CN114203992B - Positive electrode active material, electrochemical device, and electronic device - Google Patents
Positive electrode active material, electrochemical device, and electronic device Download PDFInfo
- Publication number
- CN114203992B CN114203992B CN202111484393.4A CN202111484393A CN114203992B CN 114203992 B CN114203992 B CN 114203992B CN 202111484393 A CN202111484393 A CN 202111484393A CN 114203992 B CN114203992 B CN 114203992B
- Authority
- CN
- China
- Prior art keywords
- compound
- electrochemical device
- positive electrode
- lithium
- solid electrolyte
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- 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
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/362—Composites
-
- 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
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
- H01M4/581—Chalcogenides or intercalation compounds thereof
- H01M4/5815—Sulfides
-
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Composite Materials (AREA)
- Inorganic Chemistry (AREA)
- Battery Electrode And Active Subsutance (AREA)
- Secondary Cells (AREA)
Abstract
本发明公开了一种正极活性材料、电化学装置和电子设备，所述正极活性材料包括第一化合物和第二化合物，所述第一化合物能够使第二化合物在充电过程中分解出活性锂。本发明采用特定的第一化合物与第二化合物混合，能够减少负极活性材料的使用，提高电化学装置的体积/质量能量密度和循环稳定性。The invention discloses a positive active material, an electrochemical device and an electronic device. The positive active material includes a first compound and a second compound. The first compound enables the second compound to decompose active lithium during charging. The present invention uses a specific first compound and a second compound to be mixed, which can reduce the use of negative active materials and improve the volume/mass energy density and cycle stability of the electrochemical device.
Description
Technical Field
The invention belongs to the technical field of batteries, and relates to a positive electrode active material, an electrochemical device and electronic equipment.
Background
Solid state electrolytes in solid state lithium ion batteries have characteristics of nonflammability and high safety, and thus, solid state lithium ion batteries are considered as next-generation high reliability battery systems and are being widely researched and developed. Solid state lithium ion batteries generally comprise a three-part structure: a positive/negative electrode material layer and a solid electrolyte layer; in order to prevent internal short-circuiting of the battery during assembly, the thickness of the solid electrolyte layer is often thicker (generally more than 50 μm), and lithium-containing materials are needed for the negative electrode and/or the positive electrode to ensure that lithium ions shuttle between the positive electrode and the negative electrode, so that the lithium ion battery works normally.
In summary, the thickness of the solid-state battery core in the electrochemical device is often several times higher than that of the liquid electrolyte-based electrochemical device with the same ratio, so that the volume/mass energy density of the electrochemical device is greatly influenced; therefore, how to reduce the material quality of the electrochemical device and the overall volume of the electrochemical device has been a relatively challenging task.
Disclosure of Invention
The present invention provides a positive electrode active material, an electrochemical device, and an electronic apparatus, which address the problems of the prior art. The invention adopts the specific first compound and the second compound to be mixed, can improve the stability of the electrochemical device, reduce or avoid the use of the cathode active material, and further improve the volume/mass energy density of the electrochemical device.
In order to achieve the aim of the invention, the invention adopts the following technical scheme:
in a first aspect, the present invention provides a positive electrode active material including a first compound and a second compound;
the first compound is capable of causing the second compound to decompose active lithium during charging.
According to the invention, a specific first compound is mixed with a second compound, and the first compound can promote the decomposition of the second compound and remove active lithium under high voltage (for example, 2.5V to 3.0V), so that a lithium source is provided, and the lithium source is subjected to self-lithiation reaction at the positive electrode and combined with the first compound to form an intermediate product, so that the extra working procedures required by pre-lithiation of the positive electrode are reduced, and the production efficiency is improved.
The positive electrode active material can reduce or avoid the use of the negative electrode active material in the negative electrode, lithium is separated from the positive electrode and deposited on the negative electrode in the charging process, and lithium metal deposited on the negative electrode can be used as the active material, so that the direct use of the negative electrode active material is reduced or avoided, and the volume/mass energy density of an electrochemical device is improved.
Preferably, the first compound comprises S, se, tiS 2 Or FeS 2 Any one or a combination of at least two of them, for example, S and Se, se and TiS 2 TiS, of the combination of (C) 2 And FeS 2 S, se and TiS 2 Or S, se, tiS 2 And FeS 2 Combinations of (a) and the like.
The first compound S, se, tiS 2 Or FeS 2 Has higher theoretical specific capacity and reaction potential and high energy density for lithium.
Preferably, the first compound is Se, and when Se is selected, the battery has higher energy density, and also has dynamic performance, and the electrochemical device prepared by matching with the solid electrolyte has better comprehensive electrochemical performance.
Preferably, the second compound comprises 70Li 2 S-30P 2 S 5 、75Li 2 S-25P 2 S 5 、Li 7 P 3 S 11 、Li 3 PS 4 、Li 10 GeP 2 S 12 、Li 10 SnP 2 S 12 、LiBH 4 Or Li (lithium) 4 (BH 4 ) 3 I, or a combination of at least two, may be, for example, 70Li 2 S-30P 2 S 5 And 75Li 2 S-25P 2 S 5 Is a combination of Li 3 PS 4 And Li (lithium) 10 GeP 2 S 12 Is a combination of Li 10 SnP 2 S 12 LiBH 4 Is a combination of Li 3 PS 4 、Li 10 GeP 2 S 12 And Li (lithium) 10 SnP 2 S 12 Or Li 10 GeP 2 S 12 、Li 10 SnP 2 S 12 、LiBH 4 And Li (lithium) 4 (BH 4 ) 3 Combinations of I, etc.; wherein, 70Li 2 S-30P 2 S 5 May be in a glassy state 70Li 2 S-30P 2 S 5 ，75Li 2 S-25P 2 S 5 May be in a glassy state 75Li 2 S-25P 2 S 5 ，Li 7 P 3 S 11 May be glass ceramic Li 7 P 3 S 11 ，Li 3 PS 4 May be glass ceramic Li 3 PS 4 . The solid electrolyte not only can remove active lithium, but also can decompose to generate oxidation products, and the oxidation products serve as an interface protection layerThe stability of the electrochemical device is improved.
Preferably, the second compound is LiBH 4 Or/and Li 7 P 3 S 11 Because the second compound is selected, more active lithium is generated in the reaction, the stability of the reaction byproducts is better, and the energy density and the stability of the battery are higher.
As a preferable embodiment of the positive electrode active material according to the present invention, the mass ratio of the first compound to the second compound is (40 to 90): (10 to 30), wherein the selection range (40 to 90) of the first compound may be, for example, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85 or 90, etc., and the selection range (10 to 30) of the second compound may be, for example, 10, 12, 15, 18, 20, 22, 25, 28 or 30, etc.
The invention selects the proper proportion of the first compound and the second compound, and can further improve the specific capacity and the cycle stability of the positive electrode active material.
In an alternative embodiment, when the positive electrode active material is used for preparing a positive electrode, a conductive agent can be added into the positive electrode, and the conductive agent is matched with the first compound and the second compound for use, so that the conductivity and the stability of the positive electrode active material are improved together.
Preferably, the conductive agent includes any one or a combination of at least two of Super P, ketjen black, or graphene, and may be, for example, a combination of Super P and ketjen black, a combination of ketjen black and graphene, a combination of Super P and graphene, or a combination of Super P, ketjen black, and graphene. But is not limited to the above-listed types, other conductive agents commonly used in the art are also suitable for the present invention.
As a preferable embodiment of the positive electrode active material according to the present invention, the mass ratio of the first compound to the second compound to the conductive agent is (40 to 90): (10 to 30): 0 to 10 and is free of (40 to 90): 10 to 30): 0, wherein the selection range of the first compound (40 to 90) may be, for example, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85 or 90, etc., the selection range of the second compound (10 to 30) may be, for example, 10, 12, 15, 18, 20, 22, 25, 28 or 30, etc., and the selection range of the conductive carbon black (0 to 10) may be, for example, 0.01, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10, etc.
In a second aspect, the present invention provides an electrochemical device comprising a positive electrode comprising the positive electrode active material according to the first aspect, a negative electrode, and a solid electrolyte layer.
The method for preparing the electrochemical device is not limited, and the electrochemical device is obtained by pressing a solid electrolyte into a solid electrolyte layer, pressing a positive electrode active material layer on one side of the solid electrolyte layer, attaching a positive current collector on one side of the positive electrode active material layer far away from the solid electrolyte layer, attaching a negative electrode on one side of the solid electrolyte layer far away from the positive electrode active material layer, and then packaging under preset internal stress.
In an alternative embodiment, the solid electrolyte layer is pressed at a temperature of 25 ℃ to 60 ℃, for example 25 ℃, 30 ℃, 35 ℃, 40 ℃, 45 ℃, 50 ℃, 55 ℃, 60 ℃, etc., preferably 43 ℃ to 45 ℃.
In an alternative embodiment, the pressure of the pressing of the solid electrolyte layer is 20MPa to 80MPa, for example, 20MPa, 30MPa, 40MPa, 50MPa, 60MPa, 70MPa, 80MPa, or the like, preferably 40MPa to 42MPa.
In an alternative embodiment, the preset internal stress is 5MPa to 30MPa, for example, 5MPa, 6MPa, 8MPa, 10MPa, 15MPa, 20MPa or 30MPa, etc., preferably 20MPa to 22MPa.
In an alternative embodiment, the current collector of the positive electrode comprises an aluminum foil having a thickness of 10 μm to 20 μm, which may be, for example, 10 μm, 12 μm, 14 μm, 16 μm, 18 μm or 20 μm, etc., preferably 12 μm to 13 μm.
The electrochemical device with better comprehensive performance can be prepared by matching the better pressing pressure and pressing temperature and selecting the aluminum foil with proper parameters.
As a preferred technical scheme of the method for preparing an electrochemical device according to the present invention, the positive electrode active material layer is prepared according to the following method:
and mixing the first compound, the second compound and the conductive agent to obtain a mixture, coating the mixture on the surface of the solid electrolyte layer, and pressing to obtain the positive electrode active material layer.
In an alternative embodiment, the mixed environment is a shielding gas filled with argon or a dry room with dew point below-60 ℃.
The method of mixing the first compound, the second compound and the conductive carbon black is not limited in the present invention, and for example, ball milling, mechanical stirring, or the like may be used.
In an alternative embodiment, ball milling mixing is selected, and the rotational speed of the ball milling is 300r/min to 800r/min, for example, 300r/min, 400r/min, 500r/min, 600r/min, 700r/min, 800r/min, etc., preferably 450r/min to 480r/min.
In an alternative embodiment, the ball milling time is 6 to 48 hours, for example, 6, 8, 10, 15, 20, 30 or 48 hours, etc., preferably 22 to 24 hours.
In an alternative embodiment, the ratio of the total mass of the first compound, the second compound and the conductive agent to the mass of the ball-milled steel balls is (30 to 60): 1, which may be, for example, 30:1, 35:1, 40:1, 45:1, 50:1 or 60:1, etc., preferably (40 to 42): 1.
In an alternative embodiment, mechanical stirring and mixing are selected, and the rotation speed of the mechanical stirring is 800r/min to 2200r/min, for example, 800r/min, 850r/min, 900r/min, 1000r/min, 1100r/min or 1200r/min, and the like, preferably 1100r/min to 1200r/min.
In an alternative embodiment, the mechanical agitation time is 12h to 36h, which may be, for example, 12h, 14h, 16h, 20h, 30h, 36h, or the like.
The invention selects a proper mixing mode and matches a certain rotating speed and time, thus obtaining the material of the positive electrode with better comprehensive effect.
In an alternative embodiment, the temperature of the pressing of the positive electrode active material layer is 25 to 60 ℃, for example, 25 ℃, 30 ℃, 35 ℃, 40 ℃, 45 ℃, 50 ℃, 55 ℃, 60 ℃, or the like, preferably 43 to 45 ℃.
In an alternative embodiment, the pressure of the pressing of the positive electrode active material layer is 5MPa to 60MPa, for example, 5MPa, 10MPa, 20MPa, 30MPa, 40MPa, 50MPa, 60MPa, or the like, preferably 25MPa to 27MPa.
The electrochemical device provided by the invention has higher initial charge/discharge specific capacity, higher mass energy density and better cycling stability.
As a preferable embodiment of the electrochemical device according to the invention, the negative electrode is a current collector.
When the negative electrode only uses the current collector and does not directly add the negative electrode active material, the electrochemical device can still work, and the negative electrode active material mainly comes from lithium metal deposition in the charging process of the electrochemical device, so that the use of most of the negative electrode active material is saved, and the volume/mass energy density of the electrochemical device is improved.
Preferably, the current collector comprises copper foil and/or stainless steel foil.
Preferably, the thickness of the current collector is 4 μm to 12 μm, and may be, for example, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, or the like.
Preferably, the current collector has a thickness of 7 μm to 9 μm, which is capable of combining specific area energy density and electrode reaction kinetics, and is excellent in combination with the positive electrode of the present invention.
As a preferable embodiment of the electrochemical device of the present invention, the surface of the current collector is further provided with a lithium layer.
In the present invention, a current collector may be used alone as a negative electrode to increase the volume/mass energy density of the electrochemical device, or a lithium layer may be provided on the current collector to increase the capacity of the electrochemical device as a whole.
Preferably, the mass ratio of the lithium layer to the first compound is 0 to 50 and does not contain 0, and may be, for example, 0.01, 0.05, 0.1, 0.2, 0.3, 0.5, 1, 2, 3, 5, 10, 20, 30, 50, or the like.
Preferably, the mass ratio of the lithium layer to the first compound is 0.1 to 20. By arranging the lithium layer with low content, the volume and the quality of the battery can be reduced, and the energy density of the battery can be improved.
As a preferred embodiment of the electrochemical device of the present invention, the solid electrolyte layer includes a solid electrolyte including 70Li 2 S-30P 2 S 5 、75Li 2 S-25P 2 S 5 、Li 7 P 3 S 11 、Li 3 PS 4 、Li 10 GeP 2 S 12 、Li 10 SnP 2 S 12 、LiBH 4 Or Li (lithium) 4 (BH 4 ) 3 I, or a combination of at least two, may be, for example, 70Li 2 S-30P 2 S 5 And 75Li 2 S-25P 2 S 5 Is a combination of Li 3 PS 4 And Li (lithium) 10 GeP 2 S 12 Is a combination of Li 10 SnP 2 S 12 LiBH 4 Is a combination of Li 3 PS 4 、Li 10 GeP 2 S 12 And Li (lithium) 10 SnP 2 S 12 Or Li 10 GeP 2 S 12 、Li 10 SnP 2 S 12 、LiBH 4 And Li (lithium) 4 (BH 4 ) 3 I, preferably LiBH 4 The method comprises the steps of carrying out a first treatment on the surface of the Wherein, 70Li 2 S-30P 2 S 5 May be in a glassy state 70Li 2 S-30P 2 S 5 ，75Li 2 S-25P 2 S 5 May be in a glassy state 75Li 2 S-25P 2 S 5 ，Li 7 P 3 S 11 May be glass ceramic Li 7 P 3 S 11 ，Li 3 PS 4 May be glass ceramic Li 3 PS 4 。
The solid electrolyte is 70Li 2 S-30P 2 S 5 、75Li 2 S-25P 2 S 5 、Li 7 P 3 S 11 、Li 3 PS 4 、Li 10 GeP 2 S 12 、Li 10 SnP 2 S 12 、LiBH 4 Or Li (lithium) 4 (BH 4 ) 3 In IWhen at least two of them are combined, the present invention is not limited to the ratio of each component in the combination thereof.
Preferably, the operating temperature of the electrochemical device is 25 ℃ to 150 ℃, for example, 25 ℃, 30 ℃, 40 ℃, 60 ℃, 80 ℃, 100 ℃, 120 ℃, 150 ℃ or the like, and in this temperature range, the solid electrolyte has high ionic conductivity (> 1 mS/cm) to ensure the normal operation of the battery.
In an alternative embodiment, a hydrogen-based solid electrolyte (e.g., liBH 4 And Li (lithium) 4 (BH 4 ) 3 I) The working temperature is 118 ℃ to 122 ℃.
In an alternative embodiment, a sulfur-based solid state electrolyte (e.g., 70Li 2 S-30P 2 S 5 、75Li 2 S-25P 2 S 5 And Li 7 P 3 S 11 Etc.) operating at 58 to 62 c.
The temperature more suitable for the operation of the electrochemical device is selected according to the difference of the solid electrolyte, so that the performance of the electrochemical device can be further improved.
Preferably, the thickness of the solid electrolyte layer is 30 μm to 100 μm, and may be, for example, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, or the like.
Preferably, the thickness of the solid electrolyte layer is 45 μm to 75 μm, and a solid electrolyte layer of a proper thickness is advantageous for lithium ion transport and can improve battery energy density.
As a preferable embodiment of the electrochemical device according to the present invention, the ratio of the mass of lithium metal in the negative electrode to the mass of the first compound in the positive electrode after one charge to 100% of the state of charge (SOC) is (2 to 10): 10, and for example, may be 2:10, 3:10, 4:10, 5:10, 6:10, 7:10, 8:10, 9:10, 10:10, or the like. The mass of lithium metal in the negative electrode refers to the total mass of lithium metal in the negative electrode, and the mass ratio can improve the utilization rate of the negative electrode and the energy density of the battery.
Illustratively, after one charge to 100% soc, the upper limit voltage of the charge may be 2.8V to 3.0V, for example, 2.8V, 2.85V, 2.9V, 2.95V, 3V, or the like.
In a third aspect, the present invention provides an electronic device comprising the electrochemical apparatus according to the second aspect.
The electronic device according to the invention may be, for example, a mobile computer, an automobile, a motorcycle, an electric car or a camera, etc.
Compared with the prior art, the invention has the following beneficial effects:
(1) According to the invention, a specific first compound is mixed with the solid electrolyte, and the first compound can promote the decomposition of the solid electrolyte and remove lithium under high voltage (for example, 2.5V to 3.0V), so that a lithium source is provided, and the lithium source is subjected to self-lithiation reaction at the positive electrode and combined with the first compound to form an intermediate product, so that the extra working procedures required by pre-lithiation of the positive electrode are reduced, and the production efficiency is improved; at the same time, the solid electrolyte decomposes to produce oxidation products, which act as an interface protection layer, improving the stability of the electrochemical device.
(2) The positive electrode active material can reduce or avoid the use of the negative electrode active material in the negative electrode, lithium is separated from the positive electrode and deposited on the negative electrode in the charging process, and lithium metal deposited on the negative electrode can be used as the active material, so that the direct use of the negative electrode active material is reduced or avoided, and the volume/mass energy density of an electrochemical device is improved.
Detailed Description
The technical scheme of the invention is further described by the following specific embodiments.
Example 1
The embodiment provides a positive electrode active material, which is Se and LiBH with a mass ratio of 80:25 4 。
The embodiment also provides an electrochemical device and a preparation method thereof, the electrochemical device comprises a positive electrode, a negative electrode and a solid electrolyte layer, the positive electrode comprises the positive electrode active material and conductive carbon black, the negative electrode is a current collector, the current collector adopts copper foil with the thickness of 8 mu m, the thickness of the solid electrolyte layer is 60 mu m, and the solid electrolyte layer is solid state electricityThe electrolyte is LiBH 4 。
The preparation method of the electrochemical device comprises the following steps:
(1) Preparation of materials of the positive electrode: se and LiBH with the mass ratio of 80:25:3 are added 4 And Super P is placed in a ball milling tank filled with argon, ball milling is carried out for 24 hours at a rotating speed of 450r/min, and the ratio of the total mass of Se, liBH4 and Super P to the mass of ball milling steel balls is 40:1; and taking out the mixture in a glove box filled with argon after ball milling to obtain the material of the positive electrode.
(2) Preparation of electrochemical device: liBH is carried out 4 Pressing at 45 ℃ to form a solid electrolyte layer under 40MPa, pressing the material of the positive electrode in the step (1) under 25MPa on one side of the solid electrolyte layer, attaching an aluminum foil with the thickness of 12 mu m to one side of the pressed material of the positive electrode, attaching a copper foil with the thickness of 8 mu m to the other side of the solid electrolyte layer, and packaging with preset internal stress of 20MPa to obtain the electrochemical device with the capacity of 1Ah.
The electrochemical device of this example had a ratio of the mass of lithium metal in the negative electrode to the mass of the first compound in the positive electrode of 3:10 after one charge to 100% soc.
Examples 2 and 3 were obtained by changing parameters based on the procedure of example 1, and the parameters of the specific changes are shown in table 1.
The electrochemical devices in examples and comparative examples of the present invention were tested for a specific capacity for initial charge/discharge, a specific mass energy density, and a retention rate for capacity of 200 weeks using a Cheng Hong electric instruments and electric company, inc. battery performance test system (equipment model: BTS05/10C 8D-HP), and specific test parameters were as follows:
charging to 2.8V at 120deg.C with a current density of 0.01A to obtain a specific capacity C0, and discharging to 1.0V with a current density of 0.01A to obtain a specific capacity C 1 The method comprises the steps of carrying out a first treatment on the surface of the Then, the charge-discharge cycle was carried out at a current density of 0.5A for 200 weeks in a voltage interval of 1.0V to 2.8V, and the specific discharge capacity thereof during the first week of 0.5A discharge was C 2 Specific discharge capacity at 200 weeksIs C 3 ，C 3 /C 2 Namely, the capacity retention rate of the electrochemical device at 200 weeks.
The test results of examples 1 to 3 are shown in table 2.
TABLE 1
TABLE 2
Examples 4 to 13 were parameter changes based on the procedure of example 1, and the specific changed parameters and test results are shown in tables 3 to 8.
TABLE 3 Table 3
As is clear from a comparison of example 1 and example 4 in Table 3, the electrochemical device has a better capacity retention rate when Se is used as the first compound of the present invention, and S selected in example 4 has a higher specific capacity for initial charge and discharge, but has poor conductivity and poor stability after combining with the solid electrolyte of the present invention due to the hysteresis of the electrochemical reaction kinetics, and thus has a lower cycle stability than that of example 1.
TABLE 4 Table 4
As can be seen from a comparison of example 1 and examples 5 to 6 in Table 4, the first compound and the second compound are present in a proper ratio, and when the content of the first compound is higher, the amount of active lithium decomposed from the electrolyte is smaller, and the specific capacity is lower; when the content of the first compound is lower, the electrolyte side reaction is more, the non-active side reaction product is more, and the reaction kinetics of the battery is retarded. Thus, the effects of examples 5 to 6 are slightly lower than example 1.
TABLE 5
As is apparent from a comparison of example 1 and examples 7 to 8 in table 5, the present invention has a loss in mass energy density when a lithium layer is provided on a current collector of a negative electrode.
TABLE 6
As can be seen from comparison of examples 1 and 9 to 10 in table 6, when the negative electrode is a current collector, the matching effect of the current collector with proper thickness, the solid electrolyte layer and the positive electrode is better; when the thickness of the current collector copper foil is thicker, the battery quality is increased, the energy density is reduced, when the thickness of the current collector is thinner, the battery dynamics is reduced, the specific discharge capacity and the energy density are both reduced, and the cycle stability is deteriorated.
TABLE 7
As can be seen from comparison of example 1 and examples 11 to 12 in table 7, the solid electrolyte layer of the present invention has a suitable thickness, and the performance of matching with the positive electrode and the negative electrode is better in a suitable thickness range; when the thickness of the solid electrolyte layer is thicker, the battery is heavier, the energy density is reduced, and when the thickness of the solid electrolyte layer is thinner, the discharge capacity of the battery is lower, and the cycling stability is deviated.
TABLE 8
As can be seen from comparison of example 1 and example 13 in table 8, when the mass ratio of negative electrode lithium to positive electrode material after formation exceeds the optimum ratio, both the energy density and the cycle stability are deteriorated.
Comparative example 1
This comparative example provides a positive electrode active material that is LiNi 0.7 Co 0.1 Mn 0.2 O 2 。
The embodiment also provides an electrochemical device, which includes a positive electrode, a negative electrode, and a solid electrolyte layer, wherein the positive electrode includes the positive electrode active material and conductive carbon black, and the preparation method of the material of the negative electrode includes:
placing graphite and Super P with the mass ratio of 95:5 into a ball milling tank filled with argon, and ball milling for 12 hours at the rotating speed of 350r/min, wherein the ratio of the total mass of the graphite and Super P to the mass of ball-milled steel balls is 40:1; taking out the mixture in a glove box filled with argon after ball milling to obtain a material of the negative electrode;
the remainder were identical to example 1.
The test results of the electrochemical devices prepared in this comparative example are shown in table 9.
TABLE 9
As can be seen from the comparison of example 1 and comparative example 1 in table 9, in example 1 of the present invention, the first compound Se is mixed with the second compound, and only the current collector is used for the negative electrode, the first charge specific capacity thereof is 858mAh/g, and it can be seen that the positive electrode can remove more active lithium ions through the self-pre-lithium reaction; the initial discharge specific capacity is 457mAh/g, which is close to the theoretical specific capacity 675mAh/g of Se, and the capacity retention rate is higher after 200 weeks of circulation; in comparative example 1, a conventional ternary material was used, and the active material of the negative electrode was graphite, which had both a charge-discharge specific capacity and a mass energy density inferior to those of the present invention, and a capacity retention rate of 200 weeks was much lower than that of the present invention.
As is apparent from the above examples 1 to 9, the present invention can improve the stability of an electrochemical device, reduce the use of a negative electrode active material, and improve the volume/mass energy density of the electrochemical device by mixing a specific first compound with a solid electrolyte.
The applicant states that the detailed method of the present invention is illustrated by the above examples, but the present invention is not limited to the detailed method described above, i.e. it does not mean that the present invention must be practiced in dependence upon the detailed method described above. It should be apparent to those skilled in the art that any modification of the present invention, equivalent substitution of raw materials for the product of the present invention, addition of auxiliary components, selection of specific modes, etc., falls within the scope of the present invention and the scope of disclosure.
Claims (13)
1. An electrochemical device comprising a positive electrode, a negative electrode, and a solid electrolyte layer, wherein the positive electrode comprises a positive electrode active material comprising a first compound and a second compound;
the first compound is capable of causing the second compound to decompose active lithium during charging;
the first compound is Se, and the second compound is LiBH 4 Or/and Li 7 P 3 S 11 ；
The negative electrode is a current collector.
2. The electrochemical device of claim 1 wherein the mass ratio of the first compound to the second compound is (40 to 90): (10 to 30).
3. The electrochemical device of claim 1, wherein the current collector comprises copper foil and/or stainless steel foil.
4. The electrochemical device of claim 3, wherein the current collector has a thickness of 4 μm to 12 μm.
5. The electrochemical device of claim 4, wherein the current collector has a thickness of 7 μm to 9 μm.
6. The electrochemical device of claim 1, wherein the surface of the current collector is further provided with a lithium layer.
7. The electrochemical device of claim 6, wherein the mass ratio of the lithium layer to the first compound is 0 to 50 and is free of 0.
8. The electrochemical device of claim 7, wherein the mass ratio of the lithium layer to the first compound is from 0.1 to 20.
9. The electrochemical device of claim 1, wherein the solid electrolyte layer comprises a solid electrolyte comprising 70Li 2 S-30P 2 S 5 、75Li 2 S-25P 2 S 5 、Li 7 P 3 S 11 、Li 3 PS 4 、Li 10 GeP 2 S 12 、Li 10 SnP 2 S 12 、LiBH 4 Or Li (lithium) 4 (BH 4 ) 3 I or a combination of at least two thereof.
10. The electrochemical device of claim 9, wherein the solid electrolyte layer has a thickness of 30 μιη to 100 μιη.
11. The electrochemical device of claim 10, wherein the solid electrolyte layer has a thickness of 45 μιη to 75 μιη.
12. The electrochemical device of claim 1 wherein the ratio of the mass of lithium metal in the negative electrode to the mass of the first compound in the positive electrode is (2 to 10): 10 after the electrochemical device has been charged to 100% soc at a time.
13. An electronic device, characterized in that it comprises an electrochemical apparatus according to any one of claims 1 to 12.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111484393.4A CN114203992B (en) | 2021-12-07 | 2021-12-07 | Positive electrode active material, electrochemical device, and electronic device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111484393.4A CN114203992B (en) | 2021-12-07 | 2021-12-07 | Positive electrode active material, electrochemical device, and electronic device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114203992A CN114203992A (en) | 2022-03-18 |
| CN114203992B true CN114203992B (en) | 2024-01-30 |
Family
ID=80650929
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111484393.4A Active CN114203992B (en) | 2021-12-07 | 2021-12-07 | Positive electrode active material, electrochemical device, and electronic device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114203992B (en) |
Citations (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103000934A (en) * | 2011-09-16 | 2013-03-27 | 苏州宝时得电动工具有限公司 | Lithium-sulfur battery |
| CN107078295A (en) * | 2014-10-22 | 2017-08-18 | 国立研究开发法人科学技术振兴机构 | All solid state secondary battery positive pole and preparation method thereof and all solid state secondary battery |
| CN109449383A (en) * | 2018-09-21 | 2019-03-08 | 中国科学院青岛生物能源与过程研究所 | A kind of all solid state lithium-sulfur cell of high capacity |
| CN110048083A (en) * | 2019-04-30 | 2019-07-23 | 哈尔滨工业大学 | A kind of preparation method of anode of solid lithium battery |
| CN110061286A (en) * | 2019-04-30 | 2019-07-26 | 郑州中科新兴产业技术研究院 | A kind of lithium ion battery with high energy density and preparation method thereof with prelithiation effect |
| CN110120510A (en) * | 2019-05-23 | 2019-08-13 | 桑德新能源技术开发有限公司 | A kind of all-solid-state battery and preparation method thereof |
| CN110911634A (en) * | 2018-09-14 | 2020-03-24 | 比亚迪股份有限公司 | Positive electrode material and preparation method thereof, lithium battery positive plate and solid-state lithium battery |
| CN111370751A (en) * | 2018-12-25 | 2020-07-03 | 深圳市比亚迪锂电池有限公司 | Solid-state battery, preparation method thereof and electric automobile |
| CN111834625A (en) * | 2020-08-25 | 2020-10-27 | 中南大学 | A selenium composite cathode material, its preparation method and its all-solid-state lithium selenium battery |
| CN112038590A (en) * | 2019-06-04 | 2020-12-04 | 中国科学院物理研究所 | Novel solid-state battery and positive electrode material thereof |
| CN112272875A (en) * | 2018-04-20 | 2021-01-26 | 阿科玛法国公司 | Lithium/sulfur batteries with improved capacity and related methods of making |
| WO2021096708A1 (en) * | 2019-11-13 | 2021-05-20 | Enevate Corporation | Sacrificial salts in li-rich, defect anti-fluorite compounds in cathodes for prelithiation in lithium ion batteries |
| CN113451543A (en) * | 2021-06-30 | 2021-09-28 | 中汽创智科技有限公司 | Solid-state lithium ion battery prelithiation electrode and preparation method thereof |
| CN113555600A (en) * | 2020-04-26 | 2021-10-26 | 深圳新宙邦科技股份有限公司 | a solid state battery |
| CN113745638A (en) * | 2020-05-27 | 2021-12-03 | 北京卫蓝新能源科技有限公司 | High-safety and high-power ternary positive plate for lithium battery and preparation method and application thereof |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BR112016004279B1 (en) * | 2013-09-02 | 2021-12-14 | Mitsubishi Gas Chemical Company, Inc. | SOLID STATE BATTERY |
| CN105449186B (en) * | 2015-11-18 | 2018-11-27 | 深圳先进技术研究院 | A kind of secondary cell and preparation method thereof |
| CN111293352A (en) * | 2018-12-06 | 2020-06-16 | 三星电子株式会社 | All-solid-state secondary battery and method of manufacturing all-solid-state secondary battery |
| CN110120508B (en) * | 2019-05-23 | 2021-02-19 | 桑德新能源技术开发有限公司 | All-solid-state battery and preparation method thereof |
| CN110120509B (en) * | 2019-05-23 | 2021-01-12 | 桑德新能源技术开发有限公司 | All-solid-state battery and preparation method thereof |
| US11527745B2 (en) * | 2019-09-03 | 2022-12-13 | GM Global Technology Operations LLC | Methods of pre-lithiating electrodes |
-
2021
- 2021-12-07 CN CN202111484393.4A patent/CN114203992B/en active Active
Patent Citations (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103000934A (en) * | 2011-09-16 | 2013-03-27 | 苏州宝时得电动工具有限公司 | Lithium-sulfur battery |
| CN107078295A (en) * | 2014-10-22 | 2017-08-18 | 国立研究开发法人科学技术振兴机构 | All solid state secondary battery positive pole and preparation method thereof and all solid state secondary battery |
| CN112272875A (en) * | 2018-04-20 | 2021-01-26 | 阿科玛法国公司 | Lithium/sulfur batteries with improved capacity and related methods of making |
| CN110911634A (en) * | 2018-09-14 | 2020-03-24 | 比亚迪股份有限公司 | Positive electrode material and preparation method thereof, lithium battery positive plate and solid-state lithium battery |
| CN109449383A (en) * | 2018-09-21 | 2019-03-08 | 中国科学院青岛生物能源与过程研究所 | A kind of all solid state lithium-sulfur cell of high capacity |
| CN111370751A (en) * | 2018-12-25 | 2020-07-03 | 深圳市比亚迪锂电池有限公司 | Solid-state battery, preparation method thereof and electric automobile |
| CN110048083A (en) * | 2019-04-30 | 2019-07-23 | 哈尔滨工业大学 | A kind of preparation method of anode of solid lithium battery |
| CN110061286A (en) * | 2019-04-30 | 2019-07-26 | 郑州中科新兴产业技术研究院 | A kind of lithium ion battery with high energy density and preparation method thereof with prelithiation effect |
| CN110120510A (en) * | 2019-05-23 | 2019-08-13 | 桑德新能源技术开发有限公司 | A kind of all-solid-state battery and preparation method thereof |
| CN112038590A (en) * | 2019-06-04 | 2020-12-04 | 中国科学院物理研究所 | Novel solid-state battery and positive electrode material thereof |
| WO2021096708A1 (en) * | 2019-11-13 | 2021-05-20 | Enevate Corporation | Sacrificial salts in li-rich, defect anti-fluorite compounds in cathodes for prelithiation in lithium ion batteries |
| CN113555600A (en) * | 2020-04-26 | 2021-10-26 | 深圳新宙邦科技股份有限公司 | a solid state battery |
| CN113745638A (en) * | 2020-05-27 | 2021-12-03 | 北京卫蓝新能源科技有限公司 | High-safety and high-power ternary positive plate for lithium battery and preparation method and application thereof |
| CN111834625A (en) * | 2020-08-25 | 2020-10-27 | 中南大学 | A selenium composite cathode material, its preparation method and its all-solid-state lithium selenium battery |
| CN113451543A (en) * | 2021-06-30 | 2021-09-28 | 中汽创智科技有限公司 | Solid-state lithium ion battery prelithiation electrode and preparation method thereof |
Non-Patent Citations (3)
| Title |
|---|
| "全固态锂硫电池的研究进展";高静 等;《储能科学与技术》;第6卷(第3期);第557-571页 * |
| Xiaoyan Xu,et al.."Li7P3S11 solid electrolyte coating silicon for high-performance lithiumion batteries".《Electrochimica Acta》.2018,第276卷第325-332页. * |
| 高容量硫/碳复合正极材料;赖超 等;化学进展;第23卷(第2/3期);第527-532页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114203992A (en) | 2022-03-18 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN1208866C (en) | Lithium secondary battery using nano surface coating composite material as positive electrode active material | |
| CN102306783A (en) | Multi-layer graphene/lithium iron phosphate intercalated composite material, preparation method thereof, and lithium ion battery adopting multi-layer grapheme/lithium iron phosphate intercalated composite material as anode material | |
| CN106935793A (en) | Negative pole, the method for preparing negative pole and the lithium secondary battery comprising the negative pole | |
| CN111816859A (en) | Silicon-based negative electrode material, its preparation method and lithium ion secondary battery | |
| CN112771693B (en) | Three-dimensional composite metal lithium cathode, metal lithium battery and device | |
| CN115810733A (en) | Modified lithium iron manganese phosphate material, preparation method thereof and lithium ion battery | |
| CN114050263B (en) | Negative electrode materials and their preparation methods and applications | |
| Dhaiveegan et al. | Investigation of carbon coating approach on electrochemical performance of Li4Ti5O12/C composite anodes for high-rate lithium-ion batteries | |
| CN107170968A (en) | A kind of positive electrode material of secondary Mg battery and preparation method thereof | |
| CN114122372A (en) | Low-expansion silicon-carbon negative electrode material for lithium ion battery and preparation method thereof | |
| CN116404131A (en) | Silicon-carbon negative electrode material with nano homogeneous structure, and preparation method and application thereof | |
| Lim et al. | Optimization of electrolyte and carbon conductor for dilithium terephthalate organic batteries | |
| CN100370644C (en) | Lithium-ion battery cathode material and preparation method thereof | |
| CN114188521A (en) | A kind of light-weight coating layer on the surface of graphite positive electrode material of dual-ion battery and preparation method | |
| CN105609771A (en) | Nitrogen-doped multi-porous carbon negative electrode material and preparation method and application thereof | |
| CN101414678B (en) | Method for preparing lithium ion battery cathode material | |
| CN100447077C (en) | Preparation method of artificial graphite carbon negative electrode material and prepared artificial graphite carbon negative electrode material | |
| CN114203992B (en) | Positive electrode active material, electrochemical device, and electronic device | |
| CN118336094B (en) | Solid electrolyte composite diaphragm and preparation method and application thereof | |
| CN113066988A (en) | Negative pole piece and preparation method and application thereof | |
| CN107808957A (en) | The method of metatitanic acid lithium doping titanous | |
| Ke et al. | A sheet-like SnO2@ SiO2/graphite composite as anode material with excellent performance for lithium-ion batteries | |
| CN112421049A (en) | Method for preparing lithium battery silicon-carbon negative electrode material through ball milling and silicon-carbon negative electrode material | |
| CN100391830C (en) | Method for preparing lithium vanadium phosphoric acid of anode material of lithium ion battery under high pressure | |
| CN1884053A (en) | Process for solid phase synthesis of lithium iron phosphate anode materials under high pressure |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |