Method for recovering metal lithium from waste lithium ion battery

文档序号：1811465 发布日期：2021-11-09 浏览：33次中文

阅读说明：本技术 从废旧锂离子电池中回收金属锂的方法 (Method for recovering metal lithium from waste lithium ion battery ) 是由樊美岑赵云李宝华康飞宇于 2021-08-05 设计创作，主要内容包括：一种从废旧锂离子电池中回收金属锂的方法,包括以下步骤：提供手套箱、电化学沉积装置、碳酸酯类电解液、惰性电极、及废旧锂离子电池的锂正极；将电化学沉积装置、碳酸酯类电解液、惰性电极、及废旧锂离子电池的锂正极置于手套箱中；于手套箱中,将碳酸酯类电解液、惰性电极、及废旧锂离子电池的锂正极置于电化学沉积装置中,并以废旧锂离子电池的锂正极为电化学沉积装置的阳极,以惰性电极为电化学沉积装置的阴极；及向电化学沉积装置中通入电流,以使电化学沉积装置的电压大于废旧锂离子电池的锂正极的工作平台电压,废旧锂离子电池的锂正极的结构坍塌,且废旧锂离子电池的锂正极内的锂元素被还原为金属锂并沉积于惰性电极的表面。(A method for recovering metallic lithium from waste lithium ion batteries comprises the following steps: providing a glove box, an electrochemical deposition device, a carbonate electrolyte, an inert electrode and a lithium anode of a waste lithium ion battery; placing an electrochemical deposition device, a carbonate electrolyte, an inert electrode and a lithium anode of a waste lithium ion battery in a glove box; placing the carbonate electrolyte, the inert electrode and the lithium anode of the waste lithium ion battery in an electrochemical deposition device in a glove box, and taking the lithium anode of the waste lithium ion battery as an anode of the electrochemical deposition device and the inert electrode as a cathode of the electrochemical deposition device; and introducing current into the electrochemical deposition device so that the voltage of the electrochemical deposition device is greater than the working platform voltage of the lithium anode of the waste lithium ion battery, the structure of the lithium anode of the waste lithium ion battery collapses, and lithium elements in the lithium anode of the waste lithium ion battery are reduced into metal lithium and deposited on the surface of the inert electrode.)

1. The method for recovering the metallic lithium from the waste lithium ion batteries is characterized by comprising the following steps of:

providing a glove box, an electrochemical deposition device, a carbonate electrolyte, an inert electrode and a lithium anode of a waste lithium ion battery;

placing the electrochemical deposition device, the carbonate electrolyte, the inert electrode and the lithium anode of the waste lithium ion battery in a glove box;

placing the carbonate electrolyte, the inert electrode and the lithium anode of the waste lithium ion battery in an electrochemical deposition device in the glove box, and taking the lithium anode of the waste lithium ion battery as an anode of the electrochemical deposition device and the inert electrode as a cathode of the electrochemical deposition device; and

and introducing current into the electrochemical deposition device so that the voltage of the electrochemical deposition device is greater than the working platform voltage of the lithium anode of the waste lithium ion battery, the structure of the lithium anode of the waste lithium ion battery collapses, and lithium elements in the lithium anode of the waste lithium ion battery are reduced into metal lithium and deposited on the surface of the inert electrode.

2. The method for recovering metallic lithium from waste lithium ion batteries according to claim 1, wherein the method for recovering metallic lithium from waste lithium ion batteries further comprises the following steps:

providing a heating device;

separating the inert electrode with the metal lithium deposited on the surface from the electrochemical deposition device in the glove box; and

and placing the heating device in a glove box, and carrying out heating treatment on the inert electrode with the metal lithium deposited on the surface through the heating device so as to remove the solid electrolyte interface film which is produced by contacting the metal lithium with the carbonate electrolyte and covers the metal lithium.

3. The method for recovering the metallic lithium from the waste lithium ion batteries according to claim 2, wherein the temperature of the heating treatment is 200-300 ℃.

4. The method for recovering the metallic lithium from the waste lithium ion battery according to claim 1, wherein the voltage of the electrochemical deposition device is 4.4-5V.

5. The method for recovering the metallic lithium from the waste lithium ion batteries according to claim 1, wherein the carbonate electrolyte contains a lithium salt and a solvent, and the concentration of the lithium salt is 1-3 mol/L.

6. The method for recovering metallic lithium from waste lithium ion batteries according to claim 5, wherein the lithium salt is LiPF₆、LiClO₄、LiBF₄、LiAsF₆At least one of (1).

7. The method for recovering the metallic lithium from the waste lithium ion battery according to claim 5, wherein the solvent is at least one of ethylene carbonate, propylene carbonate and diethyl carbonate.

8. The method for recovering the metallic lithium from the waste lithium ion battery according to claim 1, wherein the inert electrode is made of copper, stainless steel, platinum or gold.

9. The method for recovering metallic lithium from waste lithium ion batteries according to claim 1, wherein the lithium positive electrode of the waste lithium ion battery is a lithium iron phosphate positive electrode, a lithium cobalt oxide positive electrode, a lithium nickelate positive electrode, a lithium nickel cobalt manganese ternary positive electrode, or a lithium nickel cobalt aluminum ternary positive electrode.

10. The method for recovering the metallic lithium from the waste lithium ion battery according to claim 1, wherein the thickness of the metallic lithium deposited on the surface of the inert electrode is 5-30 μm.

Technical Field

The invention relates to the technical field of battery recovery, in particular to a method for recovering metal lithium from waste lithium ion batteries.

Background

Lithium ion batteries have been widely used in portable electronic products, electric vehicles, and large-scale energy systems, etc., as one of the most promising renewable clean energy sources in the 21 st century. The service life of the lithium ion battery is generally 5 years, and the total amount of the waste lithium ion battery can reach 1.1 million tons by 2030 years. Therefore, it is a great trend to recover metal lithium from waste lithium ion batteries and recycle the metal lithium. The method can be used for recovering the metal lithium in the waste lithium ion battery by adopting a wet method and a fire method. However, the wet and fire methods have disadvantages of low recovery efficiency, high energy consumption, environmental pollution, etc.

Disclosure of Invention

In view of the above, there is a need to provide a method for recovering lithium metal from waste lithium ion batteries, so as to solve the problems of low recovery efficiency, high energy consumption and environmental pollution of the existing wet and fire methods.

A method for recovering metallic lithium from waste lithium ion batteries comprises the following steps:

providing a glove box, an electrochemical deposition device, a carbonate electrolyte, an inert electrode and a lithium anode of a waste lithium ion battery;

placing the electrochemical deposition device, the carbonate electrolyte, the inert electrode and the lithium anode of the waste lithium ion battery in a glove box;

Further, the method for recovering the metallic lithium from the waste lithium ion battery further comprises the following steps:

providing a heating device;

separating the inert electrode with the metal lithium deposited on the surface from the electrochemical deposition device in the glove box; and

Further, the temperature of the heating treatment is 200-300 ℃.

Further, the voltage of the electrochemical deposition device is 4.4-5V.

Further, the carbonate electrolyte contains a lithium salt and a solvent, and the concentration of the lithium salt is 1-3 mol/L.

Further, the lithium salt is LiPF₆、LiClO₄、LiBF₄、LiAsF₆At least one of (1).

Further, the solvent is at least one of ethylene carbonate, propylene carbonate, and diethyl carbonate.

Furthermore, the inert electrode is made of copper, stainless steel, platinum or gold.

Further, the lithium anode of the waste lithium ion battery is a lithium iron phosphate anode, a lithium cobaltate anode, a lithium nickelate anode, a lithium nickel cobalt manganese ternary anode or a lithium nickel cobalt aluminum ternary anode.

Furthermore, the thickness of the metal lithium deposited on the surface of the inert electrode is 5-30 μm.

In the method for recovering the metallic lithium from the waste lithium ion battery, the carbonate electrolyte, the inert electrode and the lithium anode of the waste lithium ion battery are placed in an electrochemical deposition device in the glove box, the lithium anode of the waste lithium ion battery is taken as the anode of the electrochemical deposition device, the inert electrode is taken as the cathode of the electrochemical deposition device, and current is introduced into the electrochemical deposition device, so that the voltage of the electrochemical deposition device is greater than the working platform voltage of the lithium anode of the waste lithium ion battery. At this time, the structure of the lithium anode of the waste lithium ion battery collapses, and lithium elements in the lithium anode of the waste lithium ion battery are reduced into metal lithium and deposited on the surface of the inert electrode, so that the purpose of recovering the metal lithium from the waste lithium ion battery is achieved. When the voltage of the electrochemical deposition device is greater than the working platform voltage of the lithium anode of the waste lithium ion battery, the structure of the lithium anode of the waste lithium ion battery collapses, and lithium elements in the lithium anode of the waste lithium ion battery can be fully reduced into metal lithium and deposited on the surface of the inert electrode, so that the method for recovering the metal lithium from the waste lithium ion battery has the advantage of high recovery efficiency. Moreover, the lithium element in the lithium anode of the waste lithium ion battery can be further fully reduced into the metal lithium and deposited on the surface of the inert electrode only by adjusting the voltage of the electrochemical deposition device to be larger than the working platform voltage of the lithium anode of the waste lithium ion battery, which shows that the method for recovering the metal lithium from the waste lithium ion battery has the advantage of low energy consumption. Furthermore, toxic substances are not adopted in the method for recovering the metal lithium from the waste lithium ion batteries, and no toxic substances are generated, so that the method for recovering the metal lithium from the waste lithium ion batteries also has the advantage of environmental protection.

Drawings

Fig. 1 is a rate performance diagram of first to fourth lithium ion batteries according to an embodiment of the present invention.

Fig. 2 is a coulomb efficiency chart of the first to fourth lithium ion batteries according to the embodiment of the present invention.

The following detailed description will further illustrate the invention in conjunction with the above-described figures.

Detailed Description

So that the manner in which the above recited objects, features and advantages of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to the embodiments thereof which are illustrated in the appended drawings. In addition, the embodiments and features of the embodiments of the present application may be combined with each other without conflict. In the following description, numerous specific details are set forth to provide a thorough understanding of the present invention, and the described embodiments are merely a subset of the embodiments of the present invention, rather than a complete embodiment. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes all and any combination of one or more of the associated listed items.

In various embodiments of the present invention, for convenience in description and not in limitation, the term "coupled" as used in the specification and claims of the present application is not limited to physical or mechanical couplings, either direct or indirect. "upper", "lower", "left", "right", and the like are used merely to indicate relative positional relationships, and when the absolute position of the object being described is changed, the relative positional relationships are changed accordingly.

The embodiment of the invention provides a method for recovering metal lithium from waste lithium ion batteries, which comprises the following steps:

step S1: providing a glove box, an electrochemical deposition device, a carbonate electrolyte, an inert electrode and a lithium anode of a waste lithium ion battery;

step S2: placing the electrochemical deposition device, the carbonate electrolyte, the inert electrode and the lithium anode of the waste lithium ion battery in a glove box;

step S3: placing the carbonate electrolyte, the inert electrode and the lithium anode of the waste lithium ion battery in an electrochemical deposition device in the glove box, and taking the lithium anode of the waste lithium ion battery as an anode of the electrochemical deposition device and the inert electrode as a cathode of the electrochemical deposition device; and

step S4: and introducing current into the electrochemical deposition device, so that the voltage of the electrochemical deposition device is greater than the working platform voltage (equivalent to overcharge) of the lithium anode of the waste lithium ion battery, the structure of the lithium anode of the waste lithium ion battery collapses, and lithium elements in the lithium anode of the waste lithium ion battery are reduced into metal lithium and deposited on the surface of the inert electrode.

In at least one embodiment, the carbonate electrolyte contains a lithium salt and a solvent, and the concentration of the lithium salt is 1-3 mol/L. The lithium salt is LiPF₆、LiClO₄、LiBF₄、LiAsF₆At least one of (1). The solvent is at least one of ethylene carbonate, propylene carbonate and low-viscosity diethyl carbonate.

In at least one embodiment, the inert electrode is made of copper (melting point 1083.4 ℃), stainless steel (melting point 650-1450 ℃), platinum (melting point 1772 ℃), or gold (melting point 1064 ℃).

In at least one embodiment, the lithium positive electrode of the waste lithium ion battery is a lithium iron phosphate positive electrode, a lithium cobaltate positive electrode, a lithium nickelate positive electrode, a lithium nickel cobalt manganese ternary positive electrode, or a lithium nickel cobalt aluminum ternary positive electrode. The working platform voltage of the lithium iron phosphate anode is 3.65V. The working platform voltage of the lithium cobaltate anode is 4.2V. The working platform voltage of the lithium nickelate anode is 4.7V. The working platform voltage of the nickel cobalt lithium manganate ternary positive electrode is 4.3-4.35V. The working platform voltage of the nickel cobalt lithium aluminate ternary positive electrode is 4.3-4.35V.

In at least one embodiment, after the current is introduced into the electrochemical deposition device for 8-10 hours, the voltage of the electrochemical deposition device can be greater than the working platform voltage of the lithium anode of the waste lithium ion battery.

In at least one embodiment, the electrochemical deposition device is energized with current at a rate of 0.1-1C.

In at least one embodiment, the voltage of the electrochemical deposition device is 4.4-5V, such as 4.4V, 4.5V, and 5V.

In at least one embodiment, the thickness of the lithium metal deposited on the surface of the inert electrode is 5 to 30 μm, such as 5 μm, 15 μm, 20 μm, 25 μm, or 30 μm.

In at least one embodiment, the recovery rate of the metal lithium in the method for recovering the metal lithium from the waste lithium ion battery is 90-95%.

In at least one embodiment, the recovered lithium metal can be reused as a negative electrode material or a prelithiated negative electrode material for a battery.

It can be understood that the electrochemical deposition device, the carbonate electrolyte, the inert electrode and the lithium anode of the waste lithium ion battery are placed in the glove box, and the metal lithium is recovered in the glove box, so that impurities caused by overhigh oxygen content can be avoided.

The method for recovering the metal lithium from the waste lithium ion battery further comprises the following steps:

providing a heating device;

separating the inert electrode with the metal lithium deposited on the surface from the electrochemical deposition device in the glove box; and

and placing the heating device in a glove box, and heating the inert electrode with the metallic lithium deposited on the surface through the heating device to remove a Solid Electrolyte Interface (SEI) which is produced by the contact of the metallic lithium and the carbonate Electrolyte and covers the metallic lithium.

In at least one embodiment, the temperature of the heat treatment is 200 to 300 ℃ which is higher than the melting point (180 ℃) of the lithium metal and lower than the melting point of the inert electrode.

It is understood that when the metal lithium is in contact with the carbonate electrolyte, the carbonate electrolyte reacts with the metal lithium to generate impurities such as an organolithium compound, lithium fluoride, lithium hydroxide, and lithium carbonate, and covers the metal lithium to form a solid electrolyte interface film. Therefore, it is necessary to remove the solid electrolyte interface film on the surface of the metallic lithium.

In the technical scheme of the invention, in the glove box, the inert electrode with the metal lithium deposited on the surface is heated by the heating device to remove a solid electrolyte interface film which is produced by the contact of the metal lithium and the carbonate electrolyte and covers the metal lithium, so that the purpose of recovering the metal lithium from the waste lithium ion battery is achieved. During the heating treatment, the metallic lithium and the solid electrolyte interface film are melted, and since the affinity between Li and Li is much greater than that between Li and SEI, the solid electrolyte interface film floats on the surface of the molten metallic lithium, and the molten solid electrolyte interface film is removed with tweezers, so that pure metallic lithium can be obtained.

The present invention will be specifically described below with reference to specific examples.

Example one

Providing a glove box, a heating device, an electrochemical deposition device, an electrolyte, a copper electrode and a lithium cobaltate anode of a waste lithium ion battery, wherein the electrolyte contains LiPF with the concentration of 1mol/L₆And ethylene carbonate, wherein the working platform voltage of the lithium cobaltate anode of the waste lithium ion battery is 4.2V;

placing the heating device, the electrochemical deposition device, the electrolyte, the copper electrode and the lithium cobaltate anode of the waste lithium ion battery in a glove box;

placing the electrolyte, the copper electrode and the lithium cobaltate anode of the waste lithium ion battery in an electrochemical deposition device in the glove box under the argon atmosphere, and taking the lithium cobaltate anode of the waste lithium ion battery as the anode of the electrochemical deposition device and the copper electrode as the cathode of the electrochemical deposition device; and

introducing current into the electrochemical deposition device, enabling the voltage of the electrochemical deposition device to reach 5V at a multiplying power of 0.1C, collapsing the structure of a lithium cobaltate positive electrode of the waste lithium ion battery, extracting lithium elements in the lithium positive electrode of the waste lithium ion battery from the lithium positive electrode, reducing the extracted lithium elements into metal lithium and depositing the metal lithium on the surface of the copper electrode, wherein the thickness of the metal lithium deposited on the surface of the copper electrode is 10 microns;

separating the copper electrode with the metal lithium deposited on the surface from an electrochemical deposition device in the glove box; and

and heating the inert electrode with the surface deposited with the metal lithium by the heating device to remove a solid electrolyte interface film which is produced by the contact of the metal lithium and the carbonate electrolyte and covers the metal lithium, so as to obtain pure metal lithium, wherein the temperature of the heating treatment is 220 ℃.

The recovery rate of the method for recovering metallic lithium from the waste lithium ion battery in the first embodiment is 90.68% as measured by inductively coupled plasma mass spectrometry (ICP-MS).

Example two

The difference from the first embodiment comprises: the working platform voltage of the lithium iron phosphate anode of the waste lithium ion battery is 3.65V;

the voltage of the electrochemical deposition device is 4.4V.

Other steps are the same as the first embodiment and are not repeated.

The recovery rate of the method for recovering metallic lithium from the used lithium ion battery of example two was 90.34%, as measured by inductively coupled plasma mass spectrometry (ICP-MS).

The metal lithium prepared by the method for recovering the metal lithium from the waste lithium ion battery is used as a prelithiation negative electrode material of the lithium ion battery, so that the cycle performance of the lithium ion battery can be improved. Specifically, the metal lithium prepared by the method for recovering the metal lithium from the waste lithium ion battery is respectively deposited on the three copper sheet electrodes, the deposition times are respectively 1 time, 2 times and 3 times, and a first pre-lithiation negative electrode, a second pre-lithiation negative electrode and a third pre-lithiation negative electrode are obtained. Wherein the thickness of the lithium metal layer of the first pre-lithiated negative electrode is 10 microns, the thickness of the lithium metal layer of the second pre-lithiated negative electrode is 20 microns, and the thickness of the lithium metal layer of the third pre-lithiated negative electrode is 30 microns. And preparing a first lithium ion battery, a second lithium ion battery and a third lithium ion battery by taking the first pre-lithiation negative electrode, the second pre-lithiation negative electrode and the third pre-lithiation negative electrode as negative electrodes and lithium cobaltate as a positive electrode.

And (3) taking the copper sheet electrode which is not loaded with the lithium metal layer as a negative electrode and lithium cobaltate as a positive electrode to prepare the fourth lithium ion battery.

Referring to fig. 1 and 2, after the first lithium ion battery, the second lithium ion battery, the third lithium ion battery and the fourth lithium ion battery are activated at 0.1C, charge and discharge cycles are performed at a rate of 0.5C and a voltage of 3-4.2V, and electrochemical performances of the first lithium ion battery, the second lithium ion battery, the third lithium ion battery and the fourth lithium ion battery are tested.

The test result shows that the thickness of the lithium metal layer is in positive correlation with the cycle stability of the lithium ion battery. The negative electrode of the third lithium ion battery can still maintain 51.86mAh g after 60 times of circulation^-1Capacity of 99.75% and high coulombic efficiency. The negative electrode of the second lithium ion battery and the negative electrode of the first lithium ion battery are respectively circulated for 60 circles and 41 circles, and the capacity is 0mAh g^-1. After the fourth lithium ion battery is cycled for 21 circles, the capacity of the fourth lithium ion battery is 0mAh g^-1. Obviously, the metal lithium prepared by the method for recovering the metal lithium from the waste lithium ion battery can be used as a prelithiation negative electrode material of the lithium ion battery, and the cycle performance of the lithium ion battery can be effectively improved.

Although the present invention has been described in detail with reference to the preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the spirit and scope of the invention.

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