Electrolyte additive, electrolyte and battery for lithium carbon dioxide battery
By using nitrone-based additives as electrolyte additives in lithium carbon dioxide batteries, the problems of low energy efficiency and cycle life have been solved, resulting in higher discharge capacity, lower overpotential, and better cycle stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
- Filing Date
- 2023-08-17
- Publication Date
- 2026-07-21
Smart Images
Figure CN117013155B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of lithium carbon dioxide battery technology, specifically to an electrolyte additive, electrolyte, and battery for lithium carbon dioxide batteries. Background Technology
[0002] Lithium-carbon dioxide (LCC) batteries possess extremely high specific energy density, and by using carbon dioxide as the active material, they can effectively mitigate the greenhouse effect and reduce dependence on traditional fossil fuels. Due to their exceptionally high theoretical specific energy density (1876 Wh / kg), LCC batteries have significant development potential in electric vehicles, smart grids, and Mars exploration. However, LCC batteries face challenges such as low energy efficiency, high charging overpotential, low actual specific capacity, and poor cycle stability, which greatly limit their practical applications and future development.
[0003] Redox mediators are believed to improve the reaction kinetics of lithium-carbon dioxide batteries and reduce cathode polarization, thereby enhancing electrochemical performance. However, current redox additives cannot significantly improve the discharge capacity of lithium-carbon dioxide batteries, nor can they effectively reduce the battery charging overpotential, thus failing to achieve reliable and stable cycling. Therefore, a novel redox additive is urgently needed to improve the energy efficiency and cycle life of lithium-carbon dioxide batteries. Summary of the Invention
[0004] In view of this, this application provides an electrolyte additive, an electrolyte, and a battery for lithium carbon dioxide batteries, in order to solve the problems of low energy efficiency and cycle life of lithium carbon dioxide batteries in the prior art.
[0005] In a first aspect, embodiments of this application provide an electrolyte additive for lithium carbon dioxide batteries, comprising:
[0006] Nitroketone-based additives, wherein the nitrketone-based additives include at least one of open-chain nitrketones, open-chain nitrketone derivatives, cyclic nitrketones, cyclic nitrketone derivatives, and imidazole derivatives.
[0007] In one possible implementation, the open-chain nitrone and its derivatives include:
[0008] Derivatives of 2-methyl-2-nitrosopropane (MNP), N-tert-butyl-α-phenylnitrone (PBN), and N-tert-butyl-α-phenylnitrone (PBN) in which the tert-butyl group is substituted with a substituent, wherein the substituent includes at least one of alkyl, cyano, benzene, and benzene derivatives.
[0009] In one possible implementation, the cyclic nitrone and cyclic nitrone derivatives include:
[0010] 5,5-Dimethyl-1-pyrrololine-N-oxide DMPO and derivatives thereof in which the methyl group is substituted with a substituent, said substituent including at least one of alkyl, cyano, benzene and benzene derivatives.
[0011] In one possible implementation, the imidazole derivative comprises:
[0012] Derivatives of 2-phenyl-4,4,5,5-tetramethylimidazoline-3-oxo-1-oxoPTIO and 2-phenyl-4,4,5,5-tetramethylimidazoline-3-oxo-1-oxoPTIO in which the methyl group is substituted with a substituent, said substituent including at least one of alkyl, cyano, benzene and benzene derivatives.
[0013] Secondly, embodiments of this application provide an electrolyte for lithium carbon dioxide batteries, comprising:
[0014] Lithium salts, proton-inert solvents, and electrolyte additives as described in any one of the first aspects.
[0015] In one possible implementation, the concentration of the electrolyte additive in the electrolyte is from 0.001 mol / L to a saturation concentration.
[0016] In one possible implementation, the lithium salt includes at least one of lithium bis(trifluoromethanesulfonyl)imide, lithium perchlorate, lithium hexafluorophosphate, and lithium difluorooxalate borate.
[0017] In one possible implementation, the concentration of the lithium salt in the electrolyte is 0.1-10 mol / L.
[0018] In one possible implementation, the proton-inert solvent includes at least one of tetraethylene glycol dimethyl ether, diethylene glycol dimethyl ether, and dimethyl sulfoxide.
[0019] Thirdly, embodiments of this application provide a lithium carbon dioxide battery, comprising a porous carbon dioxide positive electrode, a lithium metal negative electrode, a separator, and an electrolyte as described in any one of the second aspects.
[0020] The nitrone-based additives provided in this application can effectively improve the solubility of carbon dioxide in the electrolyte, thereby significantly enhancing the discharge capacity of the battery; moreover, they can promote the formation of Li2CO3 and accelerate the decomposition efficiency of Li2CO3, reduce the overpotential of lithium carbon dioxide batteries, and improve the cycle life of the battery. Attached Figure Description
[0021] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0022] Figure 1 The above are CV scan images of the electrolytes in Example 1 and Comparative Example 1 of this application;
[0023] Figure 2 The constant current full discharge diagram of the battery obtained in Application Example 1 of this application and Comparative Application Example 1 is shown below.
[0024] Figure 3 The circuit performance test graphs of the batteries obtained in Application Example 1 and Comparative Application Example 1 are shown.
[0025] Figure 4 The above are CV scan images of the electrolytes in Example 2 and Comparative Example 2 of this application;
[0026] Figure 5 The electron spin resonance spectra of the electrolytes in Embodiment 2 and Comparative Example 2 of this application are shown.
[0027] Figure 6 These are scanning electron microscope images of the products obtained after discharging the batteries of Example 2 and Comparative Example 2 of this application;
[0028] Figure 7 The cycle performance test graphs of the batteries obtained in Application Example 3 and Comparative Application Example 3 are shown.
[0029] Figure 8 The graphs show the rate performance test results of the batteries obtained in Application Example 3 and Comparative Application Example 3. Detailed Implementation
[0030] To better understand the technical solution of this application, the embodiments of this application will be described in detail below with reference to the accompanying drawings.
[0031] It should be understood that the described embodiments are merely some, not all, of the embodiments in this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.
[0032] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.
[0033] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.
[0034] To address the issues of low energy efficiency and cycle life in existing lithium carbon dioxide batteries, this application provides an electrolyte additive for lithium carbon dioxide batteries, comprising: a nitrone-based additive, which includes at least one of open-chain nitrone, open-chain nitrone derivatives, cyclic nitrone, cyclic nitrone derivatives, and imidazole derivatives.
[0035] Compared with redox mediators in existing technologies, nitrone-based additives have at least the following advantages when applied to lithium carbon dioxide batteries:
[0036] 1) Nitroketone-based additives can adsorb carbon dioxide and also act as spin traps to capture carbon dioxide anion free radicals. This not only promotes the physical adsorption of carbon dioxide gas and provides more reactants for redox reactions, but also greatly enhances the redox kinetics process, directly converting carbon dioxide anions into lithium carbonate through intramolecular disproportionation.
[0037] 2) Nitroketone-based additives can change the mechanism of carbon dioxide redox, converting the four-electron reaction into a reversible two-electron reaction, giving the battery ultra-high specific capacity and energy efficiency.
[0038] 3) Nitroketone-based additives can also promote the decomposition of lithium carbonate, significantly regulate the morphology of the product, and transform particulate lithium carbonate into flake lithium carbonate, which greatly reduces the charging platform and improves rate performance and cycle life.
[0039] In one possible implementation, the open-chain nitrone and its derivatives include:
[0040] Derivatives of 2-methyl-2-nitrosopropane (MNP), N-tert-butyl-α-phenyl nitrone (PBN) and N-tert-butyl-α-phenyl nitrone (PBN) in which the tert-butyl group is substituted with a substituent, said substituent including at least one of alkyl, cyano, benzene and benzene derivatives.
[0041] In one possible implementation, the cyclic nitrone and cyclic nitrone derivatives include:
[0042] 5,5-Dimethyl-1-pyrrololine-N-oxide (DMPO) and derivatives of 5,5-dimethyl-1-pyrrololine-N-oxide (DMPO) in which the methyl group is substituted with a substituent, said substituent including at least one of alkyl, cyano, benzene and benzene derivatives.
[0043] In one possible implementation, the imidazole derivative comprises:
[0044] Derivatives of 2-phenyl-4,4,5,5-tetramethylimidazoline-3-oxo-1-oxo (PTIO) and 2-phenyl-4,4,5,5-tetramethylimidazoline-3-oxo-1-oxo (PTIO) in which the methyl group is substituted with a substituent, said substituent including at least one of alkyl, cyano, benzene and benzene derivatives.
[0045] Corresponding to the above embodiments, this application also provides an electrolyte for lithium carbon dioxide batteries, comprising: lithium salt, proton inert solvent and electrolyte additives described in the above embodiments.
[0046] In one possible implementation, the concentration of the electrolyte additive in the electrolyte is from 0.001 mol / L to a saturation concentration. For example, 0.001 mol / L, 0.5 mol / L, 1 mol / L, 1.5 mol / L, 2 mol / L, and 2.5 mol / L, etc., can be adaptively selected within this range according to actual needs, and this application does not impose specific limitations in this regard. In a preferred embodiment, the concentration of the electrolyte additive in the electrolyte is a saturation concentration.
[0047] In one possible implementation, the lithium salt includes at least one of lithium bis(trifluoromethanesulfonyl)imide, lithium perchlorate, lithium hexafluorophosphate, and lithium difluorooxalate borate.
[0048] In one possible implementation, the concentration of the lithium salt in the electrolyte is 0.1-10 mol / L. For example, 0.1 mol / L, 1 mol / L, 2 mol / L, 3 mol / L, 4 mol / L, 4.8 mol / L, etc. Those skilled in the art can make adaptive selections within this range according to actual needs, and this application does not impose specific limitations in this regard. In a preferred embodiment, the concentration of the lithium salt in the electrolyte is 1 mol / L.
[0049] In one possible implementation, the proton-inert solvent includes at least one of tetraethylene glycol dimethyl ether, diethylene glycol dimethyl ether, and dimethyl sulfoxide.
[0050] Corresponding to the above embodiments, this application also provides a lithium carbon dioxide battery, including a porous carbon dioxide positive electrode, a lithium metal negative electrode, a separator, and the electrolyte described in the above embodiments.
[0051] For ease of understanding, the technical solutions provided in this application will be described in detail below with reference to specific embodiments.
[0052] Example 1:
[0053] The structural formula of the nitrone-based additive in this embodiment is:
[0054]
[0055] LiTFSI and TEGDME were uniformly mixed to obtain an organic mixed solution with a lithium salt concentration of 1 mol / L. Then, 2-phenyl-4,4,5,5-tetramethylimidazoline-3-oxo-1-oxo (PTIO) of this embodiment was added to the obtained mixed solution and stirred for 48 h to obtain an electrolyte, wherein the concentration of the nitrone-based additive in the electrolyte was 0.1 mol / L.
[0056] Comparative Example 1:
[0057] LiTFSI and TEGDME were mixed uniformly to obtain a mixed solution with a lithium salt concentration of 1 mol / L, which was then used as the electrolyte.
[0058] Under an argon atmosphere, CV scans were performed on the electrolytes of Example 1 and Comparative Example 1 using a three-electrode system. The CV scan conditions were as follows: working electrode was a carbon electrode, reference electrode was a silver electrode, counter electrode was a lithium metal electrode, scan rate was 50 mV / s, and voltage range was 2.0–4.0 V vs. Li / Li + The obtained CV scan image is shown below. Figure 1 .Depend on Figure 1 It can be seen that the electrolyte system provided in Example 1 showed redox peaks, while Comparative Example 1 did not show any redox peaks.
[0059] Application Example 1:
[0060] Graphene oxide, PVDF, and acetylene black were mixed at a mass ratio of 8:1:1 and N-methylpyrrolidone was added to obtain a positive electrode slurry. The obtained positive electrode slurry was coated onto the surface of carbon paper and dried at 110℃ for 12 hours to obtain a porous carbon dioxide positive electrode. The total loading of graphene oxide on the surface of the porous carbon dioxide positive electrode was 0.2–0.3 mg / cm³. 2 ;
[0061] The battery separator is made of glass fiber optic membrane GF / D, with a pore size of 2.7μm and a diameter of 19mm.
[0062] Following the assembly sequence of lithium metal anode, separator, and porous oxygen cathode, Swagelok-type batteries were assembled in a glove box with a high-purity carbon dioxide atmosphere (H2O < 0.1 ppm, O2 < 0.1 ppm). In Example 1, the electrolyte was added dropwise after the battery was assembled, with a drop volume of 60-120 μL.
[0063] Performance Testing: The obtained Swagelok-type batteries were subjected to constant current charge-discharge tests using the Land battery testing system. The test conditions were: constant temperature 25℃, current density of 100-1000 mA / g, specific capacity limit of 500 mAh / g (all calculated based on the mass of graphene oxide in the carbon dioxide cathode), and potential range of 2.2-5.0 V vs. Li / Li. + .
[0064] Comparative application example 1:
[0065] The electrolyte of Comparative Example 1 was used instead of the electrolyte of Example 1, and the rest of the technical means were the same as in Application Example 1, to obtain a Swagelok type battery.
[0066] For example 1, the Swagelok-type battery obtained in comparison application example 1 was subjected to constant current full discharge test. The obtained constant current full discharge graph is shown below. Figure 2 .Depend on Figure 2 As can be seen, the discharge capacity of Application Example 1 is 74.6 Ah / g, compared to 4.6 Ah / g in Application Example 1. Therefore, the Swagelok-type battery provided in Application Example 1 of this invention exhibits a higher discharge capacity. The reason for this is that the NO bonds in the nitroketone-based additive in the electrolyte efficiently promote the formation of lithium carbonate.
[0067] Corresponding to use case 1, the Swagelok-type batteries obtained from comparison application example 1 were subjected to cycle performance tests, and the resulting cycle performance test graphs are shown below. Figure 3 Among them, the Swagelok-type battery provided in Application Example 1 of the present invention exhibits higher cycle stability.
[0068] Example 2:
[0069] The structural formula of the nitrone-based additive in this embodiment is:
[0070]
[0071] LiTFSI and TEGDME were uniformly mixed to obtain an organic mixed solution with a lithium salt concentration of 1 mol / L. Then, N-tert-butyl-α-phenyl nitrone (PBN) of this embodiment was added to the obtained mixed solution, and the mixture was stirred for 48 h to obtain an electrolyte. The concentration of the nitrone-based additive in the electrolyte was 0.5 mol / L.
[0072] Comparative Example 2:
[0073] LiTFSI and TEGDME were mixed uniformly to obtain a mixed solution with a lithium salt concentration of 1 mol / L, which was then used as the electrolyte.
[0074] Under an argon atmosphere, CV scans were performed on the electrolytes of Example 2 and Comparative Example 2 using a three-electrode system. The CV scan conditions were as follows: working electrode was a carbon electrode, reference electrode was a silver electrode, counter electrode was a lithium metal electrode, scan rate was 50 mV / s, and voltage range was 2.0–4.0 V vs. Li / Li + The obtained CV scan image is shown below. Figure 4 .Depend on Figure 4 It can be seen that the electrolyte system provided in Example 2 showed redox peaks and a significant increase in current density; while Comparative Example 2 showed no redox peaks and a lower current density.
[0075] Application Example 2:
[0076] Graphene oxide, PVDF, and acetylene black were mixed at a mass ratio of 8:1:1 and N-methylpyrrolidone was added to obtain a positive electrode slurry. The obtained positive electrode slurry was coated onto the surface of carbon paper and dried at 110℃ for 12 hours to obtain a porous carbon dioxide positive electrode. The total loading of graphene oxide on the surface of the porous carbon dioxide positive electrode was 0.2–0.3 mg / cm³. 2 ;
[0077] The battery separator is made of glass fiber optic membrane GF / D, with a pore size of 2.7μm and a diameter of 19mm.
[0078] Following the assembly sequence of lithium metal anode, separator, and porous oxygen cathode, Swagelok-type batteries were assembled in a glove box with a high-purity carbon dioxide atmosphere (H2O < 0.1 ppm, O2 < 0.1 ppm). In Example 2, the electrolyte was added dropwise after the battery was assembled, with a drop volume of 60-120 μL.
[0079] Performance Testing: The obtained Swagelok-type batteries were subjected to constant current charge-discharge tests using the Land battery testing system. The test conditions were: constant temperature 25℃, current density 100-500 mA / g, specific capacity limited to 500 mAh / g (calculated based on the mass of graphene oxide in the carbon dioxide cathode), and potential range 2.2-5.0V vs. Li / Li. + .
[0080] Compare with application example 2:
[0081] The electrolyte of Comparative Example 2 was used instead of the electrolyte of Example 2, and the rest of the technical means were the same as in Application Example 2, to obtain a Swagelok type battery.
[0082] Corresponding to use case 2, the Swagelok-type battery obtained in comparison to use case 2 was subjected to carbon dioxide free radical capture tests after discharge. The resulting spin compound spectra are shown below. Figure 5 .Depend on Figure 5 It is evident that the electrolyte in Application Example 2 can effectively capture carbon dioxide anion radicals and form stable carbon dioxide spin compounds; however, no characteristic peaks appeared in Comparative Example 2, indicating that Comparative Example 2 is unable to capture carbon dioxide radicals.
[0083] Corresponding to use case 2, the products of the Swagelok-type battery obtained in comparison application example 2 after discharge are compared. The morphology of the obtained lithium carbonate product is shown in [reference needed]. Figure 6 The left image shows a comparative application example 2, and the right image shows an application example 2. (From...) Figure 6 As can be seen, after disassembling the Swagelok-type battery provided in Application Example 2 of the present invention, the lithium carbonate on the positive electrode has a leaf-like or plate-like morphology, while the lithium carbonate in Comparative Application Example 2 has a granular morphology. Comparing the sizes of the two, the diameter of the lithium carbonate in Application Example 2 of the present invention is significantly smaller than that in the Comparative Application Example.
[0084] Example 3:
[0085] The structural formula of the nitrone-based additive in this embodiment is:
[0086] (H3C)3C-NO
[0087] LiTFSI and TEGDME were uniformly mixed to obtain an organic mixed solution with a lithium salt concentration of 1 mol / L. Then, 2-methyl-2-nitrosopropane (MNP) of this embodiment was added to the obtained mixed solution, and the mixture was stirred for 48 h to obtain an electrolyte. The concentration of the nitrone-based additive in the electrolyte was 0.3 mol / L.
[0088] Comparative Example 3
[0089] LiTFSI and TEGDME were mixed uniformly to obtain a mixed solution with a lithium salt concentration of 1 mol / L, which was then used as the electrolyte.
[0090] Under an argon atmosphere, CV scans were performed on the electrolytes of Example 3 and Comparative Example 3 using a three-electrode system. The CV scan conditions were as follows: working electrode was a carbon electrode, reference electrode was a silver electrode, counter electrode was a lithium metal electrode, scan rate was 50 mV / s, and voltage range was 2.0–4.0 V vs. Li / Li + The electrolyte system provided in Example 3 showed redox peaks; while Comparative Example 3 did not show any redox peaks.
[0091] Application Example 3:
[0092] Graphene oxide, PVDF, and acetylene black were mixed at a mass ratio of 8:1:1 and N-methylpyrrolidone was added to obtain a positive electrode slurry. The obtained positive electrode slurry was coated onto the surface of carbon paper and dried at 110℃ for 12 hours to obtain a porous carbon dioxide positive electrode. The total loading of graphene oxide on the surface of the porous carbon dioxide positive electrode was 0.2–0.3 mg / cm³. 2 ;
[0093] The battery separator is made of glass fiber optic membrane GF / D, with a pore size of 2.7μm and a diameter of 19mm.
[0094] Swagelok-type batteries were assembled in a glove box with a high-purity carbon dioxide atmosphere (H2O<0.1ppm, O2<0.1ppm) according to the assembly sequence of lithium metal anode, separator, and porous oxygen cathode. In Example 3, the electrolyte was added dropwise after the battery was assembled, with a drop volume of 60-120μL.
[0095] Performance Testing: The obtained Swagelok-type batteries were subjected to constant current charge-discharge tests using the Land battery testing system. The test conditions were: constant temperature 25℃, current density 100-500 mA / g, specific capacity limited to 500 mAh / g (all calculated based on the mass of graphene oxide in the carbon dioxide cathode), and potential range 2.2-5.0 V vs. Li / Li. + .
[0096] Compare with example 3:
[0097] The electrolyte of Comparative Example 3 was used instead of the electrolyte of Example 3, and the rest of the technical means were the same as those of Application Example 3, to obtain a Swagelok type battery.
[0098] Corresponding to use case 3, the Swagelok-type battery obtained in comparison application example 3 was subjected to constant current charge-discharge tests, and the resulting cycle stability graphs are shown below. Figure 7 .Depend on Figure 7 As can be seen, Application Example 3 exhibits smaller cyclic polarization and higher cyclic stability, with its charging voltage remaining below 3.7V throughout 100 cycles, while Comparative Example 3 has a charging voltage above 4V.
[0099] For use case 3, the Swagelok-type batteries obtained from comparison application example 3 were subjected to rate performance tests respectively. The resulting rate performance graphs are shown below. Figure 8 .Depend on Figure 8 As can be seen, Application Example 3 exhibits less polarization and higher stability when the current increases. Its charging voltage is lower than that of Comparative Application Example 3, and its discharging voltage is always higher than that of Comparative Application Example 3.
[0100] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
[0101] Example 4:
[0102] The structural formula of the nitrone-based additive in this embodiment is:
[0103]
[0104] LiTFSI and DMSO were uniformly mixed to obtain an organic mixed solution with a lithium salt concentration of 1 mol / L. Then, 2-phenyl-4,4,5,5-tetramethylimidazoline-3-oxo-1-oxo (PTIO) of this embodiment was added to the obtained mixed solution and stirred for 48 h to obtain an electrolyte, wherein the concentration of the nitrone-based additive in the electrolyte was 0.5 mol / L.
[0105] Comparative Example 4:
[0106] LiTFSI and DMSO were mixed uniformly to obtain a mixed solution with a lithium salt concentration of 1 mol / L, which was then used as the electrolyte.
[0107] Under an argon atmosphere, CV scans were performed on the electrolytes of Example 4 and Comparative Example 4 using a three-electrode system. The CV scan conditions were as follows: working electrode was a carbon electrode, reference electrode was a silver electrode, counter electrode was a lithium metal electrode, scan rate was 50 mV / s, and voltage range was 2.0–4.0 V vs. Li / Li + The electrolyte system provided in Example 4 showed redox peaks; while Comparative Example 3 did not show any redox peaks.
[0108] Application Example 4:
[0109] Graphene oxide, PVDF, and acetylene black were mixed at a mass ratio of 8:1:1 and N-methylpyrrolidone was added to obtain a positive electrode slurry. The obtained positive electrode slurry was coated onto the surface of carbon paper and dried at 110℃ for 12 hours to obtain a porous carbon dioxide positive electrode. The total loading of graphene oxide on the surface of the porous carbon dioxide positive electrode was 0.2–0.3 mg / cm³. 2 ;
[0110] The battery separator is made of glass fiber optic membrane GF / D, with a pore size of 2.7μm and a diameter of 19mm.
[0111] Following the assembly sequence of lithium metal anode, separator, and porous oxygen cathode, Swagelok-type batteries were assembled in a glove box with a high-purity carbon dioxide atmosphere (H2O < 0.1 ppm, O2 < 0.1 ppm). In Example 4, the electrolyte was added dropwise after the battery was assembled, with a drop volume of 60-120 μL.
[0112] Performance Testing: The obtained Swagelok-type batteries were subjected to constant current charge-discharge tests using the Land battery testing system. The test conditions were: constant temperature 25℃, current density of 100-1000 mA / g, specific capacity limit of 500 mAh / g (all calculated based on the mass of graphene oxide in the carbon dioxide cathode), and potential range of 2.2-5.0 V vs. Li / Li. + .
[0113] Compare with application example 4:
[0114] The electrolyte of Comparative Example 4 was used instead of the electrolyte of Example 4, and the rest of the technical means were the same as those of Application Example 4, to obtain a Swagelok type battery.
[0115] The Swagelok-type batteries obtained in Application Example 4 and Comparative Application Example 4 were subjected to constant current full discharge tests. The discharge capacity of Application Example 4 was 56.6 Ah / g, while the discharge capacity of Comparative Application Example 4 was 3.4 Ah / g. It is evident that the Swagelok-type battery provided in Application Example 4 of this invention exhibits a higher discharge capacity. The reason for this is that the NO bonds contained in the nitroketone-based additive in the electrolyte efficiently promote the formation of lithium carbonate.
[0116] The Swagelok-type batteries obtained in Application Example 4 and Comparative Application Example 4 were subjected to cycle performance tests. The Swagelok-type battery provided in Application Example 4 of this invention showed higher cycle stability.
[0117] The above description is merely a specific embodiment of this application. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the protection scope of this application. The protection scope of this application should be determined by the protection scope of the claims.
Claims
1. A lithium carbon dioxide battery, characterized in that, It includes a porous carbon dioxide positive electrode, a lithium metal negative electrode, a separator, and an electrolyte; The electrolyte includes lithium salt, proton-inert solvent and electrolyte additives; The electrolyte additive includes: a nitrone-based additive, wherein the nitrone-based additive includes at least one of open-chain nitrone, open-chain nitrone derivative, cyclic nitrone, cyclic nitrone derivative and imidazole derivative; The imidazole derivatives include derivatives of 2-phenyl-4,4,5,5-tetramethylimidazoline-3-oxo-1-oxoPTIO and 2-phenyl-4,4,5,5-tetramethylimidazoline-3-oxo-1-oxoPTIO in which the methyl group is substituted with a substituent, wherein the substituent includes at least one of alkyl, cyano, benzene and benzene derivatives.
2. The lithium carbon dioxide battery according to claim 1, characterized in that, The open-chain nitrones and open-chain nitrone derivatives include: Derivatives of 2-methyl-2-nitrosopropane (MNP), N-tert-butyl-α-phenylnitrone (PBN), and N-tert-butyl-α-phenylnitrone (PBN) in which the tert-butyl group is substituted with a substituent, wherein the substituent includes at least one of alkyl, cyano, benzene, and benzene derivatives.
3. The lithium carbon dioxide battery according to claim 1, characterized in that, The cyclic nitrones and cyclic nitrone derivatives include: 5,5-Dimethyl-1-pyrrololine-N-oxide DMPO and derivatives thereof in which the methyl group is substituted with a substituent, said substituent including at least one of alkyl, cyano, benzene and benzene derivatives.
4. The lithium carbon dioxide battery according to claim 1, characterized in that, The concentration of the electrolyte additive in the electrolyte is from 0.001 mol / L to saturation concentration.
5. The lithium carbon dioxide battery according to claim 1, characterized in that, The lithium salt includes at least one of lithium bis(trifluoromethanesulfonyl)imide, lithium perchlorate, lithium hexafluorophosphate, and lithium difluorooxalate borate.
6. The lithium carbon dioxide battery according to claim 1, characterized in that, The concentration of the lithium salt in the electrolyte is 0.01–10 mol / L.
7. The lithium carbon dioxide battery according to claim 1, characterized in that, The proton-inert solvent includes at least one of tetraethylene glycol dimethyl ether, diethylene glycol dimethyl ether, and dimethyl sulfoxide.