Carbon dioxide-mediated lithium-oxygen battery with ultrahigh discharge voltage and preparation method and application thereof
By introducing carbon dioxide and metal phthalocyanine additives into lithium-oxygen batteries, the oxygen reduction pathway is altered, forming new intermediates. This solves the problem of limited discharge voltage in lithium-oxygen batteries, achieving ultra-high discharge voltage and good cycle performance, thus promoting applications in the field of new energy storage.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NANKAI UNIV
- Filing Date
- 2026-03-06
- Publication Date
- 2026-05-19
AI Technical Summary
The discharge voltage of existing lithium-oxygen batteries is limited by the thermodynamic limit of 2.96 V, resulting in a large gap between their energy density and the theoretical energy density. In addition, carbon dioxide in the air will generate lithium carbonate, which will hinder the transport of active materials, leading to increased battery polarization and deterioration of cycle performance.
Introducing carbon dioxide gas into the lithium-oxygen battery system, by adding metal phthalocyanine additives to the electrolyte, alters the oxygen reduction pathway, forming Li2CO4 and Li2C2O6 intermediates, thereby increasing the Gibbs free energy change, and promoting the mass transfer process of oxygen and carbon dioxide by using iron phthalocyanine as a molecular reaction carrier.
The discharge voltage of the lithium-oxygen battery was extended from 2.96 V to 3.3 V, significantly improving the battery's energy density and cycle performance. It can operate stably for over 200 h at a current density of 500 mA·g⁻¹, comparable to that of an ion battery.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of novel battery manufacturing technology, and relates to a carbon dioxide-mediated lithium-oxygen battery with ultra-high discharge voltage, its manufacturing method, and its application. Background Technology
[0002] Modern commercial battery technology has largely developed based on the chemical framework of ion insertion / extraction, and is currently approaching its theoretical energy density limit. Lithium-oxygen batteries utilize oxygen as a reactant, thus eliminating the limitations of the solid framework and achieving energy densities as high as 3500 Wh·kg⁻¹. -1 The theoretical energy density is [not specified]. However, the redox chemical reaction in traditional lithium-oxygen batteries is limited to the formation of lithium peroxide (2Li + O2 → Li2O2). Its fixed Gibbs free energy change determines a theoretical discharge voltage of 2.96 V, but in reality, it is lower than 2.85 V, significantly lower than the discharge voltage of commercial lithium-ion batteries. eScience , 2023, 3(4): 100123). Low operating voltage hinders the effective utilization of the high capacity characteristics of lithium-oxygen batteries, resulting in a large gap between theoretical and actual energy density. In the prior art, the formation path of lithium peroxide can be changed by controlling the discharge path of lithium-oxygen batteries, thereby affecting the discharge voltage ( Nat. Chem. , 2014, 6(12): 1091-1099). However, this strategy is still controlled by the Gibbs free energy change of the discharge reaction, and the discharge voltage cannot exceed the theoretical limit of 2.96 V.
[0003] To improve the electrochemical performance of lithium-oxygen batteries, researchers have attempted to introduce catalysts into the electrolyte. For example, Chinese patent application CN103311602A proposes an electrolyte for lithium-air batteries containing a soluble catalyst, specifically a mononuclear phthalocyanine transition metal compound such as iron phthalocyanine. This approach improves the contact state between the catalyst and the solid discharge product (Li₂O₂) by constructing a solution-phase catalytic system, thereby reducing the charging overpotential to some extent. However, the core of this approach still focuses on catalyzing the formation and decomposition of lithium peroxide, and its discharge product remains lithium peroxide, limiting the discharge voltage to the thermodynamic theoretical value of 2.96V.
[0004] Furthermore, in the actual operation of lithium-air batteries, carbon dioxide in the air reacts with discharge products to form lithium carbonate (Li₂CO₃), or directly participates in electrochemical reactions to form lithium carbonate. Lithium carbonate is non-conductive and insoluble in common electrolytes at room temperature, accumulating on the positive electrode surface and hindering the transport of active materials, leading to increased battery polarization and deteriorated cycle performance. To address this issue, Chinese patent application CN106654465A proposes an electrolyte that promotes carbonate decomposition. This electrolyte uses a binuclear or multinuclear phthalocyanine transition metal coordination compound as a soluble catalyst, aiming to catalyze the decomposition of lithium carbonate during charging to reduce its accumulation in the air electrode, thereby improving battery cycle performance. This approach treats lithium carbonate as a harmful byproduct, and its technical approach is to promote its decomposition and removal during charging through a catalyst, without fundamentally altering the discharge reaction pathway.
[0005] To address the aforementioned issues, there is an urgent need to develop a novel metal-gas battery system that can significantly improve the output voltage during the discharge process while ensuring the high capacity of the gas battery, thereby promoting the practical application of ultra-high energy density battery systems in the field of new energy storage. Summary of the Invention
[0006] To overcome the shortcomings of existing technologies, this invention provides a carbon dioxide-mediated lithium-oxygen battery with ultra-high discharge voltage, its preparation method, and its application. The prepared carbon dioxide-mediated lithium-oxygen battery exhibits excellent discharge voltage and good rate performance, reaching 500 mA·g. -1 It can operate stably for over 200 hours at current density, overcoming the thermodynamic limitation of the theoretical discharge voltage of 2.96 V for traditional lithium-oxygen batteries, and extending its theoretical discharge voltage window to 3.82 V.
[0007] The technical solution of the present invention is as follows:
[0008] The first aspect of the present invention provides a carbon dioxide-mediated lithium-oxygen battery with ultra-high discharge voltage. The battery structure includes a negative electrode, an organic electrolyte, a separator, and a porous positive electrode. The organic electrolyte is composed of lithium salt, organic solvent, and metal phthalocyanine additive. The battery operates in an oxygen / carbon dioxide mixed atmosphere, wherein the oxygen content is 20-60% and the carbon dioxide content is 40-80%.
[0009] Furthermore, the negative electrode material is one of lithium metal, lithium iron phosphate, and lithium titanate.
[0010] Furthermore, in the organic electrolyte, the mass fraction of lithium salt is 22-32 wt%, the mass fraction of organic solvent is 67-77.9 wt%, and the mass fraction of metal phthalocyanine additive is 0.1-1 wt%.
[0011] Furthermore, the lithium salt is at least one of lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, and lithium perchlorate.
[0012] Furthermore, the organic solvent is at least one of dimethyl sulfoxide, tetraethylene glycol dimethyl ether, and diethylene glycol dimethyl ether.
[0013] Furthermore, the metal phthalocyanine additive is at least one selected from iron phthalocyanine, cobalt phthalocyanine, nickel phthalocyanine, copper phthalocyanine, zinc phthalocyanine, and manganese phthalocyanine.
[0014] Furthermore, the substrate of the porous positive electrode is at least one of porous carbon cloth, carbon paper, and nickel foam.
[0015] Furthermore, the method for preparing the porous positive electrode is as follows: carbon nanotubes and sodium carboxymethyl cellulose binder are mixed evenly, and an appropriate amount of deionized water and ethanol are added to disperse them into a slurry. The slurry is then evenly sprayed onto a substrate and dried to obtain a porous positive electrode.
[0016] The second aspect of the present invention provides a method for preparing the carbon dioxide-mediated lithium-oxygen battery, wherein a negative electrode, a separator, an organic electrolyte and a porous positive electrode are sequentially assembled in an argon atmosphere.
[0017] Furthermore, the diaphragm is at least one of glass fiber and Celgard diaphragm.
[0018] A third aspect of the present invention provides an application of the aforementioned carbon dioxide-mediated lithium-oxygen battery in battery energy storage or carbon dioxide conversion and utilization.
[0019] This invention introduces carbon dioxide gas into a lithium-oxygen battery system, extending the discharge process from a single Li-O bond chemistry to a Li-OC bond chemistry, providing a new direction for expanding the redox range of lithium-oxygen batteries. The constructed carbon dioxide-mediated lithium-oxygen battery can output an ultra-high discharge voltage of up to 3.3 V. This is attributed to the fact that the addition of carbon dioxide alters the oxygen reduction pathway, forming key intermediates Li₂CO₄ and Li₂C₂O₆, making lithium carbonate (Li₂CO₃) the final discharge product, significantly increasing the Gibbs free energy change of the discharge reaction, and broadening the thermodynamic voltage limit range. However, due to the slow mass transfer kinetics of oxygen and carbon dioxide in the electrolyte, the carbon dioxide-mediated oxygen reduction pathway reaction is insufficient, and its high-voltage discharge platform cannot be effectively utilized at high rates. By adding metal phthalocyanine additives as molecular reaction carriers to the electrolyte, the mass transfer process of oxygen and carbon dioxide in the electrolyte is effectively improved under the action of metal phthalocyanine additives, and the carbon dioxide-mediated oxygen reduction pathway is promoted. At the same time, with the effective stabilizing effect of the M-N4 structure on the discharge intermediate, the battery can maintain a stable operation with an ultra-high discharge voltage of 3.3 V during cycling.
[0020] Advantages and beneficial effects of the present invention:
[0021] (1) This invention constructs a novel carbon dioxide-mediated lithium-oxygen battery system by introducing carbon dioxide into the lithium-oxygen battery and adding metal phthalocyanine additives to the electrolyte, breaking the discharge voltage limit of lithium-oxygen batteries and solving the practical problem of low discharge voltage in lithium-oxygen batteries. The assembled carbon dioxide-mediated lithium-oxygen coin cell achieves a discharge voltage of 500 mA·g. -1 It can still maintain an ultra-high discharge voltage of 3.3 V after 200 hours of cycling, which is comparable to that of lithium-ion batteries, something that existing lithium-oxygen battery technology cannot achieve.
[0022] (2) Carbon dioxide gas used in this invention is one of the most common greenhouse gases. The battery system constructed with it as a reactant can effectively promote the conversion and utilization of carbon dioxide. Attached Figure Description
[0023] Figure 1 This is a schematic diagram of the battery device structure in Example 1;
[0024] Figure 2 The carbon dioxide-mediated lithium-oxygen battery of Example 1 at 500 mA·g -1 Charge-discharge curves at current density. (Active material is carbon nanotubes, active material loading: 0.3 mg·cm⁻¹) -2 Cut-off capacity: 1000 mAh·g -1 (CO2 content is 50%)
[0025] Figure 3 For Comparative Example 1, a carbon dioxide-mediated lithium-oxygen battery was tested at 500 mA·g. -1 Charge-discharge curves at current density. (Active material is carbon nanotubes, active material loading: 0.3 mg·cm⁻¹) -2 Cut-off capacity: 1000 mAh·g -1 (CO2 content 30%)
[0026] Figure 4 For Comparative Example 2, a carbon dioxide-mediated lithium-oxygen battery was tested at 500 mA·g. -1 Charge-discharge curves at current density. (Active material is carbon nanotubes, active material loading: 0.3 mg·cm⁻¹) -2 Cut-off capacity: 1000 mAh·g -1 (CO2 content 90%)
[0027] Figure 5 To compare the carbon dioxide-mediated lithium-oxygen batteries of Comparative Example 1 and Example 1 at 500 mA·g -1Comparison of battery cycle performance at current density. (Active material is carbon nanotubes, active material loading: 0.3 mg·cm³) -2 Capacity cutoff: 1000mAh·g -1 )
[0028] Figure 6 For Comparative Example 3, a carbon dioxide-mediated lithium-oxygen battery was tested at 500 mA·g. -1 Charge-discharge curves at current density. (Active material is carbon nanotubes, active material loading: 0.3 mg·cm⁻¹) -2 Cut-off capacity: 1000 mAh·g -1 (CO2 content is 50%)
[0029] Figure 7 For Comparative Example 4, a carbon dioxide-mediated lithium-oxygen battery was tested at 500 mA·g. -1 Charge-discharge curves at current density. (Active material is carbon nanotubes, active material loading: 0.3 mg·cm⁻¹) -2 Cut-off capacity: 1000 mAh·g -1 (CO2 content is 50%).
[0030] Figure 8 For Comparative Example 6, a carbon dioxide-mediated lithium-oxygen battery was tested at 500 mA·g. -1 Charge-discharge curves at current density. (Active material is carbon nanotubes, active material loading: 0.3 mg·cm⁻¹) -2 Cut-off capacity: 1000 mAh·g -1 (CO2 content is 50%).
[0031] Figure 9 The lithium-oxygen batteries of Example 1 and Comparative Example 7 were tested at 500 mA·g. -1 Discharge curve at current density. (Active material is carbon nanotubes, active material loading: 0.3 mg·cm⁻¹) -2 Cut-off capacity: 1000 mAh·g -1 (In Example 1, the CO2 content was 50%, and in Comparative Example 7, the O2 content was 100%). Detailed Implementation
[0032] The present invention will now be described in detail and completely with reference to the embodiments, but these embodiments are not intended to limit the scope of protection of the present invention.
[0033] Unless otherwise specified, all reagents and materials used in the following examples are commercially available or obtained through conventional synthesis methods in the art.
[0034] Example 1
[0035] A carbon dioxide-mediated lithium-oxygen battery with ultra-high discharge voltage includes: a negative electrode being a lithium metal sheet, and an organic electrolyte consisting of 75 wt% dimethyl sulfoxide, 24.6 wt% lithium bis(trifluoromethanesulfonyl)imide, and 0.4 wt% iron phthalocyanine; and a porous positive electrode being a porous carbon cloth coated with a composite slurry of carbon nanotubes and sodium carboxymethyl cellulose.
[0036] The preparation method of the above-mentioned carbon dioxide-mediated lithium-oxygen battery includes the following steps:
[0037] (1) An organic electrolyte was prepared by mixing 75 wt% dimethyl sulfoxide, 24.6 wt% lithium bis(trifluoromethanesulfonylimide) and 0.4 wt% iron phthalocyanine in an argon-protected glove box.
[0038] (2) Carbon nanotubes and the binder sodium carboxymethyl cellulose were mixed evenly at a mass ratio of 9:1. After adding an appropriate amount of deionized water and ethanol to disperse and prepare a slurry, the slurry was evenly sprayed onto the porous carbon cloth using a spray bottle. After drying in a vacuum environment at 80°C for 24 h, it was cut into round pieces with a diameter of 10 mm to be used as the positive electrode sheet of the battery.
[0039] (3) Assemble the CR2032 coin cell in an argon-protected glove box, following the order of negative electrode shell, lithium metal sheet, glass fiber separator, positive electrode sheet, and perforated positive electrode shell, and match the organic electrolyte from step (1). Subsequent battery tests were conducted in an oxygen / carbon dioxide mixed atmosphere, with a carbon dioxide content of 50%. A schematic diagram of the battery device is shown below. Figure 1 .
[0040] Example 2
[0041] The difference from Example 1 is that the organic electrolyte is composed of 75 wt% dimethyl sulfoxide, 24.6 wt% lithium bis(trifluoromethanesulfonyl)imide, and 0.4 wt% cobalt phthalocyanine, while the other experimental conditions remain unchanged.
[0042] Example 3
[0043] The difference from Example 1 is that the organic electrolyte was prepared by mixing 77.7 wt% dimethyl sulfoxide and 22.3 wt% lithium bis(trifluoromethanesulfonyl)imide, while the other experimental conditions remained unchanged.
[0044] Comparative Example 1
[0045] The difference from Example 1 is that the battery test was conducted in an environment with a carbon dioxide content of 30%, while the other experimental conditions remained unchanged.
[0046] Comparative Example 2
[0047] The difference from Example 1 is that the battery test was conducted in an environment with a carbon dioxide content of 90%, while the other experimental conditions remained unchanged.
[0048] Comparative Example 3
[0049] The difference from Example 1 is that the additive in the organic electrolyte is replaced with ferrous chloride, while the proportion of each component remains unchanged, and the other experimental conditions are kept the same.
[0050] Comparative Example 4
[0051] The difference from Example 1 is that phthalocyanine iron in the organic electrolyte is replaced with phthalocyanine, while the proportions of each component remain unchanged, and the other experimental conditions are kept the same.
[0052] Comparative Example 5
[0053] The difference from Example 1 is that the organic electrolyte is prepared by mixing 77.7 wt% dimethyl sulfoxide and 22.3 wt% lithium bis(trifluoromethanesulfonyl)imide, and the battery test is conducted in a high-purity oxygen atmosphere, while the other experimental conditions remain unchanged.
[0054] Comparative Example 6
[0055] The only difference from Example 1 is that in step (1), the dual-core cobalt phthalocyanine from patent CN106654465A is used as an electrolyte additive, and iron phthalocyanine is not used. The electrolyte composition is dimethyl sulfoxide + lithium bis(trifluoromethanesulfonyl)imide + dual-core cobalt phthalocyanine.
[0056] Comparative Example 7
[0057] The only difference from Example 1 is that the battery test was conducted in a pure oxygen atmosphere.
[0058] Test methods
[0059] At 25°C, using 500 mA·g -1 Current density, 1000 mA·g -1 The cutoff specific capacity was used to test the discharge voltage and cycle performance of the battery; at 100 mA·g -1 The battery's full discharge capacity was tested at a current density of 2.2 V and a cutoff voltage of 2.2 V.
[0060] The electrochemical performance test results of Examples 1-3 and Comparative Examples 1-3 were statistically analyzed, as shown in Table 1.
[0061] Table 1. Electrochemical performance test results of the examples and comparative examples
[0062]
[0063] Analysis based on the data in Table 1:
[0064] (1) Compared with traditional lithium-oxygen batteries, the carbon dioxide-mediated lithium-oxygen battery of the present invention has significantly improved discharge voltage and discharge capacity, which are the highest values in the current field of metal-air batteries. In Example 3 and Comparative Example 5, no phthalocyanine iron was added; only the testing environment differed. Example 3 added 50% carbon dioxide, while Comparative Example 5 used high-purity oxygen. Compared with Comparative Example 5, Example 3, by introducing carbon dioxide, significantly improved both discharge voltage and full discharge capacity. Furthermore, Example 1 ( Figure 2 ) and Comparative Example 1 ( Figure 3 Comparative Example 2 Figure 4 Comparative Example 7 Figure 9 In all cases, ferrophthalocyanine was added to the electrolyte as a soluble additive, with the only change being the carbon dioxide content in the test environment. The results showed that simply adding ferrophthalocyanine under pure oxygen conditions did not increase the discharge voltage; a CO2 atmosphere was required to achieve a discharge voltage of 3.3 V. This highlights the synergistic effect of "CO2-mediated" and "metallic phthalocyanine." Furthermore, battery performance varied significantly under different carbon dioxide contents; only within the range of 40-80% carbon dioxide content did the interaction between ferrophthalocyanine and CO2 molecules reach its optimal effect, significantly widening the thermodynamic voltage window of the discharge reaction. Figure 5 The comparison chart of the cycle performance of the carbon dioxide-mediated lithium-oxygen battery in Comparative Example 1 and Example 1 shows that Example 1 exhibits the highest discharge voltage and full discharge capacity, while being able to cycle stably for more than 50 cycles.
[0065] (2) Compare Examples 1 and 2 with Comparative Examples 3-5, and combine Example 1 ( Figure 2 Comparative Example 3 Figure 6 Comparative Example 4 Figure 7 Comparative Example 6 Figure 8 The charge-discharge curves of the carbon dioxide-mediated lithium-oxygen battery show that, compared with Comparative Example 3 (using ferrous chloride in the organic electrolyte), Comparative Example 4 (using phthalocyanine in the organic electrolyte), and Comparative Example 6 (using dinuclear cobalt phthalocyanine), the carbon dioxide-mediated lithium-oxygen battery of this invention, within the carbon dioxide content range of 40%-80%, can only effectively accelerate the bulk mass transfer of the carbon dioxide-mediated oxygen reduction process and significantly improve the discharge reaction efficiency by using mononuclear iron phthalocyanine as the molecular reaction carrier. This demonstrates that mononuclear iron phthalocyanine has certain characteristics in improving the discharge voltage.
[0066] The foregoing description represents only preferred embodiments of the present invention, and while the description is specific and detailed, it should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the inventive concept, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.
Claims
1. A carbon dioxide-mediated lithium-oxygen battery with ultra-high discharge voltage, characterized in that, The battery includes a negative electrode, an organic electrolyte, a separator, and a porous positive electrode, and operates in an oxygen / carbon dioxide mixed atmosphere. The organic electrolyte is composed of lithium salt, organic solvent, and metal phthalocyanine additive. The oxygen / carbon dioxide mixed atmosphere contains 20-60% oxygen and 40-80% carbon dioxide. The metal phthalocyanine additive is at least one of iron phthalocyanine, cobalt phthalocyanine, nickel phthalocyanine, copper phthalocyanine, zinc phthalocyanine, and manganese phthalocyanine. The addition of carbon dioxide alters the oxygen reduction pathway, forming key intermediates Li2CO4 and Li2C2O6, making lithium carbonate the final discharge product. This increases the Gibbs free energy change of the discharge reaction and broadens the thermodynamic voltage limit range. By adding the metal phthalocyanine additive as a molecular reaction carrier to the electrolyte, the mass transfer process of oxygen and carbon dioxide in the electrolyte is effectively enhanced under the action of the metal phthalocyanine additive.
2. The carbon dioxide-mediated lithium-oxygen battery with ultra-high discharge voltage according to claim 1, characterized in that, The negative electrode material is one of lithium metal, lithium iron phosphate, and lithium titanate.
3. The carbon dioxide-mediated lithium-oxygen battery with ultra-high discharge voltage according to claim 1, characterized in that, The organic electrolyte contains 22-32 wt% lithium salt, 67-77.9 wt% organic solvent, and 0.1-1 wt% metal phthalocyanine additive.
4. The carbon dioxide-mediated lithium-oxygen battery with ultra-high discharge voltage according to claim 3, characterized in that, The lithium salt is at least one of lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, and lithium perchlorate.
5. The carbon dioxide-mediated lithium-oxygen battery with ultra-high discharge voltage according to claim 3, characterized in that, The organic solvent is at least one of dimethyl sulfoxide, tetraethylene glycol dimethyl ether, and diethylene glycol dimethyl ether.
6. The carbon dioxide-mediated lithium-oxygen battery with ultra-high discharge voltage according to claim 1, characterized in that, The substrate of the porous positive electrode is at least one of porous carbon cloth, carbon paper, and nickel foam.
7. The carbon dioxide-mediated lithium-oxygen battery with ultra-high discharge voltage according to claim 6, characterized in that, The porous positive electrode is prepared by mixing carbon nanotubes with sodium carboxymethyl cellulose binder, adding an appropriate amount of deionized water and ethanol to disperse and prepare a slurry, then uniformly spraying the slurry onto a substrate and drying it to obtain a porous positive electrode.
8. A method for preparing a carbon dioxide-mediated lithium-oxygen battery with ultra-high discharge voltage as described in any one of claims 1-7, characterized in that, The negative electrode, separator, organic electrolyte, and porous positive electrode are assembled sequentially in an argon atmosphere.
9. The application of a carbon dioxide-mediated lithium-oxygen battery with ultra-high discharge voltage as described in any one of claims 1-7 in battery energy storage or carbon dioxide conversion and utilization.