WO2013029208A1

WO2013029208A1 - High-specific-energy lithium-rich multi-element-based lithium-ion storage battery and method for fabricating same

Info

Publication number: WO2013029208A1
Application number: PCT/CN2011/001869
Authority: WO
Inventors: 黄莉; 解晶莹; 王可; 顾海涛; 丰震河; 谢朝香
Original assignee: 上海空间电源研究所
Priority date: 2011-08-29
Filing date: 2011-11-07
Publication date: 2013-03-07
Also published as: CN102315481A

Abstract

The present invention relates to a high-specific-energy lithium-rich multi-element lithium-ion storage battery and a method for fabricating the same. The storage battery comprises a positive pole, a negative pole, a separation film, an electrolyte, and a package. The positive pole comprises an adhesive, a conductive agent, and a positive pole electroactive substance. The positive pole electroactive substance is a lithium-rich multi-element material. The negative pole comprises an adhesive, a conductive agent, and a negative pole electroactive substance. More than any one of a graphite-based material, silicon, silicon carbide, and a silicon-based composite material, and a tin-based alloy material is selected as the negative pole electroactive substance. The adhesive of the negative pole is a polymer adhesive of styrene-butadiene rubber, organic alkenoic or carboxylic ester. The electrolyte is a fluorine-containing high-voltage resistant organic electrolyte system. The method for fabricating a storage battery provided in the present invention adopts a two-step chemical formation process, so as to guarantee the high capacity of battery, electrochemical stability, and safety performance, so that the fabricated storage battery has the advantages such as high specific energy, desirable cycle performance and safety performance, and good chemical stability, and can be used as a new and clean energy source.

Description

High specific energy lithium-rich multi-element lithium ion battery and its manufacturing method

TECHNICAL FIELD The present invention relates to the field of high-energy lithium ion batteries, and relates to a lithium ion battery, and in particular to a lithium ion battery having high voltage, high specific capacity, and high specific energy charge and discharge characteristics. Background technique

Since the 20th century, the massive use of coal and oil has not only polluted the environment, but also caused a huge greenhouse effect. The resulting oil shortage, food crisis and environmental changes have even had a certain impact on world stability. Therefore, countries are looking for clean and fresh energy.

As a stable radioactive energy source, nuclear energy has long been a problem of radioactive pollution. Natural energy sources such as solar energy, wind energy, and tidal energy, as well as the collection and use of bioenergy, face the problem of how energy is stored and transported. The battery is a versatile and practical energy storage device that can perform high-efficiency conversion of chemical energy and electrical energy without any elimination of waste gas, and will not cause harm to the environment. At the same time, the development of electric vehicles also requires energy-saving devices that are light in weight and high in energy. Therefore, the community has focused on the development of secondary battery systems with low cost, high safety, high voltage, high specific capacity, and high specific energy.

Since its commercialization in 1991, lithium-ion batteries have been widely used in information, energy, transportation and other fields due to their high operating voltage, high energy density, long cycle life, and environmental protection. In recent years, as governments are competing to develop new energy industries, such as new energy vehicles and renewable energy power generation, the performance requirements of batteries in these areas are constantly increasing, especially for high specific energy. A battery prepared from a conventional battery active material such as lithium cobaltate, lithium manganate or lithium iron phosphate can not meet the requirements of practical applications, and a new type of safe high specific energy lithium ion battery must be developed based on materials. system.

In 2000, Ammundsen et al. proposed a new type of lithium ion that can be regarded as a solid solution of Li ₂ Mn0 ₃ and LiCr0 _{2 .}

Later researchers used Cr Ni _1/3 C0 _1/3 Mn _{1/3 is} substituted to form I^MnO^ClLi Ni^Mn Co^Cb solid solution. This type of solid solution material is discharged at 0.1C in the range of 2.5~4.5V, and the capacity can reach 220mAh/g. Above, some even have 260mAh/g, which has the advantages of high specific capacity, good thermal stability, excellent cycle performance, wide charge and discharge range, low price, and environmental friendliness. It is considered to be the most promising substitute for traditional lithium ion cathode materials. New cathode material. Disclosure of invention

SUMMARY OF THE INVENTION An object of the present invention is to provide a lithium ion secondary battery having a high specific capacity and a high voltage, which is characterized by high specific energy and high cycle stability.

To achieve the above object, the present invention provides a high specific energy lithium-rich lithium ion battery, which comprises a positive electrode, a negative electrode, a separator, an electrolyte and an outer package, wherein:

The positive electrode includes a binder, a conductive agent, and a positive electrode active material, and the positive electrode active material is a lithium-rich multicomponent material.

The negative electrode includes a binder, a conductive agent, and a negative electrode electroactive substance. The negative electrode electroactive material is selected from any one of a graphite material, a silicon, a silicon carbon, a silicon composite material, and a tin base alloy material; the negative electrode electroactive material has a high specific capacity, a low specific surface area, and a relatively high specific surface area. High compaction density and good safety. The graphite-based material is selected from a novel graphite system in which natural graphite or artificial graphite is surface-modified (the modified graphite is commercially available as commercially available from Hitachi Chemical Co., Ltd.). The prepared negative electrode has the advantages of high specific capacity, high solid density, and stability to the electrolyte solvent.

The negative electrode binder is a polymer binder of styrene-butadiene rubber, organic olefinic acid or carboxylate; the binder has good bonding property and excellent elasticity, and can withstand the negative electrode in the battery charge and discharge cycle The stress caused by the expansion and contraction of the active material gives the battery excellent cycle performance.

The electrolyte is a fluorine-containing high-voltage organic electrolyte system.

The above high specific energy lithium-rich multi-element lithium ion battery, wherein: the lithium-rich multi-component has the formula: xLi[Li _1/3 Mn2/ ₃ ]02-yLiM0 ₂ -(lxy)LiMe ₂ 0 ₄ ,

Wherein M = Mn, Ni, Co, Al, Cr, Mg, Zr, Ti, Zn, Fe, Me = Mn, Ni, Co, Al, Cr, Mg, Zr, Ti, Zn, Fe Any one, 0 < x ≤ 0.7, 0 < y ≤ 0.9.

Further, the lithium-rich multi-component material is a composite structure of layered Li[Li _1/3 Mn _2/3 ]0 ₂ , layered LiM0 ₂ and spinel LiMe ₂ 0 ₄ ; Kby capacity and high charge and discharge voltage. The high specific energy lithium-rich multi-element lithium ion battery, wherein: the solvent of the electrolyte is any one of an organic carbonate, an organic carboxylic acid ester, an ether, an organic fluorinated ester, an organic sulfone, and an organic boride. The above-mentioned high-voltage resistant solvent has stable electrochemical performance at high voltage, can withstand up to 4.6V charge and discharge of the battery, and has the characteristics of flame retardancy, so that the battery has good safety performance and cycle performance. The electrolyte of the electrolytic solution is any one or more of electrolyte salts containing LiCF ₃ S0 ₃ , LiBF ₄ , LiC10 ₄ , LiPF ₆ , LiN(CF ₃ S0 ₂ ) ₂ and LiAsF ₆ to ensure that the battery is as high as 4.6. The battery of V is charged and discharged.

More preferably, the electrolyte further comprises a fluorine-containing substituted succinic anhydride or a fluorine-containing substituted succinic anhydride derivative additive, the additive

Where n=l~15, x+ y=2n+l.

The above high specific energy lithium-rich multi-element lithium ion battery, wherein: the positive electrode binder is a high molecular weight polyvinylidene fluoride.

The above high-energy-rich lithium multi-element lithium ion battery, wherein: the positive electrode conductive agent selects superconducting carbon black, flake graphite, carbon nanotube, carbon fiber, graphene or superconducting carbon black, flake graphite, carbon nanotube, carbon fiber And a mixture of any one or more of graphene.

The above high energy-enriched lithium multi-element lithium ion battery, wherein: the negative electrode conductive agent selects one or more of superconducting carbon black, carbon nanotube, carbon fiber or superconducting carbon black, carbon nanotube, carbon fiber mixture.

The invention also provides a preparation method of the above high specific energy lithium-rich multi-element lithium ion battery, wherein the method comprises the following specific steps:

Step 1, mixing and stirring the positive electrode binder with the solvent, adding the positive electrode conductive agent and stirring, then adding the positive electrode active material to obtain a solid-liquid mixture, and finally applying the solid-liquid mixture on the surface of the aluminum foil, drying That is, the positive electrode is obtained; - Step 2, the distilled water and the negative electrode binder are mixed and stirred, and then the negative electrode conductive agent is added to stir, and then the negative electrode electroactive material is added to stir to obtain a solid-liquid mixture, and finally the solid-liquid mixture is applied to the surface of the copper foil. Above, drying to obtain the negative electrode;

Step 3, cutting the positive electrode prepared in the above step 1 and the negative electrode in the step 2 are respectively cut into several Small pieces, will be thousands of positive, negative pieces, stacked in the positive and negative alternate way, all the small pieces are separated by a diaphragm, then all the positive pieces are connected, all the negative pieces are connected, and respectively in the positive piece Weld the aluminum piece at the joint, weld the nickel piece or the nickel plated piece at the negative electrode connection, and finally fix all the positive and negative pieces together by tape to make it in close contact, which is the battery core;

Step 4, loading the above-mentioned battery core into the outer package, and removing moisture in the battery core;

Step 5, adding an electrolyte to the outer package, sealing and standing, so that the electrolyte fully wets the coating material on the copper foil and the aluminum foil;

Step 6. Perform a chemical conversion process on the battery (for the two-stage formation process): remove the gas in the outer package after the first charge to the predetermined voltage, and then continue charging to a higher specified voltage and perform the charge-discharge cycle three times before removing the outer package. The gas in the chamber is then closed to the gas exhaust passage to complete the manufacture of the high specific energy lithium ion battery of the present invention. The formation process of the battery is a special two-stage chemical conversion process to ensure high capacity, electrochemical stability and safety of the battery system.

Due to the adoption of the above technical solutions, the present invention has the following beneficial effects:

1) Since a lithium-rich multi-component composite cathode material is used in the positive electrode: xLi[Li _1/3 Mn _2/3 ]0 ₂ -yLiM0 ₂ -(lxy)LiMe ₂ 0 ₄ , where M= Mn, Ni, Co, Any one of Al, Cr, Mg, Zr, Ti, Zn, Fe, Me = Mn, Ni, Co, Al, Cr, Mg, Zr, Ti, Zn, Fe, 0 < x ≤ 0.7, 0<y<0.9 _; The lithium-rich multi-component composite cathode material exhibits a charging characteristic of LiM0 ₂ at a low potential, and lithium in the Li ₂ Mn0 ₃ component is released at 4.5 V, and a layered Mn0 is formed accompanying the release of oxygen. ₂ structure, so a new electrochemical platform will appear, so that the battery prepared by this material has a high specific capacity, greater than 230mAh / g. At the same time, Li ₂ Mn0 ₃ plays a role in stabilizing the positive electrode structure during charge and discharge of the battery.

2) Since the negative electrode is made of a surface modification material of natural graphite or artificial graphite, the prepared negative electrode has a high specific capacity, a high-pressure solid density, a solvent stability to the electrolyte, and a smooth surface structure to make less solid. The electrolyte interface film (ie, SEI film) is formed, and the surface amorphous coating controls the formation of metal lithium dendrites, so that the battery has better cycle performance and safety performance.

3) Because the special solvent and fluorination additive with high voltage resistance are added to the electrolyte, the electrolyte has high conductivity and good wettability to the material, and the electrolyte and electrode interface can be kept at high voltage. The electrochemical stability, and the dissolution of metal manganese ions in the electrolyte is controlled by means of complexation bonds.

4) Due to the special two-stage chemical conversion process, the SEI is guaranteed to form a stable and dense SEI. At the same time, the membrane eliminates the adverse effects of oxygen on the entire battery system, and at the same time enables the positive active material to be fully activated, and the two-phase fusion supplementation and transformation process is successfully completed. BRIEF DESCRIPTION OF THE DRAWINGS

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a graph showing the charge and discharge characteristics of a battery during the formation of a high specific energy lithium ion battery prepared in accordance with Example 1.

2a-2b are cycle curves of a lAh high specific energy lithium ion battery prepared in accordance with Example 1. Fig. 3 is a comparison of cycle curves of a lAh high specific energy lithium ion secondary battery prepared in accordance with Example 1 and Comparative Example 1, respectively. The best way to implement the invention

Specific embodiments of the present invention will be described in detail below with reference to the drawings and embodiments.

In the following examples:

The preparation method of the lithium-rich multi-component material is as follows: x=0.4, y=0.55, that is, the molar ratio of Mn, Ni, Co metal ions is 0.57:0.23:0.2, and the manganese sulfate, nickel sulfate and cobalt sulfate are dissolved in deionized water. , formulated into a uniform transparent solution with a total concentration of Mn, Ni, Co metal ions of 2mol / L; Preparation of a 0.2mol / L polyacrylamide solution (ΡΑΑΜ, non-ionic dispersant), 1.2 times the stoichiometric amount Sodium carbonate is added to the polyacrylamide solution to obtain a mixed precipitant solution of polyacrylamide and sodium carbonate; the precipitant solution is slowly added dropwise to the metal ion solution to carry out a coprecipitation reaction; the precipitated product is filtered, washed, and dried. Obtain a carbonate precursor. The carbonate precursor is mixed with a stoichiometric amount of 1.02 times of lithium carbonate ball mill, and maintained at 900 ° C for 10 h to obtain a fluorine-containing electrolyte. The preparation method is as follows: LiPF6 is dissolved in ethylene carbonate (EC) :), ethyl methyl carbonate (EMC) (volume ratio EC / EM03 〃), prepare 1.2mol / L LiPF6 solution, add 5% by weight of fluoroethylene carbonate (FEC) as an additive, stir well to make it even , and defoaming.

Example 1

Mix 90 g of N-methylpyrrolidone and 4.75 g of polyvinylidene fluoride (ie, polyvinylidene fluoride, PVDF) until the viscosity of the mixture changes less than 3% within 10 minutes, and then add 3.5 g of particle size less than 2 μm. Microspherical superconducting carbon black and 1.75 g of scaly conductive graphite stirred until the mixture is sticky within 10 minutes The degree of change is less than 3%, and finally 90 grams of lithium-rich multicomponent material Li[Lio. ₁₃₃ Mna ₄ 6 ₇ Ni _a2 Co ₂ ]0 _{2 is added to} stir until the viscosity of the mixture changes less than 5% within 10 minutes, and then the above solid-liquid mixture is coated. It was coated on an aluminum foil and dried under vacuum at 110 ° C for 24 hours to obtain a positive electrode.

100 g of distilled water and 1.5 g of sodium carboxymethylcellulose were mixed and stirred until the viscosity of the mixture changed less than 3% within 10 minutes, and then 2.0 g of microspherical superconducting carbon black having a particle diameter of less than 3 μm was added and stirred for 10 minutes. The internal mixture viscosity change is less than 3%, and then add 95 g of graphite negative electrode to stir until the viscosity change of the mixture is less than 3% within 10 minutes, then add 1.5 g of styrene-butadiene rubber (SBR) and stir until the viscosity of the mixture changes less than 3% within 10 minutes. The above solid-liquid mixture was coated on a copper foil, dried under vacuum for 100 hours at 100 Torr, and dried to prepare a negative electrode.

The positive and negative electrodes prepared above are cut into small pieces of a certain shape, and a plurality of positive and negative electrode pieces are sequentially stacked in an alternating manner of positive and negative electrodes, and the positive and negative electrodes are insulated by a separator, and aluminum strips are welded on the aluminum foil, respectively. The nickel strip is welded on the foil, and finally the positive and negative electrodes are fixed with tape to prevent the positive and negative electrodes from being electrically conductive, and the battery is made of a capacity of 1 Ah. Then, the cell is loaded into the outer package and the water is removed in a vacuum.

4 g of a self-made high-voltage fluorine-containing electrolyte was added to the outer package containing the water cell, and the solution was sealed and allowed to stand to sufficiently wet the solid particles on the aluminum foil and the copper foil. Charging for the first time to 4.3V and discharging the gas generated during the charging process, continue to charge to 4.6V and discharge, after 3 cycles of recycling, the gas generated during the charging and discharging process of the battery is discharged, and the exhaust passage is closed, that is, the invention is completed. The manufacture of specific energy lithium ion batteries. As shown in Fig. 1, the charge and discharge curve of the battery during the formation of the battery is 23 ± 2 ° C, and the specific capacity of the battery is 240 mAh / g. As shown in FIG. 2a, the cycle curve of the 1Ah high-energy lithium ion battery prepared according to the first embodiment has a temperature condition of 23±2° C., and still maintains 91.5% of the initial capacity after 100 cycles. As shown in Fig. 2b, it is still more than 84% of the initial capacity after 176 cycles, which proves that the battery has good cycle performance. Comparative example 1

90 g of N-methylpyrrolidone and 4.75 g of polyvinylidene fluoride were mixed and stirred until the viscosity of the mixture changed less than 3% within 10 minutes, and then 3.5 g of microspherical superconducting carbon black having a particle diameter of less than 2 μm and 1.75 were added. The gram-like conductive graphite is stirred until the viscosity change of the mixture is less than 3% within 10 minutes. Finally, 90 g of the lithium-rich multicomponent material is added and stirred until the viscosity of the mixture changes less than 5% within 10 minutes, and then the above solid-liquid mixture is coated on the aluminum foil. After drying at 110 ° C for 24 hours, a positive electrode was obtained. 100 g of distilled water and 1.5 g of sodium carboxymethylcellulose were mixed and stirred until the viscosity of the mixture changed less than 3% within 10 minutes, and then 2.0 g of microspherical superconducting carbon black having a particle diameter of less than 3 μm was added and stirred to 10 Within minutes, the viscosity of the mixture changes by less than 3%. Then add 95 grams of graphite negative electrode and stir until the viscosity of the mixture changes less than 3% within 10 minutes. Then add 1.5g SBR and stir until the viscosity of the mixture changes less than 3% within 10 minutes. The liquid mixture was coated on a copper foil and dried under vacuum at 100 ° C for 8 hours to prepare a negative electrode.

The positive and negative electrodes prepared above are cut into small pieces of a certain shape, and a plurality of positive and negative electrode pieces are sequentially stacked in an alternating manner of positive and negative electrodes, and the positive and negative electrodes are insulated by a separator, and the aluminum strips are respectively spliced on the aluminum foil. The nickel strip is welded on the copper foil, and finally the positive and negative electrodes are fixed with tape to prevent the positive and negative electrodes from being electrically conductive, and the battery is made of a capacity of 1 Ah. Then, the cell is loaded into the outer package and the water is removed in a vacuum.

Add 4g of common electrolyte (EC: DMC=1:1, 1.0M LiPF ₆ ) to the moisture-containing outer core of the battery, seal and let stand, so that the electrolyte fully wets the solid particles on the aluminum foil and copper foil. . The first charge to 4.3V and discharge the gas generated during the charging process, continue to charge to 4.6V and then discharge, after 3 cycles of recycling, the gas generated during the charging and discharging process of the battery is discharged, and the exhaust passage is closed, that is, complete with ordinary electrolysis The manufacture of liquid lithium ion batteries.

As shown in Fig. 3, for the comparison of the cycle curves of the lAh high-energy lithium-ion battery prepared in accordance with Example 1 and Comparative Example 1, the temperature condition of the cycle was 23 ± 2 C. It can be seen from the figure that the battery capacity of the battery prepared by the ordinary lithium ion battery electrolyte drops sharply during the cycle, indicating that the electrolyte has an oxidative decomposition reaction at a high voltage, while the fluorination resistant high voltage electrolyte It can support 91.5% of the initial capacity after supporting the battery cycle for 100 times. Comparative example 2

90 g of N-methylpyrrolidone and 4.75 g of polyvinylidene fluoride were mixed and stirred until the viscosity of the mixture changed less than 3% within 10 minutes, and then 3.5 g of microspherical superconducting carbon black having a particle diameter of less than 2 μm was added. And 1.75 g of scaly conductive graphite was stirred until the viscosity change of the mixture was less than 3% within 10 minutes, and finally 90 g of the lithium-rich multicomponent was added and stirred until the viscosity change of the mixture was less than 5 °/ within 10 minutes. Then, the above solid-liquid mixture was coated on an aluminum foil, and dried under vacuum at 110 ° C for 24 hours to obtain a positive electrode.

100 g of distilled water and 1.5 g of sodium carboxymethylcellulose were mixed and stirred until the viscosity of the mixture changed less than 3% within 10 minutes, and then 2.0 g of microspherical superconducting carbon black having a particle diameter of less than 3 μm was added thereto and stirred. The viscosity change of the mixture is less than 3% within 10 minutes, and then adding 95 g of graphite negative electrode to stir until the viscosity change of the mixture is less than 3% within 10 minutes, and then adding 1.5 g of SBR and stirring until the viscosity of the mixture changes less than 3% within 10 minutes. The solid-liquid mixture was coated on a copper foil, and dried at 100 ° C for 8 hours under vacuum to prepare a negative electrode.

The positive and negative electrodes prepared above are cut into small pieces of a certain shape, and a plurality of positive and negative electrode pieces are sequentially stacked in an alternating manner of positive and negative electrodes, and the positive and negative electrodes are insulated by a diaphragm, and the aluminum strips are respectively spliced on the aluminum foil. The nickel strip is welded on the copper foil, and finally the positive and negative electrodes are fixed with tape to prevent the positive and negative electrodes from being electrically conductive, and the battery is made of a capacity of 1 Ah. Then, the cell is loaded into the outer package and the water is removed in a vacuum.

4 g of a high-voltage fluorine-containing electrolyte was placed in the outer package containing the water-containing core, sealed, and allowed to stand, so that the electrolyte sufficiently wetted the solid particles on the aluminum foil and the copper foil. After charging to 4.6V, the battery is discharged, and then the gas generated during the charging and discharging process is exhausted, and the exhaust passage is closed to complete the preparation of the lithium ion battery of Comparative Example 2. The battery prepared by the one-time forming process has a specific capacity of only 192 mAh/g. Moreover, the cycle performance is poor, and the remaining capacity after 80 cycles is less than 80% of the initial capacity. Example 2

90 g of N-methylpyrrolidone and 4.75 g of polyvinylidene fluoride were mixed and stirred until the viscosity of the mixture changed less than 3% within 10 minutes, and then 3.5 g of microspherical superconducting carbon black having a particle diameter of less than 2 μm and 1.75 g were added. The scaly conductive graphite is stirred until the viscosity change of the mixture is less than 3% within 10 minutes. Finally, 90 g of the lithium-rich multicomponent material is added and stirred until the viscosity of the mixture changes less than 5% within 10 minutes, and then the above solid-liquid mixture is coated on the aluminum foil. Drying at 110 ° C for 24 hours gave a positive electrode.

100 g of distilled water and 2.5 g of sodium carboxymethylcellulose were mixed and stirred until the viscosity of the mixture changed less than 3% within 10 minutes, and then 4.5 g of microspherical superconducting carbon black having a particle diameter of less than 3 μm was added and stirred for 10 minutes. The internal mixture viscosity change is less than 3%, and then 90 g of Si-C composite is added to stir until the viscosity change of the mixture is less than 3% within 10 minutes, and then 3.0 g of SBR is added and stirred until the viscosity change of the mixture is less than 3% within 10 minutes. The solid-liquid mixture was coated on a copper foil, and vacuum-dried at 100 ° C for 8 hours to prepare a negative electrode.

The positive and negative electrodes prepared above are cut into small pieces of a certain shape, and a plurality of positive and negative electrode pieces are sequentially stacked in an alternating manner of positive and negative electrodes, and the positive and negative electrodes are insulated by a separator, and the aluminum strips are respectively spliced on the aluminum foil. Weld the nickel strip on the copper foil, and finally use the tape to fix the positive and negative electrodes to avoid the positive and negative electrodes. It is electronically conductive and made into a battery with a capacity of lAh. Then, the cell is loaded into the outer package and the water is removed in a vacuum.

4 g of a high-voltage special electrolyte was added to the outer casing containing the water-containing material, sealed, and allowed to stand, so that the electrolyte sufficiently wetted the solid particles on the aluminum foil and the copper foil. Charging for the first time to 4.3V and discharging the gas generated during the charging process, continuing to charge to 4.6V and discharging, recycling 3 times, discharging the gas generated during the charging and discharging process of the battery, and closing the exhaust passage, thereby completing the invention Production of high specific energy lithium ion batteries. The weight ratio energy of the battery prepared in this example was as high as 280 wh/kg, but the cycle performance was poor, and the remaining capacity after 32 cycles was only 80% or less of the initial capacity.

The high specific energy lithium ion battery provided by the invention has the advantages of high specific energy, good cycle performance, safety performance and good chemical stability, and can be used as a clean new energy source.

Although the present invention has been described in detail by the preferred embodiments thereof, it should be understood that the description is not to be construed as limiting. Various modifications and alterations of the present invention will be apparent to those skilled in the art. Therefore, the scope of the invention should be limited by the appended claims.

Claims

Rights request

A high specific energy lithium-rich multi-element lithium ion battery comprising a positive electrode, a negative electrode, a separator, an electrolyte and an outer package, characterized in that:

The positive electrode comprises a positive electrode binder, a positive electrode conductive agent and a positive electrode electroactive material, and the positive electrode active material is a lithium-rich multi-component material;

The negative electrode includes a negative electrode binder, a negative electrode conductive agent, and a negative electrode electroactive material, and the negative electrode electroactive material is selected from any one of a graphite material, a silicon, a silicon carbon, a silicon composite material, and a tin base alloy material; The negative electrode binder is a polymer binder of styrene-butadiene rubber, organic olefinic acid or carboxylic acid ester;

2. The high specific energy lithium-rich multi-element lithium ion battery according to claim 1, wherein: the lithium-rich multicomponent material has the formula: xLi[Li _1/3 Mn _2/3 ]0 ₂ -yLiM0 ₂ - (lxy)LiMe ₂ 0 ₄ , wherein M = Mn, Ni, Co, Al, Cr, Mg, Zr, Ti, Zn, Fe, Me = Mn, Ni, Co, Al, Cr, Any one of Mg, Zr, Ti, Zn, Fe, 0 < x ≤ 0.7, 0 < y ≤ 0.9.

3. The high specific energy lithium-rich multi-element lithium ion battery according to claim 2, wherein: the lithium-rich multi-element cathode material has a layered Li[Li _1/3 Mn _2/3 ]0 ₂ , layer A composite structure of LiM0 ₂ and spinel LiMe ₂ 0 ₄ .

The high specific energy lithium-rich multi-component lithium ion secondary battery according to any one of claims 1 to 3, wherein the graphite-based material is selected from a surface-modified graphite system of natural graphite or artificial graphite.

The high specific energy lithium-rich lithium ion battery according to any one of claims 1 to 3, wherein the solvent of the electrolyte is organic carbonate, organic carboxylate or ether. Any one or more high voltage resistant solvents of an organic fluorinated ester, an organic sulfone, or an organic boride, wherein the electrolyte contains LiCF ₃ S0 ₃ , LiBF ₄ , L1CIO4 , LiPF ₆ , LiN(CF ₃ S0 ₂ ) ₂ and Any one or more of the electrolyte salts of LiAsF ₆ to ensure battery charging and discharging up to 4.6V

6. The high specific energy lithium-rich multi-element lithium ion battery according to claim 5, wherein: the electrolyte further comprises an additive selected from fluorine-containing substituted succinic anhydride or fluorine-containing substituted succinic anhydride. Things.

7. The high specific energy lithium-rich multi-element lithium ion battery according to claim 6, wherein: the additive has the structural formula:

Where n=l~15, x+ y=2n+l.

The high specific energy lithium-rich lithium ion battery according to claim 1 or 2 or 3 or 6 or 7, wherein the positive electrode binder is polyvinylidene fluoride.

The high specific energy lithium-rich lithium ion battery according to claim 1 or 2 or 3 or 6 or 7, wherein: the positive electrode conductive agent selects superconducting carbon black, flake graphite, carbon nanotubes, carbon fiber Any one or more of them.

The high specific energy lithium-rich lithium ion battery according to claim 1 or 2 or 3 or 6 or 7, wherein: the positive electrode conductive agent selects superconducting carbon black, flake graphite, carbon nanotubes, carbon fiber Any one or more of graphene.

The high-energy-enriched lithium multi-element lithium ion battery according to claim 1 or 2 or 3 or 6 or 7, wherein: the negative electrode conductive agent selects any of superconducting carbon black, carbon nanotubes, and carbon fibers. More than one.

12. A method of fabricating a high specific energy lithium-rich multi-element lithium ion battery according to claim 1 The feature is that it contains the following specific steps:

Step 1, mixing and stirring the positive electrode binder with the solvent, adding the positive electrode conductive agent to stir together, then adding the positive electrode active material to stir the solid-liquid mixture, and finally applying the solid-liquid mixture to the surface of the aluminum foil, drying That is to obtain the positive electrode;

Step 2: mixing and stirring the distilled water and the negative electrode binder, adding a negative electrode conductive agent to stir, then adding the negative electrode electroactive material to obtain a solid-liquid mixture, and finally applying the solid-liquid mixture on the surface of the copper foil, and drying Getting a negative electrode;

Step 3, the positive electrode prepared in the above step 1 and the negative electrode in the step 2 are respectively cut into small pieces, and a plurality of positive and negative negative pieces are sequentially stacked in an alternating manner of positive and negative electrodes, and all the small pieces are separated by a diaphragm, and then Connect all the positive positive pieces, connect all the negative negative pieces, and weld the aluminum pieces at the junction of the positive electrode pieces respectively, connect the nickel piece or the nickel plated piece at the negative electrode connection, and finally fix all the positive and negative pieces by tape. Bringing it into close contact, that is, the battery core; in step 4, the above-mentioned battery cells are loaded into the outer package, and the moisture in the battery cells is removed;

Step 5, adding an electrolyte to the outer packaging, sealing and standing, so that the electrolyte fully wets the coating material on the copper foil and the aluminum foil;

Step 6. Perform a formation process on the battery: remove the gas in the outer package after the first charge to the predetermined voltage, then continue charging to a higher specified voltage and perform the charge and discharge cycle 3 times, then remove the gas in the outer package, and then close the gas. The discharge passage, that is, the manufacture of the high specific energy lithium ion secondary battery of the present invention is completed.