Liquid metal battery high-voltage positive electrode material and application

Abstract

The application discloses a high-voltage positive electrode material of a liquid metal battery, wherein the positive electrode material is a Se alloy formed by Se, an additive metal X and a second active component metal Y; the additive metal X is one or both of metals Ag and Cd; and the second active component metal Y is one or both of metals Sb and Bi. The high-voltage positive electrode material can not only significantly improve the electronic conductivity of the Se-based positive electrode, but also effectively inhibit the solubility of the Se component in the molten salt electrolyte, thereby improving the cycle stability of the battery. The high-voltage Se-based alloy positive electrode material is used in the liquid metal battery, and in the discharging process, the large chemical potential difference between Se and the negative electrode metal can significantly improve the discharging voltage of the Se-based alloy positive electrode material. In combination with the deep discharge of the second active component metal Y at the end of the discharging, the utilization rate of the Se-based alloy positive electrode material is obviously improved, and these beneficial effects can synergistically improve the energy density of the liquid metal battery.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical energy storage battery technology, specifically relating to a high-voltage positive electrode material for liquid metal batteries and its application. Background Technology

[0002] Liquid metal batteries are a type of high-temperature molten salt battery where the positive and negative electrodes and the molten salt electrolyte are all in a liquid state at the operating temperature. Due to density differences and immiscibility, the electrolyte lies between the liquid positive and negative electrodes, and the three automatically stratify. During charging and discharging, the interfaces between the positive and negative electrodes and the electrolyte are always liquid-liquid interfaces, which facilitates the rapid migration of reactants and products and charge transfer. Secondly, the conductivity of the molten salt electrolyte is relatively high, generally two orders of magnitude higher than that of lithium-ion battery electrolytes, giving liquid metal batteries ultra-fast charge transfer kinetics and thus excellent rate performance. Simultaneously, the all-liquid battery structure does not cause electrode deformation, dendrite growth, or other degradation of the electrode microstructure during cycling, endowing liquid metal batteries with an ultra-long cycle life. Furthermore, the positive and negative electrode and molten salt electrolyte materials used in liquid metal batteries are inexpensive, and the manufacturing process is simple, significantly reducing the battery's production cost. Therefore, liquid metal batteries are a highly promising large-scale energy storage technology with broad application prospects in the future smart grid energy storage field.

[0003] In recent years, metals such as Sb, Bi, Sn, and Pb, and their alloys, have been reported to exhibit superior electrochemical performance as cathode materials in liquid metal batteries. Advanced Energy Materials 6 (2016) 1600483). However, since the electrode reaction of liquid metal batteries is driven by the chemical potential difference between the positive and negative electrode materials, the chemical potential difference between the aforementioned positive electrode materials and commonly used negative electrode materials (such as alloys composed of one or more of lithium, sodium, potassium, magnesium, and calcium) is relatively small, resulting in a low battery discharge voltage (<0.95 V), which seriously affects the improvement of the energy density of liquid metal batteries. Introducing highly electronegative non-metallic components into the positive electrode material can significantly increase the chemical potential difference between the positive and negative electrode materials, and is expected to greatly improve the discharge voltage of liquid metal batteries, thereby breaking through the energy density bottleneck of liquid metal batteries. For example, the theoretical discharge potential of Li||Se can reach 2.0 V ( Joule 4 (2020) 262-274). However, non-metallic components generally have poor electrical conductivity and high solubility in molten salt electrolytes, resulting in poor battery cycle stability and extremely rapid capacity decay, which cannot meet the requirements for long-term service. Therefore, how to solve the problems of poor electronic conductivity and high solubility in molten salts of non-metallic components such as Se is the key to improving the discharge voltage and energy density of liquid metal battery cathode materials. Summary of the Invention

[0004] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0005] In view of the problems existing in the above and / or prior art, the present invention is proposed.

[0006] Therefore, the purpose of this invention is to overcome the shortcomings of the prior art and provide a high-voltage cathode material for liquid metal batteries.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a high-voltage positive electrode material for liquid metal batteries, characterized in that the positive electrode material is a Se alloy formed by Se, additive metal X, and second active component metal Y.

[0008] As a preferred embodiment of the high-voltage cathode material for the liquid metal battery described in this invention, wherein the chemical formula of the Se-based alloy cathode material is Se. a X b Y c The additive metal X is one or both of Ag and Cd, and the second active component metal Y is one or both of Sb and Bi. a is 5%~95%, b is 2%~50%, c is 3%~90%, and a+b+c=100%.

[0009] As a preferred embodiment of the high-voltage positive electrode material for liquid metal batteries according to the present invention, the preparation method of the high-voltage positive electrode material for liquid metal batteries includes: weighing Se, additive metal X and second active component metal Y according to the molar percentage, heating to 50~200°C above the alloy melting point under a protective atmosphere or vacuum and holding at that temperature for 1~8 hours to fully alloy it.

[0010] Another objective of this invention is to overcome the shortcomings of the prior art and provide a liquid metal battery comprising a battery casing, a positive electrode current collector, a positive electrode material, a molten salt electrolyte, a negative electrode material, a negative electrode current collector, and a sealing device, wherein the positive electrode material is a Se-based alloy positive electrode material as described in any one of claims 1 to 3.

[0011] In a preferred embodiment of the liquid metal battery of the present invention, the positive electrode current collector is one of graphite, tungsten, molybdenum, and titanium materials.

[0012] In a preferred embodiment of the liquid metal battery of the present invention, the negative electrode material is an alloy composed of one or more of lithium, sodium, potassium, magnesium, and calcium.

[0013] In a preferred embodiment of the liquid metal battery of the present invention, the negative electrode current collector is a porous foam material that is chemically inert to the negative electrode material, and during operation, the negative electrode material is adsorbed in the pores of the negative electrode current collector.

[0014] In a preferred embodiment of the liquid metal battery of the present invention, the negative electrode material and the molten salt electrolyte are in a liquid state at the operating temperature, and the positive electrode material is in a liquid or semi-liquid state.

[0015] As a preferred embodiment of the liquid metal battery of the present invention, the battery assembly method includes: under a protective atmosphere, placing the positive electrode current collector, the positive electrode material, the molten salt electrolyte and the negative electrode current collector adsorbed with the negative electrode material in the battery casing in sequence, such that the distance between the positive electrode material and the negative electrode current collector adsorbed with the negative electrode material is 10~18mm, and then cooling and sealing after heat preservation.

[0016] In a preferred embodiment of the liquid metal battery of the present invention, the operating temperature of the battery is 300~600℃.

[0017] Beneficial effects of this invention: This invention provides a high-voltage Se-based alloy cathode material. Se is alloyed with additive metal X and a second active component metal Y to form a Se alloy. This not only significantly improves the electronic conductivity of the Se-based cathode but also effectively suppresses the solubility of the Se component in the molten salt electrolyte, thereby improving the battery's rate performance, coulombic efficiency, and cycle stability. Simultaneously, the high-entropy effect induced by the multi-component alloying of the Se-based alloy cathode material can lower the melting point of the Se-based cathode, potentially further reducing the operating temperature of liquid metal batteries. When the high-voltage Se-based alloy cathode material designed in this invention is used in a liquid metal battery, the large chemical potential difference between Se and the negative electrode metal during discharge significantly increases the discharge voltage of the Se-based alloy cathode material. Combined with the deep discharge of the second active component metal Y at the end of the discharge process, the utilization rate of the Se-based alloy cathode material is significantly improved. These beneficial effects can synergistically enhance the energy density of the liquid metal battery. Meanwhile, during discharge, the process of Se and the second active component metal Y generating intermetallic compound discharge products leads to the dealloying of additive metal X and its dispersion in the discharge product layer. Its good conductivity allows it to act as a fast ion and electron diffusion channel for subsequent electrode reactions, further accelerating electrode reaction kinetics and battery rate performance. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein: Figure 1 This is a schematic diagram of the liquid metal battery structure of the cathode material of the present invention.

[0019] Figure 2 The above shows the charge-discharge performance curves of the liquid metal battery in Example 1 of this invention.

[0020] Figure 3 The image shows the cycle performance curve of the liquid metal battery in Example 1 of this invention.

[0021] Figure 4 The above shows the charge-discharge performance curves of the liquid metal battery in Comparative Example 1 of this invention.

[0022] Figure 5 The above shows the charge-discharge performance curves of the liquid metal battery in Example 4 of this invention. Detailed Implementation

[0023] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0024] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0025] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0026] Unless otherwise specified, all raw materials used in this invention are commercially available in the field.

[0027] This invention addresses the problems of poor electronic conductivity and high solubility of Se in molten salts by providing a high-voltage cathode material for liquid metal batteries. This cathode material is a Se alloy formed by Se, an additive metal X, and a second active component metal Y. The chemical formula of the Se-based alloy cathode material is Se. a X b Y cThe additive metal X is one or both of Ag and Cd, and the second active component metal Y is one or both of Sb and Bi. The subscripts a, b and c in the chemical formula represent the molar percentage of each component, where a is 5%-95%, b is 2%-50%, c is 3%-90%, and a+b+c=100%.

[0028] The preparation method of the Se-based alloy cathode material of the present invention is as follows: Calculate and weigh the required amount of Se, additive metal X, and second active component metal Y according to the molar percentage, place them in a graphite crucible or tungsten crucible, and heat them to 50-200°C above the melting point of the stated alloy under argon atmosphere protection or vacuum conditions. o C, and keep at a temperature of 1-8 h to fully alloy the mixed raw materials, thus obtaining Se-based alloy cathode materials.

[0029] According to another aspect of the invention, the invention also provides a liquid metal battery using a Se-based alloy cathode material, the structure of which is as follows: Figure 1 As shown, it includes a battery casing 1, a positive electrode current collector 2, a positive electrode material 3, a molten salt electrolyte 4, a negative electrode material 5, a negative electrode current collector 6, and sealing devices (graphite sealing ring 7 and ceramic seal 8).

[0030] The assembly process of the liquid metal battery using the Se-based alloy cathode material of the present invention is as follows: ① Anode preparation: Weigh a certain amount of anode metal and place it in a heating furnace until it melts. Immerse the porous foam metal current collector (Ni-Fe foam metal) into it, allowing the current collector to adsorb the required mass of anode metal, thus completing the anode preparation; ② Battery active component assembly: Place the bottom-sealed 304 stainless steel battery casing in a heating furnace, setting the temperature to be 50°C higher than the melting point of the Se-based alloy cathode material. o At temperature C, maintain a constant temperature, then sequentially add the positive electrode current collector, positive electrode material, and molten salt electrolyte from bottom to top, and hold for 30-120 min. After the positive electrode material and molten salt electrolyte have completely melted, slowly immerse the negative electrode prepared in step ① into the molten salt electrolyte, adjust the distance between the positive and negative electrodes to 10-18 mm, hold for 30-120 min, and then cool to room temperature to complete the assembly of the battery active components. ③ Battery sealing: Insulation between the negative electrode and the casing is achieved through a ceramic sealing device, and finally, a graphite sealing ring is used to complete the casing sealing, thus completing the battery sealing. The entire battery assembly process is completed in a glove box filled with argon atmosphere. After the battery assembly is completed, heat the battery to the operating temperature and hold for 3-10 h before conducting electrochemical performance tests.

[0031] Furthermore, the present invention provides a series of embodiments, and the invention will be further described in conjunction with the accompanying drawings. The structure and assembly process of the liquid or semi-liquid metal energy storage batteries in each embodiment are the same, except that the composition and preparation process of the positive and negative electrode materials and molten salt electrolytes are different in each embodiment.

[0032] Example 1 This embodiment uses a Se-Ag-Sb alloy (Se:Ag:Sb=30:30:40 mol%, Se... 30 Ag 30 Sb 40 Se was used as the positive electrode material to prepare... 30 Ag 30 Sb 40 When preparing the alloy cathode, weigh Se, Ag, and Sb according to the required molar ratio, place them in a graphite crucible, and heat to 650°C under an inert atmosphere. o After holding at temperature C for 1 hour and allowing it to cool naturally, the desired Se can be obtained. 30 Ag 30 Sb 40 alloy.

[0033] During the assembly of liquid metal batteries, the above-mentioned Se is used. 30 Ag 30 Sb 40 The alloy is used as the positive electrode material, and lithium metal is used as the negative electrode material. The molten salt electrolyte composition and ratio are LiF:LiCl:LiBr = 22:31:47 mol%. The negative electrode current collector is Ni-Fe foam metal, and the positive electrode current collector is a graphite crucible. During assembly, the distance between the positive and negative electrodes is adjusted to 15 mm.

[0034] The battery operating temperature in this embodiment is 550°C. o C, the electrochemical window for testing is 0.4-2.2 V.

[0035] Comparative Example 1 This comparative example uses pure Se as the positive electrode material. No special treatment is required for the positive electrode; simply weigh it according to the required mass.

[0036] During the assembly of the liquid metal battery, pure Se was used as the positive electrode material, and metallic lithium was used as the negative electrode material. The molten salt electrolyte composition and ratio were LiF:LiCl:LiBr = 22:31:47 mol%. The negative electrode current collector was Ni-Fe foam metal, and the positive electrode current collector was a graphite crucible. Simultaneously, the distance between the positive and negative electrodes was adjusted to 15 mm during the assembly process.

[0037] The battery operating temperature in this embodiment is 550°C. o C, the electrochemical window for testing is 0.4-2.2 V.

[0038] Example 2 This embodiment uses a Se-Cd-Bi alloy (Se:Cd:Bi=50:40:10 mol%, Se... 50 Cd 40 Bi 10 Se was used as the positive electrode material to prepare... 50 Cd 40 Bi 10 When preparing the alloy cathode, weigh Se, Cd, and Bi according to the required molar ratio, place them in a graphite crucible, and heat to 600°C under an inert atmosphere. o After holding at temperature C for 1 hour and allowing it to cool naturally, the desired Se can be obtained. 50 Cd 40 Bi 10 alloy.

[0039] During the assembly of liquid metal batteries, the above-mentioned Se is used. 50 Cd 40 Bi 10 The alloy is used as the positive electrode material, and lithium metal is used as the negative electrode material. The molten salt electrolyte composition and ratio are LiCl:KCl = 41:59 mol%. The negative electrode current collector is Ni-Fe foam metal, and the positive electrode current collector is a graphite crucible. During assembly, the distance between the positive and negative electrodes is adjusted to 12 mm.

[0040] The battery operating temperature in this embodiment is 550°C. o C, the electrochemical window for testing is 0.4-2.2 V.

[0041] Example 3 This embodiment uses a Se-Cd-Sb alloy (Se:Cd:Sb=40:40:20 mol%, Se... 40 Cd 40 Sb 20 Se was used as the positive electrode material to prepare... 40 Cd 40 Sb 20 When preparing the alloy cathode, weigh Se, Cd, and Sb according to the required molar ratio, place them in a graphite crucible, and heat to 650°C under an inert atmosphere. o After holding at temperature C for 0.5 hours and allowing it to cool naturally, the desired Se can be obtained. 40 Cd 40 Sb 20 alloy.

[0042] During the assembly of liquid metal batteries, the above-mentioned Se is used. 40 Cd 40 Sb 20The alloy is used as the positive electrode material, and metallic lithium is used as the negative electrode material. The composition and ratio of the molten salt electrolyte are LiF:LiCl:LiI = 12:29:59 mol%. The negative electrode current collector is Ni-Fe foam metal, and the positive electrode current collector is a graphite crucible. During assembly, the distance between the positive and negative electrodes is adjusted to 15 mm.

[0043] The battery operating temperature in this embodiment is 550°C. o C, the electrochemical window for testing is 0.4-2.2 V.

[0044] Example 4 This embodiment uses a Se-Ag-Cd-Sb-Bi alloy (Se:Ag:Cd:Sb:Bi=30:20:20:20:10 mol%, Se 30 Ag 20 Cd 20 Sb 20 Bi 10 Se was used as the positive electrode material to prepare... 30 Ag 20 Cd 20 Sb 20 Bi 10 When preparing the alloy cathode, weigh Se, Ag, Cd, Sb, and Bi according to the required molar ratio, place them in a graphite crucible, and heat to 550°C under an inert atmosphere. o After holding at temperature C for 1 hour and allowing it to cool naturally, the desired Se can be obtained. 30 Ag 20 Cd 20 Sb 20 Bi 10 alloy.

[0045] During the assembly of liquid metal batteries, the above-mentioned Se is used. 30 Ag 20 Cd 20 Sb 20 Bi 10 The alloy is used as the positive electrode material, and lithium metal is used as the negative electrode material. The molten salt electrolyte composition and ratio are LiF:LiCl:LiBr = 22:31:47 mol%. The negative electrode current collector is Ni-Fe foam metal, and the positive electrode current collector is a graphite crucible. During assembly, the distance between the positive and negative electrodes is adjusted to 15 mm.

[0046] The battery operating temperature in this embodiment is 500°C. o C, the electrochemical window for testing is 0.4-2.2 V.

[0047] Example 5 This embodiment uses a Se-Ag-Bi alloy (Se:Ag:Bi = 40:30:30 mol%, Se... 40Ag 30 Bi 30 Se was used as the positive electrode material to prepare... 40 Ag 30 Bi 30 When preparing the alloy cathode, weigh Se, Ag, and Bi according to the required molar ratio, place them in a graphite crucible, and heat to 600°C under an inert atmosphere. o After holding at temperature C for 1 hour and allowing it to cool naturally, the desired Se can be obtained. 40 Ag 30 Bi 30 alloy.

[0048] During the assembly of liquid metal batteries, the above-mentioned Se is used. 40 Ag 30 Bi 30 The alloy is used as the positive electrode material, and metallic sodium is used as the negative electrode material. The molten salt electrolyte composition and ratio are NaCl:CaCl2 = 50:50 mol%. The negative electrode current collector is Ni-Fe foam metal, and the positive electrode current collector is a graphite crucible. During assembly, the distance between the positive and negative electrodes is adjusted to 15 mm.

[0049] The battery operating temperature in this embodiment is 550°C. o C, the electrochemical window for testing is 0.2-2.0 V.

[0050] Example 6 This embodiment uses a Se-Cd-Sb alloy (Se:Cd:Sb=40:50:10 mol%, Se... 40 Cd 50 Sb 10 Se was used as the positive electrode material to prepare... 40 Cd 50 Sb 10 When preparing the alloy cathode, weigh Se, Cd, and Sb according to the required molar ratio, place them in a graphite crucible, and heat to 650°C under an inert atmosphere. o After holding at temperature C for 0.5 hours and allowing it to cool naturally, the desired Se can be obtained. 40 Cd 50 Sb 10 alloy.

[0051] During the assembly of liquid metal batteries, the above-mentioned Se is used. 40 Cd 50 Sb 10 The alloy is the positive electrode material, a calcium-magnesium alloy (Ca:Mg=70:30 mol%, Ca...). 70 Mg 30The negative electrode material is LiCl:CaCl2 = 65:35 mol%, the molten salt electrolyte composition and ratio are LiCl:CaCl2 = 65:35 mol%, the negative electrode current collector is Ni-Fe foam metal, and the positive electrode current collector is a graphite crucible. During assembly, the distance between the positive and negative electrodes is adjusted to 15 mm.

[0052] The battery operating temperature in this embodiment is 550°C. o C, the electrochemical window for testing is 0.2-2.0 V.

[0053] Table 1 shows the performance tests of Examples 1-6 and Comparative Example 1.

[0054] Table 1 Summary of cathode and battery performance in Examples 1-6 and Comparative Example 1

[0055] Figure 2 The charge-discharge performance curves of the liquid metal battery of Example 1 of this invention are shown, with the battery operating temperature at 550°C. o C. At 200 mA cm -2 At the specified current density, the liquid metal battery of Example 1 exhibits an initial discharge voltage plateau of up to 1.6V, a coulombic efficiency of 91%, and an energy density of 395 Wh / kg. -1 (Based on calculations of positive and negative electrode materials), it is shown that the alloy positive electrode design in this embodiment can suppress the dissolution of Se in molten salt electrolyte.

[0056] Figure 3 The cycle performance curve of the liquid metal battery of Example 1 of this invention is obtained at 550°C. o C, 200 mA cm -2 The battery can cycle stably for 30 cycles with a capacity retention rate of 95%.

[0057] Figure 4 The above describes the charge-discharge performance curve of the liquid metal battery used in Comparative Example 1 of this invention, with the battery operating temperature at 550°C. o C. At 200 mA cm -2 At current density, the initial discharge voltage plateau of the liquid metal battery using Comparative Example 1 is as high as 1.8V, but the battery coulombic efficiency is very low, only 31%, indicating that the pure Se cathode dissolves very severely in the molten salt electrolyte.

[0058] Figure 5 The charge-discharge performance curves of the liquid metal battery from Example 4 of this invention are shown, with the battery operating temperature at 500°C. o C. At 200 mA cm -2 At the specified current density, the liquid metal battery of Example 4 exhibits an initial discharge voltage plateau of up to 1.5V and an energy density of 310 Wh / kg. -1(Calculations based on positive and negative electrode materials).

[0059] In summary, the Se-based alloy cathode material of this invention, when applied to liquid metal batteries, effectively alleviates the dissolution of Se in the cathode, improves the battery discharge voltage, achieves higher energy density, and exhibits good battery cycle performance, which is expected to meet the energy storage needs of smart grids.

[0060] The assembly method for a liquid metal battery using a high-voltage Se-based alloy cathode material provided by this invention comprises the following steps: Under an argon protective atmosphere, the battery casing is placed in a heating furnace, and the furnace temperature is set to be 30-100°C above the melting point of the cathode material. o C. Subsequently, the positive electrode current collector, positive electrode material, molten salt electrolyte, and negative electrode current collector (which adsorbs the negative electrode material) are placed sequentially from bottom to top in the battery casing, ensuring a spacing of 10-18 mm between the positive electrode material and the negative electrode current collector. The battery is then held at this temperature for 30-120 minutes and cooled to room temperature. Next, the battery is sealed and the positive and negative electrodes are insulated using sealing devices. Specifically, a graphite sealing ring is used to seal the casing, and a ceramic sealing device is used to insulate the negative electrode from the casing. The battery assembly is complete after these steps. After assembly, the battery is heated to its operating temperature and held for 3-10 hours before electrochemical performance testing.

[0061] The high-voltage Se-based alloy cathode material of this invention consists of three parts: ① elemental Se, the main active component, used to improve the discharge voltage of the cathode material and the energy density of the battery; ② additive metal X, which, on the one hand, inhibits the dissolution of the Se component in the molten salt electrolyte at the operating temperature, alleviates battery self-discharge, and improves battery operational stability; on the other hand, the excellent conductivity of additive metal X can further enhance the electronic conductivity of the Se-based alloy cathode material and improve electrode kinetics; ③ second active component metal Y, which, on the one hand, the introduction of multiple components can further reduce the solubility of the Se component in the molten salt electrolyte and the melting point of the cathode, thereby improving the operational stability of the cathode and lowering the operating temperature; on the other hand, the second active component metal Y can contribute part of the capacity, support the deep discharge of the Se-based alloy cathode material, improve the cathode utilization rate, and further improve the energy density of the liquid metal battery. This design concept of liquid metal battery cathode material is significantly different from previous reports and has obvious advantages.

[0062] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the present invention.

Claims

1. A high-voltage positive electrode material for liquid metal batteries, characterized in that, The positive electrode material is a Se alloy formed by Se, additive metal X, and second active component metal Y; The chemical formula of the Se-based alloy cathode material is Se. a X b Y c The additive metal X includes one or both of Ag or Cd, and the second active component metal Y includes one or both of Sb or Bi, where a is 5%~95%, b is 2%~50%, c is 3%~90%, and a+b+c=100%.

2. The high-voltage positive electrode material for liquid metal batteries as described in claim 1, characterized in that: The preparation method of the high-voltage positive electrode material of the liquid metal battery includes: weighing Se, additive metal X and second active component metal Y according to the molar percentage, heating to 50~200°C above the alloy melting point under a protective atmosphere or vacuum and holding for 1~8 hours to fully alloy it.

3. A liquid metal battery, comprising a battery casing (1), a positive electrode current collector (2), a positive electrode material (3), a molten salt electrolyte (4), a negative electrode material (5), a negative electrode current collector (6), a graphite sealing ring (7), and a ceramic seal (8), characterized in that, The cathode material is the Se-based alloy cathode material according to any one of claims 1 or 2.

4. The liquid metal battery as described in claim 3, characterized in that: The positive current collector (2) includes one of graphite, tungsten, molybdenum, and titanium materials.

5. The liquid metal battery as described in claim 3, characterized in that: The negative electrode material (5) includes an alloy composed of one or more of lithium, sodium, potassium, magnesium, and calcium.

6. The liquid metal battery as described in claim 5, characterized in that: The negative electrode current collector (6) is a porous foam material that is chemically inert to the negative electrode material. During operation, the negative electrode material is adsorbed in the pores of the negative electrode current collector.

7. The liquid metal battery as described in claim 3, characterized in that: At the operating temperature, the negative electrode material (5) and the molten salt electrolyte (4) are in a liquid state, and the positive electrode material (3) is in a liquid or semi-liquid state.

8. The liquid metal battery as described in claim 3, characterized in that: The battery assembly method includes: under a protective atmosphere, placing the positive current collector (2), positive electrode material (3), molten salt electrolyte (4) and negative current collector (6) adsorbed with negative electrode material (5) in the battery casing (1) in sequence, so that the distance between the positive electrode material (3) and the negative current collector (6) adsorbed with negative electrode material (5) is 10~18mm, and then cooling and sealing after heat preservation.

9. The liquid metal battery as described in claim 3, characterized in that: The battery operates at a temperature of 300~600℃.

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