CN116111184A - A kind of lithium-ion battery aqueous electrolyte and its preparation method and application - Google Patents

Abstract

The invention discloses a lithium-ion battery aqueous electrolyte and its preparation method and application. In the invention, water is added to the commercial electrolyte and nano-diamond particles are introduced to prepare the mixed electrolyte of water and nano-diamond. The mixed electrolyte is introduced into the ion lithium battery half-cell and full battery. During the charge-discharge cycle, the aqueous mixed electrolyte has higher ionic conductivity and better wettability of the separator, which is beneficial to improve the transmission capacity of lithium ions. The synergistic effect of nano-diamond particles and water builds a nano-diamond-related solid electrolyte interface, which provides abundant active sites for lithium ion adsorption, protects negative electrodes such as graphite from stripping under the action of water, and improves the overall performance of the battery such as capacity and rate. The preparation method of the invention is simple, low in cost, friendly to the environment, and has good prospects for industrialized production.

Description

A kind of lithium-ion battery aqueous electrolyte and its preparation method and application

technical field

The invention belongs to the technical field of lithium ion battery electrolyte, and relates to an electrolyte containing a certain amount of water and a method for improving the comprehensive performance of the battery.

Background technique

In recent years, the rapid development of advanced electric vehicles and various electronic products has put forward higher requirements on the energy density, cycle life and safety performance of lithium-ion batteries. The electrolyte in lithium batteries is usually aqueous or anhydrous, and most commercial lithium batteries are assembled from anhydrous electrolytes and graphite negative electrodes. The incorporation of trace amounts of water in commercial anhydrous electrolytes can lead to lithium salt hydrolysis, degradation of the solid electrolyte interface (SEI), and heightened safety risks. In particular, water in carbonate-based electrolytes reacts with lithium hexafluorophosphate to form corrosive hydrofluoric acid, which degrades the performance of the electrolyte and leads to its instability. At the same time, most commercial anodes use graphite materials, which are very sensitive to trace amounts of water in the electrolyte. The intercalation of water molecules in the graphite anode will cause severe structural degradation of the graphite anode, leading to rapid failure of the battery. During the entire production and transportation process of lithium batteries, a long-term dry storage environment needs to be provided, which will increase product costs. Therefore, it is necessary to evaluate the effect of water on the performance of lithium-ion batteries and to study the possibility of using water to improve the performance of lithium-ion batteries.

Similar to the present invention is the patent application with the application number 202210909358.0 titled "A water remover for carbonate organic solvents in lithium-ion battery electrolyte and its preparation method and application", which prepared a solid water remover agent. The water remover can efficiently remove the water in the aqueous electrolyte, ensures the purity of the carbonate organic solvent in the lithium ion electrolyte, and does not involve the actual function and effect of water in the electrolyte to improve the capacity and rate performance of the lithium ion battery.

The reports related to aqueous electrolytes are all focused on designing to remove trace water, and there are few reports on improving the performance of lithium-ion batteries by increasing the concentration of trace water.

Contents of the invention

The invention provides a mixed electrolyte solution prepared by introducing high-concentration trace water with the aid of nano-diamonds to realize the improvement of the capacity and cycle stability of lithium-ion batteries.

A kind of lithium-ion battery aqueous electrolyte among the present invention, is made up of commercial electrolyte, nano-diamond particle and trace water, the concentration of nano-diamond particle is 800ppm, and trace water concentration is 5000ppm; Water is deionized water;

The particle diameter of described nano-diamond particle is 5～10nm, and described nano-diamond particle is processed as follows:

1) Add nano-diamond particles into a mixed acid solution prepared by concentrated sulfuric acid and concentrated hydrochloric acid, and heat at 180°C for 20 minutes to remove impurities on the diamond surface; the volume ratio of concentrated sulfuric acid and concentrated hydrochloric acid in the mixed acid solution is 1:1, Concentrated sulfuric acid and concentrated hydrochloric acid are commercially available concentrations;

2) Perform surface oxygen terminal treatment on the nano-diamond particles from which surface impurities have been removed in step 1).

The commercial electrolyte is preferably LiPF ₆ electrolyte, and the solvent volume ratio EC:DMC=1:1.

A kind of preparation method of lithium-ion battery aqueous electrolyte, concrete steps are as follows:

1) Add nano-diamond particles into a mixed acid solution prepared by concentrated sulfuric acid and concentrated hydrochloric acid, and heat at 180°C for 20 minutes to remove impurities on the diamond surface; the particle size of nano-diamond particles is 5-10 nm, and the concentration of The volume ratio of sulfuric acid and concentrated hydrochloric acid is 1:1, and both concentrated sulfuric acid and concentrated hydrochloric acid are commercially available concentrations;

2) carry out surface oxygen terminal treatment to step 1) the nano-diamond particle that removes surface impurity;

3) Add the nano-diamond and deionized water obtained in step 2) into the commercial electrolyte, and perform ultrasonic treatment for 15 minutes under the protection of argon to obtain a trace amount of water and nano-diamond mixed electrolyte; the concentration of nano-diamond particles in the mixed electrolyte is 800ppm , the trace water concentration is 5000ppm.

The surface oxygen termination treatment is performed under the irradiation of ultraviolet light in the atmospheric environment for 5-30s.

A lithium-ion battery aqueous electrolyte is used to prepare lithium-ion battery half-cells, the specific process is:

1) Mix the graphite negative electrode with the conductive agent (carbon black), grind it under the action of the binder polyvinylidene fluoride (PVDF), and add the solvent 1-methyl-2-pyrrolidone (NMP) to stir it with magnetic force Stirred into a viscous fluid; the proportions of graphite, conductive agent and binder are respectively 80wt%, 10wt% and 10wt%;

2) Apply the viscous fluid to the copper foil current collector and dry it at 120°C; finally compact it and cut it into a circular electrode (diameter 12mm) to prepare a graphite negative electrode for lithium-ion batteries, with a load mass of about 4 mg cm ^-2 ;

3) Under anhydrous and oxygen-free conditions, metal lithium is used as the counter electrode and graphite is used as the negative electrode, and 80 μL of trace water and nano-diamond mixed electrolyte are added dropwise to assemble a lithium-ion half-cell.

A kind of lithium-ion battery aqueous electrolyte is used to prepare the purposes of lithium-ion battery full battery, and specific process is:

1) With lithium iron phosphate (LFP) as the positive electrode of the full battery, the lithium iron phosphate powder is mixed with the conductive agent acetylene black, ground under the action of the binder polyvinylidene fluoride (PVDF), and the solvent 1- Methyl-2-pyrrolidone (NMP) is stirred into a viscous fluid with a magnetic stirrer; the ratios of lithium iron phosphate, auxiliary conductive agent and binder are respectively 80wt%, 10wt% and 10wt%;

2) Coat the viscous fluid on an aluminum foil and dry it under vacuum at 120°C for 12 hours; finally punch it into a disk (12mm in diameter) with a loading mass of 6-8mg cm ^-2 .

3) Under anhydrous and oxygen-free conditions, LFP was used as the positive electrode and graphite was used as the negative electrode, and 80 μL of trace water and nano-diamond mixed electrolyte was added dropwise to assemble a lithium-ion full battery.

Beneficial effects of the present invention:

The invention utilizes nano-diamond particles and deionized water to prepare trace water and nano-diamond mixed electrolyte; the ionic conductivity of the electrolyte and the wettability of the polypropylene diaphragm are improved; the nano-diamond and water synergistically act on the surface of the graphite negative electrode Construct nano-diamond solid electrolyte interface (SEI); use trace water and nano-diamond mixed electrolyte to prepare high-performance lithium-ion batteries, solve the limitations of commercial lithium battery preparation and use conditions (anhydrous dry environment), and solve the graphite negative electrode ratio Low capacity, low capacity retention rate and other issues. The nano-diamond solid electrolyte interface not only has high hardness, which can inhibit the growth of lithium dendrites and the volume expansion of negative electrode materials, but also facilitates the solid-phase diffusion of lithium ions and provides a large number of active sites for the rapid adsorption/desorption of lithium ions. The preparation method of the trace water and nano-diamond mixed electrolyte of the present invention has the advantages of simple process, low cost, easy realization, etc., and is expected to be mass-produced in the future.

Description of drawings

Figure 1 is a diagram of the wettability of samples 1, 2 and 3 to polypropylene separators in Example 1.

Fig. 2 is the ionic conductivity diagram of samples 1, 2 and 3 in Example 1.

Fig. 3 is a comparison chart of electrochemical performance of batteries 1, 2 and 3 in Example 2 (0.1Ag ^-1 ).

Fig. 4 is a comparison chart (1Ag ^-1 ) of the electrochemical performance of batteries 1, 2 and 3 in Example 2.

Fig. 5 is a comparison chart of electrochemical performance of batteries 1, 2 and 3 in Example 2 (variable magnification).

FIG. 6 is a graph showing the component contents of samples 4, 5 and 6 in Example 4.

FIG. 7 is a transmission electron microscope image of sample 6 in Example 4.

Fig. 8 is a comparative diagram of the electrochemical performance of batteries 4, 5 and 6 in Example 5 (0.1Ag ^-1 ).

Fig. 9 is a comparison chart of electrochemical performance of batteries 7, 8 and 9 in Example 6 (0.1Ag ^-1 ).

FIG. 10 is a comparison chart of electrochemical performance of batteries 10, 11 and 12 in Example 7 (0.1Ag ^-1 ).

Detailed ways

The present application will be described in further detail below in conjunction with the accompanying drawings and embodiments. It should be noted that the following embodiments are intended to facilitate the understanding of the present application, rather than limiting it in any way.

Embodiment 1: the preparation of trace water and nano-diamond mixed electrolyte

1) Take 10 mL of concentrated hydrochloric acid (commercially available at a mass percent concentration of 37%) and concentrated sulfuric acid (commercially available at a concentration of 98.3% by mass) respectively, and prepare a mixed acid solution with a volume ratio of 1:1;

2) Add 0.1g to 0.3g of nano-diamond particles with a particle size of 5 to 10nm into the above mixed acid solution, and heat at 180°C for 20min to remove the surface impurities of the diamond;

3) Treating the acid-treated nano-diamond particles in step 2) under ultraviolet light irradiation in the atmospheric environment for 5-30s;

4) Preparation of electrolyte samples:

a. Denote 100mL commercial LiPF ₆ (EC and DMC volume ratio is 1:1) electrolyte as sample 1.

b. Add a certain amount of deionized water to 100mL commercial LiPF ₆ electrolyte (same as sample 1) to prepare an aqueous electrolyte with a water concentration of 5000ppm, which is designated as sample 2.

c. Take 0.08g of treated nano-diamond particles and add them to the electrolyte of the same composition as sample 2, and ultrasonically treat them for 15 minutes under the protection of argon to obtain a mixture of trace water and nano-diamonds with a diamond concentration of 800ppm and a water concentration of 5000ppm Electrolyte, denoted as sample 3.

Embodiment 2: the making of lithium ion half battery

1) The negative electrode of lithium ion battery is composed of 80wt% graphite, 10wt% binder (polyvinylidene fluoride, PVDF) and 10wt% acetylene black.

2) Add a certain amount of 1-methyl-2-pyrrolidone (NMP, solvent) to the mixed negative electrode and stir for 6 hours until the mixture is a viscous fluid.

3) The fluid slurry was coated on copper foil and dried under vacuum at 120° C. for 12 hours.

4) Cut the copper foil into small disk-shaped pieces (diameter 12 mm), and control the loading density of the electrode at 4 mg cm ⁻² .

5) In an anhydrous and oxygen-free environment, assemble a CR-2025 button battery with a metal lithium sheet as the positive electrode and graphite as the negative electrode, and add 80 μL of sample 1, sample 2, and sample 3 electrolytes to each battery.

6) Weigh the mass of the electrode sheet before assembly to prepare for calculation of subsequent specific capacity parameters, etc.

7) The lithium-ion half-cells prepared using sample 1, sample 2, and sample 3 are labeled as battery 1, battery 2, and battery 3, respectively.

Embodiment 3: the making of lithium-ion full battery

1) The positive electrode of the lithium-ion full battery is composed of 80wt% lithium iron phosphate, 10wt% binder (polyvinylidene fluoride, PVDF) and 10wt% acetylene black.

2) Add a certain amount of 1-methyl-2-pyrrolidone (NMP, solvent) to the mixed positive electrode and stir for 6 hours until the mixture is a viscous fluid.

3) The fluid slurry was coated on copper foil and dried under vacuum at 120° C. for 12 hours.

4) Cut the copper foil into small disk-shaped pieces (diameter 12 mm), and control the loading density of the electrodes at 6-8 mg cm ⁻² .

5) In an anhydrous and oxygen-free environment, use lithium iron phosphate as the positive electrode and the graphite electrode prepared in Example 2 as the negative electrode to assemble a CR-2025 button battery, and add 80 μL of sample 1, sample 2 and Sample 3 Electrolyte.

6) Weigh the mass of the electrode sheet before assembly to prepare for calculation of subsequent specific capacity parameters, etc.

7) The lithium-ion full batteries prepared using sample 1, sample 2, and sample 3 are labeled as battery 4, battery 5, and battery 6, respectively.

Example 4: Testing of lithium-ion half-cells

The electrochemical performance of battery 1, battery 2 and battery 3 was tested in the blue electric test system. At 25°C, discharge to 0.01V at a certain rate; after discharge, let the battery stand for 3 minutes; then charge to 3V at a certain rate, after charging, discharge the battery at the same constant rate for 3 minutes to 0.01V; after discharging the battery, let it stand for 3 minutes, and then charge it under the same conditions. After the test was completed, the negative electrode active materials in battery 1, battery 2 and battery 3 were taken out respectively and recorded as sample 4, sample 5 and sample 6.

Embodiment 5: the test of lithium-ion full battery

The electrochemical performance of battery 4, battery 5 and battery 6 was tested in the blue electric test system. At 25°C, charge to 3.9V at a certain rate; after charging, let the battery stand still for 3 minutes; then discharge to 2.5V at a certain rate, after discharging, charge the battery at the same constant rate after standing for 3 minutes to 3.9V; after charging the battery, let it stand for 3 minutes, and then discharge it under the same conditions.

Example 6: Lithium-ion half-cell test under different trace water concentrations

The manufacturing steps of the lithium-ion half-battery in Example 2 are the same, the difference is that the electrolyte used is trace water of 10ppm, 2000ppm and 3000ppm respectively added to sample 1, and the prepared lithium-ion half-batteries are respectively marked as Battery 7, Battery 8 and Battery 9.

Example 7: Lithium-ion half-cell tests with different ND contents

The manufacturing steps of the lithium-ion half-battery in Example 2 are the same, the difference is that the electrolyte used is that the ND content in sample 3 is 200ppm, 400ppm and 1000ppm respectively, and the prepared lithium-ion half-batteries are respectively marked as battery 10 , battery 11 and battery 12.

Effect verification

1. Contact angle test:

The contact angle test results between sample 1, sample 2 and sample 3 and polypropylene diaphragm (PP diaphragm) are shown in Figure 1. It can be seen from the figure that the contact angle between sample 2 and sample 3 with high water content and PP diaphragm The contact angle between is 27.1°, which is lower than that of anhydrous sample 1 (35.1°). Therefore, the trace amount of water in the electrolyte is beneficial to improve its wettability to the separator, promote the uniform distribution of Li-ion flux, and provide more pathways for Li-ion transport.

2. Ionic conductivity test

The ion conductivity test results of sample 1, sample 2 and sample 3 are shown in Figure 2, the ion conductivity of high water concentration sample 2 and sample 3 is about 10.5mS cm ^-1 , which is significantly higher than that of low water concentration sample 1 ( 8.2 mS cm ^-1 ). The high ionic conductivity helps to improve the transport capacity of lithium ions between the electrodes, thereby enhancing the rate performance of the battery.

3. Lithium-ion half-battery charge and discharge performance test

The electrochemical performance test results of battery 1, battery 2 and battery 3 at a current density of 0.1A g ^-1 are shown in Figure 3. It can be seen from the figure that the initial discharge capacity of battery 1 is 455mA h g ^-1 , and after 100 The capacity remained at 365mAhg ^-1 after one cycle. The initial discharge capacity of battery 2 was 6500mA h g ^-1 , which decreased to 5mA h g ^-1 after 10 cycles, and the capacity loss was close to 99%. The initial discharge capacity of battery 3 is 1850mA h g ^-1 , and it remains at 900mA h g ^-1 after 100 cycles. It can be seen that the capacity of battery 3 is much higher than that of battery 1 and battery 2.

The electrochemical performance test results at a current density of 1Ag ^-1 are shown in Figure 4. The initial discharge capacity of battery 1 was 150mA h g ^-1 , and remained at 55mA h g ^-1 after 1000 cycles. The initial discharge capacity of battery 2 was 250mA h g ^-1 , which decreased to 2mA h g ^-1 after 30 cycles. The initial discharge capacity of battery 3 was 605mAh g ^-1 and remained at 350mAh g ^-1 after 1000 cycles. It can be seen that the capacity of battery 3 is almost 4 times that of battery 1 after 1000 long cycles.

Variable magnification discharge, set to 0.1Ag ^-1 , 0.5Ag ^-1 , 1Ag ^-1 , 2Ag ^-1 and 5Ag ^-1 in sequence, and conduct charge reversible specific capacity tests on battery 1, battery 2 and battery 3, as shown in Figure 5 As shown, battery 3 exhibited ^a more excellent rate capability, with capacities of 1000 ^{, 625 , 625} , 390, 240 and 150mA h g ^-1 , and had higher capacities than battery 1 at each rate test stage. Battery 2 has almost no capacity after a few cycles. When the current density decreased from 5A g ^-1 to 0.1A g ^-1 , the capacity of battery 3 recovered to 950mA h g ^-1 with a capacity retention rate of 95%, indicating that the trace water and nano-diamond hybrid electrolyte has a significant repeatability and stability.

4. Composition content characterization of sample 4, sample 5 and sample 6

Figure 6 shows the component content analysis of sample 4, sample 5 and sample 6, and the corresponding histograms show that the content of LiF in sample 4 is greater than that of Li _x PF _y , and the content of Li ₂ CO ₃ is relatively low. In sample 5, the content of Li _x PF _y is as high as 60%, which indicates that the water in the electrolyte induces the Li _x PF _y enriched SEI. However, for sample 6, the content _of LiF is significantly higher than _LixPFy , and the content of _Li2CO3 exceeds 40% _. Importantly, LiF and _Li2CO3 are the key components to stabilize the SEI layer, which can enhance the passivation function of the SEI layer and improve the interfacial transport ability of Li ions, thereby improving the rate performance and cycle stability _of Li-ion batteries.

5. Transmission electron microscope characterization of sample 6

Figure 7 shows the transmission electron microscope image of sample 6 after charging and discharging cycles. A dense SEI is formed on the surface of the graphite negative electrode with a thickness of about 150 nm, and a large number of nano-diamond particles are dispersed in the SEI matrix. Nano-diamond particles with a considerable density can inhibit the intercalation of water molecules in the graphite negative electrode, protect the structure of the negative electrode, and provide more lithium ion storage adsorption sites, shorten the transmission distance of lithium ions, and achieve high battery capacity and excellent performance. rate performance.

6. Lithium-ion full battery charge and discharge performance test

At a current density of 0.1A g ^-1 , the electrochemical performance test results of the full battery are shown in Fig. 8. It can be seen from the figure that for battery 5, the initial discharge and charge capacities are 200mA h g ^-1 and 202mA h g -1 respectively ^{. 1} , however, its performance was severely degraded and degraded after only 10 cycles. The initial discharge and charge capacities of battery 6 were 180mA h g ^-1 and 178mA h g ^-1 , respectively, and remained at 168mA h g ^-1 after 50 cycles, with a capacity retention of 95% and a Coulombic efficiency close to 100%, showing good cycle stability. At the same time, the capacity of battery 6 is significantly higher than that of battery 4 (98 mA h g ⁻¹ ).

7. Lithium-ion half-cell test under different trace water concentrations

The test results of Li-ion half-cells with different trace water concentrations at a current density of 0.1A g ^-1 are shown in Fig. exhibited better cycling stability. This suggests that water in the electrolyte has a negative impact on battery performance in the absence of nanodiamonds.

8. Lithium-ion half-cell test with different nano-diamond content

At a current density of 0.1A g ^-1 , the test results of lithium-ion half-cells based on 5000ppm water and different nanodiamond contents are shown in Figure 10. Battery 10 (200ppm), battery 11 (400ppm) and battery 12 (1000ppm) in The capacities after 50 cycles are 20mAh g ^-1 , 450mAh g ^-1 and 850mAh g ^-1 respectively, wherein the capacity of battery 12 is close to that of battery 3 (900mAh g ^-1 ).

In order to further verify the effect of the present invention except the above-mentioned examples, the present invention also uses LiClO ₄ (EC and DMC volume ratio is 1:1) electrolyte to replace the commercial LiPF ₆ (EC and DMC volume ratio) used in Examples 1 to 7. The ratio is 1:1), and it has been verified that the two have the same verification effect, and it can be inferred that the method of the present invention also has the same or similar effect in other commercial electrolytes.

Claims (8)

1. The aqueous electrolyte of the lithium ion battery is characterized by comprising commercial electrolyte, nano diamond particles and trace water, wherein the concentration of the nano diamond particles is 800ppm, and the concentration of the trace water is 5000ppm; the water is deionized water;

the particle size of the nano diamond particles is 5-10 nm, and the nano diamond particles are treated as follows:

1) Adding nano diamond particles into a mixed acid solution prepared from concentrated sulfuric acid and concentrated hydrochloric acid, and heating at 180 ℃ for 20min to remove impurities on the surface of the diamond; the volume ratio of the concentrated sulfuric acid to the concentrated hydrochloric acid in the mixed acid solution is 1:1, and the concentrated sulfuric acid and the concentrated hydrochloric acid are all in commercial concentration;

2) And 3) carrying out surface oxygen termination treatment on the nano diamond particles with the surface impurities removed in the step 1).

2. The aqueous electrolyte of claim 1, wherein the commercial electrolyte is LiPF ₆ Electrolyte, solvent volume ratio EC, dmc=1:1.

3. The method for preparing the aqueous electrolyte of the lithium ion battery according to claim 1, wherein the method comprises the following specific steps:

1) Adding nano diamond particles into a mixed acid solution prepared from concentrated sulfuric acid and concentrated hydrochloric acid, and heating at 180 ℃ for 20min to remove impurities on the surface of the diamond; the particle size of the nano diamond particles is 5-10 nm, the volume ratio of the concentrated sulfuric acid to the concentrated hydrochloric acid in the mixed acid solution is 1:1, and the concentrated sulfuric acid and the concentrated hydrochloric acid are both in commercial concentration;

2) Carrying out surface oxygen terminal treatment on the nano diamond particles with the surface impurities removed in the step 1);

3) Adding the nano-diamond obtained in the step 2) and deionized water into commercial electrolyte, and performing ultrasonic treatment for 15min under the protection of argon to obtain trace water and nano-diamond mixed electrolyte; the concentration of the nano diamond particles in the mixed electrolyte is 800ppm, and the concentration of trace water is 5000ppm.

4. The method for preparing an aqueous electrolyte for a lithium ion battery according to claim 3, wherein the surface oxygen termination treatment is carried out under the irradiation of ultraviolet light in the atmospheric environment for 5s to 30s.

5. Use of the aqueous electrolyte for lithium ion batteries according to claim 1 for the preparation of lithium ion batteries, characterized in that the specific process for the preparation of lithium ion half-batteries is:

1) Mixing a graphite cathode with a conductive aid, grinding under the action of a binder, adding a solvent, and stirring with a magnetic stirrer to form a viscous fluid; the proportion of graphite, the auxiliary conductive agent and the binder is 80wt%, 10wt% and 10wt%, respectively;

2) Coating the viscous fluid on a copper foil current collector, and drying at 120 ℃; finally compacting and cutting into round electrodes to obtain the graphite negative electrode of the lithium ion battery, wherein the load mass is about 4mg cm ^-2 ；

3) And 3) taking metal lithium as a counter electrode under the anhydrous and anaerobic condition, dripping 80 mu L trace water and nano diamond mixed electrolyte into the negative electrode obtained in the step 2), and assembling the lithium ion half cell.

6. The use of the aqueous electrolyte for lithium ion batteries according to claim 5, wherein the co-conducting agent is carbon black, the binder is polyvinylidene fluoride, and the solvent is 1-methyl-2-pyrrolidone.

7. Use of the aqueous electrolyte for lithium ion batteries according to claim 1 for the preparation of lithium ion batteries, characterized in that the specific process for the preparation of lithium ion full batteries is:

1) Taking lithium iron phosphate as the positive electrode of a full battery, mixing lithium iron phosphate powder with a conductive aid, grinding under the action of a binder, adding a solvent, and stirring with a magnetic stirrer to form a viscous fluid; the proportion of the lithium iron phosphate, the auxiliary conductive agent and the binder is 80wt%, 10wt% and 10wt%, respectively;

2) The viscous fluid was coated on an aluminum foil and dried under vacuum at 120 ℃ for 12 hours; finally, the mixture is punched into a disc with the load mass of 6 to 8mg cm ^-2 ；

3) And 3) under the anhydrous and anaerobic condition, taking the graphite as the negative electrode, dripping 80 mu L trace water and nano diamond mixed electrolyte, and assembling the lithium ion full battery.

8. The use of the aqueous electrolyte for lithium ion batteries according to claim 7, wherein the co-conducting agent is acetylene black, the binder is polyvinylidene fluoride, and the solvent is 1-methyl-2-pyrrolidone.

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