A method for pre-lithiation / sodiation of a battery

Abstract

The application belongs to the technical field of lithium / sodium batteries, and particularly relates to a method for pre-embedding lithium / sodium in a battery. The application first prepares a lithium / sodium pre-embedding material for a lithium / sodium battery, including placing a sodium salt of the material in an organic solvent, adding acid dropwise, stirring to react, extracting and drying, and evaporating the solvent; placing the product in deionized water, adding a lithium salt, stirring to react, and evaporating the solvent; recrystallizing the solid with ethyl acetate and dichloromethane; drying the obtained solid powder to obtain the final material; and then dissolving the prepared lithium / sodium pre-embedding material in a battery electrolyte to realize pre-embedding lithium / sodium in the battery; the sodium salt of the material has an organic sodium sulfinate as a skeleton and different alkyl or aryl groups as side groups; the lithium / sodium pre-embedding material prepared by the application has high specific capacity, good compatibility with a battery system, and good material stability; the method for pre-embedding lithium / sodium in the battery through electrolyte addition is safe and convenient, has a simple process, and is low in cost, and can be mass-produced.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of batteries, and particularly relates to a method for pre-embedding lithium / sodium of a battery. BACKGROUND

[0002] In the face of growing energy demand and severe environmental problems, it is imminent to develop efficient and reliable energy storage technology. Lithium / sodium battery technology is considered to be one of the most promising energy storage technologies, with the advantages of high energy density and low cost, and has been widely used in electric vehicles and portable electric devices. However, with the further development of human society, various new applications have further improved the requirements for energy storage technology, and the current lithium / sodium battery technology is facing the problem of insufficient energy density. Therefore, it is necessary to study the use of high-capacity-density negative electrode materials, such as silicon (4200 mAh g-1) and phosphorus (2596 mAh g-1) and other new lithium / sodium batteries. However, these negative electrode materials are accompanied by irreversible side reactions during the charging and discharging process, causing the loss of lithium / sodium ions and the attenuation of battery capacity. For example, silicon-based materials (SiOx) undergo irreversible electrochemical reactions to form LiySiOx and cannot be reused; at the same time, the formation of an interface protection film (SEI) on the surface of the silicon negative electrode also consumes a part of lithium / sodium ions. In the subsequent charging process, the lithium / sodium ions that can be transferred back to the positive electrode are thus reduced, resulting in the loss of battery capacity and the inability to fully utilize the positive electrode material. These side reactions result in the first cycle coulombic efficiency (ICE) and cycle efficiency (CE) of the battery being much lower than 100%. Taking SiO negative electrode as an example, the full battery ICE is only 50%-60%, which means that more than 40% of the capacity is lost in the first cycle, greatly limiting the further development of these materials. Therefore, it is necessary to solve this problem by a pre-embedding lithium / sodium method, that is, a certain amount of lithium / sodium is stored in the battery before the battery is assembled to compensate for the loss of lithium / sodium in the first cycle.

[0003] The current mature pre-embedding lithium / sodium technology mainly includes two ways: directly introducing lithium / sodium source through the negative electrode and adding through the positive electrode. For the technology of directly introducing lithium / sodium source through the negative electrode, the advantages are: high pre-embedding lithium / sodium efficiency, no introduction of invalid components, and the disadvantages are: high process requirement, high cost, poor safety, and not conducive to large-scale production. For the pre-embedding lithium / sodium technology by adding through the positive electrode, the advantages are: high safety and simple process, and the disadvantages are: the by-products are left in the battery after the lithium / sodium is supplemented, which reduces the energy density of the battery and easily causes pore formation in the positive electrode, reducing the cycle performance of the battery. SUMMARY

[0004] The purpose of the present application is to provide a method for pre-embedding lithium / sodium of a battery, which has adjustable side groups, moderate lithium / sodium embedding potential, good stability, and safe and convenient pre-embedding lithium / sodium process.

[0005] The application provides a method for pre-embedding lithium / sodium of a battery, and the specific steps are as follows:

[0006] (I) preparation of a pre-embedded lithium / sodium material of the battery:

[0007] (1) a commercially available sodium salt is weighed and placed in a solvent to obtain a pre-embedded sodium material through recrystallization;

[0008] (2) the pre-embedded sodium material is weighed and placed in an organic solvent, an appropriate amount of acid is added, stirring reaction is carried out, extraction and drying are carried out, and the solvent is evaporated;

[0009] (3) the obtained product is placed in deionized water, an appropriate amount of lithium salt is added, stirring reaction is carried out, and the solvent is evaporated;

[0010] (4) the obtained solid is recrystallized by using ethyl acetate and dichloromethane; the obtained solid powder is dried to obtain the final pre-embedded lithium material;

[0011] (II) pre-embedding lithium / sodium of the battery:

[0012] Specifically, the prepared pre-embedded lithium / sodium material is dissolved in a traditional commercially available battery electrolyte, and the electrolyte is filled into the battery to realize pre-embedding lithium / sodium of the lithium / sodium battery.

[0013] In the application, the sodium salt of the material is an organic sodium sulfinate, and the side group substitution can be any one of different alkyl groups or aryl groups.

[0014] The structure of the organic sodium sulfinate is as follows:

[0015]

[0016] R in the structure of the organic sodium sulfinate is any one of alkyl groups such as -Me, -Et and -CF3, or any one of aryl groups such as -Ph, -CH3C6H4 and -FC6H4.

[0017] In step (I) of the application, the organic solvent used is an organic solvent with good water solubility such as acetonitrile, tetrahydrofuran, diethyl ether and ethanol; the acid used is a non-oxidizing acid such as hydrochloric acid, dilute sulfuric acid and acetic acid; and the lithium salt used is a water-soluble lithium salt such as lithium hydroxide, lithium carbonate and lithium acetate.

[0018] In step (I) of the application, after the acid is added, the stirring reaction time is 1-10 hours; after the lithium salt is added, the stirring reaction time is 5-10 hours; and the drying process is vacuum drying, the temperature is 50-100 DEG C, and the time is 10-24 hours.

[0019] In step (I) of the application, the structure of the pre-embedded lithium / sodium material is as follows:

[0020]

[0021] In step (two) of the present application, the battery is pre-lithiated / sodiated, specifically, pre-lithiated / sodiated material is dissolved in the battery electrolyte at a mass fraction of 0.1%-6%, and then the electrolyte is added to the battery to realize pre-lithiation / sodiation of the battery.

[0022] In step (two) of the present application, the battery electrolyte is a carbonate electrolyte or an ether electrolyte.

[0023] The carbonate electrolyte is, for example, 1.0 mol NaClO4 (EC:DEC=1:1), 1.0 mol LiClO4 (EC:EMC=3:7), 1.0 mol LiPF6 (EC:EMC=3:7)+5% LiClO4, 0.5 mol LiBOB+0.5 mol LiTFSI (EC:EMC=3:7), etc.; and the ether electrolyte is, for example, 1.0 mol LiPF6 (DOL:DME=1:1)+5% LiClO4, etc.

[0024] The present application has the following advantages:

[0025] 1. The organic pre-lithiated / sodiated material prepared by the present application has the following advantages: 1) the structure of the organic pre-lithiated / sodiated material is diverse, and the material structure can be designed by selecting different side groups such as alkyl groups and aryl groups; 2) the specific capacity of the pre-lithiated / sodiated material is high, and the capacity can reach 311 mAh / g and 262 mAh / g, respectively; 3) the moderate delithiation / sodiation potential is 3.2V-4.1V; 4) the synthesis process is simple and the cost is low; and 5) the pre-lithiated / sodiated material has good compatibility with the battery system, can be doped in the positive electrode, and can be directly dissolved in the electrolyte.

[0026] 2. The pre-lithiation / sodiation of the battery is achieved by directly dissolving the prepared pre-lithiated / sodiated material in the battery electrolyte, which has the following advantages: 1) the battery has good compatibility and does not need to be used by doping the positive electrode, but can be directly used by adding the electrolyte; 2) the battery can be repeatedly supplemented with lithium / sodium by multiple additions of the electrolyte; and 3) the lithium / sodium supplementing process does not change the structure of the battery components, such as causing positive electrode porosity.

[0027] 3. The present application meets the application requirements of pre-lithiation / sodiation technology: the pre-lithiated / sodiated material has good stability, the pre-lithiation / sodiation process is safe and convenient, the battery system has few residual components, the production process is simple, the cost is low, and large-scale production is possible. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The CV test curve and the charge-discharge test curve of the sodium trifluoromethyl sulfinate button cell in Example 1 of the present application.

[0029] Figure 2 CV test curve and charge-discharge test curve of lithium trifluoromethyl sulfinate button cell in Example 1 of the present application.

[0030] Figure 3 In-situ Raman test of lithium trifluoromethyl sulfinate electrolyte pre-lithiation method in Example 1 of the present application, and Raman comparison of lithium trifluoromethyl sulfinate powder, pure electrolyte, lithium trifluoromethyl sulfinate dissolved in pure electrolyte, and after charging.

[0031] Figure 4 Raman comparison of freshly prepared sample and dry air stored sample of lithium trifluoromethyl sulfinate in Example 1 of the present application.

[0032] Figure 5 Charge-discharge curve test of pre-lithiated / sodium material with different side group substitutions in Examples 2, 3, 4, and 5 of the present application. DETAILED DESCRIPTION

[0033] The present application is further described below by specific examples in conjunction with the accompanying drawings.

[0034] Example 1

[0035] Take 200 mmol of commercially available sodium trifluoromethyl sulfinate and add it to 500 ml of ethyl acetate, recrystallize, and place the obtained solid powder in a vacuum oven, dry at 60-70°C for 10 hours, to obtain the final pre-sodium material sodium trifluoromethyl sulfinate. This pre-sodium material is stable in dry air, can still be used normally after drying after absorbing moisture, and has good chemical stability.

[0036] Take 100 mmol of sodium trifluoromethyl sulfinate and add it to 50 ml of acetonitrile, stir until uniform, slowly add 10 ml of concentrated hydrochloric acid, and a white precipitate is generated. After the addition is complete, stir at room temperature for 2 hours. After the reaction is complete, remove the precipitate by filtration, wash the precipitate with ethyl acetate three times, collect the filtrate, dry with anhydrous sodium sulfate, and remove the solvent to obtain trifluoromethyl sulfonic acid.

[0037] Dissolve the obtained trifluoromethyl sulfonic acid in 80 ml of water, stir until uniform, add 90 mmol of lithium hydroxide at 0°C, slowly warm to room temperature, and react for 1 hour. After the reaction is complete, remove all the solvent to obtain a white solid. Dissolve the solid in the system with an appropriate amount of ethyl acetate, add dichloromethane to the system dropwise until no more precipitate is precipitated, and filter to obtain a white solid. Recrystallize three times using the same method, place the obtained solid powder in a vacuum oven, dry at 60-70°C for 10 hours, to obtain the final pre-lithium material lithium trifluoromethyl sulfinate. This pre-lithium material is stable in dry air, can still be used normally after drying after absorbing moisture, and has good chemical stability.

[0038] Battery preparation and testing:

[0039] 50 mg of sodium trifluoromethylsulfinate was added into 1 g of sodium battery electrolyte (1.0 mol NaClO4 EC:DEC = 1:1) and stirred to dissolve, obtaining a sodium battery electrolyte with pre-embedded sodium function. Carbon paper was used as the positive electrode. In the glove box, the positive electrode shell, carbon paper, separator, sodium sheet negative electrode, gasket, spring, and negative electrode shell were placed in order, and the electrolyte was added. The assembled button cell was fixed using a battery tablet press. As shown in Figure 1 a, the assembled button cell was tested for CV curves using an electrochemical workstation, with a scan range of 2.5-4.0 V and a scan rate of 0.1 mV / s. It can be seen from the CV curve that sodium trifluoromethylsulfinate has an irreversible sodium removal capacity. As shown in Figure 1 b, the sodium trifluoromethylsulfinate removal capacity was tested using a button cell test channel, using constant current charging and discharging, with a current of 0.06 mA and a cutoff voltage of 2.5-4.0 V. It can be seen from the charge-discharge curve that sodium trifluoromethylsulfinate has a capacity of nearly 170 mAh / g, and the decomposition potential is between 3.6-3.7 V, with a suitable sodium removal potential, meeting the basic requirements of pre-embedded sodium materials.

[0040] Figure 1 a is the CV curve test of the sodium trifluoromethylsulfinate button cell in this embodiment, which shows that sodium trifluoromethylsulfinate starts to charge and decompose at 3.7 V, releasing sodium ions. Figure 1 b is the charge-discharge test of the sodium trifluoromethylsulfinate button cell in this embodiment, which shows that sodium trifluoromethylsulfinate starts to charge and decompose at 3.6 V, with a capacity of nearly 170 mAh / g.

[0041] 10 mg of lithium trifluoromethylsulfinate was added into 1 g of lithium battery electrolyte (1.0 mol LiClO4 EC:EMC = 3:7) and stirred to dissolve, obtaining a lithium battery electrolyte with pre-embedded lithium function. Carbon paper was used as the positive electrode. In the glove box, the positive electrode shell, carbon paper, separator, lithium sheet negative electrode, gasket, spring, and negative electrode shell were placed in order, and the electrolyte was added. The assembled button cell was fixed using a battery tablet press. As shown in Figure 2 a, the assembled button cell was tested for CV curves using an electrochemical workstation, with a scan range of 2.75-4.4 V and a scan rate of 0.1 mV / s. It can be seen from the CV curve that lithium trifluoromethylsulfinate has an irreversible lithium removal capacity. As shown in Figure 2 b, the lithium trifluoromethylsulfinate removal capacity was tested using a button cell test channel, using constant current charging and discharging, with a current of 0.06 mA and a cutoff voltage of 2.75-4.3 V. It can be seen from the charge-discharge curve that lithium trifluoromethylsulfinate has a capacity of nearly 190 mAh / g, and the decomposition potential is between 3.8-3.9 V, with a suitable lithium removal potential, meeting the basic requirements of pre-embedded lithium materials.

[0042] Figure 2 a is the CV curve test of lithium trifluoromethyl sulfinate button cell in this embodiment. It can be seen that lithium trifluoromethyl sulfinate starts to decompose at 3.8V and releases lithium ions. Figure 2 b is the charge-discharge test of lithium trifluoromethyl sulfinate button cell in this embodiment. It can be seen that lithium trifluoromethyl sulfinate starts to decompose at 3.8V and has a capacity close to 190mAh / g.

[0043] Figure 3 a is the in-situ Raman test of lithium trifluoromethyl sulfinate electrolyte pre-lithiation method in this embodiment. It can be seen that the Raman characteristic peaks of lithium trifluoromethyl sulfinate gradually disappear during the charging process, indicating that lithium trifluoromethyl sulfinate in the electrolyte gradually decomposes and releases lithium ions. Figure 3 b is the Raman comparison of lithium trifluoromethyl sulfinate powder, pure electrolyte, lithium trifluoromethyl sulfinate dissolved in pure electrolyte, and after charging in this embodiment. It can be seen that the Raman characteristic peaks of lithium trifluoromethyl sulfinate disappear after charging, and at this time the electrolyte characteristic peaks are basically consistent with the pure electrolyte Raman characteristic peaks, indicating that lithium trifluoromethyl sulfinate completely disappears in the electrolyte after charging, and the pre-lithiation process has little effect on the electrolyte system.

[0044] Figure 4 The Raman comparison of freshly prepared samples and dry air storage samples of lithium trifluoromethyl sulfinate in this embodiment can be seen that the Raman characteristic peaks of freshly prepared samples and samples stored in air are basically consistent, indicating that the pre-lithiation material has good chemical stability.

[0045] Example 2

[0046] Take 200mmol of commercially available sodium methyl sulfinate and add it to water, recrystallize, and place the obtained solid powder in a vacuum oven, dry at 60-70℃ for 10 hours to obtain the final pre-sodium material sodium methyl sulfinate. The pre-sodium material is stable in dry air, and after hygroscopic drying it can still be used normally, and has good chemical stability.

[0047] Take 100mmol of sodium methyl sulfinate and add it to 50ml of acetonitrile, stir uniformly, slowly add 10ml of concentrated hydrochloric acid, and white precipitate is generated. After the addition is completed, stir at room temperature for 2 hours. After the reaction is completed, remove the precipitate by filtration, wash the precipitate with ethyl acetate three times, collect the filtrate, add anhydrous sodium sulfate to dry, and remove the solvent to obtain methyl sulfinate.

[0048] The obtained methylsulfinic acid was dissolved in 80 ml of water, stirred uniformly, and then 90 mmol of lithium hydroxide was added at 0°C, slowly warmed to room temperature, and reacted for 1 hour. After the reaction was completed, all the solvent was removed, and a white solid was obtained. The solid was washed with ethanol three times. The obtained solid powder was placed in a vacuum oven and vacuum dried at 60-70°C for 10 hours to obtain the final pre-lithiated material lithium methylsulfinic acid. The pre-lithiated material is stable in dry air, can still be used normally after being dried after absorbing moisture, and has good chemical stability.

[0049] Battery preparation and testing:

[0050] 100 mg of sodium methylsulfinic acid, 80 mg of Super P, 400 mg of a PVDF solution (5% in NMP), and an appropriate amount of NMP were added to a ball mill tank, and were uniformly milled using agate beads. A 200-micron-thick film was scraped onto an aluminum foil using a film coating machine, vacuum dried at 60-70°C for 10 hours in a vacuum oven, and a sodium methylsulfinic acid electrode sheet was obtained. The electrode sheet was cut into a Φ12 round sheet. In a glove box, a positive electrode shell, a sodium methylsulfinic acid electrode sheet, a separator, a sodium sheet negative electrode, a gasket, a spring, and a negative electrode shell were sequentially placed, and were fixed using a battery sheet press to assemble a button cell. As shown in FIG. a, the sodium methylsulfinic acid disengagement capacity was tested using a button cell test channel, and constant current charging and discharging were used, with a current of 0.06 mA and a cutoff voltage of 2.5-4.0 V. It can be seen from the charge-discharge curve that the sodium methylsulfinic acid has a capacity of approximately 262 mAh / g, and the decomposition potential is between 3.2-3.3 V, which has a suitable sodium disengagement potential, meeting the basic requirements of a pre-sodium intercalation material. Figure 5 a as shown in the figure, the sodium methylsulfinic acid disengagement capacity was tested using a button cell test channel, and constant current charging and discharging were used, with a current of 0.06 mA and a cutoff voltage of 2.5-4.0 V. It can be seen from the charge-discharge curve that the sodium methylsulfinic acid has a capacity of approximately 262 mAh / g, and the decomposition potential is between 3.2-3.3 V, which has a suitable sodium disengagement potential, meeting the basic requirements of a pre-sodium intercalation material.

[0051] Figure 5 a as shown in the figure, the sodium methylsulfinic acid disengagement capacity was tested using a button cell test channel, and constant current charging and discharging were used, with a current of 0.06 mA and a cutoff voltage of 2.5-4.0 V. It can be seen from the charge-discharge curve that the sodium methylsulfinic acid has a capacity of approximately 262 mAh / g, and the decomposition potential is between 3.2-3.3 V, which has a suitable sodium disengagement potential, meeting the basic requirements of a pre-sodium intercalation material.

[0052] 100 mg of lithium methylsulfinic acid, 80 mg of Super P, 400 mg of a PVDF solution (5% in NMP), and an appropriate amount of NMP were added to a ball mill tank, and were uniformly milled using agate beads. A 200-micron-thick film was scraped onto an aluminum foil using a film coating machine, vacuum dried at 60-70°C for 10 hours in a vacuum oven, and a lithium methylsulfinic acid electrode sheet was obtained. The electrode sheet was cut into a Φ12 round sheet. In a glove box, a positive electrode shell, a lithium methylsulfinic acid electrode sheet, a separator, a lithium sheet negative electrode, a gasket, a spring, and a negative electrode shell were sequentially placed, and were fixed using a battery sheet press to assemble a button cell. As shown in FIG. a, the sodium methylsulfinic acid disengagement capacity was tested using a button cell test channel, and constant current charging and discharging were used, with a current of 0.06 mA and a cutoff voltage of 2.5-4.0 V. It can be seen from the charge-discharge curve that the sodium methylsulfinic acid has a capacity of approximately 262 mAh / g, and the decomposition potential is between 3.2-3.3 V, which has a suitable sodium disengagement potential, meeting the basic requirements of a pre-sodium intercalation material. Figure 5b, lithium methylsulfinate was tested using a coin cell test channel, using constant current charge and discharge, current 0.06 mA, cut-off voltage 2.75-4.3 V. From the charge-discharge curve, it can be seen that lithium methylsulfinate has a capacity close to 310 mAh / g, and the decomposition potential is between 3.7-3.8 V, with a suitable delithiation potential, meeting the basic requirements of pre-lithiated materials.

[0053] Figure 5 For the charge-discharge test of lithium methylsulfinate coin cell in this embodiment, it can be seen that lithium methylsulfinate starts to charge and decompose at 3.7 V, with a capacity close to 311 mAh / g. This indicates that the pre-lithiated material has a suitable delithiation potential, meeting the basic requirements of pre-lithiated materials.

[0054] Example 3

[0055] Take 200 mmol of commercially available sodium ethylsulfinate and add it to water, recrystallize, and place the obtained solid powder in a vacuum oven, dry at 60-70°C for 10 hours, to obtain the final pre-sodium material, sodium ethylsulfinate. This pre-sodium material is stable in dry air, and after absorbing moisture and drying, it can still be used normally, with good chemical stability.

[0056] Take 100 mmol of sodium ethylsulfinate and add it to 50 ml of acetonitrile, stir until uniform, slowly add 10 ml of concentrated hydrochloric acid, and a white precipitate is generated. After the addition is complete, stir at room temperature for 2 hours. After the reaction is complete, filter out the precipitate, wash the precipitate with ethyl acetate three times, collect the filtrate, add anhydrous sodium sulfate to dry, and remove the solvent to obtain ethylsulfonic acid.

[0057] Dissolve the obtained ethylsulfonic acid in 80 ml of water, stir until uniform, and then add 90 mmol of lithium hydroxide at 0°C, slowly warm to room temperature and react for 1 hour. After the reaction is complete, remove all the solvent to obtain a white solid, wash the solid with ethanol three times. Place the obtained solid powder in a vacuum oven, dry at 60-70°C for 10 hours, to obtain the final pre-lithium material, lithium ethylsulfinate. This pre-lithium material is stable in dry air, and after absorbing moisture and drying, it can still be used normally, with good chemical stability.

[0058] Battery preparation and testing:

[0059] Put 100 mg sodium ethyl sulfinate, 80 mg Super P, 400 mg PVDF solution (5% in NMP) and appropriate amount of NMP into a ball mill tank, and mill uniformly using agate beads. Use a film coater to draw a 200-micron-thick film on an aluminum foil, and vacuum dry in a vacuum oven at 60-70°C for 10 hours to obtain a sodium ethyl sulfinate electrode sheet, and cut the electrode sheet into Φ12 round sheets. In a glove box, place the positive electrode shell, sodium ethyl sulfinate electrode sheet, separator, sodium sheet negative electrode, gasket, spring and negative electrode shell in order, and use a battery sheet press to fix and assemble a button cell. As shown in Figure 5 a, test the sodium ethyl sulfinate disengagement capacity using a button cell test channel, use constant current charging and discharging, current 0.06 mA, cutoff voltage 2.5-4.0 V. It can be seen from the charge-discharge curve that the sodium ethyl sulfinate has a capacity close to 230 mAh / g, and the decomposition potential is between 3.1-3.2 V, has a suitable sodium disengagement potential, meets the basic requirements of the pre-embedded sodium material.

[0060] Figure 5 a is the charge-discharge test of the sodium ethyl sulfinate button cell in this embodiment, it can be seen that the sodium ethyl sulfinate starts to charge and decompose at 3.1 V, and has a capacity close to 230 mAh / g. It shows that the pre-embedded sodium material has a suitable sodium disengagement potential, meets the basic requirements of the pre-embedded sodium material.

[0061] Put 100 mg lithium ethyl sulfinate, 80 mg Super P, 400 mg PVDF solution (5% in NMP) and appropriate amount of NMP into a ball mill tank, and mill uniformly using agate beads. Use a film coater to draw a 200-micron-thick film on an aluminum foil, and vacuum dry in a vacuum oven at 60-70°C for 10 hours to obtain a lithium ethyl sulfinate electrode sheet, and cut the electrode sheet into Φ12 round sheets. In a glove box, place the positive electrode shell, lithium ethyl sulfinate electrode sheet, separator, lithium sheet negative electrode, gasket, spring and negative electrode shell in order, and use a battery sheet press to fix and assemble a button cell. As shown in Figure 5 b, test the lithium ethyl sulfinate disengagement capacity using a button cell test channel, use constant current charging and discharging, current 0.06 mA, cutoff voltage 2.75-4.3 V. It can be seen from the charge-discharge curve that the lithium ethyl sulfinate has a capacity close to 265 mAh / g, and the decomposition potential is between 3.8-3.9 V, has a suitable lithium disengagement potential, meets the basic requirements of the pre-embedded lithium material.

[0062] Figure 5 b is the charge-discharge test of the lithium ethyl sulfinate button cell in this embodiment, it can be seen that the lithium ethyl sulfinate starts to charge and decompose at 3.8 V, and has a capacity close to 265 mAh / g. It shows that the pre-embedded lithium material has a suitable lithium disengagement potential, meets the basic requirements of the pre-embedded lithium material.

[0063] Example 4

[0064] Take 200 mmol of commercially available sodium phenyl sulfinate and add to water, recrystallize, and place the obtained solid powder in a vacuum oven, vacuum dry at 60-70 °C for 10 hours to obtain the final pre-sodium intercalation material sodium phenyl sulfinate. This pre-sodium intercalation material is stable in dry air and can still be used normally after drying after absorbing moisture, and has good chemical stability.

[0065] Take 100 mmol of sodium phenyl sulfinate and add to 50 ml of acetonitrile, stir uniformly, slowly drop 10 ml of concentrated hydrochloric acid, and white precipitate is generated. After the drop is completed, stir at room temperature for 2 hours. After the reaction is completed, remove the precipitate by filtration, wash the precipitate with ethyl acetate three times, collect the filtrate, add anhydrous sodium sulfate to dry, and remove the solvent to obtain phenyl sulfonic acid.

[0066] Dissolve the obtained phenyl sulfonic acid in 80 ml of water, stir uniformly, and then add 90 mmol of lithium hydroxide at 0 °C, slowly warm to room temperature, and react for 1 hour. After the reaction is completed, remove all the solvent to obtain a white solid, wash the solid with ethanol three times. Place the obtained solid powder in a vacuum oven, vacuum dry at 60-70 °C for 10 hours to obtain the final pre-lithium intercalation material lithium phenyl sulfinate. This pre-lithium intercalation material is stable in dry air and can still be used normally after drying after absorbing moisture, and has good chemical stability.

[0067] Battery preparation and testing:

[0068] Take 100 mg of sodium phenyl sulfinate, 80 mg of Super P, 400 mg of a PVDF solution (5% in NMP), and an appropriate amount of NMP into a ball mill tank, and mill uniformly using a marumezu bead. Use a film coating machine to scrape a 200 micrometer thick film on an aluminum foil, vacuum dry in a vacuum oven at 60-70 °C for 10 hours to obtain a sodium phenyl sulfinate electrode sheet, and cut the electrode sheet into a Φ12 round sheet. In a glove box, place a positive electrode shell, a sodium phenyl sulfinate electrode sheet, a separator, a sodium sheet negative electrode, a gasket, a spring, and a negative electrode shell in order, and use a battery sheet fixing machine to fix, and assemble a button cell. As shown in FIG. a, use a button cell test channel to test the sodium phenyl sulfinate disengagement capacity, use constant current charging and discharging, the current is 0.06 mA, and the cutoff voltage is 2.5-4.0 V. As can be seen from the charge-discharge curve, the sodium phenyl sulfinate has a capacity close to 163 mAh / g, and the decomposition potential is between 3.3-3.4 V, has a suitable sodium disengagement potential, and meets the basic requirements of a pre-sodium intercalation material. Figure 5 a, use a button cell test channel to test the sodium phenyl sulfinate disengagement capacity, use constant current charging and discharging, the current is 0.06 mA, and the cutoff voltage is 2.5-4.0 V. As can be seen from the charge-discharge curve, the sodium phenyl sulfinate has a capacity close to 163 mAh / g, and the decomposition potential is between 3.3-3.4 V, has a suitable sodium disengagement potential, and meets the basic requirements of a pre-sodium intercalation material.

[0069] Figure 5a is the charge-discharge test of the sodium phenyl sulfinate sodium button cell in this embodiment. It can be seen that sodium phenyl sulfinate starts to decompose at 3.3 V during charging, and has a capacity of about 163 mAh / g. This shows that the pre-sodium intercalation material has a suitable sodium extraction potential, meeting the basic requirements of the pre-sodium intercalation material.

[0070] 100 mg of lithium phenyl sulfinate, 80 mg of Super P, 400 mg of a PVDF solution (5% in NMP), and an appropriate amount of NMP were added to a ball milling tank and uniformly milled using agate beads. A 200-micron-thick film was scraped onto an aluminum foil using a film coating machine, and vacuum dried in a vacuum oven at 60-70°C for 10 hours to obtain a lithium phenyl sulfinate electrode sheet. The electrode sheet was cut into a Φ12 round sheet. In a glove box, a positive electrode shell, a lithium phenyl sulfinate electrode sheet, a separator, a lithium sheet negative electrode, a gasket, a spring, and a negative electrode shell were sequentially placed and fixed using a battery sheet press to assemble a button cell. Figure 5 b is the charge-discharge test of the lithium phenyl sulfinate button cell in this embodiment. It can be seen that lithium phenyl sulfinate starts to decompose at 3.9 V during charging, and has a capacity of about 181 mAh / g. This shows that the pre-lithium intercalation material has a suitable lithium extraction potential, meeting the basic requirements of the pre-lithium intercalation material.

[0071] Figure 5 b is the charge-discharge test of the lithium phenyl sulfinate button cell in this embodiment. It can be seen that lithium phenyl sulfinate starts to decompose at 3.9 V during charging, and has a capacity of about 181 mAh / g. This shows that the pre-lithium intercalation material has a suitable lithium extraction potential, meeting the basic requirements of the pre-lithium intercalation material.

[0072] Example 5

[0073] Take 200 mmol of commercially available p-tolyl sulfinate sodium and add it to water, recrystallize, and place the obtained solid powder in a vacuum oven, vacuum dry at 60-70°C for 10 hours to obtain the final pre-sodium intercalation material p-tolyl sulfinate sodium. This pre-sodium intercalation material is stable in dry air, and can still be used normally after drying in a humid environment, having good chemical stability.

[0074] Take 100 mmol of p-tolyl sulfinate sodium and add it to 50 ml of acetonitrile, stir uniformly, slowly add 10 ml of concentrated hydrochloric acid, and a white precipitate is generated. After the addition is complete, stir at room temperature for 2 hours. After the reaction is complete, remove the precipitate by filtration, wash the precipitate with ethyl acetate three times, collect the filtrate, add anhydrous sodium sulfate to dry, and remove the solvent to obtain p-tolyl sulfinate.

[0075] The obtained p-tolylsulfinic acid was dissolved in 80 ml of water, stirred uniformly, and then 90 mmol of lithium hydroxide was added at 0°C, slowly warmed to room temperature, and reacted for 1 hour. After the reaction was completed, all the solvent was removed to obtain a white solid, which was washed with ethanol three times. The obtained solid powder was placed in a vacuum oven and vacuum dried at 60-70°C for 10 hours to obtain the final pre-lithiated material lithium p-tolylsulfinic acid. The pre-lithiated material is stable in dry air, can still be used normally after being dried after absorbing moisture, and has good chemical stability.

[0076] Battery preparation and testing:

[0077] 100 mg of sodium p-tolylsulfinic acid, 80 mg of Super P, 400 mg of a PVDF solution (5% in NMP), and an appropriate amount of NMP were added to a ball mill tank and uniformly milled using marume beads. A 200-micron-thick film was scraped on an aluminum foil using a film coating machine, vacuum dried at 60-70°C for 10 hours in a vacuum oven, and a sodium p-tolylsulfinic acid electrode sheet was obtained. The electrode sheet was cut into a Φ12 round sheet. In a glove box, a positive electrode shell, a sodium p-tolylsulfinic acid electrode sheet, a separator, a sodium sheet negative electrode, a gasket, a spring, and a negative electrode shell were sequentially placed, fixed using a battery sheet press, and a button cell was assembled. As shown in FIG. a, the sodium p-tolylsulfinic acid disengagement capacity was tested using a button cell test channel, constant current charging and discharging were used, the current was 0.06 mA, and the cutoff voltage was 2.5-4.0 V. As can be seen from the charge-discharge curve, the sodium p-tolylsulfinic acid has a capacity of nearly 150 mAh / g, and the decomposition potential is between 3.3-3.4 V, has a suitable sodium disengagement potential, and meets the basic requirements of a pre-sodium intercalation material. Figure 5

[0078] Figure 5 a is the charge-discharge test of the sodium p-tolylsulfinic acid button cell in this embodiment. As can be seen, the sodium p-tolylsulfinic acid starts to charge and decompose at 3.3 V, has a capacity of nearly 150 mAh / g. This indicates that the pre-sodium intercalation material has a suitable sodium disengagement potential, and meets the basic requirements of a pre-sodium intercalation material.

[0079] 100 mg of lithium p-tolylsulfinic acid, 80 mg of Super P, 400 mg of a PVDF solution (5% in NMP), and an appropriate amount of NMP were added to a ball mill tank and uniformly milled using marume beads. A 200-micron-thick film was scraped on an aluminum foil using a film coating machine, vacuum dried at 60-70°C for 10 hours in a vacuum oven, and a lithium p-tolylsulfinic acid electrode sheet was obtained. The electrode sheet was cut into a Φ12 round sheet. In a glove box, a positive electrode shell, a lithium p-tolylsulfinic acid electrode sheet, a separator, a lithium sheet negative electrode, a gasket, a spring, and a negative electrode shell were sequentially placed, fixed using a battery sheet press, and a button cell was assembled. As shown in FIG. a, the lithium p-tolylsulfinic acid disengagement capacity was tested using a button cell test channel, constant current charging and discharging were used, the current was 0.06 mA, and the cutoff voltage was 2.5-4.0 V. As can be seen from the charge-discharge curve, the lithium p-tolylsulfinic acid has a capacity of nearly 150 mAh / g, and the decomposition potential is between 3.3-3.4 V, has a suitable sodium disengagement potential, and meets the basic requirements of a pre-sodium intercalation material. Figure 5 ​b shows that the lithium p-tolyl sulfinate is tested by using a button cell test channel, using constant current charging and discharging, current 0.06 mA, cut-off voltage 2.75-4.3 V. It can be seen from the charge-discharge curve that the lithium p-tolyl sulfinate has a capacity of nearly 165 mAh / g, and the decomposition potential is between 3.9-4.0 V, has a suitable delithiation potential, meets the basic requirements of pre-lithium-embedded materials.

[0080] ​ b is the charge-discharge test of lithium p-tolyl sulfinate button cell in this embodiment, it can be seen that lithium p-tolyl sulfinate starts to charge and decompose at 3.9 V, has a capacity of nearly 165 mAh / g. It shows that the pre-lithium-embedded material has a suitable delithiation potential, meets the basic requirements of pre-lithium-embedded materials.

Claims

1. A method of pre-lithiating / sodiation of a battery, characterized in that, The specific steps are: (I) preparation of a battery pre-embedded lithium / sodium material: (1) weigh the material sodium salt, place it in a solvent, recrystallize to obtain a pre-embedded sodium material; (2) weigh the pre-embedded sodium material, place it in an organic solvent, add acid dropwise, stir the reaction, extract and dry, and evaporate the solvent; (3) place the obtained product in deionized water, add lithium salt, stir the reaction, and evaporate the solvent; (4) recrystallize the obtained solid with ethyl acetate and dichloromethane; dry the obtained solid powder to obtain the final pre-embedded lithium material; The structure of the material sodium salt is as follows: ; wherein R is any one of -Me, -Et; In step (I), after adding the acid, the stirring reaction time is 1-10 hours; after adding the lithium salt, the stirring reaction time is 5-10 hours; the drying process is vacuum drying, the temperature is 50-100℃, and the time is 10-24 hours; (II) pre-embedding lithium / sodium for the battery; Add 100mg of pre-embedded lithium / sodium material, 80mg of Super P, 400mg of 5% PVDF solution in NMP, and NMP to a ball mill tank, and mill uniformly using agate beads; use a film coating machine to scrape a 200-micron-thick film on an aluminum foil, and dry in a vacuum oven at 60-70℃ for 10 hours to obtain an electrode sheet; The pre-embedded lithium / sodium material is one of sodium methyl sulfinate, sodium ethyl sulfinate, lithium methyl sulfinate, and lithium ethyl sulfinate.

2. The method of pre-lithiating / sodiating a battery cell according to claim 1, wherein, In step (I), the solvent is selected from one of water, ethyl acetate, and ethanol.

3. The method of pre-lithiating / sodiating a battery cell according to claim 1, wherein, In step (I): The organic solvent is selected from one of acetonitrile, tetrahydrofuran, diethyl ether, and ethanol; The acid is selected from one of hydrochloric acid, sulfuric acid, and acetic acid; The lithium salt is selected from one of lithium hydroxide, lithium carbonate, and lithium acetate.

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