CN111313101B - Low-internal-resistance solid sulfide electrolyte lithium battery cell, battery and preparation method thereof - Google Patents

Low-internal-resistance solid sulfide electrolyte lithium battery cell, battery and preparation method thereof Download PDF

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CN111313101B
CN111313101B CN201911025613.XA CN201911025613A CN111313101B CN 111313101 B CN111313101 B CN 111313101B CN 201911025613 A CN201911025613 A CN 201911025613A CN 111313101 B CN111313101 B CN 111313101B
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layer
electrolyte
powder
negative electrode
positive electrode
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CN111313101A (en
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许晓雄
黄晓
张秩华
吴林斌
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Zhejiang Funlithium New Energy Tech Co Ltd
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Zhejiang Funlithium New Energy Tech Co Ltd
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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
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0561—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of inorganic materials only
    • H01M10/0562—Solid materials
    • 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
    • H01M10/04—Construction or manufacture in general
    • H01M10/0481—Compression means other than compression means for stacks of electrodes and separators
    • 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
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • 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
    • H01M10/058—Construction or manufacture
    • H01M10/0585—Construction or manufacture of accumulators having only flat construction elements, i.e. flat positive electrodes, flat negative electrodes and flat separators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/04—Processes of manufacture in general
    • H01M4/043—Processes of manufacture in general involving compressing or compaction
    • H01M4/0435—Rolling or calendering
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • 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
    • 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
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Abstract

The invention relates to a full solid lithium battery of sulfide electrolyte, and discloses a solid sulfide electrolyte lithium battery with low internal resistance and a preparation method thereof, wherein the technical scheme is characterized in that a positive electrode layer, an electrolyte layer and a negative electrode layer are formed by sequentially laminating and pressing powder of corresponding materials to obtain a prefabricated battery cell, wherein the powder of the electrolyte layer is obtained by solid electrolysis of sulfide; applying pressure to the outer sides of the positive electrode layer and the negative electrode layer of the prefabricated battery cell towards the direction of the electrolytic layer, and processing at high temperature for 5-10min to obtain a finished product battery cell; and mounting a lug on the finished product battery core, coating the lug with an aluminum plastic film, and mounting a battery shell to obtain the solid sulfide electrolyte lithium battery with low internal resistance, and relieving the battery heating and cycle performance reduction caused by the internal resistance of the solid sulfide electrolyte lithium battery.

Description

Low-internal-resistance solid sulfide electrolyte lithium battery cell, battery and preparation method thereof
Technical Field
The invention relates to an all-solid-state lithium battery with sulfide electrolyte, in particular to a solid-state lithium battery with low internal resistance with sulfide electrolyte and a preparation method thereof.
Background
Lithium ion batteries are widely used in the fields of energy, traffic, communication, electric tools, etc. as a chemical power source with high specific energy. Lithium ion batteries have been commercialized since 1991 to be used in large scale, and there is a constant progress in this process from less safe electrolytes to today's more safe solid electrolytes.
Solid electrolytes commonly used at present are classified into polymer solid electrolytes and inorganic solid electrolytes. However, the problem of interfacial resistance is commonly existed in the following solid electrolyte applications. The main reason for the interface impedance problem is that the solid is adopted for the anode, the solid electrolyte and the cathode in the all-solid battery, so that the interface bonding performance among the anode, the solid electrolyte and the cathode is poor, the initial interface impedance is large, and simultaneously, the interface bonding is further deteriorated due to the respective expansion and contraction of the anode, the solid electrolyte and the cathode when the all-solid battery is used along with charging and discharging, so that the interface impedance is increased along with the service time of the lithium ion battery.
In the solution in the prior art, the polymer solid electrolyte is an electrolyte wetting method, and the improvement is different from the traditional all-solid battery, the polymer solid electrolyte is composed of a polymer solid electrolyte compound framework and a lithium salt electrolyte, the lithium salt electrolyte is filled in the polymer solid electrolyte framework, and the lithium salt electrolyte is used as a transfer to weaken the interface impedance between the polymer solid electrolyte and the anode and the cathode.
The sulfide solid electrolyte in the inorganic solid electrolyte is a novel type compared with other inorganic solid electrolytes, has good chemical stability, wide temperature suitable range, good lithium ion conductivity and processing convenience, and becomes one of the hot directions of the current inorganic solid electrolyte research.
For the sulfide solid electrolyte, the sulfide solid electrolyte is easy to react with most solvents, and the irreversible phase change reaction can occur in the long-term contact process of the sulfide solid electrolyte and the dissolved lithium salt, so that the performance of the battery is reduced, and therefore, the method for improving the polymer solid electrolyte cannot directly obtain a good effect on the sulfide solid electrolyte.
Therefore, in the prior art, a solid electrolyte layer is formed by depositing a sulfide solid electrolyte on the side surface of the anode or the cathode by using a chemical vapor deposition method. The close physical bonding brought about by the chemical vapor deposition method reduces the interfacial resistance between the sulfide solid electrolyte and the positive/negative electrodes.
However, the method brings new problems that the positive electrode and the negative electrode are limited by the materials, the temperature required by the chemical vapor deposition method for the materials of the positive electrode and the negative electrode is higher than the decomposition temperature of the sulfide solid electrolyte, and therefore the positive electrode and the negative electrode are difficult to form on the solid electrolyte layer by the chemical vapor deposition method, so that the chemical vapor deposition method can only weaken the interface resistance of the sulfide solid electrolyte to one of the positive electrode and the negative electrode. The method for improving the sulfide solid electrolyte by the chemical vapor deposition method has limited actually obtained effect, and particularly when the method is used for a large-size lithium battery, the method has large vapor deposition area, high cost, obvious fluctuation of deposition uniformity and unstable effect, so that the method is difficult to be widely applied.
Therefore, the all-solid-state lithium battery needs to be improved, and the limitation on the popularization and application of the all-solid-state lithium battery is reduced.
Disclosure of Invention
In view of the defects in the prior art, the first object of the present invention is to provide a solid sulfide electrolyte lithium battery with low internal resistance, which reduces the internal resistance of the solid sulfide electrolyte lithium battery, and alleviates the battery heating and cycle performance degradation caused by the internal resistance of the battery.
The technical purpose of the invention is realized by the following technical scheme:
the solid sulfide electrolyte lithium battery cell with low internal resistance is characterized by comprising a positive electrode layer, an electrolyte layer and a negative electrode layer which are sequentially overlapped;
the positive electrode layer is formed by pressing positive electrode pressing powder, and the positive electrode pressing powder comprises positive electrode material powder and sulfide solid electrolyte powder which are uniformly mixed;
the electrolyte layer is formed by pressing electrolyte pressed powder, and the electrolyte pressed powder is sulfide solid electrolyte powder;
the negative electrode layer is formed by pressing negative electrode pressed powder, and the negative electrode pressed powder comprises uniformly mixed negative electrode material powder and sulfide solid electrolyte powder;
the sulfide solid electrolyte powder in the positive electrode pressed powder, the electrolyte pressed powder and the negative electrode pressed powder are respectively and independently selected components, and can be the same or different;
the lithium ion battery is characterized in that a first interface layer is further arranged between the positive electrode layer and the electrolyte layer, a second interface layer is further arranged between the negative electrode layer and the electrolyte layer, the first interface layer and the second interface layer are SEI film mixing layers, and the SEI film mixing layers are formed after the electrolyte layer is subjected to interface reaction with the positive electrode layer or the negative electrode layer on the corresponding side under the pressure of more than or equal to 600MPa or the environment of 300 ℃ and 1-10 MPa.
By adopting the technical scheme, the solid sulfide electrolyte lithium battery has the negative electrode material and the sulfide solid electrolyte to react between the negative electrode layer and the electrolyte layer so as to form the second interface layer. The second interface layer is formed by embedding or immersing SEI film components into the side surface of the negative electrode layer and the side surface of the electrolyte layer, so that the interface combination stability of the negative electrode layer and the electrolyte layer is enhanced, and the cyclicity of the solid-state lithium battery is improved. Meanwhile, the second interface layer is used as an SEI film mixing layer, has good ionic conductivity, blurs the interface separation between the negative electrode layer and the electrolyte layer, weakens the interface effect between the negative electrode layer and the electrolyte layer, and reduces the interface impedance between the negative electrode layer and the electrolyte layer.
The solid sulfide electrolyte lithium battery of the present application also forms a first interface layer between the positive electrode layer and the electrolyte layer, which improves the bonding stability between the positive electrode layer and the electrolyte layer and reduces the interface impedance between the positive electrode layer and the electrolyte layer, similarly to the second interface layer.
Therefore, the internal resistance of the solid sulfide electrolyte lithium battery is reduced, and the heat generation and cycle performance reduction of the battery caused by the internal resistance of the battery are relieved.
The invention is further configured to: the anode material powder is one of a lithium cobaltate material, a nickel-cobalt-manganese ternary material and a nickel-cobalt-aluminum ternary material.
The invention is further configured to: the sulfide solid electrolyte powder in the electrolyte layer is a chalcogenide lithium ion solid electrolyte of a silver germanite type.
By adopting the technical scheme, when the graphite is used as the cathode material, the potential of the graphite is close to 0V vs Li in the later stage of Li insertion + and/Li, under the potential condition, sulfide is easy to be reduced and deteriorated. Meanwhile, the potential of the existing anode material is high, for example, when the voltage of the solid-state lithium battery of the transition metal anode is charged to about 4V, ni, co and Mn in the anode reach high valence states, the oxidation is strong, the anode can easily react with sulfide solid-state electrolyte to break the sulfide solid-state electrolyteP-S bonds in the electrolyte form P-O bonds and M-S bonds (M is a transition metal element such as Ni, co, mn, or the like), which cause elution of the transition metal element and decrease in the capacity of the solid lithium battery, and sulfide impurities formed from the eluted transition metal element increase the interface impedance between the positive electrode layer and the electrolyte layer.
In the application, the sulfide solid electrolyte powder component is a sulfide lithium ion solid electrolyte of a Geranite type (Li-Argyrodite is hereinafter referred to as a typical representative). Li-Argyrodite belongs to ternary sulfide solid electrolyte, and has higher stability to oxidizing substances in the positive electrode compared with the existing binary sulfide solid electrolyte which has poor crystallinity and is easy to oxidize.
Meanwhile, compared with other existing ternary sulfide solid electrolytes such as LGPS, the Li-Argyrodite has no valence-variable high-valence ions, such as Ge in LGPS 4+ The lithium ion battery has the advantages that the reduction contact reduction degradation degree of the graphite after lithium intercalation is smaller, the Li-Argyrodite has better compatibility with the graphite, the good interface binding property is facilitated when the electrolyte layer and the negative electrode are laminated, the interface reaction is promoted to be carried out, so that a more uniform and compact second interface layer is formed, the internal resistance reduction of the solid-state lithium battery is further reduced, and the cycle performance of the solid-state lithium battery is improved.
The invention is further configured to: the negative electrode material powder is obtained by mixing flake graphite and spheroidal graphite with equal volume equivalent diameter, and the mixing ratio of the flake graphite to the spheroidal graphite is 1.
By adopting the technical scheme, the flaky graphite contributes high specific volume to the negative electrode material, and the granular spheroidal graphite is mixed and added, so that the uniform mixing of the negative electrode material powder and the solid sulfide electrolyte powder can be promoted. Meanwhile, the pressed nodular graphite embedded on the surface of the negative electrode layer can improve the density of the SEI film component during generation, so that the densities of the first interface layer and the second interface layer are improved, and the damage of the first interface layer and the second interface layer caused by expansion and shrinkage of the lithium battery during recycling is reduced.
In view of the defects of the prior art, a second object of the present invention is to provide a method for preparing a low internal resistance solid-state sulfide electrolyte lithium battery cell, which further reduces the internal resistance of the sulfide electrolyte solid-state battery and improves the cycle performance of the sulfide electrolyte solid-state battery.
The technical purpose of the invention is realized by the following technical scheme:
a preparation method of a solid sulfide electrolyte lithium battery cell with low internal resistance comprises the following steps of A, placing negative electrode pressed powder which is uniformly mixed with negative electrode material powder and sulfide solid electrolyte powder into a die for cold isostatic pressing to form a negative electrode layer;
B. uniformly spreading a layer of electrolyte pressing powder on the upper surface of the negative electrode layer, and carrying out cold isostatic pressing to obtain the negative electrode layer and the electrolyte layer which are pressed into a whole;
C. paving a layer of positive electrode pressing powder containing uniformly mixed positive electrode material powder and sulfide solid electrolyte powder on the upper surface of the electrolyte layer, and carrying out cold isostatic pressing to form a negative electrode layer, an electrolyte layer and a positive electrode layer which are pressed into a whole, so as to obtain a prefabricated battery core;
D. after taking out the prefabricated battery cell, applying pressure of 1-10MPa to the direction of the electrolytic layer on the outer sides of the positive electrode layer and the negative electrode layer, and performing high-temperature treatment at 300-500 ℃ for 5-10 min to obtain a finished battery cell;
or comprises the following steps of,
A. placing the anode pressing powder uniformly mixed with the anode material powder and the sulfide solid electrolyte powder into a die for cold isostatic pressing to form an anode layer;
B. uniformly spreading a layer of electrolyte pressing powder on the upper surface of the positive electrode layer, and carrying out cold isostatic pressing to obtain the positive electrode layer and the electrolyte layer which are pressed into a whole;
C. uniformly paving a layer of negative electrode pressing powder containing the negative electrode material powder and the sulfide solid electrolyte powder which are uniformly mixed on the upper surface of the electrolyte layer, and carrying out cold isostatic pressing to form a positive electrode layer, an electrolyte layer and a negative electrode layer which are pressed into a whole, so as to obtain a prefabricated battery core;
D. and (3) after taking out the prefabricated battery core, applying pressure of 1-10MPa to the direction of the electrolytic layer on the outer sides of the positive electrode layer and the negative electrode layer, and performing high-temperature treatment at 300-500 ℃ for 5-10 min to obtain a finished product battery core.
By adopting the technical scheme, the positive electrode layer, the negative electrode layer and the electrolyte layer are formed by pressing corresponding powder. In the pressing process, the two layers subjected to post pressing are pressed and formed after corresponding to the previous layer, and then corresponding powder is spread and pressed to obtain the finished product, and the pressing result is combined into a whole in each pressing, so that the positive electrode layer, the electrolyte layer and the negative electrode layer are combined tightly after the positive electrode layer, the electrolyte layer and the negative electrode layer are combined, the substance interaction of the interface between the positive electrode layer and the electrolyte layer and the substance interaction of the interface between the electrolyte layer and the negative electrode layer are promoted during pressurization and high-temperature treatment, the interface reaction is uniform, a continuous and complete SEI film mixing layer which is connected with two sides of the interface is formed, the uniformity and compactness of the first interface layer and the second interface layer are improved, and the combination stability of the first interface layer and the second interface layer with the corresponding layer bodies on the two sides is improved.
Meanwhile, because the potential of the conventional negative electrode material is low, after the negative electrode material is embedded with lithium, the electrolyte layer is in direct contact with the negative electrode layer for a long time, and sulfide solid electrolyte in the electrolyte layer is reduced and deteriorated. However, compared to conventional liquid electrolytes, in the solid lithium battery in which a sulfide solid electrolyte is directly in contact with a negative electrode layer, the SEI film formation on the negative electrode and the positive electrode is slow. During formation and use of the solid lithium battery, the SEI films are formed on the surfaces of the negative electrode and the positive electrode through slow deposition under the action of voltage and current, the SEI films are only stably combined with the surfaces of the negative electrode and the positive electrode, the combination between the SEI films and an electrolyte layer is weak, the combination between the SEI films and the electrolyte layer is seriously deteriorated during use of the solid lithium battery, and the cycle performance is rapidly reduced. Moreover, the density of the SEI film formed in the formation and use processes of the solid-state lithium battery in the prior art is poor, and the SEI film formed in the initial stage is provided with more pinholes, so that more Li needs to be consumed to form a thicker SEI film, and the upper limit of the capacity of the solid-state lithium battery is reduced.
Before the solid-state lithium battery is formed and used, a second interface layer is formed between the negative electrode layer and the electrolyte layer, the second interface layer is generated by interface reaction under the promotion of heating and pressurizing (pressure), the second interface layer is uniform and compact so as to separate the negative electrode layer and the electrolyte layer, the Li consumption is low, the electrolyte layer is protected, the degradation of sulfide solid-state electrolyte is reduced, and the cycle performance of the solid-state lithium battery is enhanced.
In addition, after the solid lithium battery is charged, the potential of the anode material is higher, for example, ni, co and Mn in the anode using transition metal can reach higher valence state, and the oxidation property is strong, for the solid lithium battery in which the sulfide solid electrolyte in the prior art is directly contacted with the cathode layer, the transition metal element in the anode is easy to react with the sulfide solid electrolyte, so that the transition metal element is dissolved out, the capacity of the solid lithium battery is reduced, and the interface impedance is increased.
Before the solid-state lithium battery is formed and used, a first interface layer is formed between the positive electrode layer and the electrolyte layer, the first interface layer is generated by interface reaction under the promotion of heating and pressurizing (pressure), the first interface layer is uniform and compact so as to separate the positive electrode layer from the electrolyte layer, protect the positive electrode layer and the electrolyte layer, reduce the dissolution of transition metal elements, enhance the cycle performance of the solid-state lithium battery, and slow down the increase of internal resistance of the solid-state lithium battery after long-term cyclic use.
Therefore, the uniformity, compactness and bonding performance of the first interface layer and the second interface layer are improved, the protection of the negative electrode layer, the electrolyte layer and the positive electrode layer is improved, the degradation of the sulfide solid electrolyte and the dissolution of transition metal in a positive electrode material are reduced, the internal resistance of the sulfide electrolyte solid battery is further reduced, and the cycle performance of the sulfide electrolyte solid battery is improved.
The invention is further configured to: the anode material powder is one of a lithium cobaltate material, a nickel-cobalt-manganese ternary material and a nickel-cobalt-aluminum ternary material, and the cathode material powder is graphite; the particle size ratio of the negative electrode pressed powder to the electrolyte pressed powder is 1; the particle size ratio of the electrolyte pressed powder to the positive electrode pressed powder is 2 to 7.
By adopting the technical scheme, the negative electrode pressing powder, the electrolyte pressing powder and the positive electrode pressing powder are configured step by step according to the proportion, when the negative electrode layer, the electrolyte layer and the positive electrode layer are laminated and pressed layer by layer, the electrolyte pressing powder and the negative electrode layer are better embedded between the positive electrode layer, and then the combination of two side faces of the electrolyte layer with the positive electrode layer and the negative electrode layer is strengthened, the depth of the first interface and the second interface embedded into the layers at the two corresponding sides is increased, the interface effect is weakened, so that the interface impedance is reduced, and between the negative electrode layer and the electrolyte layer, SEI film substances produced when the interface reaction occurs under the pressure between the positive electrode layer and the electrolyte layer are distributed more uniformly, and the uniform and complete SEI film is formed.
The invention is further configured to: and when the prefabricated battery core is subjected to high-temperature treatment, the prefabricated battery core is placed in a preheating greenhouse with the temperature of 300-500 ℃ for high-temperature treatment.
By adopting the technical scheme, the prefabricated battery core is directly placed into the environment heated to 300-500 ℃ for heating, the temperature rise of the prefabricated battery core is accelerated, the production efficiency is improved compared with the slow temperature rise at the room temperature, the heat damage caused by temperature rise from the room temperature every time is avoided, and the energy is saved.
The invention is further configured to: in the step of high-temperature treatment of the prefabricated battery core, the prefabricated battery core is initially pressurized to 1-3 MPa and then heated, after the temperature of the prefabricated battery core reaches 300-500 ℃, the high-temperature treatment time is counted at 1MPa/min, the pressure is increased to 5-10 MPa and kept, and the high-temperature treatment time is ended.
By adopting the technical scheme, the prefabricated battery cell is firstly stressed to keep the negative electrode layer, the electrolyte layer and the positive electrode layer under pressure, so that the prefabricated battery cell is under the action of the prestress when thermal deformation occurs in the temperature rise process, and the compaction compactness of the interior is improved; and after the temperature rises to the interface threshold temperature, interface reactions begin to occur between the negative electrode layer and the electrolyte layer and between the electrolyte layer and the positive electrode layer, at the moment, the pressure is gradually increased at 1MPa/min, the production balance of SEI film forming components is inhibited in the pressurizing operation process, but the SEI film forming components are pressed and immersed into the negative electrode layer, the electrolyte layer and the positive electrode layer due to the increase of the pressure, the interface bonding between the negative electrode layer and the electrolyte layer and the interface bonding between the electrolyte layer and the positive electrode layer are improved, the compactness of a mixed layer of the SEI film is improved, and on the contrary, under the conditions of less Li consumption and SEI film thickness reduction, the interface impedance is further reduced and the internal resistance of the sulfide solid-state lithium battery per se is reduced compared with the case of keeping static pressure heating.
In view of the defects in the prior art, a third object of the present invention is to provide a method for preparing a low internal resistance solid sulfide electrolyte lithium battery cell, which further reduces the internal resistance of the sulfide electrolyte solid battery of the present application and improves the cycle performance of the sulfide electrolyte solid battery of the present application.
The technical purpose of the invention is realized by the following technical scheme:
a preparation method of a solid sulfide electrolyte lithium battery with low internal resistance comprises the following steps of A, placing negative electrode pressed powder which is uniformly mixed with negative electrode material powder and sulfide solid electrolyte powder into a die for cold isostatic pressing to form a negative electrode layer;
B. uniformly paving a layer of electrolyte pressing powder on the upper surface of the negative electrode layer, and carrying out cold isostatic pressing to obtain the negative electrode layer and the electrolyte layer which are pressed into a whole;
C. paving a layer of positive electrode pressing powder containing uniformly mixed positive electrode material powder and sulfide solid electrolyte powder on the upper surface of the electrolyte layer, and carrying out cold isostatic pressing to form a negative electrode layer, an electrolyte layer and a positive electrode layer which are pressed into a whole, so as to obtain a prefabricated battery cell;
D. after taking out the prefabricated battery cell, applying a pressure of 600-700 MPa to the direction of the electrolytic layer on the outer sides of the positive electrode layer and the negative electrode layer, and keeping the pressure for 20-30 s to obtain a finished product battery cell;
E. mounting a tab on the finished product battery core, and coating the tab with an aluminum plastic film to obtain a battery inner core;
F. installing a battery shell to obtain a solid sulfide electrolyte lithium battery;
or comprises the following steps of,
A. placing the anode pressing powder uniformly mixed with the anode material powder and the sulfide solid electrolyte powder into a die for cold isostatic pressing to form an anode layer;
B. uniformly paving a layer of electrolyte pressing powder on the upper surface of the positive electrode layer, and carrying out cold isostatic pressing to obtain the positive electrode layer and the electrolyte layer which are pressed into a whole;
C. uniformly paving a layer of negative electrode pressing powder containing the negative electrode material powder and the sulfide solid electrolyte powder which are uniformly mixed on the upper surface of the electrolyte layer, and carrying out cold isostatic pressing on the positive electrode layer, the electrolyte layer and the negative electrode layer which are pressed into a whole to obtain a prefabricated battery core;
D. and after taking out the prefabricated battery cell, applying a pressure of 600-700 MPa to the direction of the electrolytic layer on the outer sides of the positive electrode layer and the negative electrode layer, and keeping the pressure for 20-30 s to obtain a finished product battery cell.
By adopting the technical scheme, the positive electrode layer, the negative electrode layer and the electrolyte layer are formed by pressing corresponding powder. In the pressing process, the two layers subjected to post pressing are pressed and formed after corresponding to the previous layer, and then corresponding powder is spread and pressed to obtain the composite material, and the pressing result which is combined into a whole is obtained in each pressing, so that the positive electrode layer, the electrolyte layer and the negative electrode layer are combined tightly after the positive electrode layer, the electrolyte layer and the negative electrode layer are combined, the substance interaction of the interface between the positive electrode layer and the electrolyte layer and the interface between the electrolyte layer and the negative electrode layer is promoted at high pressure, the interface reaction is uniform, a continuous and complete SEI film mixing layer which is connected with two sides of the interface is formed, the uniformity and compactness of the first interface layer and the second interface layer are improved, and the combination stability of the first interface layer and the second interface layer with the corresponding layer on the two sides is improved.
Before the solid-state lithium battery is formed and used, a second interface layer is formed between the negative electrode layer and the electrolyte layer, the second interface layer is generated by interface reaction under the promotion of high pressure, the second interface layer is uniform and compact to separate the negative electrode layer and the electrolyte layer, the Li loss is low, the electrolyte layer is protected, the degradation of sulfide solid-state electrolyte is reduced, and the cycle performance of the solid-state lithium battery is enhanced.
Therefore, the uniformity, compactness and bonding performance of the first interface layer and the second interface layer are improved, the protection of the negative electrode layer, the electrolyte layer and the positive electrode layer is improved, the degradation of the sulfide solid electrolyte and the dissolution of transition metal in a positive electrode material are reduced, the internal resistance of the sulfide electrolyte solid battery is further reduced, and the cycle performance of the sulfide electrolyte solid battery is improved.
The invention is further configured to: the composition of the sulfide solid electrolyte powder in the positive electrode pressed powder, the electrolyte layer and the negative electrode pressed powder is the same.
By adopting the technical scheme, when the negative electrode layer, the electrolyte layer and the positive electrode layer or the positive electrode layer, the electrolyte layer and the negative electrode layer are sequentially pressed by corresponding powder, because the negative electrode pressed powder, the electrolyte pressed powder and the positive electrode pressed powder contain the same components, the compatibility of the negative electrode layer, the electrolyte layer and the positive electrode layer is improved, the interface between the negative electrode layer, the electrolyte layer and the positive electrode layer in the prefabricated battery cell formed by pressing in an integrated manner is fuzzified, the binding property at the interface is improved, the interface impedance is weakened, the subsequent interface reaction is promoted to be uniformly carried out, the compactness of the first interface layer and the second interface layer is improved, the internal resistance of the solid sulfide electrolyte lithium battery is reduced, and the cycle performance of the solid sulfide electrolyte lithium battery is improved.
In view of the defects of the prior art, a fourth object of the present invention is to provide a solid-state sulfide electrolyte lithium battery with low internal resistance, which reduces the internal resistance of the sulfide electrolyte solid-state battery and improves the cycle performance of the battery.
The technical purpose of the invention is realized by the following technical scheme:
a low internal resistance solid sulfide electrolyte lithium battery comprises the low internal resistance solid sulfide electrolyte lithium battery cell.
In conclusion, the invention has the following beneficial effects:
1. according to the solid sulfide electrolyte lithium battery, two side faces of an electrolyte layer respectively generate interface reaction with a negative electrode layer and a positive electrode layer on two sides under a pressurized (pressure) heating environment to generate SEI (solid electrolyte interphase) membrane components, and the SEI membrane components are embedded into or soaked into the surfaces of layer bodies on two sides to form a corresponding first interface layer and a second interface layer, so that the fuzzy interface separation is realized, the interface effect is weakened, the interface combination stability is improved, the internal resistance of the solid sulfide electrolyte lithium battery is reduced, and the battery heating and cycle performance reduction caused by the internal resistance of the battery are relieved.
2. The solid electrolyte powder component of the sulfide selects Li-Argyrodite, so that the stability of oxidizing substances in the positive electrode is high, the reductive contact reduction degradation degree of the graphite embedded with lithium is low, the compatibility is good, the interface binding performance is good when the electrolyte layer and the negative electrode are laminated, the interface reaction is promoted to be carried out, a second uniform and compact interface layer is formed, the internal resistance of the solid lithium battery is further reduced, and the cycle performance of the solid lithium battery is improved.
4. The positive electrode layer, the negative electrode layer and the electrolyte layer are obtained by gradually pressing corresponding powder on the basis that the corresponding powder is pressed and formed by the layer body of the previous layer, so that the interfaces among the three layers are tightly combined, the material interaction of the interfaces among the layers during pressurization and high-temperature treatment is promoted, the interface reaction is uniform, the uniformity and compactness of the first interface layer and the second interface layer are improved, and the respective combination stability of the first interface layer and the second interface layer is improved.
5. The first interface layer separates the positive electrode layer from the electrolyte layer, protects the positive electrode layer and the electrolyte layer, and reduces the dissolution of transition metal elements. The second interface layer separates the negative electrode layer from the electrolyte layer, the Li loss is low, the electrolyte layer is protected, the degradation of the sulfide solid electrolyte is reduced, and therefore the cycle performance of the solid lithium battery is enhanced, and the increase of the internal resistance of the solid lithium battery after long-term cycle use is slowed down.
7. The negative electrode pressed powder, the electrolyte pressed powder and the positive electrode pressed powder are configured step by step according to the proportion, so that the electrolyte pressed powder is better embedded with the negative electrode layer and the positive electrode layer, the depth of the first interface and the second interface embedded into the corresponding two side layer bodies is increased, and the interface effect is weakened, so that the interface impedance is reduced.
8. The prefabricated battery cell is prestressed firstly, so that the thermal deformation force of the prefabricated battery cell is counteracted, and the compaction compactness inside the prefabricated battery cell is improved; and then gradually pressurizing after the temperature rises to the interface threshold temperature, so that the interface combination and the compactness of an SEI film mixing layer are improved, the interface impedance is further reduced under the conditions of less Li consumption and SEI film thickness reduction, and the internal resistance of the sulfide solid-state lithium battery is reduced.
Detailed Description
In the examples 1 to 3, the following examples were conducted,
a solid sulfide electrolyte lithium battery with low internal resistance comprises a positive electrode layer, an electrolyte layer and a negative electrode layer which are sequentially overlapped.
The anode layer is formed by pressing anode pressed powder, the anode pressed powder comprises anode material powder and sulfide solid electrolyte powder which are uniformly mixed, and the particle size of the anode pressed powder is 5-15 mu m. The anode material powder is one of a lithium cobaltate material, a nickel-cobalt-manganese ternary material and a nickel-cobalt-aluminum ternary material. The mixing mass ratio of the positive electrode material powder to the sulfide solid electrolyte powder was 7.
The electrolyte layer is formed by pressing electrolyte pressed powder, and the electrolyte pressed powder is sulfide solid electrolyte powder.
The negative electrode layer is formed by pressing negative electrode pressed powder, the negative electrode pressed powder comprises negative electrode material powder and sulfide solid electrolyte powder which are uniformly mixed, and the volume equivalent diameter of the negative electrode pressed powder is 10-35 mu m. The negative electrode material powder is obtained by mixing flake graphite and spheroidal graphite, the mixing ratio of the flake graphite to the spheroidal graphite is 1. The mixing mass ratio of the negative electrode material powder to the sulfide solid electrolyte powder is 1.
The particle size ratio of the negative electrode pressed powder to the electrolyte pressed powder is 1; the particle size ratio of the electrolyte pressed powder to the positive electrode pressed powder is 2. And simultaneously, the sulfide solid electrolyte powder in the anode pressed powder, the electrolyte pressed powder and the cathode pressed powder is respectively and independently selected, and can be the same or different, and the sulfide solid electrolyte powder in the anode pressed powder, the electrolyte pressed powder and the cathode pressed powder has the same composition and is selected to be Li-Argyrodite.
A first interface layer is further arranged between the positive electrode layer and the electrolyte layer, and a second interface layer is further arranged between the negative electrode layer and the electrolyte layer. The first interface layer and the second interface layer are SEI film mixing layers formed after the electrolyte layer is subjected to interface reaction with the anode layer or the cathode layer on the corresponding side under the pressure and heating environment.
The preparation method of the solid sulfide electrolyte lithium battery with low internal resistance comprises the following steps:
A. placing the cathode pressed powder mixed with cathode material powder and sulfide solid electrolyte powder in a mold, cold isostatic pressing to form a cathode layer with a thickness of 50 μm and a pressed density of 1.7g cm -3 ；
B. Uniformly spreading a layer of electrolyte pressed powder on the upper surface of the negative electrode layer, and carrying out cold isostatic pressing to obtain the negative electrode layer and the electrolyte layer which are pressed into a whole, wherein the thickness of the electrolyte layer is 30 mu m, and the compaction density is 2.0 g-cm -3 ；
C. Paving a positive electrode pressed powder containing uniformly mixed positive electrode material powder and sulfide solid electrolyte powder on the upper surface of the electrolyte layer, cold isostatic pressing to form a negative electrode layer, an electrolyte layer and a positive electrode layer which are integrated by pressing, wherein the thickness of the positive electrode layer is 60 mu m, and the compaction density is 3.0g cm -3 Obtaining a prefabricated battery core;
D. taking out the prefabricated battery core, applying pressure of 1-3 MPa to the direction of the electrolytic layer on the outer sides of the positive electrode layer and the negative electrode layer, placing the prefabricated battery core into a preheating greenhouse with the temperature of 300-500 ℃ during high-temperature treatment, timing high-temperature treatment time after the temperature of the prefabricated battery core reaches interface threshold temperature, increasing the applied pressure by 1MPa/min, keeping the pressure after pressurizing to 5-10 MPa, wherein the high-temperature treatment time is 5-10 min, and obtaining a finished product battery core after the high-temperature treatment time is finished, wherein the interface threshold temperature is determined according to different positive electrode materials, negative electrode materials and sulfide solid electrolytes and is obtained by experimental tests.
E. Mounting a tab on a finished product battery core, and coating the tab by using an aluminum plastic film to obtain a battery inner core;
F. and installing the battery case to obtain the solid sulfide electrolyte lithium battery.
The solid sulfide electrolyte lithium batteries of the present application were fabricated according to the above-described fabrication method to obtain examples 1 to 3, specific parameters of which are shown in table one.
TABLE I concrete parameter tables of examples 1 to 3
Figure BDA0002248536190000101
In the examples 4 to 6, the following examples were carried out,
a solid sulfide electrolyte lithium battery with low internal resistance, based on the basis of examples 1 to 3, characterized in that the solid sulfide electrolyte lithium battery is prepared by the following method:
A. placing the anode pressed powder uniformly mixed with anode material powder and sulfide solid electrolyte powder into a die to be cooled and isostatic-pressed to form an anode layer, wherein the thickness of the anode layer is 60 mu m, and the pressing density is 3.0 g.cm -3 ；
B. Uniformly spreading a layer of electrolyte pressed powder on the upper surface of the positive electrode layer, and carrying out cold isostatic pressing to obtain the positive electrode layer and the electrolyte layer which are pressed into a whole, wherein the thickness of the electrolyte layer is 30 mu m, and the compaction density is 2.0 g.cm -3 ；
C. Paving a layer of negative electrode pressed powder containing uniformly mixed negative electrode material powder and sulfide solid electrolyte powder on the upper surface of the electrolyte layer, and cold isostatic pressing to form a positive electrode layer, an electrolyte layer and a negative electrode layer which are integrated by pressing, wherein the thickness of the negative electrode layer is 50 mu m, and the compaction density is 1.7 g-cm -3 Obtaining a prefabricated battery core;
D. after taking out the prefabricated battery core, applying 1-3 MPa pressure to the direction of the electrolytic layer at the outer sides of the positive electrode layer and the negative electrode layer, putting the prefabricated battery core into a preheating greenhouse with the temperature of 300-500 ℃ during high-temperature treatment, increasing the applied pressure by 1MPa/min after the temperature of the prefabricated battery core reaches the interface threshold temperature, pressurizing to 5-10 MPa and keeping the pressure, performing high-temperature treatment for 5-10 min, and obtaining a finished product battery core after the high-temperature treatment time is over, wherein the interface threshold temperature is the temperature of interface reaction occurring under 1-3 MPa, and the finished product battery core is obtained by experimental tests.
E. Mounting a tab on the finished product battery core, and coating the tab with an aluminum plastic film to obtain a battery inner core;
F. and installing the battery case to obtain the solid sulfide electrolyte lithium battery.
The amounts of the positive electrode pressed powder, the electrolyte pressed powder and the negative electrode pressed powder used in the above preparation methods were the same as those used in examples 1 to 3.
The solid sulfide electrolyte lithium batteries of the present application were fabricated according to the above-described fabrication method to obtain examples 4 to 6, specific parameters of which are shown in table two.
TABLE II specific parameters of examples 4 to 6
Figure BDA0002248536190000111
In the comparative example 1,
the solid sulfide electrolyte lithium battery with low internal resistance is based on the embodiment 1, and is characterized in that a prefabricated battery core is not subjected to pressurizing heat treatment and is directly used as a finished battery core for preparing the solid sulfide electrolyte lithium battery.
In a comparative example 2,
based on example 2, a solid sulfide electrolyte lithium battery with low internal resistance is characterized in that a prefabricated battery cell is directly used as a finished battery cell without pressure heat treatment to prepare the solid sulfide electrolyte lithium battery.
In the comparative example 3,
a solid-state sulfide electrolyte lithium battery with low internal resistance, which is based on the embodiment 3, and is characterized in that a prefabricated battery core is directly used as a finished product battery core without pressure heat treatment to prepare the solid-state sulfide electrolyte lithium battery.
The solid sulfide electrolyte lithium batteries obtained in examples 1 to 6 and comparative examples 1 to 3 were subjected to tests for finished cell resistance and all-solid-state lithium battery performance, and the test results are shown in table three.
Wherein the testing of the all-solid-state lithium battery is as follows:
the all-solid lithium battery was placed at a constant temperature of 25 ℃, constant-current charging was performed at a current value of 0.05C (20 h, calculated as the mass of the positive electrode active material) relative to the theoretical capacity of the all-solid lithium battery, and charging was terminated at a voltage of 4.2V. Then, the discharge was similarly performed at a current of 0.05C, and the discharge was terminated when the voltage was 3.0V. Thereby obtaining the coulombic efficiency and the discharge capacity of the battery. From the second cycle, 50 charge and discharge cycles were performed at 0.1C, and the larger the discharge capacity retention rate after 50 weeks, the better the cycle performance.
TABLE III test results of cycle performance test and finished cell resistance test of solid sulfide electrolyte lithium batteries obtained in examples 1 to 6 and comparative examples 1 to 3
Figure BDA0002248536190000121
As can be seen from comparison of the test results of examples 1 to 6 and comparative examples 1 to 3, in examples 1 to 6, after the prefabricated battery core is obtained, the prefabricated battery core is subjected to high-temperature treatment under pressure, so that a second interface layer is formed between the negative electrode layer and the electrolyte layer, and a first interface layer is formed between the electrolyte layer and the positive electrode layer, so that interface separation is blurred, the interface effect is weakened, the interface bonding stability is improved, the cell interface impedance is reduced, the internal resistance of the solid sulfide electrolyte lithium battery is reduced, and the battery heating and cycle performance degradation caused by the internal resistance of the battery are reduced.
As can be seen from the results of comparing examples 1 to 3 and examples 4 to 6, the internal resistance of the solid sulfide electrolyte lithium battery of the present application is advantageously reduced by first pressing the negative electrode layer with the negative electrode pressing powder and then pressing the electrolyte layer and the positive electrode layer gradually during the production process.
In the case of the example 7, the following examples are given,
a solid sulfide electrolyte lithium battery with low internal resistance is based on the embodiment 1, and is characterized in that the sulfide solid electrolyte is Li 2 S-P 2 S 5 。
In the case of the example 8, the following examples are given,
a solid sulfide electrolyte lithium battery with low internal resistance, which is based on example 1, is distinguished in that its sulfide solid electrolyte is LGPS.
In the case of the example 9, the following examples are given,
a solid sulfide electrolyte lithium battery with low internal resistance is based on the embodiment 1, and is characterized in that the sulfide solid electrolytes in the negative electrode pressed powder and the positive electrode pressed powder are Li 2 S-P 2 S 5 Electrolyte pressingThe sulfide solid electrolyte in the powder is Li 6 PS 5 Cl。
In the working example 10, the method comprises the following steps of,
a solid sulfide electrolyte lithium battery with low internal resistance, which is based on the embodiment 1, and is characterized in that the process D in the preparation method is modified, and the modified process D is as follows:
and (3) after taking out the prefabricated battery cell, applying pressure of 1MPa to the direction of the electrolytic layer on the outer sides of the positive electrode layer and the negative electrode layer, putting the prefabricated battery cell into a preheating greenhouse with the temperature of 300-500 ℃ during high-temperature treatment, performing high-temperature treatment for 8min after the temperature of the prefabricated battery cell reaches the interface threshold temperature of 415 ℃, and obtaining a finished product battery cell after the high-temperature treatment time is over.
In the case of the embodiment 11, the following examples are given,
a solid sulfide electrolyte lithium battery with low internal resistance, which is based on the embodiment 1, and is characterized in that the process D in the preparation method is modified, and the modified process D is as follows:
and (3) after taking out the prefabricated battery cell, applying 8MPa pressure to the electrolytic layer direction at the outer sides of the positive electrode layer and the negative electrode layer, putting the prefabricated battery cell into a preheating greenhouse with the temperature of 300-500 ℃ during high-temperature treatment, performing high-temperature treatment for 8min after the temperature of the prefabricated battery cell reaches the interface threshold temperature of 415 ℃, and obtaining a finished product battery cell after the high-temperature treatment time is over.
In a comparative example 4,
a solid sulfide electrolyte lithium battery with low internal resistance, which is based on example 1, is distinguished by a positive electrode pressed powder particle size of 7 μm, an electrolyte pressed powder particle size of 16 μm, and a negative electrode pressed powder particle size of 35 μm.
In a comparative example 5,
a solid sulfide electrolyte lithium battery with low internal resistance, which is based on example 1, is distinguished by a positive electrode pressed powder particle size of 10 μm, an electrolyte pressed powder particle size of 12 μm, and a negative electrode pressed powder particle size of 15 μm.
The solid sulfide electrolyte lithium batteries obtained in examples 7 to 12 and comparative examples 6 to 7 were subjected to tests for finished cell resistance and all-solid-state lithium battery performance, and the test results are shown in table four.
TABLE IV test results of cycle performance test and finished cell resistance test of solid sulfide electrolyte lithium batteries obtained in examples 7 to 12 and comparative examples 6 to 7
Figure BDA0002248536190000131
As can be seen by comparing the test results of example 1 with those of examples 7 to 8 in table four, the cycle performance of the solid sulfide electrolyte lithium battery of example 1 is superior to those of examples 7 to 8.
The solid electrolyte powder component of the sulfide in the application selects Li 6 PS 5 Cl, which belongs to ternary sulfide solid electrolyte, is Li, compared with the existing binary sulfide solid electrolyte with poor crystallinity and easy oxidation 6 PS 5 Cl has strong stability to oxidizing substances in the positive electrode. While Li is a more abundant solid electrolyte than other ternary sulfide solid electrolytes such as LGPS 6 PS 5 Non-valency-changing high-valency ions in Cl, e.g. Ge in LGPS 4+ Which has a small degree of reductive contact reduction deterioration after intercalation of graphite with lithium, and Li 6 PS 5 The Cl has better compatibility with graphite, is favorable for good interface bonding property when the electrolyte layer and the negative electrode are laminated, and promotes the interface reaction to form a more uniform and compact second interface layer, thereby further reducing the internal resistance drop of the solid-state lithium battery and improving the cycle performance of the solid-state lithium battery.
As can be seen by comparing the test results of example 1 and example 9 in table four, the cycle performance of the solid sulfide electrolyte lithium battery of example 1 is superior to that of example 9.
The same sulfide solid electrolyte is used in the negative electrode pressed powder, the electrolyte pressed powder and the positive electrode pressed powder, so that interfaces among the negative electrode layer, the electrolyte layer and the positive electrode layer in the prefabricated battery core formed by pressing in an integrated mode are fuzzified, the interface impedance is weakened, the internal resistance of the solid sulfide electrolyte lithium battery is reduced, and the cycle performance of the solid sulfide electrolyte lithium battery is improved.
As is clear from a comparison of the test results of example 1 and examples 10 to 11 in Table IV, the cell resistance of the product of example 1 is lower than those of examples 10 to 11.
According to the solid sulfide electrolyte lithium battery, the prefabricated battery core is firstly stressed in a prestressed mode, then is gradually pressurized after the temperature rises to the interface threshold temperature along with the temperature, and compared with the solid sulfide electrolyte lithium battery which is heated in a static pressure maintaining mode, the interface impedance can be further reduced, and the internal resistance of the sulfide solid lithium battery is reduced.
As can be seen by comparing the test results of example 1 and comparative examples 4 to 5 in Table IV, the cell resistance of the product obtained in example 1 is lower than those of comparative examples 4 to 5.
Therefore, for the solid sulfide electrolyte lithium battery, the negative electrode pressed powder, the electrolyte pressed powder and the positive electrode pressed powder are prepared according to the particle size ratio of the negative electrode pressed powder to the electrolyte pressed powder of 1.7-1, and the particle size ratio of the electrolyte pressed powder to the positive electrode pressed powder of 2.
In the examples 12 to 14, the following examples were conducted,
a solid sulfide electrolyte lithium battery with low internal resistance comprises a positive electrode layer, an electrolyte layer and a negative electrode layer which are sequentially overlapped.
The anode layer is formed by pressing anode pressed powder, the anode pressed powder comprises anode material powder and sulfide solid electrolyte powder which are uniformly mixed, and the particle size of the anode pressed powder is 5-15 mu m. The positive electrode material powder is one of a lithium cobaltate material, a nickel-cobalt-manganese ternary material and a nickel-cobalt-aluminum ternary material. The mixing mass ratio of the positive electrode material powder to the sulfide solid electrolyte powder was 7.
The electrolyte layer is formed by pressing electrolyte pressed powder, and the electrolyte pressed powder is sulfide solid electrolyte powder.
The negative layer is formed by pressing negative pressed powder, the negative pressed powder comprises uniformly mixed negative material powder and sulfide solid electrolyte powder, and the volume equivalent diameter of the negative pressed powder is 10-35 mu m. The negative electrode material powder is obtained by mixing flake graphite and spheroidal graphite, the mixing ratio of the flake graphite to the spheroidal graphite is 1. The mixing mass ratio of the negative electrode material powder to the sulfide solid electrolyte powder is 1.
The particle size ratio of the negative electrode pressed powder to the electrolyte pressed powder is 1; the particle size ratio of the electrolyte pressed powder to the positive electrode pressed powder is 2. Meanwhile, the sulfide solid electrolyte powder in the anode pressed powder, the electrolyte pressed powder and the cathode pressed powder is respectively and independently selected and can be the same or different, the sulfide solid electrolyte powder in the anode pressed powder, the electrolyte pressed powder and the cathode pressed powder has the same composition and is selected to be Li 6 PS 5 Cl。
A first interface layer is further arranged between the positive electrode layer and the electrolyte layer, and a second interface layer is further arranged between the negative electrode layer and the electrolyte layer. The first interface layer and the second interface layer are SEI film mixing layers formed after the electrolyte layer and the positive electrode layer or the negative electrode layer on the corresponding side are subjected to interface reaction in a pressure and heating environment.
The preparation method of the solid sulfide electrolyte lithium battery with low internal resistance comprises the following steps:
A. placing the cathode pressed powder mixed with cathode material powder and sulfide solid electrolyte powder in a mold, cold isostatic pressing to form a cathode layer with a thickness of 50 μm and a pressed density of 1.7g cm -3 ；
B. Uniformly spreading a layer of electrolyte pressed powder on the upper surface of the negative electrode layer, and carrying out cold isostatic pressing to obtain the negative electrode layer and the electrolyte layer which are pressed into a whole, wherein the thickness of the electrolyte layer is 30 mu m, and the compaction density is 2.0 g.cm -3 ；
C. Paving a positive electrode pressed powder containing uniformly mixed positive electrode material powder and sulfide solid electrolyte powder on the upper surface of the electrolyte layer, cold isostatic pressing to form a negative electrode layer, an electrolyte layer and a positive electrode layer which are pressed into a whole, wherein the thickness of the positive electrode layer is 60 mu m, and the compaction density isIs 3.0 g.cm -3 Obtaining a prefabricated battery core;
D. and after taking out the prefabricated battery core, applying a pressure of 600-750 MPa to the outside of the positive electrode layer and the negative electrode layer in the direction of the electrolytic layer, and keeping the pressure for 20-30 s to obtain a finished battery core, wherein the interface threshold temperature is determined according to different positive electrode materials, negative electrode materials and sulfide solid electrolytes and is obtained by experimental tests.
E. Mounting a tab on the finished product battery core, and coating the tab with an aluminum plastic film to obtain a battery inner core;
F. and installing the battery case to obtain the solid sulfide electrolyte lithium battery.
The solid sulfide electrolyte lithium batteries of the present application were fabricated according to the above-described fabrication method to obtain examples 12 to 14, specific parameters of which are shown in table five.
TABLE V specific parameters for examples 12 to 14
Figure BDA0002248536190000151
Figure BDA0002248536190000161
The solid sulfide electrolyte lithium batteries of examples 12 to 14 were subjected to tests for finished cell resistance and all solid state lithium battery performance, and the test results are shown in table six.
TABLE VI cycling Performance test and finished cell resistance test results for solid sulfide electrolyte lithium batteries of examples 12-14
Figure BDA0002248536190000162
As can be seen from comparison between the test results of examples 12 to 14 in table six and the test results of comparative examples 1 to 3 in table three, the finished cell resistance and the all-solid-state lithium battery performance obtained in examples 12 to 14 are superior to those of comparative examples 1 to 3, so that the interface reactions between the electrolyte layer and the positive electrode layer, between the electrolyte layer and the negative electrode layer can be initiated by using the pressure-pressurized combined cell with a pressure greater than 600MPa in the present application, and a continuous and complete SEI film mixed layer connecting both sides of the interface can be formed, so that the uniformity and compactness of the first interface layer and the second interface layer can be improved, and the bonding stability of the first interface layer and the second interface layer with the corresponding layer bodies on both sides can be improved. The degradation of the sulfide solid electrolyte and the dissolution of transition metal in the anode material are reduced, so that the internal resistance of the sulfide electrolyte solid battery is further reduced, and the cycle performance of the sulfide electrolyte solid battery is improved.
Meanwhile, as shown by comparing the test results of examples 12 to 14 in table six with the test results of examples 1 to 3 in table three, the high-pressure induced interfacial reaction is adopted in the preparation methods of examples 12 to 14, and the obtained finished product cell resistance and the all-solid-state lithium battery performance are superior to those of the finished product cell resistance and the all-solid-state lithium battery obtained by the preparation method of low-pressure interfacial reaction induced by heating (examples 1 to 3). However, the preparation methods of examples 1 to 3 in which low pressure is accompanied by heating are superior to those of examples 12 to 14 in applicability to the preparation method in which high pressure-initiated interfacial reaction is employed, and are difficult to industrially operate, and the investment in equipment cost is lower than that of the preparation method in which high pressure-initiated interfacial reaction is employed.
The above-mentioned embodiments are merely illustrative and not restrictive, and those skilled in the art can modify the embodiments without inventive contribution as required after reading this specification, but only fall within the scope of the claims of the present invention.

Claims (9)

1. The solid sulfide electrolyte lithium battery cell with low internal resistance is characterized by comprising a positive electrode layer, an electrolyte layer and a negative electrode layer which are sequentially overlapped;
the positive electrode layer is formed by pressing positive electrode pressing powder, and the positive electrode pressing powder comprises uniformly mixed positive electrode material powder and sulfide solid electrolyte powder;
the electrolyte layer is formed by pressing electrolyte pressed powder, and the electrolyte pressed powder is sulfide solid electrolyte powder;
the negative electrode layer is formed by pressing negative electrode pressed powder, and the negative electrode pressed powder comprises uniformly mixed negative electrode material powder and sulfide solid electrolyte powder;
the sulfide solid electrolyte powder in the positive electrode pressed powder, the electrolyte pressed powder and the negative electrode pressed powder is respectively and independently selected components, and the components are the same or different;
a first interface layer is arranged between the positive electrode layer and the electrolyte layer, a second interface layer is arranged between the negative electrode layer and the electrolyte layer, the first interface layer and the second interface layer are SEI film mixing layers, and the SEI film mixing layers are formed after the electrolyte layer is subjected to interface reaction with the positive electrode layer or the negative electrode layer on the corresponding side under the pressure of more than or equal to 600MPa or the environment of 300 ℃ and 1-10 MPa;
the sulfide solid electrolyte powder in the electrolyte layer is a chalcogenide lithium ion solid electrolyte of a silver germanite type.
2. The low internal resistance solid state sulfide electrolyte lithium battery cell of claim 1, wherein the positive electrode material powder is one of a lithium cobaltate material, a nickel cobalt manganese ternary material, and a nickel cobalt aluminum ternary material.
3. The method for producing a low internal resistance solid sulfide electrolyte lithium battery cell according to claim 1 or 2, comprising the steps of,
A. putting the cathode pressed powder evenly mixed with the cathode material powder and the sulfide solid electrolyte powder into a mould to be cooled and isostatic pressed to form a cathode layer;
B. uniformly spreading a layer of electrolyte pressing powder on the upper surface of the negative electrode layer, and carrying out cold isostatic pressing to obtain the negative electrode layer and the electrolyte layer which are pressed into a whole;
C. paving a layer of positive electrode pressing powder containing uniformly mixed positive electrode material powder and sulfide solid electrolyte powder on the upper surface of the electrolyte layer, and carrying out cold isostatic pressing to form a negative electrode layer, an electrolyte layer and a positive electrode layer which are pressed into a whole, so as to obtain a prefabricated battery core;
D. after taking out the prefabricated battery cell, applying pressure of 1 to 10MPa to the outside of the positive electrode layer and the negative electrode layer in the direction of the electrolytic layer, and processing at the high temperature of 300 to 500 ℃ for 5 to 10min to obtain a finished product battery cell;
or comprises the following steps of,
A. placing the anode pressing powder uniformly mixed with the anode material powder and the sulfide solid electrolyte powder into a die for cold isostatic pressing to form an anode layer;
B. uniformly spreading a layer of electrolyte pressing powder on the upper surface of the positive electrode layer, and carrying out cold isostatic pressing to obtain the positive electrode layer and the electrolyte layer which are pressed into a whole;
C. uniformly paving a layer of negative electrode pressing powder containing the negative electrode material powder and the sulfide solid electrolyte powder which are uniformly mixed on the upper surface of the electrolyte layer, and carrying out cold isostatic pressing to form a positive electrode layer, an electrolyte layer and a negative electrode layer which are pressed into a whole, so as to obtain a prefabricated battery core;
D. and (3) taking out the prefabricated battery cell, applying pressure of 1-10MPa to the outside of the positive electrode layer and the negative electrode layer in the direction of the electrolytic layer, and processing at the high temperature of 300-500 ℃ for 5-10 min to obtain a finished product battery cell.
4. The method of claim 3, wherein the positive electrode material powder is one of a lithium cobaltate material, a nickel-cobalt-manganese ternary material and a nickel-cobalt-aluminum ternary material, and the negative electrode material powder is graphite; the particle size ratio of the negative electrode pressing powder to the electrolyte pressing powder is 1; the particle size ratio of the electrolyte pressed powder to the positive electrode pressed powder is 2 to 7.
5. The method for preparing the low-internal-resistance solid sulfide electrolyte lithium battery cell according to claim 3, wherein the prefabricated cell is put into a preheating greenhouse with the temperature of 300-500 ℃ for high-temperature treatment during high-temperature treatment.
6. The method for preparing a solid sulfide electrolyte lithium battery cell with low internal resistance as claimed in claim 3, wherein in the step of processing the prefabricated cell at high temperature, the prefabricated cell is initially pressurized at 1 to 3MPa in a heating embedding manner and then heated, the high temperature processing time is counted at 1MPa/min after the temperature of the prefabricated cell reaches 300 to 500 ℃, the pressure is increased to 5 to 10MPa, the pressure is maintained, and the high temperature processing time is ended.
7. The method of producing a low internal resistance solid sulfide electrolyte lithium battery cell of claim 1 or 2, comprising the steps of,
A. placing the cathode pressed powder in which the cathode material powder and the sulfide solid electrolyte powder are uniformly mixed into a die, and carrying out cold isostatic pressing on the cathode layer;
B. uniformly paving a layer of electrolyte pressing powder on the upper surface of the negative electrode layer, and carrying out cold isostatic pressing to obtain the negative electrode layer and the electrolyte layer which are pressed into a whole;
C. paving a layer of positive electrode pressing powder containing uniformly mixed positive electrode material powder and sulfide solid electrolyte powder on the upper surface of the electrolyte layer, and carrying out cold isostatic pressing to form a negative electrode layer, an electrolyte layer and a positive electrode layer which are pressed into a whole, so as to obtain a prefabricated battery core;
D. after taking out the prefabricated battery cell, applying a pressure of 600 to 700MPa to the outside of the positive electrode layer and the negative electrode layer in the direction of the electrolytic layer, and keeping the pressure for 20 to 30 seconds to obtain a finished product battery cell;
or comprises the following steps of (a) preparing the solution,
A. placing the anode pressing powder uniformly mixed with the anode material powder and the sulfide solid electrolyte powder into a die for cold isostatic pressing to form an anode layer;
B. uniformly spreading a layer of electrolyte pressing powder on the upper surface of the positive electrode layer, and carrying out cold isostatic pressing to obtain the positive electrode layer and the electrolyte layer which are pressed into a whole;
C. uniformly paving a layer of negative electrode pressing powder containing the negative electrode material powder and the sulfide solid electrolyte powder which are uniformly mixed on the upper surface of the electrolyte layer, and carrying out cold isostatic pressing on the positive electrode layer, the electrolyte layer and the negative electrode layer which are pressed into a whole to obtain a prefabricated battery core;
D. and (3) taking out the prefabricated battery cell, and applying pressures of 600 to 700MPa to the outside of the positive electrode layer and the negative electrode layer in the direction of the electrolytic layer, and keeping the pressures for 20 to 30s to obtain a finished product battery cell.
8. The method of claim 5 or 6, wherein the composition of the sulfide solid electrolyte powders in the positive electrode pressed powder, the electrolyte layer and the negative electrode pressed powder is the same.
9. A solid sulfide electrolyte lithium battery with low internal resistance, characterized in that it comprises the solid sulfide electrolyte lithium battery cell with low internal resistance of claim 1 or 2.
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CN113782840B (en) * 2020-08-31 2023-11-28 蜂巢能源科技有限公司 All-solid-state battery cell, preparation method thereof and solid-state battery
CN113394463A (en) * 2021-04-25 2021-09-14 浙江锋锂新能源科技有限公司 Sulfide-based solid electrolyte all-solid-state battery and preparation method thereof
CN113659192B (en) * 2021-08-24 2023-07-14 蜂巢能源科技有限公司 Sulfide all-solid-state battery cell, preparation method thereof and all-solid-state lithium ion battery
CN113937355B (en) * 2021-08-31 2023-08-22 河北光兴半导体技术有限公司 Solid electrolyte sheet, and preparation method and application thereof

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101675553A (en) * 2007-05-11 2010-03-17 奈米克斯股份有限公司 Lithium ion rechargeable battery and process for producing the lithium ion rechargeable battery
CN103904360A (en) * 2012-12-27 2014-07-02 华为技术有限公司 Solid electrolyte, manufacturing method thereof, and all-solid-state lithium battery
CN106450482A (en) * 2016-12-09 2017-02-22 中国电子新能源（武汉）研究院有限责任公司 Method for manufacturing all-solid soft-packaged lithium ion battery
CN106663840A (en) * 2014-08-28 2017-05-10 应用材料公司 Electrochemical device stacks including interlayers for reducing interfacial resistance and over-potential
CN107240718A (en) * 2017-06-19 2017-10-10 中国科学院物理研究所 Solid state battery and preparation method thereof
CN109256555A (en) * 2018-10-16 2019-01-22 清华大学 A kind of sulphur system composite positive pole and its solid lithium battery and their preparation method
CN110112457A (en) * 2019-05-23 2019-08-09 桑德新能源技术开发有限公司 A kind of all-solid-state battery and preparation method thereof
CN110233298A (en) * 2019-07-09 2019-09-13 珠海冠宇电池有限公司 A kind of preparation method of novel all-solid lithium-ion battery
CN110336085A (en) * 2019-05-28 2019-10-15 浙江锋锂新能源科技有限公司 A method of reduction sulfide electrolyte solid state battery internal resistance

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103636054B (en) * 2011-07-08 2016-03-02 株式会社村田制作所 All-solid-state battery and manufacture method thereof
JP6380254B2 (en) * 2015-06-23 2018-08-29 トヨタ自動車株式会社 Manufacturing method of all solid state battery
CN109193026A (en) * 2018-10-17 2019-01-11 浙江工业大学 A kind of preparation method of argyrodite type sulfide solid electrolyte
CN110085868B (en) * 2019-04-25 2022-05-17 浙江锋锂新能源科技有限公司 Lithium metal cathode, preparation method thereof and method for preparing all-solid-state battery
CN110311100B (en) * 2019-05-28 2022-02-18 浙江锋锂新能源科技有限公司 All-solid-state lithium battery and preparation method thereof

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101675553A (en) * 2007-05-11 2010-03-17 奈米克斯股份有限公司 Lithium ion rechargeable battery and process for producing the lithium ion rechargeable battery
CN103904360A (en) * 2012-12-27 2014-07-02 华为技术有限公司 Solid electrolyte, manufacturing method thereof, and all-solid-state lithium battery
CN106663840A (en) * 2014-08-28 2017-05-10 应用材料公司 Electrochemical device stacks including interlayers for reducing interfacial resistance and over-potential
CN106450482A (en) * 2016-12-09 2017-02-22 中国电子新能源（武汉）研究院有限责任公司 Method for manufacturing all-solid soft-packaged lithium ion battery
CN107240718A (en) * 2017-06-19 2017-10-10 中国科学院物理研究所 Solid state battery and preparation method thereof
CN109256555A (en) * 2018-10-16 2019-01-22 清华大学 A kind of sulphur system composite positive pole and its solid lithium battery and their preparation method
CN110112457A (en) * 2019-05-23 2019-08-09 桑德新能源技术开发有限公司 A kind of all-solid-state battery and preparation method thereof
CN110336085A (en) * 2019-05-28 2019-10-15 浙江锋锂新能源科技有限公司 A method of reduction sulfide electrolyte solid state battery internal resistance
CN110233298A (en) * 2019-07-09 2019-09-13 珠海冠宇电池有限公司 A kind of preparation method of novel all-solid lithium-ion battery

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