Self-oxygen-supplying electrolyte and catalytic positive electrode for closed lithium-oxygen battery
Patent Information
- Application Number
- CN202610983629.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-03
- Publication Date
- 2026-09-22
AI Technical Summary
[0005]有鉴于此，本发明为解决现有封闭式锂氧气电池依赖外部氧气源（如高压气瓶或固态储氧材料）导致的系统复杂、安全隐患、体积重量大、释氧不可控等技术问题，提出一种自供氧电解液及催化正极用于封闭式锂氧气电池
[0022]内部供氧，环境适应性强：无需依赖外部环境氧气或笨重的外部储氧装置，可在完全封闭或氧气受限环境中稳定工作，极大拓展了锂氧气电池的应用场景（如深海设备、航天器、密封便携设备）。
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Figure CN122800747A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of lithium-oxygen battery technology, specifically relating to a self-oxygen-supplying electrolyte and a catalytic cathode for use in a closed lithium-oxygen battery. Background Technology
[0002] Lithium-oxygen (Li-O2) batteries are considered a promising next-generation energy storage system due to their extremely high theoretical energy density (~3500 Wh / kg). The working principle of traditional lithium-oxygen batteries relies on the reversible oxygen reduction (ORR) and oxygen evolution (OER) reactions of oxygen in the air at the positive electrode. However, this open structure leads to significant defects in the battery: (1) Environmental dependence: The battery performance is heavily dependent on the ambient oxygen concentration and cannot work properly in enclosed spaces (such as submarines, spacecraft, sealed equipment) or low-oxygen environments. (2) Moisture and impurity intrusion: The open design makes it easy for impurities such as moisture and carbon dioxide in the environment to intrude into the battery system, causing side reactions with the lithium anode or electrolyte and accelerating battery failure.
[0003] To address the oxygen supply problem in enclosed environments, current technologies primarily focus on carrying high-pressure oxygen cylinders or solid oxygen storage materials. However, high-pressure oxygen cylinders present safety hazards, are bulky, and heavy; solid oxygen storage materials often have slow release rates, poor cycle stability, and high costs, and the oxygen release process may be accompanied by heat release or byproduct generation, affecting battery performance and safety.
[0004] Therefore, developing a compact, safe, and reliable solution that can continuously provide a stable internal oxygen source for closed lithium-oxygen batteries is of great significance for promoting the application of lithium-oxygen batteries in special environments. Summary of the Invention
[0005] In view of this, to address the technical problems of existing closed-loop lithium-oxygen batteries that rely on external oxygen sources (such as high-pressure gas cylinders or solid oxygen storage materials), including system complexity, safety hazards, large size and weight, and uncontrollable oxygen release, this invention proposes a self-supplying electrolyte and catalytic cathode for closed-loop lithium-oxygen batteries. This technical solution introduces controllably decomposable oxygen-containing compounds as sacrificial agents into the electrolyte and loads a highly efficient catalyst on the cathode surface. This allows the electrolyte sacrificial agent to decompose in situ and on demand within the battery to generate oxygen, which is then directly supplied to the cathode for electrochemical reactions. This invention offers advantages such as stable and controllable oxygen supply, simple and compact system structure, high safety, and low cost, significantly improving the practicality of closed-loop lithium-oxygen batteries.
[0006] This invention provides a self-oxygenating electrolyte for a closed lithium-oxygen battery, comprising a lithium salt, a solvent, and a sacrificial agent:
[0007] The lithium salt concentration is from 0.5 mol / L to 2 mol / L, and is selected from one of lithium oxalate borate (LiBOB), lithium hexafluorophosphate (LiPF6), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium perchlorate (LiClO4), and lithium tetrafluoroborate (LiBF4);
[0008] The solvent is selected from one of tetraethylene glycol dimethyl ether (TEGDME), dimethyl sulfoxide (DMSO), dimethylformamide (DMF), ethylene glycol dimethyl ether (DME), acetonitrile (AN), propylene carbonate (PC), ethylene carbonate (EC), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC).
[0009] The sacrificial agent is 5 wt% to 30 wt% of the solvent mass and is selected from at least one of organic peroxides or inorganic peroxides;
[0010] Preferably, the organic peroxide is selected from one of tert-butyl hydroperoxide (TBHP), cumene hydroperoxide (CHP), and 1,1,3,3-tetramethylbutyl hydroperoxide;
[0011] The inorganic peroxide is selected from hydrogen peroxide (H2O2) and urea peroxide.
[0012] This invention provides a catalytic cathode for a closed lithium-oxygen battery, comprising a cathode current collector, a conductive agent, a binder, and a catalyst:
[0013] The positive current collector is selected from one of carbon paper, carbon cloth, nickel foam, stainless steel mesh, and aluminum foil;
[0014] The conductive agent is selected from one of carbon black (Super P, acetylene black), graphene, and carbon nanotubes.
[0015] The adhesive is selected from one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), sodium carboxymethyl cellulose (CMC), and styrene-butadiene rubber (SBR);
[0016] The catalyst is used to catalyze the decomposition of the sacrificial agent in the electrolyte to produce oxygen, and is selected from one of manganese dioxide (MnO2), cobalt oxide (Co3O4), nickel oxide (NiO), copper oxide (CuO), and iron oxide (Fe2O3), preferably manganese dioxide (MnO2).
[0017] Preferably, in the catalyst layer of the catalytic positive electrode, the catalyst loading is 5 wt% to 50 wt% of the total mass of the catalyst layer, the conductive agent loading is 20 wt% to 70 wt% of the total mass of the catalyst layer, and the binder loading is 5 wt% to 20 wt% of the total mass of the catalyst layer.
[0018] Preferably, the catalytic cathode is prepared by the following method: a conductive agent, a catalyst, and a binder are mixed in a predetermined ratio, an appropriate amount of solvent (N-methylpyrrolidone NMP) is added to form a uniform slurry, which is then coated onto the cathode current collector and dried and compacted to obtain the cathode.
[0019] The present invention also provides a closed lithium-oxygen battery, comprising: a self-oxygen-supplying electrolyte as described above; a catalytic positive electrode as described above; a lithium metal negative electrode or a lithium-containing negative electrode; a separator; and a closed battery casing.
[0020] The working principle of this invention is as follows: In a closed lithium-oxygen battery, the sacrificial agent in the electrolyte (such as TBHP or H2O2) undergoes a catalytic decomposition reaction under the action of the positive electrode catalyst (such as MnO2) (e.g., 2TBHP → 2TBOH + O2↑ or 2H2O2 → 2H2O + O2↑), continuously generating oxygen. The generated oxygen directly participates in electrochemical reactions near the positive electrode catalyst layer: during discharge, an oxygen reduction reaction occurs (O2 + 2Li). + + 2e - → Li2O2), during charging, an oxygen evolution reaction occurs (Li2O2 → O2 + 2Li). + + 2e - The oxygen produced by the decomposition of the sacrificial agent compensates for the oxygen consumed by the battery in the enclosed space, maintains the dynamic balance of oxygen inside the battery, and ensures the continuous operation of the battery in an environment without external oxygen supply.
[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0022] Internal oxygen supply and strong environmental adaptability: It does not rely on external oxygen or bulky external oxygen storage devices, and can work stably in completely closed or oxygen-limited environments, which greatly expands the application scenarios of lithium oxygen batteries (such as deep-sea equipment, spacecraft, and sealed portable devices).
[0023] Stable and controllable oxygen supply: By adjusting the concentration of sacrificial agent, the type of catalyst and the loading, the oxygen production rate and total amount can be precisely controlled to meet the needs of different working conditions.
[0024] System simplification and enhanced safety: The complex air management system and high-pressure oxygen cylinder are eliminated, simplifying the battery structure and reducing potential safety risks (such as oxygen leakage and high pressure risks).
[0025] Cost-effectiveness: The sacrificial agents (such as TBHP, H2O2) and catalysts (such as MnO2) used are relatively inexpensive and readily available, which helps to reduce the overall battery cost.
[0026] In-situ oxygen supply, high efficiency: Oxygen is generated in situ near the reaction site (positive electrode), which reduces the oxygen transport path and concentration gradient, which is beneficial to improving reaction efficiency and battery performance.
[0027] Good compatibility: The self-oxygenated electrolyte and catalytic cathode structure are compatible with existing lithium-oxygen battery manufacturing processes, making industrialization easy. Attached Figure Description
[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some specific embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0029] Figure 1 These are optical microscope images of the catalytic cathodes obtained in Example 1 and Comparative Example 1 of this invention after 200 μL of self-oxygenated electrolyte was added to their surfaces.
[0030] Figure 2 The DEMS curve of oxygen generated by the self-oxygenated electrolyte in Example 1 of this invention;
[0031] Figure 3 The LSV curves of the closed / open lithium-oxygen batteries assembled in Example 1 and Comparative Example 1 of this invention are shown.
[0032] Figure 4 The first full discharge performance curves of the closed lithium-oxygen batteries assembled in Example 1 and Comparative Example 3 of the present invention at a current density of 100 mA / g are shown.
[0033] Figure 5 The first discharge-charge performance curves of the closed / open lithium-oxygen batteries assembled in Example 1 and Comparative Example 1 of the present invention at a current density of 100 mA / g and a maximum capacity of 500 mAh / g are shown.
[0034] Figure 6 Rate performance tests of the closed / open lithium-oxygen batteries assembled in Example 1 and Comparative Example 1 of the present invention at different current densities;
[0035] Figure 7 The circuit performance curves of the closed / open lithium-oxygen batteries assembled in Example 1 and Comparative Example 1 of this invention are shown at a current density of 500 mA / g and a maximum capacity of 500 mAh / g. Detailed Implementation
[0036] To enable those skilled in the art to better understand the technical solution of the present invention, the self-oxygenated electrolyte, catalytic cathode, and sealed lithium-oxygen battery of the present invention are described in detail below with reference to specific embodiments. In the following embodiments, experimental processes and operating methods not described in detail are all conventional methods known in the art; the materials, reagents, apparatus, and equipment used, unless otherwise specified, can be obtained commercially. All electrolyte preparations and battery assemblies were carried out in an argon-protected glove box (H2O < 0.1 ppm, O2 < 0.1 ppm), and all reagents used were dried.
[0037] Example 1
[0038] This embodiment provides a closed-type lithium-oxygen battery, the preparation steps of which are as follows:
[0039] Catalytic cathode preparation: 80 mg Super P, 100 mg MnO2, and 20 mg PVDF powder were placed in a mortar, thoroughly mixed, and ground evenly. An appropriate amount of NMP was added and ground to form a uniform slurry. The slurry was uniformly coated onto a carbon paper current collector with a thickness of about 300 μm and dried in a vacuum oven at 80 ℃ for 12 h. Subsequently, it was compacted with a 10 MPa pressure roller to obtain a catalytic cathode sheet with a diameter of 13 mm. The MnO2 loading in the catalyst layer was about 50 wt%. MnO2 can be replaced by one of Co3O4, NiO, CuO, or Fe2O3. The catalyst acts as a catalytic sacrificial agent to decompose and generate oxygen.
[0040] Preparation of self-oxygenated electrolyte: Dissolve 1 mol / L LiTFSI in DME solvent, add 5 wt% TBHP (TBHP mass is 5% of DME solvent mass) to the solution, and stir until homogeneous to obtain the self-oxygenated electrolyte. The sacrificial agent mass fraction can be changed to 15 wt% and 30 wt%.
[0041] Battery assembly: In an argon glove box, the negative electrode shell of the 2032 battery, the high-purity lithium foil (cut into 16 mm diameter discs) with a thickness of 500 μm and a purity of ≥99.9%, the Whatman GF / D glass fiber separator, the above-mentioned catalytic positive electrode, and the positive electrode shell of the 2032 battery are stacked and packaged to obtain a closed lithium-oxygen battery.
[0042] Description of the rendering: (e.g.) Figure 1 As shown, the self-oxygenated electrolyte can generate small, medium, and large amounts of electrolyte on the positive electrode surface depending on the concentration of the sacrificial agent. For example... Figure 4 As shown, a closed-cell battery can be normally discharged and charged, and has a lower overpotential.
[0043] Example 2
[0044] The only difference between this embodiment and Example 1 is that the electrolyte solvent is replaced with DMSO, the sacrificial agent is replaced with 5 wt% H2O2 (H2O2 mass is 5% of the DMSO solvent mass), and the MnO2 loading in the catalyst layer is adjusted to 30 wt%. DMSO can be replaced with one or more of TEGDME, DMF, AN, PC, EC, DMC, and EMC. Solvents such as DMSO are mainly used to dissolve lithium salts and sacrificial agents. The sacrificial agent can be replaced with one of CHP, 1,1,3,3-tetramethylbutyl hydroperoxide, tert-butyl hydroperoxide, and urea peroxide. The rest of the operation is exactly the same as in Example 1.
[0045] Rendering description: (Similar to) Figure 1 Similarly, self-oxygenated electrolytes can be decomposed into oxygen under the action of a catalyst, and sacrificial agents can also generate oxygen. The decomposition rate is positively correlated with the amount of catalyst.
[0046] Example 3
[0047] The only difference between this embodiment and Embodiment 1 is that LiTFSI is replaced with LiBOB, and LiBOB can also be replaced with one of LiPF6, LiFSI, LiClO4, or LiBF4. The utility of the lithium salt is only to provide Li + The transmission; the rest of the operation is exactly the same as in Example 1.
[0048] Rendering description: (Similar to) Figure 1 Similarly, the self-oxygenated electrolyte can be decomposed into oxygen under the action of a catalyst.
[0049] Example 4
[0050] The only difference between this embodiment and Example 1 is that the types and mass ratios of the positive electrode current collector, conductive agent, binder, and catalyst in the catalytic positive electrode are changed; the rest of the operations are exactly the same as in Example 1.
[0051] Specifically, the positive electrode current collector is replaced by carbon paper with one of carbon cloth, nickel foam, stainless steel mesh, or aluminum foil; the conductive agent is replaced by Super P with one of acetylene black, graphene, or carbon nanotubes; the binder is replaced by PVDF with one of PTFE, CMC, or SBR; and the catalyst is replaced by MnO2 with one of Co3O4, NiO, CuO, or Fe2O3.
[0052] In this embodiment, the mass ratio of catalyst, conductive agent, and binder in the catalyst layer can be adjusted as follows: 10 wt% catalyst, 70 wt% conductive agent, and 20 wt% binder; 15 wt% catalyst, 65 wt% conductive agent, and 20 wt% binder; and 30 wt% catalyst, 60 wt% conductive agent, and 10 wt% binder. For example, 60 mg of carbon nanotubes, 30 mg of Co3O4, and 10 mg of PTFE are thoroughly mixed, and an appropriate amount of solvent is added to form a uniform slurry. This slurry is then coated onto a nickel foam current collector, and after drying and compaction, a catalytic cathode is obtained.
[0053] Rendering description: (Similar to) Figure 1 Similarly, the self-oxygenating electrolyte can be decomposed into oxygen under the action of a catalyst. Changing the type of conductive agent, binder, and current collector does not affect the oxygen production efficiency.
[0054] Comparative Example 1
[0055] The only difference between this comparative example and Example 1 is that no TBHP sacrificial agent is added to the electrolyte; during battery assembly, a through hole with a diameter of 1 cm is opened on the surface of the 2032 type positive electrode shell, and the rest of the assembly steps are exactly the same as in Example 1.
[0056] Description of the rendering: (e.g.) Figure 1 As shown, unlike electrolytes with added sacrificial agents, no oxygen is generated on the positive electrode surface of electrolytes without added TBHP.
[0057] Comparative Example 2
[0058] The only difference between this comparative example and Example 1 is that no MnO2 catalyst is added to the catalytic cathode; the rest of the assembly conditions and operating steps are the same as in Example 1.
[0059] Rendering description: The effect is similar to Figure 1 Unlike the positive electrode with added MnO2 catalyst, no oxygen is generated on the electrode surface of the electrolyte without added TBHP.
[0060] Comparative Example 3
[0061] This comparative example follows the method of Comparative Example 1 to prepare the electrolyte and assemble the battery. The difference is that the positive electrode shell of the 2032 type does not have through holes on its surface. The other conditions and operating steps are the same as those of Comparative Example 1.
[0062] Description of the rendering: (e.g.) Figure 3 As shown, a closed-cell battery without added sacrificial agent cannot discharge and charge normally.
[0063] Test Example 1:
[0064] 200 μL of the self-oxygenated electrolyte from Example 1 was dropped onto the surface of the catalytic cathodes prepared in Example 1 and Comparative Example 2, and the state changes at the interface between the electrolyte and the cathode were observed using an optical microscope. The test results are shown in Figure 1. No bubbles were generated on the surface of the cathode without catalyst, while bubbles were generated on the surface of the cathode with catalyst, and the number of bubbles increased with the increase of the mass fraction of the sacrificial agent.
[0065] Test Example 2:
[0066] The self-oxygenated electrolyte prepared in Example 1 was tested using electrochemical differential mass spectrometry (DEMS). The test results are as follows: Figure 2 As shown, this proves that the gas produced by the self-oxygenated electrolyte is oxygen.
[0067] Test Example 3:
[0068] The sealed lithium-oxygen batteries of Example 1 and Comparative Example 3 were subjected to their first full discharge test using the Newwell battery testing system, with a current density set at 200 mA / g and a cutoff voltage of 2.2 V. The test results are as follows. Figure 3 As shown, the specific capacity of the battery in Comparative Example 3 is close to 0 mAh / g, while the specific capacity of the battery in Example 1 can reach ~8000 mAh / g, confirming that the self-oxygenated electrolyte can supply the oxygen required for the discharge of the lithium oxygen battery in situ, thus meeting the requirements of the battery's electrochemical reaction.
[0069] Test Example 4:
[0070] The batteries from Example 1 and Comparative Example 1 were subjected to their first discharge-charge test using a battery testing system. The current density was set at 100 mA / g, and the cutoff voltage was 2.2-4.5 V. The test results are as follows: Figure 4 As shown, compared to Comparative Example 1, the battery of Example 1 has a lower overpotential.
[0071] Test Example 5:
[0072] The batteries from Example 1 and Comparative Example 1 were tested using a high-power electrochemical workstation with linear cyclic voltammetry (LSV) at a scan rate of 5 mV / s. -1 The voltage range is 3-2.2 V and 3-4.5 V. Test results are as follows: Figure 5 As shown, compared to Comparative Example 1, the LSV curve of the battery in Example 1 has a higher current density and discharge initiation potential as well as a lower charging initiation potential, indicating that the battery in Example 1 has faster reaction kinetics.
[0073] Test Example 6:
[0074] The batteries from Example 1 and Comparative Example 1 were subjected to rate performance testing using a battery testing system. The current density was set to 50-1000 mA / g, and the cutoff voltage to 2.2-4.5 V. The test results are as follows: Figure 6 As shown, Example 1 has better rate performance compared to Comparative Example 1.
[0075] Test Example 7:
[0076] The batteries from Example 1 and Comparative Example 1 were subjected to constant current discharge-charge tests using a battery testing system, with a current density set at 500 mA / g and a cutoff voltage of 2.2-4.5 V. The test results are as follows: Figure 7 As shown, the battery in Example 1 has a longer cycle life compared to Comparative Example 1.
[0077] Obviously, the above embodiments, comparative examples, and test examples are merely illustrative and not intended to limit the scope of the embodiments. Those skilled in the art can make various variations or modifications based on the above description. For example, these could include: replacing the type of sacrificial agent (e.g., using CHP), optimizing the type of catalyst (e.g., using a Pt / MnO2 composite catalyst), adjusting the electrolyte solvent system, optimizing the catalyst loading and morphology, and improving the design of the closed-cell battery structure. It is neither necessary nor possible to exhaustively list all embodiments here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.
Claims
1. A self-oxygen-supplying electrolyte for a closed-cell lithium-oxygen battery, characterized in that, Including lithium salts, solvents, and sacrificial agents; The concentration of the lithium salt is from 0.5 mol / L to 2 mol / L, and it is selected from lithium dioxaborate, lithium hexafluorophosphate, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium perchlorate, and lithium tetrafluoroborate. The solvent is selected from tetraethylene glycol dimethyl ether, dimethyl sulfoxide, dimethylformamide, ethylene glycol dimethyl ether, acetonitrile, propylene carbonate, ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate; The sacrificial agent is selected from organic peroxides or inorganic peroxides, and its mass is 5 wt% to 30 wt% of the solvent mass.
2. The self-oxygenating electrolyte for a closed-cell lithium-oxygen battery according to claim 1, characterized in that, The organic peroxide is selected from tert-butyl hydroperoxide, cumene hydroperoxide, and 1,1,3,3-tetramethylbutyl hydroperoxide.
3. The self-oxygenating electrolyte for a closed-cell lithium-oxygen battery according to claim 1, characterized in that, The inorganic peroxide is selected from hydrogen peroxide and urea peroxide.
4. A catalytic cathode for a closed-cell lithium-oxygen battery, characterized in that, This includes positive electrode current collectors, conductive agents, binders, and catalysts; The catalyst is used to catalyze the decomposition of the sacrificial agent in the self-oxygenated electrolyte according to any one of claims 1-3 to generate oxygen, and is selected from manganese dioxide, cobalt oxide, nickel oxide, copper oxide, and iron oxide.
5. The catalytic cathode according to claim 4, characterized in that, The positive current collector is selected from carbon paper, carbon cloth, nickel foam, stainless steel mesh, and aluminum foil.
6. The catalytic cathode according to claim 4, characterized in that, The conductive agent is selected from Super P carbon black, acetylene black, graphene, and carbon nanotubes.
7. The catalytic cathode according to claim 4, characterized in that, The adhesive is selected from polyvinylidene fluoride, polytetrafluoroethylene, sodium carboxymethyl cellulose, and styrene-butadiene rubber.
8. The catalytic cathode according to claim 4, characterized in that, The catalyst, conductive agent, and binder together account for 100% of the total mass of the catalyst layer; the catalyst content is controlled at 5%~50%, the conductive agent at 20%~70%, and the binder at 5%~20%, and the three should be combined to make up 100% during preparation.
9. The catalytic cathode according to claim 4, characterized in that, The catalytic cathode is prepared by the following method: a conductive agent, a catalyst, and a binder are mixed, N-methylpyrrolidone is added to form a slurry, which is then coated onto the cathode current collector and dried and compacted.
10. A closed-type lithium-oxygen battery, characterized in that, include: The self-oxygenated electrolyte according to any one of claims 1-3; The catalytic positive electrode according to any one of claims 4-9; the lithium metal negative electrode or the lithium-containing negative electrode; the separator; and the sealed battery casing.