Complex for supplementing lithium or sodium, non-aqueous electrolyte containing complex and battery

Abstract

The invention belongs to the technical field of electrochemical energy storage, and particularly relates to a complex for supplementing lithium or sodium, the chemical general formula of the complex is # imgabs0, R is methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, vinyl, allyl, ethynyl, phenyl, trifluoromethyl, difluoromethyl, pentafluoroethyl, trifluoroethyl or 4-fluorophenyl, and R is methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, vinyl, allyl, ethynyl, phenyl, trifluoromethyl, difluoromethyl, pentafluoroethyl, trifluoroethyl or 4-fluorophenyl. A is BF3 or PF5; b is S or C; m is Li or Na. Compared with the prior art, the complex provided by the invention has a relatively high concentration degree in an organic solvent, and is beneficial to high-capacity lithium supplement, so that the performance of a lithium ion battery or a sodium ion battery using the complex in gram volume, long-cycle capacity retention rate, capacity recovery rate after high-temperature storage and the like is remarkably improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrochemical energy storage, and particularly relates to a complex for lithium or sodium supplementation, a non-aqueous electrolyte containing the complex, and a battery. Background Art

[0002] Currently, for commercial lithium (sodium) ion batteries, due to irreversible side reactions occurring during the formation stage of electrode materials and interfaces and subsequent cycling processes, the loss of lithium / sodium ions and the attenuation of battery capacity are caused. Therefore, the industry attempts to solve this problem by means of lithium (sodium) supplementation.

[0003] Currently, relatively mature methods for lithium (sodium) supplementation include:

[0004] 1) Adding a lithium (sodium) source (such as lithium powder, sodium powder, etc.) to the negative electrode;

[0005] 2) Adding a lithium (sodium) source (such as lithium ferrate, etc.) to the positive electrode;

[0006] 3) Adding a lithium (sodium) source (such as lithium trifluoromethanesulfonate, etc.) to the electrolyte.

[0007] The lithium supplementation process through the negative electrode has high process requirements, high costs, and poor safety, which is not conducive to large-scale production. After lithium / sodium supplementation through the positive electrode, by-products remain in the battery, reducing the energy density of the battery, easily creating pores in the positive electrode, and reducing the cycle performance of the battery. Adding lithium trifluoromethanesulfonate to the electrolyte, through the electrochemical oxidation-reduction process, the trifluoromethanesulfonate group is converted into a gas. The lithium supplement is cheap and easily available, and no by-products remain in the battery system. However, the solubility of lithium trifluoromethanesulfonate in the electrolyte is relatively poor, and the lithium supplementation effect is relatively limited.

[0008] In view of this, the present invention aims to provide a complex for lithium or sodium supplementation, a non-aqueous electrolyte containing the complex, and a battery. The complex can play a good role in lithium supplementation in a lithium ion battery or a sodium ion battery and extend the service life of the battery. Summary of the Invention

[0009] A complex for lithium or sodium supplementation is provided to overcome the deficiencies of the prior art. The complex can play a good role in lithium supplementation in a lithium ion battery or a sodium ion battery and extend the service life of the battery.

[0010] To solve the above problems, the technical solution of the present invention is as follows:

[0011] A complex for lithium or sodium supplementation, the chemical general formula of the complex is:

[0012]

[0013] Among them, R is methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, vinyl, allyl, ethynyl, phenyl, trifluoromethyl, difluoromethyl, pentafluoroethyl, trifluoroethyl or 4-fluorophenyl;

[0014] A is BF 3 or PF 5 ;

[0015] B is S or C;

[0016] M is Li or Na.

[0017] As an improvement of the complex for lithium or sodium supplementation of the present invention, the preparation method of the complex at least includes the following steps:

[0018] Step 1: Weigh the sodium sulfinate or carboxylate substituted with R group, add concentrated sulfuric acid and stir, distill out the sulfonic acid or carboxylic acid substituted with R group, then add water and lithium hydroxide, and after the neutralization reaction is completed, dry to obtain the following substances substituted with R group: lithium sulfinate compound or lithium carboxylate compound; among them, the R group is methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, vinyl, allyl, ethynyl, phenyl, trifluoromethyl, difluoromethyl, pentafluoroethyl, trifluoroethyl or 4-fluorophenyl;

[0019] Step 2: Add the lithium sulfinate compound or lithium carboxylate compound obtained in Step 1 to the reaction flask, then add an organic solvent, stir, control the temperature, and then add a boron fluoride compound or phosphorus pentafluoride compound, and stir;

[0020] Step 3: Filter to remove insoluble substances to obtain a complex solution.

[0021] As an improvement of the complex for lithium or sodium supplementation of the present invention, the organic solvent described in Step 2 is at least one of ethyl methyl carbonate, dimethyl carbonate, ethylene carbonate, ethyl propionate and propyl propionate.

[0022] The present invention also provides a non-aqueous electrolyte, which includes a conductive sodium salt or a conductive lithium salt, a non-aqueous organic solvent and an additive, and is characterized in that it further includes the complex for lithium or sodium supplementation of the present invention.

[0023] As an improvement of the non-aqueous electrolyte of the present invention, the mass percentage content of the complex in the electrolyte is 0.1% - 40%.

[0024] As an improvement of the non-aqueous electrolyte of the present invention, the mass percentage content of the complex in the electrolyte is 0.3% - 30%.

[0025] As an improvement of the non-aqueous electrolyte of the present invention, the conductive lithium salt includes LiBF 4 、LiPF 6 、LiPO2 F 2 , LiAsF 6 , LiClO 4 , LiSO 3 CF 3 , LiB(C 2 O 4 ) 2 , LiBF 2 C 2 O 4 , LiN(SO 2 CF 3 ) 2 , LiN(SO 2 F) 2 at least one of; the conductive sodium salt includes NaBF 4 , NaPF 6 , NaPO 2 F 2 , NaAsF 6 , NaClO 4 , NaSO 3 CF 3 , NaB(C 2 O 4 ) 2 , NaBF 2 C 2 O 4 , NaN(SO 2 CF 3 ) 2 , NaN(SO 2 F) 2 at least one of;

[0026] The non-aqueous organic solvent is at least one of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, γ-butyrolactone, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, ethyl propionate, propyl propionate, propyl butyrate;

[0027] The additive is at least one of vinylene carbonate, ethylene vinyl carbonate, fluoroethylene carbonate, difluoroethylene carbonate, 1,3-propane sultone, 1,4-butane sultone, ethylene sulfate, propylene sulfate, ethylene sulfite, propylene sulfite, succinonitrile, adiponitrile, 1,2-cyanoethoxyethane, hexane trinitrile.

[0028] The present invention also provides a battery, including a positive electrode sheet, a negative electrode sheet and a separator, and further including the non-aqueous electrolyte of the present invention.

[0029] As an improvement of the battery of the present invention, both the positive electrode sheet and the negative electrode sheet include active materials, conductive agents, current collectors, and binders for binding the active materials and the conductive agents to the current collectors;

[0030] The positive electrode sheet includes a positive electrode active material capable of reversibly intercalating / deintercalating lithium or sodium ions, and the positive electrode active material is a composite metal oxide of lithium or sodium, and the metal oxide includes oxides of nickel, cobalt, manganese elements and any proportion combination thereof;

[0031] The negative electrode sheet includes a negative electrode active material capable of accepting or releasing lithium or sodium ions, and the negative electrode active material includes lithium or sodium metal, lithium or sodium alloy, crystalline carbon, amorphous carbon, carbon fiber, hard carbon, soft carbon; wherein the crystalline carbon includes natural graphite, graphitized coke, graphitized MCMB, graphitized mesophase pitch carbon fiber; the lithium or sodium alloy includes alloys of lithium or sodium and metals such as aluminum, zinc, silicon, tin, gallium, antimony.

[0032] As an improvement of the battery of the present invention, the positive electrode active material further includes at least one of chemical elements, and the chemical elements include Mg, Al, Ti, Sn, V, Ge, Ga, B, Zr, Cr, Fe, Sr and rare earth elements; the positive electrode active material further includes a polyanion lithium compound LiM x (PO 4 ) y , wherein, M is Ni, Co, Mn, Fe, Ti, V, 0≤x≤5, 0≤y≤5.

[0033] Compared with the prior art, the complex provided by the present invention has a higher solubility in organic solvents, which is beneficial to large-capacity lithium supplementation, so that the lithium-ion battery or sodium-ion battery using this complex has significantly improved performance in terms of specific capacity, long-cycle capacity retention rate, and capacity recovery rate after high-temperature storage. Description of the Drawings

[0034] Figure 1 It is the cyclic voltammetry test curve of the lithium trifluoromethanesulfonate boron trifluoride complex battery in Example 2-1 of the present invention. Detailed Embodiments

[0035] The present invention provides a complex for lithium or sodium supplementation, and the chemical general formula of the complex is:

[0036]

[0037] Among them, R is methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, vinyl, allyl, ethynyl, phenyl, trifluoromethyl, difluoromethyl, pentafluoroethyl, trifluoroethyl or 4-fluorophenyl;

[0038] A is BF 3or PF 5 ; B is S or C; M is Li or Na.

[0039] Among them, the preparation method of the complex at least includes the following steps:

[0040] Step 1: Weigh sodium sulfonate or carboxylate substituted with R group, add concentrated sulfuric acid and stir, distill out sulfonic acid or carboxylic acid substituted with R group, then add water and lithium hydroxide, and after the neutralization reaction is completed, dry to obtain the following substances substituted with R group: lithium sulfonate compound or lithium carboxylate compound; among them, the R group is methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, vinyl, allyl, ethynyl, phenyl, trifluoromethyl, difluoromethyl, pentafluoroethyl, trifluoroethyl or 4-fluorophenyl;

[0041] Step 2: Add the lithium sulfonate compound or lithium carboxylate compound obtained in Step 1 into the reaction flask, then add an organic solvent, stir, control the temperature, and then add a boron fluoride compound or a phosphorus pentafluoride compound, and stir;

[0042] Step 3: Filter to remove insoluble substances to obtain a complex solution.

[0043] Among them, the organic solvent in Step 2 is at least one of ethyl methyl carbonate, dimethyl carbonate, ethylene carbonate, ethyl propionate and propyl propionate.

[0044] The present invention also provides a non-aqueous electrolyte, which includes a conductive sodium salt or a conductive lithium salt, a non-aqueous organic solvent and an additive, and is characterized in that it further includes the lithium or sodium supplementing complex of the present invention.

[0045] Among them, the mass percentage content of the complex in the electrolyte is 0.1% - 40%, preferably 0.3% - 30%.

[0046] The conductive lithium salt includes LiBF 4 , LiPF 6 , LiPO 2 F 2 , LiAsF 6 , LiClO 4 , LiSO 3 CF 3 , LiB(C 2 O 4 ) 2 , LiBF 2 C 2 O 4 , LiN(SO 2 CF 3 ) 2 , LiN(SO 2 F) 2 at least one of them; the conductive sodium salt includes NaBF4 , NaPF 6 , NaPO 2 F 2 , NaAsF 6 , NaClO 4 , NaSO 3 CF 3 , NaB(C 2 O 4 ) 2 , NaBF 2 C 2 O 4 , NaN(SO 2 CF 3 ) 2 , NaN(SO 2 F) 2 at least one of;

[0047] The non-aqueous organic solvent is at least one of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, γ-butyrolactone, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, ethyl propionate, propyl propionate, butyl propionate;

[0048] The additive is at least one of vinylene carbonate, ethylene vinyl carbonate, fluoroethylene carbonate, difluoroethylene carbonate, 1,3-propane sultone, 1,4-butane sultone, ethylene sulfate, propylene sulfate, ethylene sulfite, propylene sulfite, succinonitrile, adiponitrile, 1,2-cyanoethoxyethane, hexane trinitrile.

[0049] The present invention also provides a battery, including a positive electrode sheet, a negative electrode sheet and a separator, and further including the non-aqueous electrolyte of the present invention.

[0050] As an improvement of the battery of the present invention, both the positive electrode sheet and the negative electrode sheet include an active material, a conductive agent, a current collector and a binder for combining the active material and the conductive agent with the current collector;

[0051] The positive electrode sheet includes a positive electrode active material capable of reversibly inserting / extracting lithium or sodium ions, and the positive electrode active material is a composite metal oxide of lithium or sodium, and the metal oxide includes oxides of nickel, cobalt, manganese elements and any proportion combination thereof;

[0052] The negative electrode sheet includes a negative electrode active material capable of accepting or releasing lithium or sodium ions, and the negative electrode active material includes lithium or sodium metal, lithium or sodium alloy, crystalline carbon, amorphous carbon, carbon fiber, hard carbon, soft carbon; wherein the crystalline carbon includes natural graphite, graphitized coke, graphitized MCMB, graphitized mesophase pitch carbon fiber; the lithium or sodium alloy includes an alloy of lithium or sodium and aluminum, zinc, silicon, tin, gallium, antimony metals.

[0053] The positive electrode active material further includes at least one of chemical elements, and the chemical elements include Mg, Al, Ti, Sn, V, Ge, Ga, B, Zr, Cr, Fe, Sr, and rare earth elements; the positive electrode active material further includes a polyanion lithium compound LiM x (PO 4 ) y , where M is Ni, Co, Mn, Fe, Ti, V, 0 ≤ x ≤ 5, 0 ≤ y ≤ 5.

[0054] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below. Apparently, the described embodiments are some, but not all, of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present application. Although only some substances are listed in the following embodiments, it should be emphasized that all substances listed in the present invention can be applicable.

[0055] Unless otherwise specified, the experimental methods used in the embodiments of the present application are all conventional methods.

[0056] In the following embodiments and comparative examples, unless otherwise specified, all raw materials can be prepared and synthesized by conventional methods or obtained commercially.

[0057] Example 1-1

[0058] This example provides a preparation method for a complex for lithium supplementation, and its chemical principle is:

[0059]

[0060] 70 g (0.5 mol) of lithium trifluoromethanesulfonate was added to a 1000 mL reaction flask, 243 g of dimethyl carbonate was added, 34 g (0.5 mol) of boron trifluoride was introduced, the temperature was controlled at 25 °C, and the mixture was stirred and reacted for 8 hours. The mixture was filtered under reduced pressure to obtain a clear solution, and 104 g of product was obtained, where the concentration of the lithium trifluoromethanesulfonate boron trifluoride complex was 30%.

[0061] Among them, the preparation method of lithium trifluoromethanesulfonate is:

[0062] Sodium trifluoromethanesulfonate was weighed, concentrated sulfuric acid was added and stirred, trifluoromethanesulfonic acid was distilled out, then water and lithium hydroxide were added, and after the neutralization reaction was completed, it was dried to obtain lithium trifluoromethanesulfonate.

[0063] Example 1-2

[0064] This example provides a preparation method for a complex for lithium supplementation, and its chemical principle is:

[0065]

[0066] Add 70 g (0.5 mol) of lithium trifluoromethanesulfonate to a 1000 mL reaction flask, add 214 g of diethyl carbonate, introduce 63 g (0.5 mol) of phosphorus pentafluoride, control the temperature at 25 °C, and stir the reaction for 8 hours. Filter under reduced pressure to obtain 113 g of a clear solution product, in which the concentration of the lithium trifluoromethanesulfonate phosphorus pentafluoride complex is 30%.

[0067] Among them, the preparation method of lithium trifluoromethanesulfonate is as follows:

[0068] Weigh sodium trifluoromethanesulfonate, add concentrated sulfuric acid and stir, distill out trifluoromethanesulfonic acid, then add water and lithium hydroxide, and dry after the neutralization reaction is completed to obtain lithium trifluoromethanesulfonate.

[0069] Examples 1 - 3

[0070] This example provides a preparation method of a complex for lithium supplementation, and its chemical principle is:

[0071]

[0072] Add 60 g (0.5 mol) of lithium trifluoroacetate to a 1000 mL reaction flask, add 243 g of dimethyl carbonate, introduce 34 g (0.5 mol) of boron trifluoride, control the temperature at 25 °C, and stir the reaction for 8 hours. Filter under reduced pressure to obtain a clear solution, and obtain 94 g of product, in which the concentration of the lithium trifluoroacetate boron trifluoride complex is 30%.

[0073] Among them, the preparation method of lithium trifluoroacetate is as follows:

[0074] Weigh sodium trifluoroacetate, add concentrated sulfuric acid and stir, distill out trifluoroacetic acid, then add water and lithium hydroxide, and dry after the neutralization reaction is completed to obtain lithium trifluoroacetate.

[0075] Examples 1 - 4

[0076] This example provides a preparation method of a complex for lithium supplementation, and its preparation method is as follows:

[0077] Step 1: Weigh sodium benzenesulfinate, add concentrated sulfuric acid and stir, distill out benzenesulfinic acid, then add water and lithium hydroxide, and dry after the neutralization reaction is completed to obtain lithium benzenesulfinate;

[0078] Step 2: Add the lithium benzenesulfinate obtained in Step 1 to a reaction flask, then add ethyl propionate, stir, control the temperature, and then add a phosphorus pentafluoride compound, and stir at 35 °C for 6 hours;

[0079] Step 3: Filter out the insoluble substances to obtain a complex solution.

[0080] Examples 1 - 5

[0081] This example provides a preparation method for a complex used for lithium supplementation, and the preparation method is as follows:

[0082] Step 1: Weigh sodium isopropylsulfinate, add concentrated sulfuric acid and stir. Distill out isopropylsulfinic acid, then add water and lithium hydroxide. After the neutralization reaction is completed, dry to obtain lithium isopropylsulfinate.

[0083] Step 2: Add the lithium isopropylsulfinate obtained in Step 1 to a reaction flask, then add ethyl methyl carbonate, stir, control the temperature, and then add a phosphorus pentafluoride compound. Stir at 30 °C for 4 hours.

[0084] Step 3: Filter out the insoluble substances to obtain a complex solution.

[0085] Example 2 - 1

[0086] This example provides a preparation method for a lithium-ion battery:

[0087] (1) Preparation of the electrolyte

[0088] In a glove box under an argon atmosphere (H 2 O < 1 ppm), prepare the following formula electrolyte: 12.5% LiPF 6 , 2% VC, 0.5% PS, 5% CF 3 SO 2 Li·BF 3 , EC / DMC / EMC = 40 / 40 / 20. Stir well to obtain the lithium secondary battery electrolyte described in the present invention (free acid < 15 ppm, moisture < 10 ppm).

[0089] (2) Preparation of the positive electrode sheet

[0090] Dissolve polyvinylidene fluoride (PVDF) with a mass percentage of 3% in an NMP solution. Add lithium iron phosphate with a mass percentage of 94%, 2% conductive agent, and 1% dispersant to the above solution and mix evenly. After coating the mixed slurry on both sides of the aluminum foil, dry and roll it to obtain the positive electrode sheet. Other positive electrode materials such as LiMn 2 O 4 , LiCoO 2 , LiNi 0.5 Co 0.3 Mn 0.2 , LiNi 0.3 Co 0.3 Mn 0.3 are prepared in the same way.

[0091] (3) Preparation of the negative electrode plate

[0092] Dissolve an SBR binder with a mass percentage of 4% and a CMC thickener with a mass percentage of 1% in an aqueous solution. Add graphite with a mass percentage of 95% to the above solution and mix evenly. After coating the mixed slurry on both sides of the copper foil, dry it and roll it to obtain the negative electrode plate.

[0093] (4) Fabrication of the lithium-ion battery

[0094] Make the positive electrode plate, negative electrode plate and separator prepared above into a square battery cell in a winding manner, package it with a polymer, pour the electrolyte prepared above, and fabricate the lithium-ion battery through processes such as formation.

[0095] (5) Battery performance testing

[0096] Cyclic voltammetry test conditions: Select lithium as the counter electrode for the coated positive electrode material, assemble it into a coin cell, and use an electrochemical workstation to test the CV curve. The scanning range is the open circuit potential -4.6V, and the scanning rate is 0.1mV / s.

[0097] Cycling test conditions: Charge and discharge the battery at a rate of 1 / 1C for charge and discharge cycling tests; High-temperature storage test conditions: First, charge and discharge the battery that has completed formation once at 1C at room temperature, then fully charge the battery at 1C and perform high-temperature storage. After the battery has completely cooled, discharge the removed battery at 1C for testing.

[0098] For Examples 2-2 to 2-6 and Comparative Examples 3-1 to 3-7, other parameters and preparation methods are the same as those in Example 2-1 except for the following table parameters.

[0099] Table 1: Examples 2-2 to 2-6 and Comparative Examples 3-1 to 3-7

[0100]

[0101] Example 4-1

[0102] This example provides a preparation method for a sodium-ion battery:

[0103] (1) Preparation of the electrolyte

[0104] In a glove box under an argon atmosphere (H 2 O <1 ppm), prepare the following formula electrolyte: 12.5% NaPF 6 , 2% VC, 0.5% PS, 5% CF 3 SO 2 Na·BF 3, PC / DMC / EMC = 40 / 40 / 20, stir well to obtain the electrolyte for the sodium secondary battery of the present invention (free acid < 15 ppm, moisture < 10 ppm).

[0105] (2) Preparation of the positive electrode sheet

[0106] Dissolve polyvinylidene fluoride (PVDF) with a mass percentage of 3% in an NMP solution. Add a polyanionic cathode material with a mass percentage of 94%, a conductive agent with a mass percentage of 2%, and a dispersant with a mass percentage of 1% to the above solution and mix evenly. After coating the mixed slurry on both sides of the aluminum foil, dry and roll it to obtain the positive electrode sheet.

[0107] (3) Preparation of the negative electrode sheet

[0108] Dissolve an SBR binder with a mass percentage of 4% and a CMC thickener with a mass percentage of 1% in an aqueous solution. Add hard carbon with a mass percentage of 95% to the above solution and mix evenly. After coating the mixed slurry on both sides of the copper foil, dry and roll it to obtain the negative electrode sheet.

[0109] (4) Fabrication of the sodium ion battery

[0110] Make a square battery cell by winding the above-prepared positive electrode sheet, negative electrode sheet, and separator. Use polymer packaging, pour the above-prepared electrolyte, and fabricate a sodium ion battery through processes such as formation.

[0111] (5) Battery performance test

[0112] Cyclic voltammetry test conditions: For the coated positive electrode material, select lithium as the counter electrode, assemble a coin cell, and use an electrochemical workstation to test the CV curve. The scanning range is the open circuit potential -4.6 V, and the scanning rate is 0.1 mV / s.

[0113] From Figure 1 It can be seen that after the lithium insertion / extraction potential of the positive electrode, the oxidation potential of lithium trifluoromethanesulfonate boron trifluoride complex appears at about 4.05 V, and the oxidation potential of lithium trifluoromethanesulfonate boron trifluoride complex is higher than that of lithium trifluoromethanesulfonate (about 3.85 V), indicating that the pre-lithiated material has a suitable lithium extraction potential and meets the basic requirements of the pre-lithiated material.

[0114] From the results of Examples 2-1 to 2-8, Comparative Examples 3-4 to 3-7 and Comparative Examples 3-1 to 3-3, it can be seen that under the same solvent and additive components, the batteries using lithium sulfinate (carboxylate) complexes are significantly improved in terms of specific capacity, long-cycle capacity retention rate, and capacity recovery rate after high-temperature storage. From the results of Comparative Example 3-3, Examples 2-3, and Examples 2-6 to 2-8, it can be seen that increasing the amount of lithium sulfinate (carboxylate) complex is beneficial to the performance of the battery in terms of specific capacity, long-cycle capacity retention rate, and capacity recovery rate after high-temperature storage. From the results of Examples 1-1 to 1-3, Comparative Example 3-8, and Comparative Example 3-9, lithium bis(trifluoromethanesulfonyl)imide and lithium trifluoroacetate have poor solubility in carbonates, generally less than 3%, which is not conducive to large-capacity lithium supplementation. However, the solubility of lithium bis(trifluoromethanesulfonyl)imide complex and lithium trifluoroacetate complex can be as high as 30%, which is beneficial to large-capacity lithium supplementation.

[0115] The above results indicate that the lithium sulfinate (carboxylate) complex plays a good role in lithium supplementation in the battery.

[0116] According to the disclosure and teachings of the above specification, those skilled in the art to which the present invention pertains can also make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the present invention should also fall within the protection scope of the claims of the present invention. In addition, although some specific terms are used in this specification, these terms are only for convenience of description and do not constitute any limitation to the present invention.

Claims

1. A complex for lithium supplementation or sodium supplementation, characterized in that: The general chemical formula of the complex is: wherein R is methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, vinyl, allyl, ethynyl, phenyl, trifluoromethyl, difluoromethyl, pentafluoroethyl, trifluoroethyl or 4-fluorophenyl; A is BF3 or PF5; B is S or C; M is Li or Na.

2. A complex for lithium supplementation or sodium supplementation according to claim 1, characterized in that: When M is Li, the preparation method of the complex comprises at least the following steps: Step 1, weighing sodium sulfinate or sodium carboxylate substituted with R group, adding concentrated sulfuric acid and stirring, distilling out the sulfinic acid or carboxylic acid substituted with R group, then adding water and lithium hydroxide, and drying after neutralization reaction to obtain the following substance substituted with R group: lithium sulfinate compound or lithium carboxylate compound; wherein R group is methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, vinyl, allyl, ethynyl, phenyl, trifluoromethyl, difluoromethyl, pentafluoroethyl, trifluoroethyl or 4-fluorophenyl; Step 2, adding the lithium sulfinate compound or lithium carboxylate compound obtained in step 1 to the reaction flask, then adding an organic solvent, stirring, controlling the temperature, and then adding a fluorine boron compound or a phosphorus pentafluoride compound, stirring; Step 3, filtering and removing insoluble matter to obtain a complex solution.

3. The complex for lithium supplementation or sodium supplementation according to claim 2, characterized in that: The organic solvent described in step 2 is at least one of ethyl methyl carbonate, dimethyl carbonate, ethylene carbonate, ethyl propionate and propyl propionate.

4. A non-aqueous electrolyte comprising a conductive sodium salt or a conductive lithium salt, a non-aqueous organic solvent and an additive, characterized in that: It also includes the lithium-supplementing or sodium-supplementing complex according to any one of claims 1 to 3.

5. The non-aqueous electrolyte according to claim 4, characterized in that: The mass percentage of the complex in the electrolyte is 0.1% to 40%.

6. The non-aqueous electrolyte according to claim 5, characterized in that: The mass percentage of the complex in the electrolyte is 0.3% to 30%.

7. The non-aqueous electrolyte according to claim 4, characterized in that: The conductive lithium salt includes at least one of LiBF4, LiPF6, LiPO2F2, LiAsF6, LiClO4, LiSO3CF3, LiB(C2O4)2, LiBF2C2O4, LiN(SO2CF3)2, and LiN(SO2F)2; the conductive sodium salt includes at least one of NaBF4, NaPF6, NaPO2F2, NaAsF6, NaClO4, NaSO3CF3, NaB(C2O4)2, NaBF2C2O4, NaN(SO2CF3)2, and NaN(SO2F)2; The non-aqueous organic solvent is at least one of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, γ-butyrolactone, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, ethyl propionate, propyl propionate, and butyl propionate; The additive is at least one of vinylene carbonate, vinyl ethylene carbonate, fluoroethylene carbonate, difluoroethylene carbonate, 1,3-propane sultone, 1,4-butane sultone, vinyl sulfate, propylene sulfate, vinyl sulfite, propylene sulfite, succinonitrile, adiponitrile, 1,2-cyanoethoxyethane and hexanetrinitrile.

8. A battery comprising a positive electrode sheet, a negative electrode sheet and a separator, characterized in that: It also includes the non-aqueous electrolyte according to any one of claims 5 to 7.

9. The battery according to claim 8, characterized in that: The positive electrode sheet and the negative electrode sheet both include an active material, a conductive agent, a current collector, and a binder for binding the active material and the conductive agent to the current collector; The positive electrode sheet includes a positive electrode active material capable of reversibly inserting / deinserting lithium or sodium ions, the positive electrode active material is a composite metal oxide of lithium or sodium, and the metal oxide includes oxides of nickel, cobalt, manganese elements and any combination thereof; The negative electrode sheet includes a negative electrode active material capable of accepting or releasing lithium or sodium ions, and the negative electrode active material includes lithium or sodium metal, lithium or sodium alloy, crystalline carbon, amorphous carbon, carbon fiber, hard carbon, and soft carbon; wherein the crystalline carbon includes natural graphite, graphitized coke, graphitized MCMB, and graphitized mesophase asphalt carbon fiber; the lithium or sodium alloy includes an alloy of lithium or sodium and aluminum, zinc, silicon, tin, gallium, and antimony metal.

10. The battery according to claim 9, characterized in that: The positive electrode active material further includes at least one of the chemical elements, wherein the chemical elements include Mg, Al, Ti, Sn, V, Ge, Ga, B, Zr, Cr, Fe, Sr and rare earth elements; the positive electrode active material further includes a polyanion lithium compound LiM x (PO4) y , where M is Ni, Co, Mn, Fe, Ti, or V, 0≤x≤5, 0≤y≤5.

Images