A stacking fault enriched co / coo composite catalytic material and gas cell
By preparing stacked fault-enriched Co/CoO composite catalysts, the engineering challenges of carbonate formation stability and catalyst defects in metal-CO2 batteries were solved, achieving high reversibility and long lifespan of metal-CO2 batteries, which are applicable to various metal-CO2 battery systems.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- PEKING UNIV
- Filing Date
- 2026-04-30
- Publication Date
- 2026-06-02
AI Technical Summary
Existing metal-CO2 batteries suffer from problems such as stable carbonate formation, difficulty in maintaining a reversible oxalate pathway, lack of electronic states and localized strain variation in catalysts, and difficulty in large-scale preparation using defect engineering methods. This leads to difficulties in controlling the reaction pathway and insufficient battery reversibility and cycle stability.
By employing stacking fault-enriched Co/CoO composite catalytic materials, Co atoms are intercalated into the CoO lattice through pyrolysis reduction of waste plastics or gas-phase reduction to form a high-density stacking fault structure, thereby regulating the CO2 reaction pathway, promoting the formation of oxalate intermediates and inhibiting carbonate deposition.
It achieves high reversibility, long cycle life and high energy efficiency of metal-CO2 batteries, and is suitable for Mg-CO2, Al-CO2 and Ca-CO2 batteries. It exhibits low overpotential, high capacity and long cycle life, especially in Mg-CO2 batteries where it can cycle stably for more than 500 hours and maintain stable charge and discharge at high current density.
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Figure CN122136382A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the fields of metal-gas batteries and electrochemical conversion of carbon dioxide, and particularly to a stacking fault-enriched Co / CoO composite catalytic material and its derivatives, as well as a metal-carbon dioxide gas battery constructed from this material. More specifically, it relates to a Co / CoO composite catalytic material that induces the intercalation of metal Co into the CoO lattice through the pyrolysis and reduction of waste plastics to form a high-density stacking fault structure, and its application in metal-CO2 batteries such as Mg-CO2, Al-CO2, and Ca-CO2. Background Technology
[0002] Environmental pollution and energy shortages severely restrict sustainable social development, making efficient energy storage and CO2 resource utilization technologies important research directions in the current new energy field. Metal-gas batteries, especially metal-CO2 batteries, combine high energy density with CO2 conversion and utilization capabilities, showing significant application potential. Multivalent metals such as magnesium, aluminum, and calcium possess advantages such as high volumetric and gravimetric energy density, abundant resources, and low cost, making them potentially valuable for distributed and mobile CO2 management systems.
[0003] However, existing metal-CO2 batteries still have several key problems:
[0004] First, traditional systems tend to form stable carbonates, making it difficult to maintain the reversible oxalate pathway. In metal-CO2 batteries, there is an inherent coupling relationship between CO2 activation and the stability of discharge products, which leads to the reaction preferentially generating thermodynamically stable and difficult-to-decompose carbonate products, thereby causing electrode passivation, capacity decay, and reduced cycle life.
[0005] Second, ideal catalytic surfaces cannot effectively break the coupling between "CO2 activation and product stabilization". Existing catalysts are usually ideal crystal planes or near-uniform coordination structures, lacking sufficient electronic states and local strain variability, making it difficult to simultaneously achieve CO2 activation, intermediate stabilization, and reversible product decomposition. Therefore, although catalysts can promote the discharge reaction to a certain extent, they cannot fundamentally control the reaction pathway.
[0006] Third, existing defect engineering methods typically rely on strategies such as etching, annealing, and reconstruction, which suffer from limitations in defect density, insufficient stability, and difficulty in large-scale fabrication. In particular, non-equilibrium extended lattice defects such as stacking faults, although possessing the potential to control strain fields and local electronic structures, have always been difficult to prepare and utilize stably.
[0007] Therefore, there is an urgent need to develop a novel catalytic material that is simple to prepare, low in cost, scalable, and capable of regulating the electrochemical reaction pathway of CO2 through non-equilibrium structure, so as to improve the reversibility, energy efficiency and cycle stability of metal-CO2 batteries. Summary of the Invention
[0008] To address the aforementioned problems in the existing technology, this invention aims to provide a stacking fault-enriched Co / CoO composite catalytic material, its preparation method, its derived materials, and a metal-CO2 gas battery constructed from this type of material.
[0009] To achieve the above objectives, the present invention adopts the following technical solution:
[0010] In a first aspect of the present invention, a Co / CoO composite catalytic material enriched by stacking faults is provided.
[0011] The Co / CoO composite catalytic material is a composite catalytic material with CoO as the main crystal lattice, metallic Co as the intercalation component, and containing a high-density stacking fault structure. In the catalytic material, metallic Co atoms are inserted into the CoO parent crystal lattice, inducing the formation of non-equilibrium stacking faults and local strain fields, thereby obtaining a maze-like stacking fault structure and non-uniform electron distribution.
[0012] The Co / CoO composite catalytic material enters the CoO lattice through Co intercalation and forms abundant stacking faults, and there are obvious strain fluctuations and electron enrichment in the stacking fault region.
[0013] Preferably, the stacking fault is formed by an additional layer of Co atoms embedded in the stacking sequence of CoO crystal planes.
[0014] Preferably, the Co / CoO composite catalytic material has a labyrinthine stacked fault distribution structure.
[0015] Preferably, in the Co / CoO composite catalytic material, Co is in the form of Co 0 and Co 2+ Mixed valence states exist.
[0016] Preferably, the stacking fault regions of the Co / CoO composite catalytic material have electron enrichment characteristics and exhibit non-uniform charge distribution.
[0017] In a second aspect of the invention, at least two methods for preparing the above-mentioned stacking fault-enriched Co / CoO composite catalytic material are provided.
[0018] The preparation method of the Co / CoO composite catalytic material includes any one or more of the following equivalent methods:
[0019] (1) In-situ reduction method of waste plastic pyrolysis
[0020] A cobalt oxide precursor and waste plastic are subjected to a one-step high-temperature treatment in an inert atmosphere. The waste plastic is pyrolyzed at high temperature to produce CO and / or H2 reducing gases, which drive the cobalt oxide precursor to undergo a reduction reaction and generate a Co / CoO composite structure. During the reduction process, some Co atoms are further intercalated into the CoO lattice, inducing lattice expansion, compressive strain accumulation and stacking fault formation, and finally obtaining a stacking fault-enriched Co / CoO composite catalytic material, which can achieve a large-scale production of no less than 10 g per batch.
[0021] (2) Gas-phase reduction-induced intercalation method
[0022] Cobalt oxide precursors are treated with reducing gas under an inert atmosphere and high temperature to induce partial reduction and form a Co / CoO composite phase. Simultaneously, under high-temperature diffusion, Co atoms insert into the CoO lattice and induce stacking faults, resulting in a stacking fault-enriched Co / CoO composite catalytic material.
[0023] Preferably, the cobalt oxide precursor is Co3O4.
[0024] Preferably, the waste plastic includes, but is not limited to, polyethylene, polypropylene, or other carbon-containing polymers that can be pyrolyzed to generate CO and / or H2.
[0025] Preferably, the inert atmosphere includes, but is not limited to, argon or nitrogen.
[0026] Preferably, the high temperature described in methods (1) and (2) is 400-1000 °C.
[0027] Preferably, no additional pure reducing gas is required during the preparation process of method (1).
[0028] Preferably, the reducing gas in method (2) is CO and / or H2. In some specific embodiments of the present invention, the flow rate of the reducing gas is 2 μL / min to 20 mL / min.
[0029] In a third aspect of the invention, the application of the above-described Co / CoO composite catalytic material in a metal-CO2 gas battery is provided.
[0030] The aforementioned stacked fault-enriched Co / CoO composite catalyst was used as the positive electrode catalyst in metal-CO2 gas batteries, including but not limited to Mg-CO2, Al-CO2, Ca-CO2, Li-CO2, Na-CO2, and K-CO2 batteries. Experiments showed that this Co / CoO composite catalyst achieved an oxalate-dominated reversible reaction pathway and significantly reduced overpotential in all three types of multivalent metal-CO2 batteries (Mg, Al, and Ca).
[0031] Furthermore, when the Co / CoO composite catalytic material is used as a positive electrode catalyst, it can be used in conjunction with metallic magnesium, metallic aluminum, metallic calcium, or other negative electrode materials that can provide corresponding metal ions.
[0032] Preferably, when the metal-CO2 gas battery is a Mg-CO2 battery, the Co / CoO composite catalyst can induce the discharge products to preferentially generate MgC2O4 rather than MgCO3.
[0033] Furthermore, the Co / CoO composite catalytic material can maintain a relatively stable Co chemical state during charge and discharge processes and is not prone to irreversible structural deactivation.
[0034] In a fourth aspect of the present invention, a stacking fault-directed Co / CoO-based catalyst-derived material derived from the above-described Co / CoO composite catalyst material is provided.
[0035] The derived material is a Co / CoO-based catalytic material that retains the stacking fault-induced electronic structure heterogeneity, obtained by further reduction, structural regulation (including phase composition and lattice strain) or electrochemical activation from the stacking fault-enriched Co / CoO composite catalytic material.
[0036] Preferably, the derived materials include, but are not limited to: Co / CoO composite catalytic materials with increased Co content; Co / CoO composite catalytic materials with further improved stacking fault density; surface electron-enriched Co / CoO catalytic materials formed after electrochemical activation; and stacking fault composite catalytic materials composed mainly of Co / CoO and combined with other metal elements or metal oxides.
[0037] Furthermore, the derived materials can still be used to regulate the competition between the oxalate pathway and the carbonate pathway in metal-CO2 batteries.
[0038] In a fifth aspect of the invention, the application of the above-mentioned Co / CoO composite catalytic material or its derivatives in the preparation of positive electrode sheets for metal-CO2 gas batteries is provided.
[0039] The Co / CoO composite catalytic material or its derivatives are used as catalytic active materials. They are mixed with conductive agents and binders to form a slurry, which is then coated onto a gas-permeable conductor substrate to obtain a positive electrode sheet for a metal-CO2 gas battery.
[0040] Preferably, the method for preparing the positive electrode sheet of the battery includes the following steps:
[0041] (1) Mix the Co / CoO composite catalyst or its derivative with a conductive agent at a mass ratio of 0.1 to 100:1;
[0042] (2) The mixed material obtained in step (1) is mixed with an adhesive solution with a concentration of 0.01~15 wt% at a mass ratio of 0.01~100:1, and a solvent is added to prepare a uniform slurry;
[0043] (3) Apply the slurry evenly to the surface of the breathable conductor substrate;
[0044] (4) Dry at 40~180 ℃ to obtain positive electrode sheet.
[0045] Furthermore, the conductive material includes, but is not limited to, carbon black (such as Super P) and conductive carbon nanomaterials.
[0046] Furthermore, the adhesive includes, but is not limited to, polyvinylidene fluoride, polytetrafluoroethylene, carboxymethyl cellulose, and combinations thereof.
[0047] Furthermore, the solvent includes, but is not limited to, N-methylpyrrolidone, water, or other polar solvents.
[0048] Furthermore, the breathable conductor substrate includes, but is not limited to, carbon paper, nickel foam, metal mesh, or porous conductive skeleton.
[0049] In a sixth aspect of the present invention, a metal-CO2 gas battery prepared using the above-mentioned Co / CoO composite catalytic material or its derivatives as the positive electrode catalytic material is provided.
[0050] The metal-CO2 gas battery includes a positive electrode, a negative electrode, an electrolyte, and a CO2 supply system, wherein: the positive electrode contains the stacked fault enriched Co / CoO composite catalytic material or its derivatives; the negative electrode includes, but is not limited to, magnesium, aluminum, calcium, or other conductive negative electrode systems; the electrolyte includes liquid electrolyte, gel electrolyte, or solid electrolyte; and the active gas is CO2.
[0051] Preferably, the metal-CO2 gas battery is a rechargeable secondary metal-CO2 battery.
[0052] Preferably, the metal-CO2 gas battery mainly forms oxalate discharge products during discharge, and the oxalate products can be reversibly decomposed during charging.
[0053] Preferably, the metal-CO2 gas battery exhibits a stable cycling capability of over 500 h in the Mg-CO2 system and at 2000 mA g -1 The following shows a performance exceeding 100,000 mAh g -1 It has a high deep discharge capacity and still exhibits relatively low polarization at high current densities.
[0054] The beneficial technical effects of this invention include:
[0055] 1. This invention utilizes an in-situ reduction strategy based on the pyrolysis of waste plastics to intercalate Co atoms into the CoO lattice, constructing a high-density stacked fault-enriched Co / CoO composite catalytic material. This method is simple, uses inexpensive raw materials, and can be scaled up organically, making it suitable for large-scale preparation.
[0056] 2. The Co / CoO composite catalytic material described in this invention can achieve directional regulation of the CO2 reaction pathway through stacking fault-induced local strain and electronic structure reconstruction, promote the formation of oxalate intermediates and inhibit carbonate deposition, thereby fundamentally improving the reversibility of metal-CO2 batteries.
[0057] 3. In the Co / CoO composite catalytic material of the present invention, the binding between the oxalate product and the catalyst surface is weaker, which is more conducive to desorption during charging; in contrast, the carbonate adsorbs too strongly on conventional c-CoO, which easily leads to irreversible accumulation.
[0058] 4. The Co / CoO composite catalytic material described in this invention can be widely applied to multivalent metal-CO2 battery systems such as Mg-CO2, Al-CO2 and Ca-CO2, exhibiting universal advantages of low overpotential, high capacity and long cycle life.
[0059] 5. The Co / CoO composite catalyst described in this invention can achieve an ultra-long stable cycle of over 500 hours in Mg-CO2 batteries, and can reach speeds up to 25000 mA g. -1 It maintains a stable charge and discharge platform under high current density, demonstrating excellent rate performance and structural stability.
[0060] 6. Due to the presence of stacking fault interfaces and electron-rich regions, the Co / CoO composite catalytic material of the present invention can form an open, non-dense oxalate product morphology, reduce ion and electron transport resistance, avoid electrode passivation, and improve battery life. Attached Figure Description
[0061] Figure 1 The image shows a spherical aberration electron microscope image of the Co / CoO composite catalyst material prepared in Example 1.
[0062] Figure 2 The image shows the X-ray photoelectron spectrum of the Co / CoO composite catalytic material prepared in Example 1.
[0063] Figure 3 The graph shows the first charge-discharge performance of the Mg-CO2 battery based on the Co / CoO composite catalyst material in Example 2.
[0064] Figure 4 This is a long-cycle stability diagram of the Mg-CO2 battery based on the Co / CoO composite catalyst material in Example 2.
[0065] Figure 5 The image shows the X-ray diffraction (XRD) pattern of the discharge products of the Mg-CO2 battery based on the Co / CoO composite catalyst material in Example 2.
[0066] Figure 6 The image shows the X-ray diffraction (XRD) pattern of the Mg-CO2 battery based on the Co / CoO composite catalyst material in Example 2 after charging.
[0067] Figure 7 The first charge-discharge performance of the Mg-CO2 battery based on the CoO catalyst in Comparative Example 1 is shown in the figure.
[0068] Figure 8 The image shows the X-ray diffraction (XRD) pattern of the discharge products of the Mg-CO2 battery based on the CoO catalyst in Comparative Example 1.
[0069] Figure 9 The X-ray diffraction (XRD) pattern of the Mg-CO2 battery based on the CoO catalyst in Comparative Example 1 after charging.
[0070] Figure 10 The image shows a spherical aberration electron microscope image of the Co / CoO composite catalyst material prepared in Example 4.
[0071] Figure 11 The graph shows the first charge-discharge performance of the Mg-CO2 battery based on the Co / CoO composite catalyst material in Example 5.
[0072] Figure 12 The image shows the X-ray diffraction (XRD) pattern of the discharge products of the Mg-CO2 battery based on the Co / CoO composite catalyst material in Example 5.
[0073] Figure 13 The image shows the X-ray diffraction (XRD) pattern of the Mg-CO2 battery based on the Co / CoO composite catalyst material in Example 5 after charging.
[0074] Figure 14 This is a spherical aberration electron microscope image of the Co / CoO composite catalyst material prepared in Example 7. Detailed Implementation
[0075] The technical solutions and effects of the present invention will be further described below with reference to the accompanying drawings and through embodiments, but the present invention is not limited to the following embodiments.
[0076] Example 1: Preparation of Co / CoO composite catalytic material enriched by stacking faults
[0077] Using Co3O4 as a precursor and waste plastic (Mengniu milk bags) as a reducing source at a mass ratio of 1:1, 5 g of each were weighed, stirred evenly, and placed in a crucible. A one-step high-temperature treatment (600 ℃) was carried out under a nitrogen atmosphere (gas flow rate of 0.5 mL / min) for 8 hours. The waste plastic pyrolyzed at high temperature to generate CO and H2 gases, which in-situ reduced Co3O4 to form a Co / CoO composite phase. As the reduction proceeded, some Co atoms intercalated into the CoO lattice, inducing the formation of a high-density stacking fault structure. After the temperature cooled to room temperature, a labyrinthine stacking fault-enriched Co / CoO composite catalytic material was collected. Figure 1 and Figure 2 ).
[0078] Example 2: Application of Co / CoO composite catalyst in Mg-CO2 battery
[0079] (1) Prepare a mixed material by mixing 5 mg of the Co / CoO composite catalyst material prepared in Example 1 and 5 mg of conductive carbon black Super P; mix 10 mg of the above mixed material with 50 mg of polyvinylidene fluoride solution with a concentration of 5 wt% (the solvent of polyvinylidene fluoride solution is N-methylpyrrolidone), continue to add N-methylpyrrolidone solvent until the catalyst slurry is of suitable consistency, and then grind it thoroughly in an agate mortar until uniform; coat it evenly on a pre-cut circular nickel foam substrate with a thickness of 3 mm and a diameter of 12 mm, and vacuum dry it at 100°C for 12 h to obtain the positive electrode material.
[0080] The Co / CoO composite catalyst material and conductive carbon black Super P are loaded on sheet-like nickel foam to form a porous conductive network structure with a pore size of 0.23 mm. The open area of the overall electrode accounts for 98% of the total area.
[0081] The loading of the Co / CoO composite catalyst was approximately 0.2 mg / cm³. 2 .
[0082] (2) Assemble the batteries in a glove box filled with argon atmosphere, using CR2032 button cell batteries with one side opening, a hole diameter of 2 mm, and a hole density of 5-8 holes / cm. 2 The negative electrode is a magnesium sheet, the positive electrode is the positive electrode material prepared in step (1), the electrolyte is 0.5 M bis(trifluoromethanesulfonyl)imide magnesium dissolved in a mixed solution of EMIMBF4 and triethylene glycol dimethyl ether (volume ratio 1:9), and the separator is a glass fiber separator.
[0083] The positive electrode material is placed on one side of the opening in the battery casing, and the magnesium sheet is placed on the other side of the battery casing. The components are assembled in the same order as a normal button cell battery. The button cell battery sealing machine presses the components together to complete the battery assembly.
[0084] (3) Place the assembled battery in a 1000 mL homemade sealed container, fill it with carbon dioxide, and seal it. Add 40 μL of deionized water to the sealed container. Perform a discharge-charge test at a current density of 100 mA / g and a cutoff specific capacity of 500 mAh / g. The results of the first charge-discharge cycle are as follows: Figure 3 As shown in the figure, the Mg-CO2 battery exhibits a relatively small overpotential during the first cycle, indicating that the Co / CoO composite catalyst material is beneficial for reducing the overvoltage during charge and discharge, thereby improving the battery's conversion efficiency. Furthermore, it can maintain stable cycling for over 500 hours. Figure 4 The XRD pattern of the discharge products indicates that MgC2O4 was formed during the discharge process. Figure 5 During charging, MgC2O4 decomposes ( Figure 6 This demonstrates that the MgC2O4 generated during battery discharge has high reversibility.
[0085] Comparative Example 1: Application of CoO materials in Mg-CO2 batteries
[0086] The results were essentially the same as in Example 2, except that the Co / CoO composite catalyst was replaced with a commercially available CoO material at the positive electrode. A discharge-charge test was conducted at a current density of 100 mA / g and a cutoff specific capacity of 500 mAh / g. The results of the first charge-discharge cycle are as follows: Figure 7 As shown in the figure, the first-cycle overpotential of the magnesium-carbon dioxide battery is relatively large, indicating that the commercial CoO material has poor catalytic performance and the battery has low conversion efficiency. XRD analysis of the discharge products shows that MgCO3 is formed during the discharge process. Figure 8 MgCO3 remains after charging. Figure 9 This demonstrates that the MgCO3 generated during battery discharge has poor reversibility.
[0087] Example 3: Application of Co / CoO composite catalyst in Al-CO2 battery
[0088] The experiment was essentially the same as in Example 2, except that the negative electrode was made of metallic aluminum, and the electrolyte was a 0.5 M solution of aluminum bis(trifluoromethanesulfonyl)imide dissolved in a mixture of EMIMBF4 and triethylene glycol dimethyl ether (volume ratio 1:9), which was then assembled into an Al-CO2 battery. Charge-discharge cycle performance was tested under a current density of 100 mA / g and a cutoff specific capacity of 500 mAh / g. The results showed a low overpotential. XRD indicated that Al2(C2O4)3 was formed during discharge, and decomposed after charging, demonstrating high reversibility of the system.
[0089] Example 4: Preparation of Co / CoO composite catalytic material enriched by stacking faults
[0090] Similar to Example 1, except that discarded Mengniu milk bags were replaced with plastic garbage bags. The waste plastic was pyrolyzed at high temperature to generate CO and H2 gases, which in-situ reduced Co3O4 to form a Co / CoO composite phase. As the reduction proceeded, some Co atoms intercalated into the CoO lattice, inducing the formation of a high-density stacking fault structure. After the temperature dropped to room temperature, a labyrinthine stacking fault-enriched Co / CoO composite catalytic material was collected. Figure 10 ).
[0091] Example 5: Application of Co / CoO composite catalyst in Mg-CO2 battery
[0092] The results were essentially the same as in Example 2, except that the Co / CoO composite catalyst material prepared in Example 1 was replaced with the Co / CoO composite catalyst material prepared in Example 4 at the positive electrode. A discharge-charge test was conducted at a current density of 100 mA / g and a cutoff specific capacity of 500 mAh / g. The results of the first charge-discharge cycle are as follows: Figure 11 As shown in the figure, the first-cycle overpotential of the Mg-CO2 battery is relatively small, indicating that the Co / CoO composite catalyst prepared in Example 4 has good catalytic performance and the battery has high conversion efficiency. XRD analysis of the discharge products shows that MgC2O4 (…) is formed during the discharge process. Figure 12 MgC2O4 decomposes after charging ( Figure 13 This demonstrates that the MgC2O4 generated during battery discharge has good reversibility.
[0093] Example 6: Application of Co / CoO composite catalyst in Al-CO2 battery
[0094] The experiment was essentially the same as in Example 3, except that the Co / CoO composite catalyst material prepared in Example 1 was replaced with the Co / CoO composite catalyst material prepared in Example 4 at the positive electrode. Charge-discharge cycle performance was tested under a current density of 100 mA / g and a cutoff specific capacity of 500 mAh / g. The results showed a low overpotential, demonstrating high reversibility of the system.
[0095] Example 7: Preparation of Co / CoO composite catalytic material enriched by stacking faults
[0096] The process is essentially the same as in Example 1, except that the holding temperature is 800 °C. Waste plastic is pyrolyzed at high temperature to generate CO and H2 gases, and Co3O4 is reduced in situ to form a Co / CoO composite phase. As the reduction proceeds, some Co atoms intercalate into the CoO lattice, inducing the formation of a high-density stacking fault structure, ultimately yielding a labyrinthine stacking fault-enriched Co / CoO composite catalytic material. Figure 14 ).
[0097] Example 8: Application of Co / CoO composite catalyst in Mg-CO2 battery
[0098] The experiment was essentially the same as in Example 2, except that the Co / CoO composite catalyst material prepared in Example 1 was replaced with the Co / CoO composite catalyst material prepared in Example 7 at the positive electrode. A discharge-charge test was conducted at a current density of 100 mA / g and a cutoff specific capacity of 500 mAh / g. The results of the first charge-discharge cycle showed a small overpotential in the magnesium-carbon dioxide battery, indicating that the Co / CoO composite catalyst material prepared in Example 4 had good catalytic performance and the battery had high conversion efficiency. XRD analysis of the discharge products showed that MgC2O4 was formed during discharge, and decomposed after charging, demonstrating that the MgC2O4 generated during battery discharge has good reversibility.
[0099] Example 9: Application of Co / CoO composite catalyst in Al-CO2 battery
[0100] The experiment was essentially the same as in Example 3, except that the Co / CoO composite catalyst material prepared in Example 1 was replaced with the Co / CoO composite catalyst material prepared in Example 7 at the positive electrode. Charge-discharge cycle performance was tested under a current density of 100 mA / g and a cutoff specific capacity of 500 mAh / g. The results showed a small overpotential, demonstrating that the system has high reversibility.
[0101] Example 10: Application of Co / CoO composite catalyst in Li-CO2 battery
[0102] The process is essentially the same as in Example 8, except that a metallic lithium is used as the negative electrode, and the electrolyte is a 1 M lithium bis(trifluoromethanesulfonyl)imide dissolved in triethylene glycol dimethyl ether solution, assembled into a Li-CO2 battery. Charge-discharge cycle performance tests were conducted at a current density of 100 mA / g and a cutoff specific capacity of 500 mAh / g. The results showed a small overpotential, demonstrating that the system has high reversibility.
Claims
1. A stacking fault-enriched Co / CoO composite catalytic material, characterized in that, The Co / CoO composite catalytic material comprises a CoO lattice and metallic Co atoms intercalated in the CoO lattice. The insertion of metallic Co atoms into the CoO lattice induces the formation of non-equilibrium stacking faults and local strain fields, thereby obtaining a composite catalytic material with a labyrinthine stacking fault structure and a non-uniform electron distribution.
2. The Co / CoO composite catalytic material as described in claim 1, characterized in that, Metallic Co atoms are embedded in the stacking sequence of CoO crystal planes to form the stacking fault structure, and in the Co / CoO composite catalytic material, Co is in the form of Co atoms. 0 and Co 2+ Mixed valence states exist.
3. The method for preparing the Co / CoO composite catalytic material according to claim 1 or 2, characterized in that, The Co / CoO composite catalytic material is obtained using either method a or b below: a. In-situ reduction method of waste plastic pyrolysis: The cobalt oxide precursor and waste plastic are placed in an inert atmosphere for one-step high-temperature treatment. The waste plastic is pyrolyzed at high temperature to produce CO and / or H2 reducing gases, which drive the cobalt oxide precursor to undergo a reduction reaction. Some Co atoms intercalate into the CoO lattice to obtain a stacking fault-enriched Co / CoO composite catalytic material. b. Gas-phase reduction-induced intercalation method: Cobalt oxide precursors are treated with reducing gas under an inert atmosphere and high temperature to cause partial reduction, and Co atoms intercalate into the CoO lattice to obtain stacking fault-enriched Co / CoO composite catalytic materials.
4. The preparation method according to claim 3, characterized in that, The cobalt oxide precursor mentioned in methods a and b is Co3O4, the waste plastic mentioned in method a refers to carbon-containing polymers that can be pyrolyzed to generate CO and / or H2, and the reducing gas mentioned in method b is CO and / or H2.
5. The preparation method according to claim 3, characterized in that, The high temperature described in methods a and b is 400-1000℃.
6. A derivative material of the Co / CoO composite catalytic material according to claim 1 or 2, characterized in that, The derived material is a Co / CoO-based catalytic material that is evolved from the stacking fault-enriched Co / CoO composite catalytic material through further reduction, electrochemical activation, or structural regulation, and still retains the stacking fault-induced electronic structural heterogeneity.
7. The derivative material as described in claim 6, characterized in that, The derived materials include: Co / CoO composite catalytic materials with increased Co content; Co / CoO composite catalytic materials with further improved stacking fault density; Co / CoO catalytic materials with surface electron enrichment formed after electrochemical activation; and stacking fault composite catalytic materials composed mainly of Co / CoO and combined with other metal elements or metal oxides.
8. The application of the Co / CoO composite catalytic material or its derivatives as a positive electrode catalyst in a metal-CO2 gas battery according to claim 1 or 2.
9. The application as described in claim 8, characterized in that, The metal-CO2 gas battery includes Mg-CO2 battery, Al-CO2 battery, Ca-CO2 battery, Li-CO2 battery, Na-CO2 battery or K-CO2 battery.
10. A positive electrode sheet for a metal-CO2 gas battery, characterized in that, The positive electrode comprises the Co / CoO composite catalytic material or its derivatives as described in claim 1 or 2.
11. A metal-CO2 gas battery, characterized in that, The metal-CO2 gas battery comprises the positive electrode sheet as described in claim 10.