Li-CO2 battery catalytic positive electrode based on rare earth element and two-dimensional material and preparation method of Li-CO2 battery catalytic positive electrode

Abstract

The invention relates to the technical field of new energy materials and new energy devices, and discloses a Li-CO2 battery catalytic positive electrode based on a rare earth element and a two-dimensional material and a preparation method thereof, the Li-CO2 battery catalytic positive electrode comprises a collector plate and positive electrode slurry coated on the surface of the collector plate; the positive electrode slurry comprises a catalytic positive electrode active material, a conductive agent and a binder; and the mass ratio of the catalytic positive electrode active material to the conductive agent to the binder is 8: 1: 1. The catalytic positive electrode of the Li-CO2 battery is prepared, the catalytic positive electrode utilizes a unique 4f electronic layer structure of rare earth Gd to replace precious metal as a catalytic center, and the material cost is remarkably reduced while efficient catalysis of CO2 reduction / decomposition reaction is guaranteed; a two-dimensional material is adopted as a carrier of rare earth Gd, the problem of oxygenolysis of a carbon material under high pressure is avoided due to high chemical stability brought by high crystallinity of the two-dimensional material, and meanwhile, efficient electron transmission in the electrode is ensured due to high metalloid conductivity (gt, 50S cm <-1 >) of the two-dimensional material.

Description

Technical Field

[0001] This invention belongs to the field of new energy materials and new energy devices, specifically relating to a Li-CO2 battery catalytic cathode based on rare earth elements and two-dimensional materials and its preparation method, which is particularly suitable for a novel secondary battery system with high energy density and the ability to fix CO2. Background Technology

[0002] With the rapid development of portable electronic devices, electric vehicles, and energy storage systems, the energy density of traditional lithium-ion batteries (approximately 300 Wh / kg) is gradually failing to meet the application requirements of long-range and high-capacity applications. Developing new battery systems with higher energy densities has become a research hotspot. Li-CO2 batteries, with their theoretical energy density as high as 1876 Wh / kg and their ability to adsorb and anchor CO2 in the air in real time during charging and discharging (achieving synergy between "battery function" and "carbon fixation"), are considered to be the next generation of highly promising electrochemical energy storage technology, and are expected to solve the dual problems of "energy shortage" and "greenhouse effect".

[0003] However, the commercialization of Li-CO2 batteries is limited by the performance bottleneck of the positive electrode catalytic active material: the current high-efficiency positive electrode active components mainly rely on precious metals (such as Ru, Ir, Pd), such materials are scarce and expensive (such as Ru, which has a market price of about 500 yuan / g), making it difficult to apply on a large scale; at the same time, the active material usually needs to be anchored on the surface of carbon support (such as graphene, carbon nanotubes) to improve dispersibility, but traditional carbon materials have poor thermal stability. During the decomposition of the discharge product (Li2CO3) of Li-CO2 battery (charging stage), the carbon support is easily oxidized to generate CO / CO2, which leads to the collapse of the positive electrode structure and a shortened cycle life.

[0004] Therefore, developing a catalytic cathode for Li-CO2 batteries is of great significance for promoting the development of low-cost and high-stability Li-CO2 batteries. Summary of the Invention

[0005] The purpose of this invention is to provide a Li-CO2 battery catalytic cathode and its preparation method to solve the problems of high cost of existing high-efficiency cathode active components and poor thermal stability of active material carriers, thereby achieving the effect of low-cost and high-stability Li-CO2 batteries.

[0006] Based on the above concept, the technical solution adopted by this invention is as follows: According to a first aspect of the present invention, a Li-CO2 battery catalytic cathode based on rare earth elements and two-dimensional materials is provided, comprising a current collector and a cathode slurry coated on the surface of the current collector; The positive electrode slurry includes a catalytic positive electrode active material, a conductive agent, and a binder; The mass ratio of the catalytic positive electrode active material, conductive agent, and binder is 8:1:1.

[0007] In some embodiments, the catalytic cathode active material includes a two-dimensional material used as a carrier and rare earth elements loaded on the surface of the two-dimensional material.

[0008] Furthermore, the general formula of the two-dimensional material is M. n+1 X n T x ; Where M is a transition metal, X is any one of C and N elements, n is a positive integer, and T... x It is a surface functional group.

[0009] Furthermore, the surface functional groups include any one of oxygen functional groups, hydroxyl groups, and fluorine functional groups.

[0010] Optionally, the two-dimensional material includes any one of Ti3C2, V2C, or Mo2C.

[0011] Optionally, the rare earth element includes any one of La, Gd, and Lu.

[0012] Furthermore, the rare earth element loaded on the surface of the two-dimensional material is Gd.

[0013] Furthermore, the Gd element is composed of Gd 3+ Salt is produced by reduction.

[0014] Optionally, the Gd 3+ The salt includes any one of Gd(CH3COO)3·4H2O, GdCl3·6H2O, or Gd(NO3)3·6H2O, and Gd 3+ The purity of the salt is ≥99.9%.

[0015] In some embodiments, the mass ratio of the two-dimensional material to the rare earth element in the catalytic positive electrode active material is 1:1 to 10:1.

[0016] Furthermore, the mass ratio of the two-dimensional material to the rare earth element is 1:1, 5:1, or 10:1.

[0017] According to a second aspect of the present invention, a method for preparing a Li-CO2 battery catalytic cathode is provided, comprising the following steps: S1, Dispersed Adsorption Salts containing rare earth elements and two-dimensional materials are added to a dispersant to form a mixed system with a solid-liquid ratio of 1:100 g / mL to 1:200 g / mL. After ultrasonic treatment of the mixture, it was transferred to a stirred reactor and stirred continuously to obtain a uniformly distributed rare earth element-two-dimensional material dispersion. S2, flocculation into gel A flocculant is slowly added to the rare earth element-two-dimensional material dispersion obtained in step S1, and after shaking, a hydrogel precursor of rare earth element-two-dimensional material is formed. S3, freeze drying The hydrogel precursor obtained in step S2 is frozen and dried in a vacuum chamber to obtain a rare earth element-two-dimensional material aerogel precursor with a porosity of 85-95%. S4, Reduction Calcination The aerogel precursor obtained in step S3 was introduced into a tube furnace under a reducing mixed atmosphere and reacted under heating conditions to obtain a catalytic positive electrode active material. S5, Positive Electrode Preparation The catalytic positive electrode active material, conductive agent and binder are mixed, and the positive electrode slurry is coated onto the surface of the current collector by a doctor blade coating method. Then, vacuum drying and pressing are performed to obtain the catalytic positive electrode of Li-CO2 battery.

[0018] In some embodiments, the thickness of the two-dimensional material sheet in step S1 is 5~10 nm.

[0019] In some embodiments, the reducing mixed atmosphere in step S4 is a mixed atmosphere of H2 and Ar, wherein the volume fraction of H2 is 5% to 10%.

[0020] In some embodiments, the catalytic positive electrode active material in step S4 is a three-dimensional interconnected porous structure made of stacked two-dimensional sheet materials, and rare earth elements are dispersed on the surface of the two-dimensional sheet materials by anchoring with surface functional groups.

[0021] In some embodiments, the thickness of the positive electrode slurry coating on the surface of the current collector in step S5 is 50~100 μm.

[0022] According to a third aspect of the present invention, a Li-CO2 battery is provided.

[0023] In some embodiments, the Li-CO2 battery includes a negative electrode, a separator, a catalytic positive electrode based on rare earth elements and two-dimensional materials, and an electrolyte.

[0024] The beneficial effects of this invention are as follows: 1. This invention utilizes the 4f electron layer structure of rare earth elements to replace noble metals as the catalytic center, which significantly reduces material costs while ensuring efficient catalysis of CO2 reduction or decomposition reactions; the strong interaction between Gd and the functional groups on the surface of two-dimensional materials forms a stable bond, which ensures the long-cycle stability of the battery, with a capacity retention rate of more than 80% after 100 cycles.

[0025] 2. This invention uses a two-dimensional material as a carrier. Its high crystallinity and resulting chemical stability avoid the oxidation and decomposition problems of carbon materials under high pressure. Simultaneously, its metalloid-like high conductivity ensures efficient electron transport within the electrode. The three-dimensional porous structure constructed through a "flocculation-freeze-drying-heat treatment" process not only provides a huge specific surface area and abundant active sites but also offers unobstructed channels for the diffusion of reactants and products, thereby enabling the battery to exceed 10000 mAh / g. -1 It has high specific capacitance and low polarization voltage of less than 2 V. Attached Figure Description

[0026] Figure 1 This is a flowchart illustrating the preparation process of a Li-CO2 battery catalytic cathode based on rare earth elements and two-dimensional materials according to the present invention. Figure 2 This is a scanning electron microscope image of the catalytic positive electrode active material of the present invention; Figure 3 This is a transmission electron microscope image of the catalytic positive electrode active material of the present invention; Figure 4 This is the X-ray diffraction pattern of the catalytic cathode active material of the present invention; Figure 5 This is a cyclic voltammetry diagram of a Li-CO2 battery according to the present invention; Figure 6 This is a discharge-charge diagram of a Li-CO2 battery according to the present invention. Detailed Implementation

[0027] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of apparatuses and methods consistent with some aspects of the invention as detailed in the appended claims.

[0028] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. Unless otherwise defined, the technical or scientific terms used in this application should be understood in their ordinary sense by one of ordinary skill in the art to which this invention pertains. The words “a” or “one” and similar terms used in this application specification and claims do not indicate a limitation of quantity, but rather indicate the presence of at least one. “A plurality” means two or more. The words “comprising” or “including” and similar terms mean that the element or object preceding “comprising” or “including” covers the element or object listed following “comprising” or “including” and its equivalents, and does not exclude other elements or objects. The words “connected” or “linked” and similar terms are not limited to physical or mechanical connections and can include electrical connections, whether direct or indirect. The words “above” and / or “below” and similar terms are for ease of description only and are not limited to a location or spatial orientation. The singular forms “a,” “the,” and “the” used in this application specification and appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0029] This application provides a Li-CO2 battery catalytic cathode based on rare earth elements and two-dimensional materials, and its preparation method. The Li-CO2 battery catalytic cathode includes a current collector and a cathode slurry coated on the surface of the current collector; The positive electrode slurry includes a catalytic positive electrode active material, a conductive agent, and a binder; The mass ratio of the catalytic positive electrode active material, conductive agent, and binder is 8:1:1.

[0030] This invention is achieved through design such as Figure 1 This paper describes a preparation process for a Li-CO2 battery catalytic cathode. This cathode utilizes the unique 4f electron layer structure of rare-earth Gd to replace noble metals as the catalytic center, ensuring highly efficient catalysis of CO2 reduction / decomposition while significantly reducing material costs. A two-dimensional material is used as the rare-earth Gd support; its high crystallinity and resulting chemical stability avoid the oxidation and decomposition problems of carbon materials under high pressure. Simultaneously, its metalloid-like high conductivity (>50 Scm⁻¹) ensures efficient electron transport within the electrode, and the battery constructed from this material exhibits a low polarization voltage of less than 2 V. Figure 6 As shown.

[0031] The following describes in detail, with reference to specific embodiments, a Li-CO2 battery catalytic cathode based on rare earth elements and two-dimensional materials and its preparation method, provided in this application.

[0032] In this embodiment, the catalytic positive electrode active material includes a two-dimensional material used as a carrier and rare earth elements loaded on the surface of the two-dimensional material.

[0033] The two-dimensional materials mentioned here, especially MXene two-dimensional materials, have excellent electrical conductivity (e.g., Ti3C2 has a conductivity of up to 10). 5 It exhibits high S / m, high thermal stability (no significant oxidation below 800℃ in an inert atmosphere), and abundant surface hydroxyl (-OH) and fluorine (-F) functional groups. These negatively charged functional groups can anchor Gd through electrostatic interactions. 3+ This avoids the aggregation of active components, while the two-dimensional structure facilitates the construction of porous electrodes with high specific surface area, enabling CO2 diffusion and Li + The transmission provides a channel.

[0034] In this embodiment, the general formula of the two-dimensional material is M. n+1 X n T x ; Where M is a transition metal, X is any one of C and N elements, n is a positive integer, and T... x For surface functional groups, the following schemes omit surface functional groups and only provide simplified descriptions.

[0035] In this embodiment, the surface functional groups include any one of oxygen functional groups, hydroxyl groups, and fluorine functional groups.

[0036] In this embodiment, the two-dimensional material includes any one of Ti3C2, V2C, or Mo2C.

[0037] In this embodiment, the rare earth element includes any one of La, Gd, and Lu.

[0038] Furthermore, in this embodiment, the rare earth element is preferably Gd.

[0039] In this embodiment, the Gd element is composed of Gd... 3+ Salts of ions are prepared by reduction.

[0040] In this embodiment, the one with Gd 3+ The salts of the ion include any one of Gd(CH3COO)3·4H2O, GdCl3·6H2O, or Gd(NO3)3·6H2O, and Gd 3+ The purity of the salt is ≥99.9%.

[0041] In this embodiment, the mass ratio of the two-dimensional material to the rare earth element in the catalytic positive electrode active material is 5:1.

[0042] Furthermore, the mass ratio of the two-dimensional material to the rare earth element can also be 1:1, 5:1, or 10:1.

[0043] In this embodiment, the preparation process of the Li-CO2 battery catalytic cathode includes: first, adding a salt containing rare earth elements and a two-dimensional material to a dispersant to form a mixed system with a solid-liquid ratio of 1:100 g / mL to 1:200 g / mL; after ultrasonic treatment of the mixed system, transferring it to a stirred reactor and continuously stirring to obtain a uniformly distributed rare earth element-two-dimensional material dispersion; slowly adding a flocculant to the rare earth element-two-dimensional material dispersion and shaking to form a rare earth element-two-dimensional material hydrogel precursor; freezing the hydrogel precursor and drying it in a vacuum chamber to obtain a rare earth element-two-dimensional material aerogel precursor with a porosity of 85-95%; introducing a reducing mixed atmosphere into the aerogel precursor obtained in step S3 and reacting it under heating conditions to obtain a catalytic cathode active material; mixing the catalytic cathode active material, a conductive agent, and a binder, and coating the cathode slurry onto the surface of the current collector using a doctor blade coating method, followed by vacuum drying and pressing to obtain the Li-CO2 battery catalytic cathode.

[0044] In this embodiment, when Gd is present 3+ When the mass ratio of the ionic salt to the two-dimensional material is 1:1, the solid-liquid ratio of the mixture is 1:200 (g / mL), the stirring speed is 500 rpm, and the stirring time is 14 h. When with Gd 3+ When the mass ratio of the ionic salt to the two-dimensional material is 5:1, the solid-liquid ratio of the mixture is 1:150 (g / mL), the stirring speed is 400 rpm, and the stirring time is 12 h. When with Gd 3+ When the mass ratio of the ionic salt to the two-dimensional material is 10:1, the solid-liquid ratio of the mixture is 1:100 (g / mL), the stirring speed is 300 rpm, and the stirring time is 10 h.

[0045] In this embodiment, the calcination parameters are different for different two-dimensional materials: If the two-dimensional material is Ti3C2: calcination temperature 500~600℃, heating rate 5℃ / min, holding time 4h; If the two-dimensional material is V2C: calcination temperature 600~700℃, heating rate 8℃ / min, holding time 3h; If the two-dimensional material is Mo2C: calcination temperature 700~800℃, heating rate 10℃ / min, holding time 2h.

[0046] In this embodiment, the reducing mixed atmosphere includes H2 and Ar, and the preparation method and gas purity requirements of the mixed atmosphere are as follows: The purity of H2 gas is ≥99.999%, and the purity of Ar gas is ≥99.999%. The gas is prepared by volume ratio using a gas mixer. After mixing, the gas must be passed through a gas filter to remove impurities, ensuring that the O2 content in the mixed atmosphere is ≤1 ppm and the H2O content is ≤1 ppm.

[0047] In this embodiment, the thickness of the two-dimensional material sheet is 5~10 nm.

[0048] In this embodiment, a Li-CO2 battery catalytic cathode has a cathode slurry coating thickness of 50~100 μm.

[0049] In this embodiment, a Li-CO2 battery includes a metallic Li anode, a separator, a catalytic cathode based on rare earth elements and two-dimensional materials, and an electrolyte. The metallic Li anode is a Li sheet with a thickness of 0.2~0.3 mm and a purity of ≥99.99%. The diaphragm is selected from glass fiber diaphragm or polypropylene / polyethylene composite diaphragm; The electrolyte is a LiTFSI / organic solvent system, wherein the concentration of LiTFSI is 0.5~1.5 mol / L, and the organic solvent is selected from diethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, or dimethyl carbonate.

[0050] The present invention is further illustrated by the following embodiments: Example 1 Step S1: Dispersion Adsorption Accurately weigh 1.00 g of Gd(CH3COO)3·4H2O (purity 99.9%) and 1.00 g of Ti3C2 (layer thickness 7 nm), add 200 mL of deionized water prepared by an ultrapure water system to form a mixture with a solid-liquid ratio of 1:200 g / mL; place the mixture in an ultrasonic machine, and maintain the temperature at 22±0.5℃ through a circulating water bath system for ultrasonic treatment for 30 min; transfer the ultrasonicated mixture to a 50 mL stirred reactor, and stir continuously for 14 h under constant temperature water bath at 22℃ and rotation speed of 500 rpm.

[0051] Step S2: Flocculation into gel Polyvinyl alcohol solution was added dropwise to the dispersion at a rate of 2 drops / s using a micro-injection pump, with a total addition amount of 0.2 wt% of the dispersion mass. During the dropwise addition, the mixture was stirred synchronously at 500 rpm for 2 min using a mechanical stirrer to ensure uniform dispersion of the flocculant. The mixture was then transferred to a constant temperature shaking incubator at 20℃ and shaken for 40 min to obtain the hydrogel precursor.

[0052] Step S3: Freeze-drying The hydrogel precursor was evenly spread on a stainless steel tray with a thickness of 10.0 mm. The freeze dryer was started, and the cold trap temperature was first programmed to drop to -50°C and maintained for 2 h. The vacuum pump was turned on to stabilize the vacuum degree of the drying chamber at 7 Pa. The cold trap temperature was maintained at -50°C for 48 h to obtain the aerogel precursor.

[0053] Step S4: Reduction calcination 3.00 g of aerogel precursor was weighed and evenly spread on a quartz boat, which was then placed in the isothermal zone of a tube furnace. A H2 / Ar mixed gas (H2 volume fraction of 5%) was introduced at a flow rate of 50 mL / min, and the air inside the furnace was replaced four times. After each replacement, the pressure inside the furnace was maintained at 0.1 MPa. The furnace temperature was raised to 500℃ at a heating rate of 5℃ / min and held for 4 h to obtain the rare earth Gd-Ti3C2 catalytic cathode material.

[0054] Step S5: Preparation of positive electrode sheet The catalytic cathode material, Ketjen black, and PVDF were mixed in a mass ratio of 8:1:1. N-methylpyrrolidone was added to adjust the solid content to 35 wt%. The mixture was stirred at 2500 rpm and 23°C for 3.5 h. The slurry was coated onto a stainless steel mesh current collector using an automatic coating machine at a speed of 8 mm / s. After drying in a vacuum drying oven for 15 h, the cathode sheet was formed by pressing and holding the sheet under 15 MPa pressure using a flatbed press.

[0055] A lithium metal anode, a glass fiber diaphragm, and a positive electrode were placed sequentially in the box. 65 μL of LiTFSI electrolyte was injected using a pipette, and the batteries were packaged into CR2032 type batteries under 8 MPa pressure using a button cell sealing machine.

[0056] The battery was placed in a high-pressure atmosphere chamber and activated at 1 atm for 20 h; it was then tested in a 25℃ constant temperature chamber with a current density of 100 mA / g and a voltage window of 2.0~4.5 V.

[0057] The initial discharge specific capacity is 9500 mAh / g, the charging platform voltage is 3.89 V, the capacity retention rate after 100 cycles is 84%, and the average coulombic efficiency is 91%.

[0058] Example 2 Everything else is the same as in Example 1, except that: Weigh out 5.0 g of Gd(CH3COO)3·4H2O and 1.00 g of Ti3C2; The initial discharge specific capacity is 10200 mAh / g, the charging platform voltage is 3.82 V, the capacity retention rate is 85% after 100 cycles, and the coulombic efficiency is 92%.

[0059] Example 3 Everything else is the same as in Example 1, except that: Weigh out 5.0 g of GdCl3·6H2O and 1.00 g of V2C; The initial discharge capacity is 10100 mAh / g, the charging platform is 3.84 V, the capacity retention rate is 86% after 100 cycles, and the coulombic efficiency is 93%.

[0060] Example 4 Everything else is the same as in Example 1, except that: Weigh out 10.0 g of GdCl3·6H2O and 1.00 g of V2C; The initial discharge specific capacity is 10500 mAh / g, the charging platform is 3.85 V, the capacity retention rate is 83% after 100 cycles, and the coulombic efficiency is 90%.

[0061] Comparative Example 1 Everything else is the same as in Example 1, except that: No rare earth elements were added; only Ti3C2 was used as the active material for the catalytic cathode.

[0062] The initial discharge specific capacity is 3300 mAh / g, the charging platform is 4.20 V, the capacity retention rate is 40% after 100 cycles, and the coulombic efficiency is 70%.

[0063] Detailed implementation methods and principles: The core principle of this invention lies in constructing a novel catalytic cathode material with a triple synergistic effect of "active center-conductive support-macrostructure". Its mechanism of action originates from the intrinsic properties of the material: rare earth Gd, with its unique 4f electron shell structure containing unpaired electrons, exhibits noble metal-like catalytic properties, efficiently activating inert CO2 molecules during discharge and catalyzing their reduction and reaction with Li. + It combines to form Li₂CO₃; during charging, it can effectively reduce the energy barrier for Li₂CO₃ decomposition, thereby significantly reducing the overpotential of the entire reaction and achieving efficient reversible cycling. However, isolated Gd nanoparticles are prone to aggregation and deactivation, thus requiring a stable support. Two-dimensional material M n+1 X n T x As an ideal carrier, its abundant surface functional groups can provide Gd with strong anchoring points through electrostatic interactions and coordination bonds, preventing it from detaching or migrating during cycling; meanwhile, the two-dimensional material M n+1 X n T x The high conductivity of Li, being a metalloid, ensures rapid electron transport within the electrode, and its unique layered structure also provides Li with... + The diffusion of Gd provides a rapid pathway. More importantly, Gd interacts with the two-dimensional material M... n+1X n T x The interaction between them is not a simple physical load, but rather involves strong electronic interactions in the two-dimensional material M. n+1 X n T x The functional groups on the surface can modulate the electron density of neighboring Gd atoms, placing them in a more electron-rich state, thereby further optimizing their adsorption / desorption energy for reaction intermediates and enhancing intrinsic catalytic activity; conversely, the introduction of Gd nanoparticles also effectively expands the two-dimensional material M n+1 X n T x The layered structure suppresses its inherent tendency to recombine. Ultimately, the three-dimensional interconnected porous network structure constructed through the "flocculation-freeze-drying" process maximizes the aforementioned intrinsic advantages on a macroscopic scale: it not only provides a high specific surface area to expose a large number of active sites, but also forms a continuous two-dimensional material M n+1 X n T x The framework forms an electron conduction network, while the channels serve as transport channels and storage reservoirs for ions and CO2 gas, effectively mitigating the volume changes caused by Li2CO3 deposition / decomposition during charging and discharging, thus ensuring the battery's high capacity, long lifespan, and excellent reaction kinetics.

[0064] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the disclosure herein. The invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the following claims.

[0065] It should be understood that the present invention is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A Li-CO2 battery catalytic cathode based on rare earth elements and two-dimensional materials, characterized in that, Includes current collectors and positive electrode paste coated on the surface of current collectors; The positive electrode slurry includes a catalytic positive electrode active material, a conductive agent, and a binder; The mass ratio of the catalytic positive electrode active material, conductive agent, and binder is 8:1:

1.

2. The Li-CO2 battery catalytic cathode based on rare earth elements and two-dimensional materials according to claim 1, characterized in that, The catalytic cathode active material includes a two-dimensional material used as a carrier and rare earth elements loaded on the surface of the two-dimensional material.

3. The Li-CO2 battery catalytic cathode based on rare earth elements and two-dimensional materials according to claim 2, characterized in that, The general formula for the two-dimensional material is M. n+1 X n T x ; Where M is a transition metal, X is any one of C and N elements, n is a positive integer, and T... x It is a surface functional group.

4. The Li-CO2 battery catalytic cathode based on rare earth elements and two-dimensional materials according to claim 2, characterized in that, The mass ratio of the two-dimensional material to rare earth elements in the catalytic positive electrode active material is 1:1 to 10:

1.

5. A method for preparing a Li-CO2 battery catalytic cathode as described in any one of claims 1-4, characterized in that, Includes the following steps: S1, Dispersed Adsorption Salts containing rare earth elements and two-dimensional materials are added to a dispersant to form a mixed system with a solid-liquid ratio of 1:100 g / mL to 1:200 g / mL. After ultrasonic treatment of the mixture, it was transferred to a stirred reactor and stirred continuously to obtain a uniformly distributed rare earth element-two-dimensional material dispersion. S2, flocculation into gel A flocculant is slowly added to the rare earth element-two-dimensional material dispersion obtained in step S1, and after shaking, a hydrogel precursor of rare earth element-two-dimensional material is formed. S3, freeze drying The hydrogel precursor obtained in step S2 is frozen and dried in a vacuum chamber to obtain a rare earth element-two-dimensional material aerogel precursor with a porosity of 85-95%. S4, Reduction Calcination The aerogel precursor obtained in step S3 was introduced into a tube furnace under a reducing mixed atmosphere and reacted under heating conditions to obtain a catalytic positive electrode active material. S5, Positive Electrode Preparation The catalytic positive electrode active material, conductive agent and binder are mixed, and the positive electrode slurry is coated onto the surface of the current collector by a doctor blade coating method. Then, vacuum drying and pressing are performed to obtain the catalytic positive electrode of Li-CO2 battery.

6. The method for preparing a Li-CO2 battery catalytic cathode according to claim 5, characterized in that, The thickness of the two-dimensional material sheet in step S1 is 5~10 nm.

7. The method for preparing a Li-CO2 battery catalytic cathode according to claim 5, characterized in that, The catalytic positive electrode active material in step S4 is a three-dimensional interconnected porous structure made of stacked two-dimensional materials. Rare earth elements are dispersed on the surface of the two-dimensional material through anchoring with surface functional groups.

8. The method for preparing a Li-CO2 battery catalytic cathode according to claim 5, characterized in that, The thickness of the positive electrode slurry coating on the surface of the current collector in step S5 is 50~100 μm.

9. A Li-CO2 battery, characterized in that, It includes a negative electrode, a membrane, a catalytic positive electrode as described in any one of claims 1-8, and an electrolyte.

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