CN109585954B - Method for recovering capacity of lithium-sulfur battery - Google Patents
Method for recovering capacity of lithium-sulfur battery Download PDFInfo
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- CN109585954B CN109585954B CN201811632786.3A CN201811632786A CN109585954B CN 109585954 B CN109585954 B CN 109585954B CN 201811632786 A CN201811632786 A CN 201811632786A CN 109585954 B CN109585954 B CN 109585954B
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
- H01M10/4242—Regeneration of electrolyte or reactants
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
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Abstract
The invention belongs to the field of chemical power sources, and particularly relates to a method for recovering the capacity of a lithium-sulfur battery, which comprises the following steps: discharging the old battery, updating electrolyte, forming and sealing. The problem that the capacity is reduced because a sulfur positive electrode and an intermediate product thereof are easy to separate out in a lithium-sulfur battery system is effectively solved by updating the electrolyte in the old battery; the invention achieves the effect of recovering the capacity of the lithium-sulfur battery by updating the electrolyte; the invention has simple process and low cost, and effectively prolongs the service life of the lithium-sulfur battery.
Description
Technical Field
The invention belongs to the field of chemical power sources, and particularly relates to a method for recovering the capacity of a lithium-sulfur battery.
Background
Compared with a lithium ion battery, the lithium-sulfur battery has higher theoretical specific capacity and higher energy density, and has important application value in the fields of traffic energy storage and the like.
In the lithium sulfur battery, polysulfide is formed in the discharging process, and in the process, a conductive agent and a binder in the positive electrode material are partially separated from a current collector, so that a diaphragm is blocked possibly, the internal resistance of the battery is increased, and the capacity of the battery is reduced.
Patent 'lithium sulphur battery charge and discharge management method' with application number 201510041669.X discloses a lithium sulphur battery charge and discharge management method, which proposes to charge a lithium sulphur battery with attenuated capacity to a voltage of 3.2-3.8V through 0.02-0.2C for activation to repair the battery; the method is simple and convenient to operate, but the problems of internal resistance rise, charge and discharge platform decline and the like can occur after the lithium-sulfur battery is cycled for a long time, so that the capacity recovery effect is influenced.
Disclosure of Invention
The invention provides a method for recovering the capacity of a lithium-sulfur battery, which solves the problems of capacity reduction, internal resistance increase and platform decline of the lithium-sulfur battery after multiple cycles.
In order to solve the problems, the invention adopts the technical scheme that: a method for recovering the capacity of a lithium-sulfur battery is provided. The method comprises the following steps:
(1) discharging the old lithium-sulfur battery;
(2) refreshing the electrolyte for the lithium sulfur battery;
(3) forming and sealing;
the present invention is a solution proposed based on the problem that reaction intermediate products are easily precipitated in a lithium sulfur battery system to reduce the capacity, and thus the electrolyte needs to be refreshed, with the object of recovering the capacity of the lithium sulfur battery.
The chemical reaction of lithium ions and sulfur occurs during the charging and discharging processes of the lithium-sulfur battery, and multiple phase changes are involved before and after the reaction. S in the sulfur positive electrode material during discharge8With Li+Reaction to produce liquid long-chain polysulfide Li2Sn(4. ltoreq. n.ltoreq.8) with Li+Continued reaction to form short-chain polysulphides Li2Sn(2<n<4) Finally, solid Li is generated2S2And Li2S。
The method takes polysulfide separated out in the circulation process and part of fallen conductive agent and binder away by cleaning, updates electrolyte and improves the capacity of the battery; firstly, the active substances which become polysulfide fall off from the electrode and are dissolved in the electrolyte, so that the capacity is not contributed any more in the battery circulation process to form 'dead sulfur', if the battery is not cleaned in time, the polysulfide penetrates through the diaphragm and continuously corrodes the metal lithium of the negative electrode, so that irreversible loss of effective active substances is caused, and the performance of the battery is attenuated; secondly, after multiple cycles, the conductive agent and the binder on the positive electrode material fall off to different degrees and adhere to the diaphragm to block an ion migration channel, so that the internal resistance of the battery is increased, and the capacity is attenuated; after cleaning, the cleaning agent washes away the conductive agent and the binder attached to the diaphragm, and meanwhile, the electrolyte can better infiltrate active substances in the deep layer of the electrode plate, so that the utilization efficiency of sulfur is improved, and the capacity of the battery is improved.
The positive electrode of the lithium-sulfur battery prepared by the method comprises a sulfur simple substance, a sulfur-containing composite material, lithium sulfide, a lithium sulfide-containing composite material and lithium polysulfide Li2SxAnd composites thereof; the negative electrode is composed of one or more of metal lithium, lithium metal alloy, lithium-containing composite material, hard carbon, soft carbon, graphite, graphene, carbon nano tube, acetylene black material, silicon or silicon carbon material, tin oxide, tin-based alloy nano particles or germanium compound; the electrolyte is in liquid, gel or solid state, and the solute is LiTFSI, LiTF, LiClO4、LiPF6、LiBETF、LiAsF6、LiBF6、LiCF3SO3、LiBF4Any one or more of; the solvent in the liquid electrolyte is any one or more of ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,2, 2-tetrafluoroethyl-2, 2,3, 3-tetrafluoropropyl ether, tetrahydrofuran, 2-methyltetrahydrofuran and 1, 3-dioxolane; the solid electrolyte is polymethyl methacrylate (PMMA), polyethylene glycol terephthalate (PEG) or polyethylene oxide (PEO) based gel polymer electrolyte, PEO, PMMA, polyvinylidene fluoride (PVDF) or Polyacrylonitrile (PAN) based all-solid polymer electrolyte, and LiBH4Fast ion conductors, LISICON, Li3N, LiTi2P3O12Based solid solution, Li2S-P2S5One or more complexes of glass ceramic electrolytes, perovskites, and oxide solid electrolytes; the diaphragm is a porous membrane or a gel membrane formed by mixing, compounding or polymerizing one or more of polypropylene, polyethylene, fluorine-containing organic polymer, cellulose ester, polycarbonate, polyvinylidene fluoride, polytetrafluoroethylene, polyoxyethylene, polyacrylonitrile, polyvinylidene fluoride and polymethyl methacrylate, or a solid fast ion conductor membrane or a diaphragm with ion selectivity; the shell is made of high polymer materials such as a steel shell, an aluminum plastic film or polypropylene, acrylonitrile and the like; the battery is in a cylindrical shape, a button shape, a square shape or a round shape; the position relation between the positive electrode and the negative electrode is in a laminated type, a winding type, an internal series connection mode and an internal parallel connection mode.
Wherein, the discharge termination voltage of the old lithium-sulfur battery is 1.5-2.0V, the discharge current is 0.01-3C, a screening step can be added before discharge, and the screening condition is that the capacity of the old lithium-sulfur battery is recovered when the capacity of the old lithium-sulfur battery is 60-80% of the initial capacity.
The renewal electrolyte may be a replacement electrolyte, a replenishment electrolyte or an addition electrolyte to the electrolyte-free cell. Before the electrolyte is replaced or added, a cleaning agent can be added, and the cleaning agent can be the electrolyte or one or more mixed organic polar solvents of ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, diethylene glycol dimethyl ether, tetrahydrofuran and dimethyl tetrahydrofuran; the cleaning mode can be soaking and oscillation; and taking out the cleaning agent after cleaning.
The electrolyte can be renewed by opening the old electrolyte injection hole, preparing the electrolyte injection hole again or replacing the battery shell.
The formation and sealing are to place the battery with renewed electrolyte for 1-24 hours, form and then seal the battery.
And repeating the steps after the capacity of the lithium-sulfur battery is reduced.
The invention has the beneficial effects that: a method for recovering the capacity of the lithium-sulfur battery is provided; by updating the electrolyte in the old battery, the problems of electrolyte pollution and diaphragm blockage caused by the separation of a sulfur positive electrode and an intermediate product thereof in a lithium-sulfur battery system so as to reduce the capacity are effectively solved; the invention achieves the effect of recovering the capacity of the lithium-sulfur battery by updating the electrolyte; the invention has simple process and low cost, and effectively prolongs the service life of the lithium-sulfur battery.
The method overcomes the technical prejudice that if the electrolyte is replaced for the lithium-sulfur battery, the performance is reduced because the sulfur is easily dissolved in the electrolyte and the replacement of the electrolyte can take away the active sulfur. In addition, as the conductive agent and the binder in the positive electrode material of the lithium-sulfur battery fall off to different degrees in the long-term circulation process, the fallen conductive agent and the fallen binder can be adsorbed on the surface of the diaphragm to block ion transmission, so that the internal resistance of the battery is increased, and the performance of the battery is reduced; the invention washes off the fallen conductive agent and the adhesive from the surface of the diaphragm by cleaning and updating the electrolyte, thereby improving the ion transmission rate, reducing the internal resistance of the battery and improving the capacity of the battery.
Detailed Description
Example 1
Taking an old monomer laminated aluminum-plastic shell soft package lithium-sulfur battery with the nominal capacity of 10Ah, discharging to 1.7V, wherein the discharge current is 0.1C, and the measured capacity of the battery is 6.2 Ah; removing the old shell in an argon glove box, replacing the old shell with a new soft package battery shell, and injecting new electrolyte; the cell was left for 8 hours, charged to 3.5V with a constant current of 500mA, discharged to 1.7V with a constant current of 500mA after left for 0.5 hour, then charged to 2.8V with the same current, and sealed. As a result, the capacity was restored to 8.7 Ah. After 300 times of 1C multiplying power circulation, the capacity is reduced to 5.6Ah, and the capacity is recovered to 8.2Ah after the battery is processed by the same method.
Example 2
Taking an old monomer laminated stainless steel shell square lithium-sulfur battery with the nominal capacity of 50Ah, discharging to 1.7V, wherein the discharge current is 0.1C, and the capacity of the battery is 36 Ah; disassembling a liquid injection hole of an old lithium-sulfur battery, injecting an ethylene glycol dimethyl ether cleaning agent, oscillating for 2 hours, and taking out liquid in the battery; then, the battery is placed in a vacuum drying oven to be dried for 8 hours, then the battery is transferred into a glove box filled with argon, electrolyte is injected again, and the liquid injection hole is sealed again; the battery was left to stand for 8 hours, then charged to 3.5V with a constant current of 10A, left to stand for 0.5 hours, discharged to 1.7V with a constant current of 10A, and then charged to 2.8V with the same current. As a result, the capacity was restored to 44 Ah. After 250 cycles of 1C multiplying power, the capacity is reduced to 29Ah, and the capacity is recovered to 41Ah after the battery is processed by the same method.
Example 3
Taking an old monomer winding type stainless steel shell cylindrical lithium-sulfur battery with the nominal capacity of 100Ah, discharging to 1.7V, wherein the discharge current is 0.1C, and the capacity of the battery is 68 Ah; disassembling a liquid injection hole of the old lithium-sulfur battery, injecting a tetraethylene glycol dimethyl ether cleaning agent, soaking for 3 hours, and taking out liquid in the battery; then the battery is placed in a vacuum drying oven to be dried for 8 hours, then the battery is transferred into a glove box filled with argon, a new liquid injection hole is replaced, electrolyte is injected again, and the liquid injection hole is sealed; the battery was left for 8 hours, then charged to 3.5V with a constant current of 20A, discharged to 1.7V with a constant current of 20A after left for 0.5 hours, and then charged to 2.8V with the same current. As a result, the capacity was restored to 89 Ah. After 100 times of 1C multiplying power circulation, the capacity is reduced to 54Ah, and the capacity is recovered to 76Ah after the battery is processed by the same method.
Example 4
Taking an old monomer laminated polypropylene shell square lithium-sulfur battery with the nominal capacity of 10Ah, discharging to 1.7V, wherein the discharge current is 0.1C, and the capacity of the battery is 6.5 Ah; disassembling the liquid injection hole of the old lithium-sulfur battery, supplementing a part of new electrolyte, and resealing the liquid injection hole; the battery was left for 8 hours, then charged to 3.5V with a constant current of 2A, left for 0.5 hours, discharged to 1.7V with a constant current of 2A, and then charged to 2.8V with the same current. As a result, the capacity was restored to 8.7 Ah.
Example 5
Taking an old thin film all-solid-state lithium-sulfur battery with the nominal capacity of 10Ah, discharging to 1.7V, wherein the discharge current is 0.1C, and the capacity of the battery is 7 Ah; removing the aluminum-plastic soft package shell, soaking and cleaning with ethylene glycol dimethyl ether, drying, soaking for 2h with electrolyte, repackaging, and forming according to 0.1C current; and (3) after the battery is placed for 8 hours, charging the battery to 3.5V by using a current constant of 2A, discharging the battery to 1.7V by using a current constant of 2A after the battery is placed for 0.5 hour, then charging the battery to 2.8V by using the same current constant, and finally vacuumizing and packaging. As a result, the capacity was restored to 8.6 Ah.
Claims (6)
1. A method of capacity recovery for a lithium sulfur battery, the method comprising the steps of:
(1) discharging the old lithium-sulfur battery;
the positive electrode of the lithium-sulfur battery is made of elemental sulfur, a sulfur-containing composite material, lithium sulfide, a lithium sulfide-containing composite material and lithium polysulfide Li2SxAnd composites thereof; the negative electrode is composed of one or more of metal lithium, lithium metal alloy, lithium-containing composite material, hard carbon, soft carbon, graphite, graphene, carbon nano tube, acetylene black material, silicon or silicon carbon material, tin oxide, tin-based alloy nano particles or germanium compound;
the discharge termination voltage is 1.5-2.0V, and the discharge current is 0.01-3C;
adding a screening step before discharging, and when the screening condition is that the capacity of the lithium-sulfur battery is 60-80% of the initial capacity, performing capacity recovery on the old lithium-sulfur battery;
(2) refreshing the electrolyte for the lithium sulfur battery;
the electrolyte is replaced, supplemented or added into the battery without the electrolyte;
(3) and (5) forming and sealing.
2. The method for recovering the capacity of a lithium sulfur battery as claimed in claim 1, wherein the electrolyte of the lithium sulfur battery is in a liquid, gel or solid state and the solute thereof is LiTFSI, LiTF, LiClO4、LiPF6、LiBETF、LiAsF6、LiBF6、LiCF3SO3、LiBF4Any one or more of; the solvent in the liquid electrolyte is any one or more of ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,2, 2-tetrafluoroethyl-2, 2,3, 3-tetrafluoropropyl ether, tetrahydrofuran, 2-methyltetrahydrofuran and 1, 3-dioxolane; the solid electrolyte is polymethyl methacrylate (PMMA), polyethylene glycol terephthalate (PET) or polyethylene oxide (PEO) based gel polymer electrolyte, PEO, PMMA, polyvinylidene fluoride (PVDF) or Polyacrylonitrile (PAN) based all-solid polymer electrolyte, LiBH4Fast ion conductors, LISICON, Li3N, LiTi2P3O12Based solid solution, Li2S-P2S5One or more complexes of glass ceramic electrolytes, perovskites, and oxide solid electrolytes; the diaphragm is a porous membrane or a gel membrane formed by mixing, compounding or polymerizing one or more of polypropylene, polyethylene, fluorine-containing organic polymer, cellulose ester, polycarbonate, polyvinylidene fluoride, polytetrafluoroethylene, polyoxyethylene, polyacrylonitrile, polyvinylidene fluoride and polymethyl methacrylate, or a solid fast ion conductor membrane or a diaphragm with ion selectivity; the outer shell is a steel shell, an aluminum plastic film or polypropylene and acrylonitrile; the battery is in a cylindrical shape, a button shape, a square shape or a round shape; the position relation between the positive electrode and the negative electrode is in a laminated type, a winding type, an internal series connection mode and an internal parallel connection mode.
3. The method for recovering the capacity of a lithium-sulfur battery as claimed in claim 1, wherein a cleaning agent is added before the replacement or addition of the electrolyte, and the cleaning agent is the electrolyte itself or an organic polar solvent mixed with one or more of ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, diethylene glycol dimethyl ether, tetrahydrofuran and dimethyltetrahydrofuran; the cleaning mode is soaking and oscillation; and taking out the cleaning agent after cleaning.
4. The method for recovering the capacity of a lithium-sulfur battery as claimed in claim 1, wherein the electrolyte is introduced into the interior of the battery by one of opening a used electrolyte injection hole, preparing a new electrolyte injection hole, or replacing the battery case.
5. The method for recovering the capacity of a lithium sulfur battery according to claim 1, wherein the battery injected with the electrolyte is left for 1 to 24 hours, formed, and then sealed.
6. The method for recovering the capacity of a lithium sulfur battery according to claim 1, wherein the above steps are repeated after the capacity of the lithium sulfur battery is reduced.
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| JP5863631B2 (en) * | 2012-12-26 | 2016-02-16 | 株式会社日立製作所 | Method for producing non-aqueous electrolyte secondary battery |
| CN104600803B (en) * | 2015-01-28 | 2017-03-15 | 中国科学院苏州纳米技术与纳米仿生研究所 | Lithium-sulfur cell method for managing charge/discharge |
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