CN111048862B

CN111048862B - Method for efficiently recovering lithium ion battery anode and cathode materials as supercapacitor electrode materials

Info

Publication number: CN111048862B
Application number: CN201911162281.XA
Authority: CN
Inventors: 刘逸群
Original assignee: Wanhua Chemical Group Co Ltd
Current assignee: Wanhua Chemical Group Co Ltd
Priority date: 2019-11-25
Filing date: 2019-11-25
Publication date: 2021-09-07
Anticipated expiration: 2039-11-25
Also published as: CN111048862A

Abstract

The invention provides a method for recycling anode and cathode materials of waste lithium ion batteries. The method comprises the steps of disassembling the waste lithium ion battery, separating out a positive electrode and a negative electrode, and soaking and separating to obtain a positive electrode active substance and a negative electrode active substance. The positive active substance is roasted and dissolved by acid to obtain a mixed salt solution containing divalent nickel, cobalt and manganese ions, the solution is mixed into a graphene oxide solution prepared from the negative active substance, the mixed solution is subjected to precipitation reaction, separation and washing to obtain a composite nickel material, and the composite nickel material is sheet nickel hydroxide which is uniformly mixed with reduced graphene oxide and is doped with cobalt-manganese. The composite nickel material is applied to the super capacitor and has the characteristics of high specific capacitance and good rate capability.

Description

Method for efficiently recovering lithium ion battery anode and cathode materials as supercapacitor electrode materials

Technical Field

The invention belongs to the field of waste battery regeneration, and particularly relates to a method for efficiently recovering a positive electrode material and a negative electrode material of a lithium ion battery into a super capacitor electrode material.

Background

In recent years, with the portability of electronic devices and the increasing popularity of electric vehicles, such as electric automobiles, the production and use of lithium ion batteries have been increasing year by year. According to statistics, the consumption of lithium ion batteries is 5 hundred million worldwide in 2000, and reaches 70 hundred million in 2015. The service life of the lithium ion battery is limited, generally speaking, the service life of the lithium ion battery is only about three years, and the cycle period is 500-1000 times. Therefore, a large number of waste lithium ion batteries are also produced. Taking China as an example, in 2020, the number of discarded lithium batteries in China exceeds 250 hundred million, and the total weight of the lithium batteries exceeds 50 million tons.

The main components of the lithium ion battery are a positive electrode, a negative electrode, a diaphragm and electrolyte. The battery positive electrode is composed of a positive active material, a conductive agent, a binder, a current collector aluminum foil and the like. The battery negative electrode mainly comprises a negative electrode active material, a current collector and the like. A separator made of a polymer separates the positive and negative electrodes. The electrolyte serves to conduct lithium ions between the positive and negative electrodes. The waste battery, especially the lithium ion battery using lithium cobaltate and ternary material as anode material, contains poisonous heavy metal substance, which can damage soil and water in environment. These toxic substances diffuse into the human and animal body and can be harmful to health. The recycling of valuable metals not only can improve the environment, but also can improve the economic benefits of enterprises. Taking the ternary material NCM523 as an example, the anode material contains a large amount of noble metals, wherein cobalt accounts for 12%, nickel accounts for 30%, manganese accounts for 17%, and lithium accounts for 7%, most of the contained metals are rare metals, and the metals can be reasonably recycled

A super capacitor has been attracting attention in recent years as an energy storage element interposed between a conventional capacitor and a secondary battery. The super capacitor has a higher capacity than the secondary batteryAnd has a longer cycle life (greater than 10)⁵Second). Supercapacitors have a greater energy density than conventional capacitors. From the mechanism of electrochemical storage, it can be classified into electric double layer capacitance and faraday quasi-capacitance. Electric double layer capacitors are primarily made of carbon materials as electrode materials, and the capacitance is generated at the carbon electrode/electrolyte interface due to charge separation. The faradaic pseudo-capacitance is mainly generated by transition metal oxide or hydroxide and is generated by adsorption capacitance caused by redox reaction on the surface of an electrode and in a bulk phase. The capacitance value of the latter is about 10 times that of the former with the same electrode area. For the noble metal oxide capacitor, the capacitance mainly comes from two aspects, a small part of the capacitance comes from the electric double layer capacitance generated on the interface, and the large part of the capacitance comes from the faradaic capacitance caused by the redox process generated on the sp2 and sp3 dangling bonds on the carbon surface.

The electrode materials of a typical faraday pseudocapacitor, otherwise known as a pseudocapacitor, mainly comprise metal oxide materials and conductive polymer materials. Often, the metal oxide material is a noble metal such as Ru, Ir, or the like. Ni is a cheap and abundant transition metal element, and has attracted attention in recent years due to the high capacitance and chemical stability of nickel hydroxide. The theoretical specific capacitance of the nickel hydroxide reaches 2082F/g when the window voltage is 0.5V.

Graphene as a carbon material with high specific surface area has good chemical stability and rapid electron transfer property, and is an ideal electrode material of a super capacitor. However, graphene is easy to agglomerate, so that the effective specific surface area is reduced, and the specific capacitance is rapidly attenuated, thereby limiting the application of the graphene. Therefore, the graphene is compounded with the nickel hydroxide, so that agglomeration can be inhibited on the basis of utilizing the high capacitance of the graphene, the chemical stability of the nickel hydroxide is effectively improved, and the advantages of the double electric layer capacitance and the Faraday quasi-capacitor are integrated.

At present, the recovery method of the waste lithium ion battery mainly comprises a biological method, a high-temperature combustion method, an acid dissolution method, an electrochemical dissolution method and the like. However, most existing recovery methods are directed to separate recovery of elements, such as dissolving the anode material by acid or electrochemically, and then extracting with an organic solvent to obtain different metal elements. Such a method has an advantage in that the recovery rate of the metal element is high, but it is easy to cause contamination by using chemicals such as an extractant in the recovery process, and if the synthesis of the ternary material is newly performed by using the separated heavy metal, a small amount of the extractant remaining in the recovered material has a great influence on the synthesis of the precursor. Compared with the method for respectively recovering the single metal elements, a few patents exist at present for directly synthesizing a new lithium ion battery anode material or precursor by utilizing various elements in the waste anode material. Therefore, a plurality of complicated steps can be omitted, the cost is reduced, and the element utilization rate is higher. However, at present, there is no report on directly recycling lithium ion battery materials as supercapacitor electrode materials.

In a patent document of a disclosed recycling treatment of waste lithium ion batteries, CN106785177A discloses a method for recycling and preparing a nickel-cobalt-manganese-aluminum quaternary positive electrode material from a waste nickel-cobalt-manganese ternary lithium ion battery, which comprises the following steps: disassembling the waste battery, magnetically separating, crushing, soaking in an organic solvent, screening and acid leaching to obtain a leaching solution; after impurity removal, adjusting the molar ratio of metal ions, adding alkali metal hydroxide and regulating and controlling the pH value of the system to obtain turbid solution with NCMA hydroxide precipitated; and adding carbonate for secondary precipitation, performing solid-liquid separation to obtain a Li quaternary material precursor, and calcining the precursor to obtain the Al-doped NCM quaternary anode material. There is the copper process of sulphide salt decoppering in this patent, and the sulphide sediment that this process produced belongs to hazardous waste, and is great to environmental hazard, and on the other hand can lead to partial nickel cobalt to deposit, causes the loss of nickel cobalt, is unfavorable for the comprehensive recovery of resource.

CN102651490A discloses a method for regenerating a positive electrode active material of a waste battery, in which a positive electrode material obtained by peeling off an old positive electrode material is subjected to processes of lithium source supplement, sintering, crushing, water washing, and the like to obtain a regenerated positive electrode active material, however, a separation solution used for soaking the positive electrode material is a flammable organic solvent such as N-methylpyrrolidone, N-dimethylacetamide, N-dimethylformamide, dimethylsulfoxide, tetrahydrofuran, acetone, and the like, and has a certain toxicity.

CN110085440A relates to a preparation method of nickel hydroxide/reduced graphene oxide supercapacitor electrode materials. The method comprises the steps of preparing reduced graphene oxide, preparing nickel hydroxide/reduced graphene oxide, preparing an electrode and assembling a super capacitor. However, according to the method, nickel hydroxide and reduced graphene oxide are synthesized separately and physically combined. The degree of mixing in such a combination does not achieve a uniform combination effect. Especially, the separately produced reduced graphene oxide is extremely easy to agglomerate and is difficult to disperse and mix with nickel hydroxide during compounding.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a method for directly recycling a ternary positive electrode material and a graphite negative electrode material of a waste lithium ion battery into a supercapacitor electrode material which can be widely applied.

In order to achieve the purpose, the invention adopts the following technical scheme:

a method for preparing a composite nickel material which contains graphene (rGO) and is doped with cobalt-manganese by taking a positive electrode and a negative electrode of a waste lithium ion battery as raw materials is provided, the method simultaneously recycles the ternary positive electrode and the graphite negative electrode of the lithium ion battery to prepare the composite material, and the method comprises the following steps:

s1: disassembling the waste lithium ion battery to obtain a positive plate and a negative plate, and respectively placing the positive plate and the negative plate in a separation solution to obtain a positive active substance (P) and a negative active substance (N);

s2: reducing and roasting the P, treating roasting slag, and filtering insoluble substances to obtain a mixed solution L1;

s3: supplementing corresponding metal elements in L1 according to the element composition of the target product to obtain a nickel-cobalt-manganese mixed solution L2;

s4: preparing N into graphite oxide, and processing to obtain a graphene oxide (rGO) solution L3;

s5: adding alkali liquor into L2, mixing with L3, reacting, separating, washing and drying the filtrate to obtain the composite nickel material.

In the present invention, the positive electrode material of the waste lithium ion battery in step S1 contains Li, Ni, Co and Mn elements, and preferably, the positive electrode material is LiNi_1/3Co_1/3Mn_1/3O₂、LiNi_0.5Co_0.2Mn_0.3O₂、LiNi_0.6Co_0.2Mn_0.2O₂And LiNi_0.8Co_0.1Mn_0.1O₂More preferably LiNi_1/3Co_1/3Mn_1/3O₂. At present, most LiNi_1/3Co_1/ ₃Mn_1/3O₂The anode material is not coated, so that the inconsistency of different batches of products caused by doping the coating elements of the original anode material in the production process can be avoided.

In the invention, the negative electrode material of the waste lithium ion battery in the step S1 is one or more of natural graphite, artificial graphite and graphitized mesocarbon microbeads. The layered graphite can be peeled into graphene, while non-graphitized carbon such as soft carbon and hard carbon cannot be peeled and can only be smashed into finer particles by ultrasonic vibration.

In the present invention, the separation liquid in step S1 is selected from a small molecule alcohol or a small molecule alcohol aqueous solution, wherein the small molecule alcohol is selected from one or more of ethanol, n-propanol, isopropanol and glycerol.

In the present invention, optionally, in step S2, oxidizing roasting is performed before reducing roasting, and the oxidizing atmosphere of the oxidizing roasting is one or more of oxygen, air, and oxygen-nitrogen mixed gas (volume ratio is 99:1-20:80), preferably air. The anode material is roasted in an oxidizing atmosphere to remove combustible substances such as residual electrolyte, binder, conductive agent and the like in the anode material, so that organic substances cannot be remained in a salt solution after the subsequent dissolving step, and adverse effects on subsequent reactions are avoided.

In the invention, the oxidizing roasting temperature in the step S2 is 500-900 ℃, and preferably 550-700 ℃; the calcination time is 0.5 to 10 hours, preferably 1 to 3 hours.

In the present invention, the reducing atmosphere of the reduction roasting in step S2 is one or more of ammonia gas, hydrogen sulfide, hydrogen gas, carbon monoxide and water gas, and preferably water gas. The anode material is roasted in a reducing atmosphere, so that the transition metal element with the average valence of +3 in the original anode material can be reduced to be +2, otherwise, trivalent transition metal and divalent metal coexist in the solution in the subsequent acid leaching step, and the crystal shape and morphology of the synthesized precursor precipitation product are influenced. As an electrode material of the super capacitor, nickel in the nickel hydroxide must be positive divalent. The reducing atmospheres are used, particularly the water gas is low in price and has excellent reducing performance, and the reducing products are water and carbon dioxide, so that the air is not polluted, the roasting temperature is further reduced, and the energy consumption is saved.

In the invention, the reduction roasting temperature in the step S2 is 300-600 ℃; the roasting time is 0.5-4 hours.

In the present invention, the method for treating the roasted slag in step S2 is acid leaching treatment, and the acid used in the treatment is one or more of dilute sulfuric acid, dilute phosphoric acid, dilute acetic acid and dilute oxalic acid, preferably dilute sulfuric acid.

In the invention, the acid in the step S2 is prepared into an aqueous solution with the concentration of 0.1-5 mol/L.

In the present invention, the mixed solution L1 obtained by filtering off the insoluble matter after the acid leaching treatment in step S2 contains Ni²⁺、Co²⁺And Mn² ⁺。

In the present invention, in step S3, the mixed solution L1 is subjected to elemental analysis.

In the present invention, the step S3 replenishes the corresponding metal element in L1 by adding a corresponding divalent metal element salt.

Preferably, the metal element salt is one or more of a sulfate, a nitrate, a phosphate, an acetate, an oxalate, a chloride, a bromide and an iodide, and more preferably a sulfate.

In the present invention, the method of preparing N into graphite oxide in step S4 is Hummers method. As is well known, the Hummers method is the preparation of oxidized stoneMethods for graphene, e.g. weighing a quantity of graphite powder with NaNO₃Mixing, adding concentrated sulfuric acid, stirring in an ice bath, adding potassium permanganate, reacting, transferring into a warm water bath, reacting, slowly adding deionized water, keeping the reaction temperature, stirring, adding a proper amount of hydrogen peroxide until no bubbles are generated, filtering while hot, and washing with deionized water and hydrochloric acid solution for multiple times until the solution is neutral. And fully drying in a vacuum drying oven after centrifugation to obtain the graphite oxide.

In the invention, step S4 is to dissolve graphite oxide in distilled water and obtain graphene oxide by ultrasonic treatment.

In the present invention, the time of the ultrasonic treatment in step S4 is 15 min-3 hr.

In the invention, after the ultrasonic treatment in the step S4, the temperature of the graphene oxide solution L3 is raised to 50-100 ℃. Through the step, the graphite oxide can be ultrasonically stripped into graphene oxide, and then reduced into reduced graphene oxide (rGO) through heating.

In the present invention, the alkali solution added in step S5 in L2 is urea.

In the present invention, the urea ratio in L2 in step S5 is 0.5wt% to 5 wt%.

In the present invention, a dispersant is mixed with urea in step S5.

In the present invention, the dispersant in step S5 is hpmc (hydroxy propyl methyl cellulose).

In the present invention, the ratio of the amount of the substance calculated as total metal ions in L2 in step S5 to the amount of the substance calculated as C in L3 was 15 (1-5).

In the invention, the reaction time of the L2 and the L3 in the step S5 is 30min to 10h, preferably 1 to 6 h; the reaction temperature is 50-100 ℃.

In the present invention, urea functions as a precipitant. When urea is in high-temperature water bath, NH is slowly released by hydrolysis₃，NH₃Reacting with water to generate a precipitator NH₄And (5) OH. This method avoids local inhomogeneities caused by direct addition of precipitants and allows the preparation of very fine particle samples. At the same time, dispersant H was added to the reaction slurryPMC can prevent the agglomeration of small particles, so that fine flaky nickel cobalt manganese hydroxide crystals can be obtained. And, because urea releases ammonia at a slow rate, very fine samples can be obtained at a slow rate, and these slowly produced hydroxides can be uniformly combined with rGO under agitation.

Another object of the present invention is to provide a composite nickel material.

The graphene (rGO) containing and cobalt-manganese doped composite nickel material prepared by the preparation method.

In the invention, the composite nickel material is a nickel hydroxide material containing reduced graphene oxide (rGO) and doped with cobalt hydroxide and manganese hydroxide, and preferably, the cobalt-manganese doped nickel hydroxide material has a general formula Ni_xCo_yMn_z(OH)₂The composition is shown, wherein x is more than or equal to 0.8 and less than or equal to 0.95, y is more than or equal to 0.01 and less than or equal to 0.1, z is more than or equal to 0.01 and less than or equal to 0.1, and x + y + z is 1, and the proportional relation is a molar ratio.

The invention also aims to provide application of the composite nickel material.

The composite nickel material containing graphene (rGO) and doped with cobalt-manganese or the composite nickel material containing graphene (rGO) and doped with cobalt-manganese prepared by the preparation method is used as an electrode material.

Preferably, the electrode material is applied to the field of electrode materials of supercapacitors.

In the invention, the waste ternary material is used as a nickel source, and cobalt and manganese are introduced simultaneously, so that the obtained flaky nickel hydroxide is doped with cobalt and manganese. The doping of cobalt and manganese is beneficial to improving the electronic conductivity of the nickel hydroxide, and the synthesized submicron flaky particles with small particle size are beneficial to the ion diffusion performance of the nickel hydroxide. The combination of the two can further improve the rate capability of the super capacitor. Furthermore, in the method steps of the invention, as the waste graphite cathode is made into the graphene material and is uniformly compounded with the nickel cobalt manganese hydroxide, the nickel cobalt manganese hydroxide can be inserted between layers of the rGO, and the agglomeration of the rGO is avoided. When the electrode material is used, the quasi-capacitance characteristic of nickel hydroxide, cobalt and manganese hydroxide is obtained, and the characteristic of large specific surface area of rGO is fully utilized to obtain larger double electric layer capacitance. And because of the fast electronic conductivity of the rGO, the super capacitor made of the electrode material has the characteristics of large capacitance, high multiplying power and high cyclicity.

The invention has the positive effects that:

(1) the invention recovers a plurality of raw materials of the anode and the cathode of the lithium ion battery at the same time to prepare a single composite material;

(2) the doped cobalt and manganese are beneficial to forming doped ion lattice defects and improving the electronic conductivity of the nickel hydroxide, and submicron flaky particles are beneficial to ion diffusion, so that the composite material has excellent specific capacitance and rate characteristics when being used for an electrode material of an asymmetric supercapacitor, wherein the specific capacitance of some preferred schemes can reach 1068F/g under the current density of 1A/g, and the cycle life of 80% specific capacitance retention rate reaches 3670 times.

(3) The method of the invention ensures that the recovery rate of the raw materials of the anode and the cathode of the waste lithium ion battery is high, and the waste lithium ion battery can be fully recycled.

Detailed Description

The present invention will be further described with reference to the following examples, but the present invention is not limited to these examples.

The main raw material information is as follows:

nickel sulfate hexahydrate (battery grade), jinchuan group,

cobalt sulfate heptahydrate (battery grade), cobalt rochonate industry,

manganese sulfate monohydrate (battery grade), a new material limited company, Dalonghui Guizhou,

urea (analytically pure), alatin,

polyvinylidene fluoride (PVDF) (analytical grade), Solvay,

n-methylpyrrolidone (NMP) (analytical grade), alatin,

hydroxypropyl methylcellulose (HPMC) (analytical grade), alatin,

potassium hydroxide (analytically pure), group of national drugs.

The main test equipment information is as follows:

the electrochemical test equipment is a Switzerland Wantong electrochemical workstation Autolab;

the oxidizing roasting and reducing roasting equipment adopts a tube furnace of fertilizer combination crystal, and the model is OTF-1500X;

the numerical control ultrasonic cleaner is a KQ-50D model of Shanghai Binengtui ultrasonic limited company.

The general method for preparing graphene oxide by the Hummers method is as follows:

20g of graphite powder and 20g of NaNO were weighed₃Mixing, adding 800mL of concentrated sulfuric acid, placing in an ice bath, stirring, adding 60g of potassium permanganate after 30 minutes, after reacting for 60 minutes, transferring into a warm water bath at 50 ℃ to continue reacting for 30 minutes, then slowly adding deionized water, keeping the reaction temperature at 90 ℃, stirring for 10 minutes, adding a proper amount of hydrogen peroxide until no bubbles are generated, filtering while hot, and washing with deionized water and 5% hydrochloric acid for multiple times until the mixture is neutral. And (4) fully drying in a vacuum drying oven at 80 ℃ after centrifugation to obtain the graphite oxide.

The preparation method of the working electrode comprises the following steps:

weighing 5g of the composite material, mixing the composite material with carbon black serving as a conductive agent and polyvinylidene fluoride (PVDF) serving as a binder according to the mass ratio of 8:1:1, preparing slurry by using 10mL of N-methylpyrrolidone (NMP) as a dispersing agent, and uniformly stirring. The slurry was coated on a square nickel foam sheet of 15mm X15 mm, dried in a vacuum oven at 60 ℃ for 6 hours, and finally taken out and pressed into a sheet as an electrode.

The electrochemical test is carried out in a three-electrode system, wherein the reference electrode is a calomel electrode, and the counter electrode is a blank foam nickel sheet. The electrolyte is 6mol/L KOH solution. The specific capacitance of the composite electrode material was tested at a current density of 1A/g. And then continuously carrying out a charge-discharge test, and recording the cycle times when the specific capacitance is reduced to 80% of the initial specific capacitance.

Example 1

S1: using LiNi_1/3Co_1/3Mn_1/3O₂Taking a waste lithium ion battery which is a positive electrode material and takes natural graphite as a negative electrode, and manually disassembling the waste lithium ion battery to obtain a positive plate and a negative plate. Placing 100g of positive plateThe moist solid powder was dried in a forced air drying oven at 80 ℃ for 3 hours, after suction filtration in 200mL of ethanol, to give 69g of LiNi_1/3Co_1/3Mn_1/3O₂A positive electrode active material; 100g of the negative electrode sheet was treated in the same manner to obtain 57g of natural graphite powder.

S2: 140g of LiNi_1/3Co_1/3Mn_1/3O₂The positive electrode active material was baked at 600 ℃ for 1 hour in a reducing atmosphere of CO. Dissolving the obtained 128g of the roasted slag with 4L of 0.5mol/L dilute sulfuric acid aqueous solution, filtering, and removing insoluble substances to obtain the product containing Ni²⁺、Co²⁺、Mn²⁺Mixed solution L1.

S3: the mixed solution was analyzed for nickel, cobalt and manganese using ICP with a ratio of 1.02: 0.98: 0.99. taking 3L of mixed solution, and mixing the mixed solution according to the final ratio of nickel, cobalt and manganese as 8:1:1, adding 917g of nickel sulfate hexahydrate, 2.3g of cobalt sulfate heptahydrate and 0.56g of manganese sulfate monohydrate into the mixed solution, and adding deionized water to a constant volume of 5L to obtain a solution with a metal molar concentration of 1mol/L and a nickel-cobalt-manganese molar ratio of 8:1:1, L2, ready for use.

S4: preparing graphite oxide from 20g of the natural graphite obtained in the step S1 by using a Hummers method, dissolving the graphite oxide in 1L of distilled water, performing ultrasonic treatment for 30min to obtain a graphene oxide (rGO) solution L3, and heating the solution to 80 ℃ for later use.

S5: 1L of L2 was charged with 10g of urea to give a urea mass concentration of 1%. In addition, 1g of dispersing agent HPMC was added to the mixed solution, and the mass concentration thereof was 0.1%. Mixing L2 with 200mL L3, keeping the temperature constant at 80 ℃, reacting for 5 hours, separating a solid phase and a liquid phase by vacuum filtration, washing the solid powder by deionized water until the conductivity of the washing water is less than 20uS/cm, and then drying the filter cake in a forced air drying oven at 120 ℃ for 5 hours to obtain the target material.

The electrochemical performance of the prepared composite electrode material is tested and analyzed by an electrochemical workstation. The specific capacitance of the composite electrode material is 1012F/g. After 3600 cycles, the electrode material can maintain 80% of specific capacitance.

Example 2

According to the method of example 1, LiNi was used in step S1_0.5Co_0.2Mn_0.3O₂The waste lithium ion battery which is used as a positive electrode material and uses graphitized mesocarbon microbeads as a negative electrode material is used as a recovery raw material. Finally, the specific capacitance of the composite electrode material is 997F/g, and the cycle life of 80% specific capacitance retention rate is 3670 times.

Example 3

According to the method of example 1, LiNi was used in step S1_1/3Co_1/3Mn_1/3O₂The waste lithium ion battery which is used as a positive electrode material and uses artificial graphite as a negative electrode material is used as a recovery raw material. Finally, the specific capacitance of the composite electrode material is 1038F/g, and the cycle life of 80% specific capacitance retention rate is 3520 times.

Example 4

According to the method of example 1, in step S2, LiNi is added_1/3Co_1/3Mn_1/3O₂The reductive roasting of the positive active substance uses ammonia atmosphere, the roasting temperature is 300 ℃, and the roasting time is 0.5 hour. Finally, the specific capacitance of the composite electrode material is 1017F/g, and the cycle life of 80% specific capacitance retention rate is 3490 times.

Example 5

According to the method of example 1, in step S2, LiNi is added_1/3Co_1/3Mn_1/3O₂The anode active material is reductively calcined in a water gas atmosphere at 300 ℃ for 0.5 hour. Finally, the specific capacitance of the composite electrode material is 1002F/g, and the cycle life of 80% specific capacitance retention rate is 3523 times.

Example 6

According to the method of example 1, in step S2, LiNi is added_1/3Co_1/3Mn_1/3O₂The anode active material is reductively calcined at 600 deg.C in water gas atmosphereThe firing time was 0.5 hour. Finally, the specific capacitance of the composite electrode material was 1011F/g, and the cycle life of 80% specific capacitance retention rate was 3551 times.

Example 7

According to the method of example 1, in step S2, LiNi is added_1/3Co_1/3Mn_1/3O₂The anode active material is reductively calcined in a water gas atmosphere at 300 ℃ for 4 hours. Finally, the specific capacitance of the composite electrode material is 1015F/g, and the cycle life of 80% specific capacitance retention rate is 3516 times.

Example 8

According to the method of example 1, 3mol/L acetic acid was used in the acid leaching step in S2 step. Nitrate is used when adding nickel, cobalt and manganese salts. Finally, the specific capacitance of the composite electrode material is 990F/g, and the cycle life of 80% specific capacitance retention rate is 3485 times.

Example 9

According to the implementation method of the example 1, in the step of S3, the ion molar ratio of nickel, cobalt and manganese is matched to be 90: 5: 5. finally, the specific capacitance of the composite electrode material is 1046F/g, and the cycle life of 80% specific capacitance retention rate is 3366 times.

Example 10

According to the implementation method of the example 1, in the step of S3, the ion molar ratio of nickel, cobalt and manganese is mixed into 94: 1: 5. finally, the specific capacitance of the composite electrode material is 1058F/g, and the cycle life of 80% specific capacitance retention rate is 3250 times.

Example 11

According to the method of example 1, 5g of urea was used in an amount of 0.5% by mass in step S5. Finally, the specific capacitance of the composite electrode material is 985F/g, and the cycle life of 80% specific capacitance retention rate is 3565 times.

Example 12

According to the method of example 1, 50g of urea was used in an amount of 5% by mass in step S5. Finally, the specific capacitance of the composite electrode material is 974F/g, and the cycle life of 80% specific capacitance retention rate is 3619 times.

Example 13

According to the method of example 1, in the step S5, the reaction slurry was kept at a temperature of 50 ℃ for a reaction time of 1 hour. Finally, the specific capacitance of the composite electrode material is 1047F/g, and the cycle life of 80% specific capacitance retention rate is 3451 times.

Example 14

The procedure of example 1 was followed, and in step S5, the reaction slurry was maintained at 90 ℃ for 1 hour. Finally, the specific capacitance of the composite electrode material is 1032F/g, and the cycle life of 80% specific capacitance retention rate is 3398 times.

Example 15

According to the method of example 1, in the step S5, the temperature of the reaction slurry was maintained at 80 ℃ for 30 min. Finally, the specific capacitance of the composite electrode material is 1004F/g, and the cycle life of 80% specific capacitance retention rate is 3487 times.

Example 16

According to the method of example 1, in the step S5, the reaction slurry was kept at 80 ℃ for 8 hours. Finally, the specific capacitance of the composite electrode material is 1022F/g, and the cycle life of 80% specific capacitance retention rate is 3519 times.

Example 17

According to the implementation method of the example 1, in the step of S4, the ultrasonic time for the graphene oxide is 2 h. Finally, the specific capacitance of the composite electrode material is 990F/g, and the cycle life of 80% specific capacitance retention rate is 3421 times.

Example 18

According to the implementation method of the embodiment 1, in the step of S4, the ultrasonic time for the graphene oxide is 15 min. Finally, the specific capacitance of the composite electrode material is 982F/g, and the cycle life of 80% specific capacitance retention rate is 3396 times.

Example 19

According to the method of example 1, 10g of graphite was used in step S4. Finally, the specific capacitance of the composite electrode material is 1052F/g, and the cycle life of 80% specific capacitance retention rate is 2345 times.

Example 20

According to the method of example 1, 5g of graphite was used in S4. Finally, the specific capacitance of the composite electrode material is 1068F/g, and the cycle life of 80% specific capacitance retention rate is 2124 times.

Example 21

According to the method of example 1, 200g of LiNi was taken before S2_1/3Co_1/3Mn_1/3O₂The positive electrode active material was calcined at 600 ℃ for 1 hour in an oxygen atmosphere, and then 140g of the calcined slag was taken out and subjected to S2 and the subsequent steps. Finally, the specific capacitance of the composite electrode material is 1053F/g, and the cycle life of 80% specific capacitance retention rate is 3612 times.

Example 22

According to the method of example 1, 200g of LiNi was taken before S2_1/3Co_1/3Mn_1/3O₂The positive electrode active material was calcined at 800 ℃ for 6 hours in an air atmosphere, and then 140g of the calcined slag was taken out to be subjected to S2 and the subsequent steps. Finally, the specific capacitance of the composite electrode material is 1024F/g, and the cycle life of 80% specific capacitance retention rate is 3577 times.

Comparative example 1

The method of example 1 was carried out without using any anode material in all the steps. Finally, the specific capacitance of the composite electrode material is 1104F/g, and the cycle life of 80% specific capacitance retention rate is 450 times.

In the comparative example, the material of the reduced graphene oxide is not compounded, and the cycle life is greatly reduced although the initial specific capacitance is not changed.

Comparative example 2

According to the method of example 1, in step S1, the coating film coated with 2000ppm Al is used₂O₃LiNi of (2)_0.8Co_0.1Mn_0.1O₂The waste lithium ion battery as the anode material is used as a recovery raw material. Finally, the specific capacitance of the composite electrode material is 823F/g, and the cycle life of 80% specific capacitance retention rate is 1648 times.

In the present comparative example, since the cathode material containing Al impurities was used, eventually the Al impurities were introduced into the composite material, resulting in a decrease in capacitance and a decrease in cyclability.

Comparative example 3

According to the embodiment of example 1, in step S1, a used lithium ion battery using hard carbon as a negative electrode material is used as a recovery raw material. Finally, the specific capacitance of the composite electrode material is 386F/g, and the cycle life of 80% specific capacitance retention rate is 569 times.

In this comparative example, non-graphitizing carbon was used, and graphene was not available, and thus the specific capacitance and cycle life were low.

Comparative example 4

Synthesis of 90g of Fine flaky Ni according to the embodiment of comparative example 1_0.8Co_0.1Mn_0.1(OH)₂After the materials were mixed, 20g of the natural graphite oxide material subjected to ultrasonic treatment for 30 minutes was mixed, and the two materials were uniformly mixed using a high-speed mixer. Finally, the specific capacitance of the composite electrode material is 866F/g, and the cycle life of 80% specific capacitance retention rate is 689 times.

In the comparative example, after the fine flaky nickel cobalt manganese hydroxide material and the graphene are separately synthesized, the two materials are physically mixed, so that the graphene lamellar structure cannot be uniformly mixed with the flaky hydroxide, the capacitance is slightly reduced, and the cycle life is greatly reduced.

Comparative example 5

According to the embodiment of example 1, in step S5,ni with 200mL of 1mol/L ammonia water as a precipitant_0.8Co_0.1Mn_0.1(OH)₂And (4) precipitating. Finally, the appearance of the composite electrode material under an electron microscope is fine particles, the specific capacitance of the composite electrode material is 547F/g, and the cycle life of 80% specific capacitance retention rate is 1452 times.

In this comparative example, ammonia water was used directly as a precipitant, instead of urea, which slowly releases ammonia. Instead of flakes, the hydroxide precipitated here as fine particles. The specific capacitance and the cycle performance are affected.

Claims

1. A method for preparing a composite nickel material which contains reduced graphene oxide and is doped with cobalt-manganese by taking a positive electrode and a negative electrode of a waste lithium ion battery as raw materials is characterized in that the method simultaneously recycles a ternary positive electrode and a graphite negative electrode of the lithium ion battery to prepare the composite material, and the method comprises the following steps:

s1: disassembling a waste lithium ion battery to obtain a positive plate and a negative plate, and respectively placing the positive plate and the negative plate in a separation solution to obtain a positive active substance P and a negative active substance N;

s4: preparing N into graphite oxide, and treating to obtain a reduced graphene oxide solution L3;

s5: adding alkali liquor into L2, mixing with L3, reacting, separating, washing, and drying the filtrate to obtain the composite nickel material;

the anode material of the waste lithium ion battery in the step S1 contains Li, Ni, Co and Mn elements, and the cathode material is one or more of natural graphite, artificial graphite and graphitized mesocarbon microbeads;

wherein, the step S5 is to obtain the flake nickel hydroxide containing the reduced graphene oxide and doped with cobalt-manganese.

2. The method of claim 1The method is characterized in that the positive electrode material of the waste lithium ion battery in the step S1 is LiNi_1/3Co_1/3Mn_1/3O₂、 LiNi_0.5Co_0.2Mn_0.3O₂、LiNi_0.6Co_0.2Mn_0.2O₂And LiNi_0.8Co_0.1Mn_0.1O₂One or more of (a).

3. The method according to claim 1, wherein the separation liquid in step S1 is selected from small molecule alcohol or small molecule alcohol water solution, wherein the small molecule alcohol is selected from one or more of ethanol, n-propanol, isopropanol and glycerol.

4. The method of claim 1, wherein the oxidizing roasting is performed before the reducing roasting in step S2, and the oxidizing atmosphere of the oxidizing roasting is one or more of oxygen, air and mixed gas of oxygen and nitrogen in a volume ratio of 99:1-20: 80;

the oxidizing roasting temperature is 500-900 ℃; the oxidizing roasting time is 0.5-10 hours.

5. The method of claim 4, wherein the oxidizing atmosphere of the oxidizing roasting in step S2 is air;

the oxidizing roasting temperature is 550-700 ℃; the oxidizing roasting time is 1-3 hours.

6. The method of claim 1, wherein the reducing atmosphere of the reductive calcination in step S2 is one or more of ammonia, hydrogen sulfide, hydrogen, carbon monoxide and water gas;

the reduction roasting temperature is 300-600 ℃; the reduction roasting time is 0.5-4 hours.

7. The method of claim 6, wherein the reducing atmosphere of the reductive calcination in step S2 is water gas.

8. The method according to claim 1, wherein the roasting residue is treated in step S2 by acid leaching, and the acid used in the treatment is one or more of dilute sulfuric acid, dilute phosphoric acid, dilute acetic acid and dilute oxalic acid;

the acid is prepared into an aqueous solution with the concentration of 0.1-5 mol/L;

the mixed solution L1 obtained by filtering off insoluble matter after acid leaching treatment contained Ni²⁺、Co²⁺And Mn²⁺。

9. The method as claimed in claim 8, wherein the acid used in the treatment of the roasting slag in step S2 is dilute sulfuric acid.

10. The method of claim 1, wherein the mixed solution L1 is subjected to metal element analysis in step S3.

11. The method of claim 1, wherein the step S3 of supplementing the corresponding metal element in L1 is adding a corresponding divalent metal element salt.

12. The method of claim 11, wherein the divalent metal element salt supplemented in L1 at step S3 is one or more of sulfate, nitrate, phosphate, acetate, oxalate, chloride, bromide, and iodide.

13. The method of claim 12, wherein the divalent metal element salt supplemented in L1 of step S3 is a sulfate.

14. The method according to claim 1, wherein the method of preparing N into graphite oxide in step S4 is Hummers method;

dissolving graphite oxide in distilled water, and performing ultrasonic treatment to obtain graphene oxide;

the ultrasonic treatment time is 15 min-3 h;

after ultrasonic treatment, heating the graphene oxide solution L3 to 50-100 ℃.

15. The method according to claim 1, wherein the alkaline solution added in step S5 in L2 is urea;

the proportion of urea in the L2 is 0.5wt% -5 wt%;

mixing the urea with a dispersant.

16. The method according to claim 15, wherein the dispersant is hydroxypropyl methylcellulose in step S5.

17. The method according to claim 1, wherein the ratio of the amount of the substance calculated as total metal ions in L2 to the amount of the substance calculated as carbon in L3 in step S5 is 15 (1-5);

the reaction time of the L2 and the L3 is 30min-10 h; the reaction temperature is 50-100 ℃.

18. The method of claim 1, wherein the reaction time of L2 and L3 in step S5 is 1-6 h.

19. A composite nickel material comprising reduced graphene oxide and doped with cobalt-manganese prepared by the method of any one of claims 1 to 18.

20. The composite nickel material of claim 19, wherein the composite nickel material is a nickel hydroxide material comprising reduced graphene oxide and doped with cobalt hydroxide and manganese hydroxide.

21. The composite nickel material of claim 20, wherein the cobalt-manganese doped nickel hydroxide material has the general formula Ni_xCo_yMn_z(OH)₂The composition is shown in the specification, wherein x is more than or equal to 0.8 and less than or equal to 0.95, y is more than or equal to 0.01 and less than or equal to 0.1, z is more than or equal to 0.01 and less than or equal to 0.1, and x + y + z = 1.

22. Use of a reduced graphene oxide-containing cobalt-manganese doped composite nickel material prepared by the method of any one of claims 1 to 18 or a reduced graphene oxide-containing cobalt-manganese doped composite nickel material of any one of claims 19 to 21 as an electrode material.

23. The use according to claim 22, wherein the electrode material is used in the field of electrode materials for supercapacitors.