Example 4 and Example 1 is:

[0075] (1) Mechanically polishing a metal zinc electrode and a rare earth metal scandium in an inert gas atmosphere;

[0076] (2) After the polished metal zinc electrode is physically contacted with the rare earth metal scandium for 10 minutes at 50°C and 0.5 MPa pressure, a scandium-zinc alloy protective layer is in situ generated on the surface of the metal zinc electrode, thereby obtaining a metal electrode with a rare earth alloy protective layer.

[0077] Example 5

[0078] Comparing Example 5 with Example 1, the difference between Example 5 and Example 1 is:

[0079] (1) Mechanically polishing the metal aluminum electrode and the rare earth metal lanthanum in an inert gas atmosphere;

[0080] (2) At 80°C and 2 MPa pressure, the polished aluminum electrode is physically contacted with the rare earth metal lanthanum for 2 minutes, and a lanthanum-magnesium alloy protective layer is in situ generated on the surface of the aluminum electrode to obtain a metal electrode with a rare earth alloy protective layer.

[0081] Example 6

[0082] Comparing Example 6 with Example 1, the difference between Example 6 and Example 1 is:

[0083] (1) Mechanically polishing a metal lithium-boron alloy electrode and a rare earth metal lanthanum in an inert gas atmosphere;

[0084] (2) At 40°C and 5 MPa pressure, the polished metal lithium boron electrode is physically contacted with the rare earth metal lanthanum for 20 minutes, and a lanthanum lithium boron alloy protective layer is in situ generated on the surface of the metal lithium boron electrode, thereby obtaining a metal electrode with a rare earth alloy protective layer.

[0085] Comparative Example 1

[0086] Comparative Example 1 and Example 1 are compared. The difference between Comparative Example 1 and Example 1 is:

[0087] (1) Mechanically polishing a metal lithium electrode and a rare earth metal lanthanum in an inert gas atmosphere;

[0088] (2) After the polished metal lithium electrode is physically contacted with the rare earth metal lanthanum for 10 minutes at 120°C and 0 MPa pressure, a lanthanum-lithium alloy protective layer is in situ generated on the surface of the metal lithium electrode, thereby obtaining a metal electrode with a rare earth alloy protective layer.

[0089] Related experiments and effect data:

[0090] The metal electrodes obtained in Example 1, Example 2 and Comparative Example 1 were studied respectively, specifically including:

[0091] 1. The metal electrode of Example 1 was assembled into a metal lithium-based secondary battery to study the rate performance. The blank group was assembled into a metal lithium-based secondary battery with a metal electrode without a rare earth alloy protective layer, and a lithium iron phosphate positive electrode was selected as the battery positive electrode for testing. The results are as follows Figure 2 shown.

[0092] like Figure 2As shown, the performance difference of the full battery assembled with two metal lithium electrodes is small at the initial low rate (0.1C), but the performance difference is sharply amplified at high rates (0.5C, 5C and 10C). Among them, the protected metal lithium electrode can still maintain a high specific capacity and stable cycle, while the capacity of the unprotected metal lithium electrode is low and there is an obvious diving phenomenon in the later stage of the cycle. At the same time, when the later cycle rate returns to the initial rate size again, the battery assembled with the protected lithium electrode can also be restored to the original capacity. The significant performance comparison shows that the rare earth alloy protective layer of the present application can give the metal electrode excellent rate performance, which is closely related to the enhancement of the kinetic motion of ions by the rare earth alloy.

[0093] 2. The electrochemical cycle stability of the sodium metal electrode of Example 2 was studied by assembling a symmetrical battery. The blank group was assembled into a symmetrical battery with a metal electrode without a rare earth alloy protective layer. The results are as follows: Figure 3 shown.

[0094] Depend on Figure 3 It can be seen that the metal sodium electrode protected by the rare earth alloy protective layer can stably cycle for more than 600 hours in a symmetrical battery, while the unprotected metal sodium electrode can stably cycle for less than 300 hours under the same conditions. The huge difference in electrochemical performance proves the positive effect of the rare earth alloy protective layer on the electrochemical properties of the metal electrode.

[0095] 3. The electrochemical cycle stability of the symmetrical battery assembled with the metal lithium electrode of Comparative Example 1 was studied. The blank group was assembled with a symmetrical battery with a metal electrode without a rare earth alloy protective layer. The results are as follows: Figure 4 shown.

[0096] Depend on Figure 4 It can be seen that compared with the metal lithium electrode not protected by the rare earth alloy protective layer, the electrochemical performance of the protected metal lithium electrode in the symmetrical battery is improved, but the improvement is not obvious. This is mainly because the rare earth metal lanthanum and metal lithium are not in sufficient contact under no pressure, and the formed alloy protective layer is uneven, resulting in limited actual improvement effect.

[0097] One or more technical solutions in the embodiments of the present application also have at least the following technical effects or advantages:

[0098] (1) An embodiment of the present application provides a metal electrode having a rare earth alloy protective layer. By covering the surface of the metal electrode with a rare earth alloy protective layer and limiting the thickness of the rare earth alloy protective layer, the purpose of improving the rate performance of the metal electrode is achieved while solving the problem of dendrite growth of the metal electrode.

[0099] (2) The embodiment of the present application provides a metal electrode with a rare earth alloy protective layer, wherein the rare earth alloy protective layer has good film-forming properties and interface stability, can effectively alleviate the interface damage caused by the volume expansion of the electrode during the cycle, and inhibit the interface reaction between the metal electrode and the electrolyte.

[0100] (3) The embodiments of the present application provide a method for preparing a metal electrode with a rare earth alloy protective layer. By utilizing the unique physical and chemical properties of rare earth metals, a highly efficient and stable rare earth alloy protective layer is formed in situ on the surface of a metal electrode (lithium, sodium, potassium, aluminum, zinc and their alloys) through simple physical contact.

[0101] (4) The embodiments of the present application provide a method for preparing a metal electrode with a rare earth alloy protective layer. The preparation method is simple, efficient, and easy to operate on a large scale. Moreover, applying the method to a metal-based secondary battery can significantly improve the cycle life and rate performance of the battery.

[0102] (5) The embodiment of the present application provides a method for preparing a metal electrode with a rare earth alloy protective layer. The preparation process is simple, the operability is strong, the area and thickness of the protective layer are controllable, and it is easy to mass produce. Applying it to energy storage batteries can significantly improve the electrochemical performance of the battery.

[0103] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0104] In the present application, in the absence of any contrary description, the directional words used, such as "upper" and "lower", are specifically the directions of the drawings in the accompanying drawings. In addition, in the description of the present specification, the terms "including", "comprising", etc. refer to "including but not limited to". In this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. In this article, "and / or" describes the association relationship of the associated objects, indicating that there may be three relationships, for example, A and / or B, which can represent: A exists alone, A and B exist at the same time, and B exists alone. Wherein A, B can be singular or plural. In this article, "at least one" refers to one or more, and "plural" refers to two or more. "At least one", "at least one of the following" or similar expressions refer to any combination of these items, including any combination of singular or plural items. For example, "at least one of a, b or c", or "at least one of a, b and c", can both mean: a, b, c, ab (i.e. a and b), ac, bc, or abc, where a, b, c can be single or plural, respectively.

[0105] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A metal electrode having a rare earth alloy protective layer, characterized in that: The metal electrode comprises a metal electrode material and a rare earth alloy protective layer wrapped on the surface of the metal electrode material, wherein the thickness of the rare earth alloy protective layer is 5nm to 10μm; The raw material of the metal electrode material includes any one of lithium, sodium, potassium, zinc, aluminum, lithium alloy, sodium alloy, potassium alloy, zinc alloy and aluminum alloy; The metal electrode, its preparation method comprises: polishing the metal electrode material and the rare earth metal respectively; Under the conditions of a preset temperature of 25° C. to 100° C. and a preset pressure of 0.1 MPa to 20 MPa, the polished metal electrode material and the rare earth metal are brought into physical contact to realize in-situ generation of a rare earth alloy protective layer on the surface of the metal electrode to obtain a metal electrode.

2. The metal electrode according to claim 1, characterized in that: The rare earth metal in the rare earth alloy protective layer includes at least one of scandium, yttrium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium.

3. The metal electrode according to claim 1, characterized in that: The physical contact time is 0.5 min to 30 min.

4. The metal electrode according to claim 1, characterized in that: The metal electrode material and the rare earth metal are in the shape of sheets and / or foils respectively.

5. The metal electrode according to claim 1, characterized in that: The physical contact includes physical contact in the form of single-sided contact between the metal electrode material and the rare earth metal.

6. The metal electrode according to claim 5, characterized in that: The area of ​​the metal electrode material is ≤ the area of ​​the rare earth metal.

7. Use of the metal electrode as claimed in any one of claims 1 to 2 in an energy storage battery.

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