Activation method for lithium secondary batteries containing positive electrode additives

Abstract

This invention relates to an activation method for lithium secondary batteries, the advantage of which is that by performing a degassing step in the middle of the activation process to remove side reaction gases, a stable SEI film is formed on the electrode surface to improve battery performance and battery safety.

Description

Technical Field

[0001] This application claims priority to Korean Patent Application No. 10-2021-0071222 dated June 2, 2021 and Korean Patent Application No. 2022-0043177 dated April 7, 2022, and all disclosures in these Korean patent applications are incorporated herein by reference.

[0002] This invention relates to an activation method for a lithium secondary battery containing a positive electrode additive. Background Technology

[0003] With the development and increasing demand for mobile device technology, the demand for secondary batteries as an energy source is rapidly increasing. Among these secondary batteries, lithium-ion batteries, which have high energy density and operating potential, long cycle life, and low self-discharge rate, have been commercialized and are widely used.

[0004] Recently, with the increasing use of lithium-ion batteries as power sources for medium to large-sized devices such as electric vehicles, there is a growing demand for high capacity, high energy density, and low cost in lithium-ion batteries. Furthermore, the irreversible capacity of the cathode additives used in the electrodes is also required. However, the development of cathode additives with such high irreversible capacity does face limitations.

[0005] Meanwhile, conventional irreversible additives, such as Li6CoO4, are generally prepared by reacting cobalt oxides with an excess of lithium oxides. Irreversible additives prepared in this way are structurally unstable and generate large amounts of oxygen (O2) as charging progresses. Furthermore, if the irreversible additive does not fully react during the initial charging of the secondary battery and remains, it may react again during subsequent charging and discharging processes to generate large amounts of oxygen inside the battery. This generated oxygen may cause volume expansion of the electrode components and is likely one of the main factors leading to battery performance degradation.

[0006]

[0007] In addition, conventionally used irreversible additives exhibit approximately 10% higher permeability due to the 2D permeation network. -11 The powder conductivity is very low, S / cm, which is close to that of a non-conductor. This low powder conductivity increases the resistance of the positive electrode, and in this case, it exhibits a large capacity of over 200 mAh / g at low C-rates. However, as the C-rate increases, the performance rapidly declines with charging / discharging due to the high resistance, thus reducing the battery's charge / discharge capacity and limiting its ability to perform high-speed charging and discharging.

[0008] Therefore, there is a need to develop lithium secondary batteries with excellent electrical performance and improved safety. Summary of the Invention

[0009] [Technical Issues]

[0010] Therefore, the purpose of this invention is to provide an activation method for lithium secondary batteries, which can improve the electrical performance and safety of lithium secondary batteries.

[0011] [Technical Solution]

[0012] To address the aforementioned problems, in one embodiment, the present invention relates to an activation method for a lithium secondary battery comprising an electrode assembly and an electrolyte, the electrode assembly including a positive electrode containing a positive electrode active material and a positive electrode additive, and the method comprising an activation step of charging the lithium secondary battery to 100% state of charge (SOC).

[0013] In this case, the activation step is characterized by performing one or more degassing processes to remove internal gases from the secondary battery during the charging process to 100% SOC.

[0014] In one embodiment, the activation step is divided into two or more steps based on the SOC level of the lithium secondary battery. Additionally, the degassing process is performed between the steps divided according to the SOC level of the lithium secondary battery.

[0015] In another embodiment, the activation step is divided into two or more steps based on the SOC level of the lithium secondary battery, with a low-rate charge of less than 0.5C in the initial stage when the SOC level is low, and a high-rate charge of greater than 0.5C in the subsequent stage when the SOC level is higher.

[0016] In one specific implementation, the degassing process can be performed two or three times.

[0017] In another embodiment, the activation step may include: activation step 1, charging the lithium secondary battery to a state of charge (SOC) of less than 20%; activation step 2, charging the lithium secondary battery after activation step 1 to a SOC greater than 20% and less than 40%; activation step 3, charging the lithium secondary battery after activation step 2 to a SOC greater than 40% and less than 70%; and activation step 4, charging the lithium secondary battery after activation step 3 to a SOC of more than 90%. In this case, a degassing process may be performed after at least one of activation steps 1 to 3.

[0018] In one specific embodiment, a degassing process may be performed after one or more of activation steps 1 to 3. In this case, three degassing processes are performed.

[0019] In another specific embodiment, in activation step 1, a low-rate charge is performed under conditions below 0.5C, and in activation steps 2 to 4, a high-rate charge is performed under conditions above 0.5C. For example, activation step 1 is performed by charging the lithium secondary battery with a constant current in the range of 0.01C to 0.2C, and activation steps 2 to 4 are performed by charging the lithium secondary battery with a constant current in the range of 0.15C to 1C.

[0020] In addition, the degassing process can be carried out under vacuum.

[0021] Furthermore, the activation step may also include pressurizing the lithium secondary battery, and the activation step can be carried out at a temperature of 40°C to 70°C. Additionally, the activation step can be carried out at a voltage of 3.3V to 4.5V.

[0022] In addition, the positive electrode additive can be a lithium cobalt oxide represented by the following chemical formula 1.

[0023] [Chemical Formula 1]

[0024] Li p Co (1-q) M 1 q O4

[0025] Among them, M 1 It is selected from one or more elements in the group consisting of W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B and Mo, and p and q are 5≤p≤7 and 0≤q≤0.5, respectively.

[0026] Specifically, in chemical formula 1, M 1 It can be a Zn element, and q can satisfy 0.2≤q≤0.4.

[0027] In addition, based on the total weight of the compound layer, the content of the positive electrode additive can be from 0.1 to 5% by weight.

[0028] In addition, after the activation step, the method may include an aging step of aging the activated lithium secondary battery at a temperature of 40°C to 80°C.

[0029] In another embodiment, the present invention provides a lithium secondary battery including an electrode assembly and an electrolyte, the electrode assembly including a positive electrode; a negative electrode; and a separator disposed between the positive electrode and the negative electrode;

[0030] The positive electrode comprises a positive current collector, a positive electrode additive layer on the positive current collector, and the positive electrode additive layer containing a positive electrode active material, a positive electrode additive represented by the following chemical formula 1, a conductive material, and a binder.

[0031] The positive electrode active material for this lithium secondary battery is a lithium-nickel composite oxide represented by the following chemical formula 2.

[0032] [Chemical Formula 1]

[0033] Li p Co (1-q) M 1 q O4

[0034] [Chemical Formula 2]

[0035] Li x [Ni y Co z Mn w M 2 v ]O u

[0036] Among them, M 1 It is selected from one or more elements in the group consisting of W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B, and Mo, where p and q are 5 ≤ p ≤ 7 and 0 ≤ q ≤ 0.5, respectively.

[0037] M 2 It is at least one element selected from the group consisting of W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B, and Mo, and x, y, z, w, v, and u are respectively 1.0 ≤ x ≤ 1.30, 0.1 ≤ y < 0.95, 0.01 <z≤0.5,0.01<w≤0.5,0≤v≤0.2,1.5≤u≤4.5。

[0038] In addition, the negative electrode may have a negative electrode current collector and a negative electrode additive layer located on the negative electrode current collector and containing a negative electrode active material, and the negative electrode active material may contain carbon material and silicon material.

[0039] Furthermore, based on 100 parts by weight of the negative electrode binder layer, the content of silicon material can be 1 to 20 parts by weight.

[0040] [Beneficial Effects]

[0041] The activation method of the lithium secondary battery of the present invention can remove the side reaction gas by performing a degassing step in the middle of the activation, thereby forming a stable SEI film on the electrode surface to improve battery performance and has the advantage of improving battery safety. Detailed Implementation

[0042] Since the present invention can have various variations and various implementations, specific implementations will be described in detail in the detailed description.

[0043] However, this is not intended to limit the invention to the specific implementation, and should be understood to include all modifications, equivalents and substitutions included within the spirit and scope of the invention.

[0044] In this invention, it should be understood that the terms "comprising" or "having" are intended to specify the presence of the said features, numbers, steps, operations, components, components or combinations thereof, but do not exclude the presence or addition of one or more other features or numbers, steps, operations, components or combinations thereof.

[0045] Furthermore, in this invention, when a portion of a layer, film, region, plate, etc., is described as being "on" another portion, it includes not only the case where it is "directly located" on that other portion, but also the case where another portion is located in between. Conversely, when a portion of a layer, film, region, plate, etc., is described as being "below" another portion, this includes both the case where another portion is located in between and the case where it is "directly located" below that other portion. Moreover, the phrase "arranged on" can include not only being arranged at the top but also at the bottom.

[0046] The invention will be described in more detail below.

[0047] Activation method for lithium secondary batteries

[0048] In one embodiment, the present invention provides a method for activating a lithium secondary battery, the lithium secondary battery comprising an electrode assembly and an electrolyte, the electrode assembly including a positive electrode containing a positive electrode active material and a positive electrode additive, and the method comprising an activation step of charging the lithium secondary battery to a state of charge (SOC) of 90% or higher. In the activation step, a degassing process may be performed at least once to remove gases from inside the secondary battery during the process of charging to a SOC of 90% or higher.

[0049] Specifically, in the activation step, the lithium secondary battery is charged to a state of charge (SOC) of 90% or higher, 90% to 100%, 90% to 99.9%, 95% to 100%, or 95% to 99%. In this invention, the activation step includes cases where the lithium secondary battery is substantially fully charged.

[0050] The lithium secondary battery activation method of the present invention is for lithium secondary batteries containing irreversible additives (i.e., positive electrode additives). The additives are added to compensate for the loss of lithium ions due to the irreversible reaction that occurs at the negative electrode during the initial charging. The method has the effect of improving the delithiation efficiency of the positive electrode additives contained in the positive electrode during the initial charging of the battery.

[0051] Therefore, the lithium secondary battery activation method of the present invention includes the following steps: an activation step of charging a lithium secondary battery containing a positive electrode active material and a positive electrode additive to 100% SOC, and a degassing step performed at least once in the middle of the activation step to remove gases inside the lithium secondary battery. Typically, lithium secondary batteries generate a large amount of gas internally due to delithiation and / or decomposition of the positive electrode additive contained in the positive electrode additive layer. If this gas is not removed, it may lead to volume expansion of the electrode assembly, resulting in a decrease in battery performance. In the present invention, by performing one or more degassing processes in the middle of the activation step, volume expansion of the electrode assembly can be prevented, and the total amount of gas generated during charging can be reduced. That is, by removing side reaction gases using a degassing process in the middle of the activation step, the resistance between the electrolyte and electrode interface is reduced, thereby forming a robust SEI film, which improves battery performance.

[0052] In one example, the activation step is divided into two or more steps based on the SOC level of the lithium secondary battery. Additionally, a degassing process is performed between the steps divided according to the SOC level of the lithium secondary battery. In one specific example, the degassing process may be performed two or three times.

[0053] In another embodiment, the activation step is divided into two or more steps based on the SOC level of the lithium secondary battery. In the initial stage when the SOC level is low, a low-rate charge (below 0.5C) can be performed, while in the subsequent stage when the SOC level is higher, a high-rate charge (above 0.5C) can be performed. Specifically, in the initial stage, a low-rate charge is performed in the range of 0.1 to 0.5C, 0.1 to 0.4C, or 0.15 to 0.3C. Furthermore, in the subsequent stage when the SOC level is higher, a high-rate charge is performed in the range of greater than 0.5C and below 10C, 0.8 to 5C, or 0.8 to 1.2C. This is to induce stable SEI film formation through low-rate charging in the initial stage of charging and to improve process efficiency through high-rate charging in the subsequent stages.

[0054] Meanwhile, in one embodiment, the lithium secondary battery activation method of the present invention may include a total of four steps. In a specific example, the present invention may include: activation step 1, charging the lithium secondary battery to a state of charge (SOC) of less than 20%; activation step 2, charging the lithium secondary battery after activation step 1 to a SOC greater than 20% and less than 40%; activation step 3, charging the lithium secondary battery after activation step 2 to a SOC greater than 40% and less than 70%; and activation step 4, charging the lithium secondary battery after activation step 3 to a SOC of 100%. In this case, a degassing process may be performed after at least one of activation steps 1 to 3.

[0055] In lithium-ion rechargeable batteries, during initial charging, lithium ions originating from lithium transition metal oxides (such as the positive electrode active material and positive electrode additives contained in the positive electrode) migrate towards the carbon electrode of the negative electrode. Due to the high reactivity of lithium ions, they react with the carbon negative electrode to generate compounds such as Li₂CO₃, LiO, and LiOH, forming an SEI film on the surface of the negative electrode. The SEI film is a non-conductive film that forms as the amount of ion movement in the battery increases. When the SEI film forms, it prevents lithium ions from reacting with other materials in the negative electrode during subsequent recharge and acts as an ion tunnel, allowing only lithium ions to pass through. When such an SEI film is formed, lithium ions do not react with the negative electrode or other materials, thus reversibly maintaining the amount of lithium ions and reversibly maintaining the charging and discharging of the rechargeable battery. This improves the battery's lifespan, and even when placed at high temperatures or repeatedly charged and discharged, the battery is less likely to collapse, resulting in minimal changes in battery thickness.

[0056] The activation step 1 of this invention can be described as the step of forming a solid electrolyte interphase (SEI) film on the surface of the negative electrode by lithium ions derived from the positive electrode active material and / or positive electrode additive. Furthermore, the activation step 2 can be described as the step of applying current to the lithium secondary battery after activation step 1 to induce lithium ion delithiation and decomposition of the positive electrode additive, thereby charging the battery and simultaneously forming a gas derived from the positive electrode additive inside the battery. Additionally, activation steps 3 and 4 can be described as the steps of applying current to the lithium secondary battery after activation step 2 to complete the initial charging of the battery so that the state of charge (SOC) meets a certain level.

[0057] Meanwhile, in the lithium secondary battery activation method of the present invention, a degassing process can be performed after one or more of activation steps 1 to 3. Alternatively, in the lithium secondary battery activation method of the present invention, a degassing process can be performed sequentially after each of activation steps 1 to 3. In a specific example, the lithium secondary battery activation method of the present invention may include:

[0058] Activation step 1 → Degassing process → Activation step 2 → Activation step 3 → Activation step 4;

[0059] Activation step 1 → Activation step 2 → Degassing process → Activation step 3 → Activation step 4;

[0060] Activation step 1 → Degassing process → Activation step 2 → Degassing process → Activation step 3 → Activation step 4;

[0061] Activation step 1 → Degassing process → Activation step 2 → Activation step 3 → Degassing process → Activation step 4;

[0062] Activation step 1 → Activation step 2 → Degassing process → Activation step 3 → Degassing process → Activation step 4; or

[0063] Activation step 1 → Degassing process → Activation step 2 → Degassing process → Activation step 3 → Degassing process → Activation step 4, etc.

[0064] Simultaneously, the activation step may include pressurizing the lithium secondary battery. In a specific example, in the activation step of a lithium secondary battery containing a positive electrode additive of Formula 1, by pressurizing the lithium secondary battery during charging, the gases generated in the activation step can be discharged to the outside of the battery without remaining inside. That is, the process of charging the lithium secondary battery to 100% SOC can be carried out under pressurized conditions with a predetermined pressure applied. Here, pressurizing the lithium secondary battery refers to pressurizing the portion housing the electrode assembly, and the gases generated during the activation process by pressurizing the lithium secondary battery can be collected in a gas bag.

[0065] The pressurization process can utilize conventional pressurization components such as pressurization clamps to pressurize the lithium secondary battery. In this case, the pressure applied to the lithium secondary battery can be greater than 0 kgf / cm². 2 And 20 kgf / cm 2 Within the following range, or at 0.5 kgf / cm² 2 Up to 15 kgf / cm 2 Or 1 kgf / cm 2 Up to 10 kgf / cm 2 Within a certain range. When the pressure is too high, the battery may be damaged due to excessive pressure.

[0066] Furthermore, the degassing process removes gas from inside the lithium secondary battery and can be performed using methods commonly used in the battery industry without limitation. The degassing process may include the pressurization process described above. For example, in the activation step, a hole is formed in the gas bag, and the chamber containing the lithium secondary battery is constructed to a vacuum state so that the lithium secondary battery gas can be discharged to the outside and removed through the hole. Alternatively, the opening can be sealed.

[0067] In another instance, when a degassing process is performed sequentially after each activation step, the gas can be removed under the same conditions or under different conditions during each degassing process.

[0068] As described above, activation step 2 is the step of forming a gas derived from the positive electrode additive. In activation steps 2 to 4, a longer degassing process than in activation step 1 may be performed, or a greater pressure may be applied during charging. However, the present invention is not limited thereto.

[0069] Furthermore, in activation step 1, low-rate charging can be performed at conditions below 0.5C, while in activation steps 2 to 4, high-rate charging can be performed at conditions above 0.5C. Specifically, in activation step 1, the lithium secondary battery can be charged within the range of 0.1 to 0.5C, 0.1 to 0.4C, or 0.15 to 0.3C. Additionally, in activation steps 2 to 4, the lithium secondary battery can be charged within the range of above 0.5C and below 10C, 0.8 to 5C, or 0.8 to 1.2C. In this case, by charging with a low constant current in activation step 1 and charging with a relatively high constant current in activation steps 2 to 4, both battery stability and process efficiency can be improved simultaneously.

[0070] Additionally, the activation step can be performed under voltage conditions ranging from 0.1V to 4.5V. The voltage condition in the activation step is the charging voltage, and as an example, activation step 1 can be performed under voltage conditions ranging from 3.3V to 3.6V, and activation steps 2 to 4 can be performed under voltage conditions ranging from 3.4V to 3.7V, respectively.

[0071] In this invention, by controlling the voltage conditions of each activation step as described above, an SEI film can be uniformly formed in activation step 1, and the phase transition of the cathode additive can be promoted in activation steps 2 to 4 after the SEI film formation, while maintaining the redox reaction of the cathode active material, i.e., the reversible reaction rate of the cathode active material, thereby inducing high-rate delithiation of the cathode additive during the initial charging period. Furthermore, in activation steps 2 to 4, charging can be performed under low voltage conditions other than those described above to prevent the complete induction of irreversible reactions in the cathode additive, and charging can be performed under high voltage conditions other than those described above to prevent a decrease in battery life and capacity, as well as the problem of instantaneous generation of excess gas reducing safety.

[0072] Furthermore, the lithium secondary battery activation method of the present invention can gradually increase the SOC while performing each activation step. For example, the SOC of the lithium secondary battery in activation step 1 can be less than 10% to form an SEI film, and the SOC of the lithium secondary battery in activation step 2 can be greater than 10% and less than 40% to sufficiently induce the irreversible reaction of the positive electrode additive, thereby generating gas in the battery, and the SOC of the lithium secondary battery in activation step 3 can be greater than 40% and less than or equal to 70%.

[0073] As an example, the lithium secondary battery activation method of the present invention can adjust the SOC of activation step 1 to 10% to 18%, the SOC of activation step 2 to 30% to 38%, the SOC of activation step 3 to 60% to 70%, and the SOC of activation step 4 to 100%.

[0074] Furthermore, each activation step can be performed at a temperature above room temperature to reduce the electrode resistance. Specifically, each activation step can be performed at temperatures ranging from 40°C to 70°C, more specifically from 40°C to 60°C, 45°C to 60°C, 50°C to 65°C, 50°C to 60°C, or 52°C to 58°C. In this invention, by performing each activation step at temperatures within the above ranges, the secondary battery can be charged with lower positive electrode resistance, thus improving the efficiency of the activation step and the uniformity of the SEI film formed in activation step 1.

[0075] In addition, the execution time for each activation step can be from 1 minute to 100 minutes, specifically 1 minute to 100 minutes; 1 minute to 60 minutes; 1 minute to 40 minutes; 10 to 40 minutes; 20 to 40 minutes; 10 to 30 minutes; 1 minute to 10 minutes; and 2 to 9 minutes.

[0076] As an example, activation step 1 can be performed for 2 to 8 minutes, activation step 2 for 30 to 39 minutes, and activation step 3 for 21 to 29 minutes, but is not limited to these.

[0077] Furthermore, the lithium secondary battery activation method of the present invention may also include an aging step after activation step 3, in which the activated lithium secondary battery is aged. The aging step allows the SEI film to become more stable and reform into a uniform thickness by means of thermal and electrochemical energy. For this purpose, the aging step may be carried out at 40 to 80°C, 50 to 70°C, 55 to 65°C, or about 60°C for 0.5 to 30 hours.

[0078] In addition, a degassing process can be performed after activation step 4 or after the aging step to remove the gases generated in the lithium secondary battery. Since gases generated inside the battery can cause it to expand, a degassing process is performed to remove these gases.

[0079] Lithium secondary batteries

[0080] According to one embodiment, the present invention provides a lithium secondary battery, comprising an electrode assembly and an electrolyte, the electrode assembly comprising:

[0081] positive electrode;

[0082] negative electrode;

[0083] A diaphragm placed between the positive and negative electrodes.

[0084] In this case, the positive electrode includes a positive current collector and a positive electrode mixture layer prepared by coating, drying and pressing a positive electrode slurry on the positive current collector, and the positive electrode mixture layer has a structure comprising a positive electrode active material, a positive electrode additive, a conductive material and a binder.

[0085] In a specific example, the cathode additive can be a lithium cobalt oxide represented by the following chemical formula 1:

[0086] [Chemical Formula 1]

[0087] Li p Co (1-q) M 1 q O4

[0088] Among them, M 1 It is selected from one or more elements in the group consisting of W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B and Mo, and p and q are 5≤p≤7 and 0≤q≤0.5, respectively.

[0089] Specifically, in chemical formula 1, M 1 It can be a Zn element, and q can be 0.2≤q≤0.4.

[0090] Positive electrode additives can contain excess lithium to provide lithium for the irreversible chemical and physical reactions at the negative electrode during initial charging, thereby increasing the battery's charging capacity and reducing irreversible capacity to improve lifespan characteristics.

[0091] As such cathode additives, the present invention may include lithium cobalt oxide represented by Chemical Formula 1, wherein, as lithium cobalt oxide represented by Chemical Formula 1, Li6CoO4, Li6Co, etc., may be used alone or in combination. 0.5 Zn 0.5 O4, Li6Co 0.7 Zn 0.3O4, etc. The lithium cobalt oxide represented by chemical formula 1 has the following advantages: compared with nickel-containing oxides commonly used in the art, it has a high lithium-ion content, a low voltage range required for delithiation, and can deintercalate and deintercalate lithium ions during battery activation without affecting the reaction of the positive electrode active material.

[0092] Furthermore, the lithium cobalt metal oxide represented by Formula 1 can have a tetragonal crystal structure, wherein it can have the space group P42 / nmc. Typically, lithium metal oxides with a tetragonal crystal structure are structurally unstable due to the deformation of the tetrahedral structure formed by cobalt and oxygen elements. This structural instability leads to the generation of oxygen-containing gases, even during charging after battery activation. In this invention, by continuously performing a three-stage activation step under specific current and voltage conditions, the decomposition and / or delithiation efficiency of the cathode additive during initial charging can be significantly improved. Therefore, not only can the charging and discharging capacity of the lithium secondary battery be improved, but the amount of oxygen (O2) generated during charging and discharging after the initial charging can also be significantly reduced.

[0093] In addition, based on a total of 100 parts by weight of the positive electrode mixture layer, the content of the positive electrode additive can be 0.1 to 5 parts by weight, specifically 0.1 to 3 parts by weight; or 1 to 3 parts by weight.

[0094] In addition to the positive electrode active material and positive electrode additives, the compound layer may also contain conductive materials, adhesives and additives.

[0095] Meanwhile, the positive electrode used in this invention includes an agent layer formed on the current collector, and the agent layer contains a positive electrode active material exhibiting electroactivity and a positive electrode additive that imparts irreversible capacity.

[0096] The positive electrode composite layer comprises a positive electrode active material capable of reversible intercalation and deintercalation, and may include a lithium-nickel composite oxide represented by the following chemical formula 2:

[0097] [Chemical Formula 2]

[0098] Li x [Ni y Co z Mn w M 2 v ]O u

[0099] Among them, M 2 It is selected from at least one element chosen from the group consisting of W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B, and Mo, and

[0100] x, y, z, w, v, and u are respectively 1.0 ≤ x ≤ 1.30, 0.1 ≤ y < 0.95, 0.01, and 0.01. <z≤0.5,0.01<w≤0.5,0≤v≤0.2,1.5≤u≤4.5。

[0101] The lithium-nickel composite oxide represented by chemical formula 2 is a composite metal oxide comprising lithium, nickel, cobalt, and manganese, and in some cases, may be doped with another transition metal (M). 2 In the form of ), for example, the positive electrode active material may include materials selected from LiNi. 1 / 3 Co 1 / 3 Mn 1 / 3 O2, LiNi 0.6 Co 0.2 Mn 0.2 O2, LiNi 0.8 Co 0.1 Mn 0.1 O2, LiNi 0.9 Co 0.05 Mn 0.05 O2, LiNi 0.8 Co 0.1 Mn 0.05 Al 0.05 O2 and LiNi 0.7 Co 0.1 Mn 0.1 Al 0.1 At least one compound from the group consisting of O2. As an example, the positive electrode active material is a lithium nickel cobalt oxide represented by chemical formula 2, and LiNi can be used alone or in combination. 0.6 Co 0.2 Mn 0.2 O2 or LiNi 0.8 Co 0.1 Mn 0.1 O2.

[0102] In addition, based on 100 parts by weight of the compound layer, the content of the positive electrode active material can be 85 to 95 parts by weight, specifically 88 to 95 parts by weight, 90 to 95 parts by weight, 86 to 90 parts by weight, or 92 to 95 parts by weight.

[0103] In this context, conductive materials can be used to improve the performance of the positive electrode, such as conductivity, and one or more materials selected from the group consisting of natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, and carbon fiber can be used as conductive materials. For example, conductive materials may include acetylene black.

[0104] In addition, based on 100 parts by weight of the compound layer, the content of conductive material can be 1 to 10 parts by weight, specifically 2 to 8 parts by weight; or 2 to 6 parts by weight.

[0105] Additionally, the adhesive may include one or more resins selected from the group consisting of polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinylidene fluoride, polyacrylonitrile, polymethyl methacrylate, and copolymers thereof. As an example, the adhesive may include polyvinylidene fluoride.

[0106] In addition, based on 100 parts by weight of the compound layer, the content of the adhesive can be 1 to 10 parts by weight, specifically 1 to 8 parts by weight; or 1 to 6 parts by weight.

[0107] In addition, there is no particular limitation on the average thickness of the mixture layer. Specifically, it can be 50 μm to 300 μm, more specifically 100 μm to 200 μm; 80 μm to 150 μm; 120 μm to 170 μm; 150 μm to 300 μm; 200 μm to 300 μm; or 150 μm to 190 μm.

[0108] Furthermore, in the positive electrode, a current collector with high conductivity that does not cause chemical changes in the battery can be used. For example, stainless steel, aluminum, nickel, titanium, calcined carbon, etc., can be used. In the case of aluminum or stainless steel, materials whose surfaces have been treated with carbon, nickel, titanium, or silver can be used. Additionally, fine irregularities can be formed on the surface of the electrode current collector to improve the adhesion of the positive electrode active material, and various forms can be used, such as films, sheets, foils, meshes, porous bodies, foams, and nonwoven fabrics. Furthermore, considering the conductivity and total thickness of the positive electrode to be manufactured, the average thickness of the current collector can be appropriately applied in the range of 3 to 500 μm.

[0109] In addition, the negative electrode of the lithium secondary battery used in this invention is prepared by coating, drying and pressing a negative electrode active material onto a negative electrode current collector, and optionally may include conductive materials, organic binder polymers, additives, etc., as described above in the positive electrode.

[0110] Additionally, as anode active materials, for example, the following can be used: graphite with a fully layered crystal structure, such as natural graphite, and soft carbon with a low-crystallinity layered crystal structure (graphene structure; a structure in which the hexagonal honeycomb faces of carbon are arranged in layers), as well as graphite materials that are a mixture of carbon and these structures with amorphous portions, such as hard carbon, artificial graphite, expanded graphite, carbon fibers, non-graphitized carbon, carbon black, carbon nanotubes, fullerenes, activated carbon, etc.; metal composite oxides, such as Li x Fe2O3 (0≤x≤1), Li x WO2(0≤x≤1), Sn x Me 1-xMe'yOz (Me: Mn, Fe, Pb, Ge; Me': Al, B, P, Si, elements of Group 1, Group 2, and Group 3 of the periodic table, and halogens; 0 < x ≤ 1; 1 ≤ y ≤ 3; 1 ≤ z ≤ 8); lithium metal; lithium alloy; silicon-based alloy; tin-based alloy; metal oxides such as SnO, SnO2, PbO, PbO2, Pb2O3, Pb3O4, Sb2O3, Sb2O4, Sb2O5, GeO, GeO2, Bi2O3, Bi2O4, and Bi2O5; conductive polymers such as polyacetylene; Li-Co-Ni-based materials; titanium oxides; and lithium titanium oxides, etc.

[0111] As an example, the negative electrode active material may include graphite and silicon (Si)-containing particles, and the graphite includes at least one of natural graphite having a layered crystal structure and artificial graphite having an isotropic structure, and the silicon (Si)-containing particles may include particles mainly containing silicon (Si) as a metal component, such as silicon (Si) particles, SiO particles, SiO2 particles, or a mixture of one or more of these particles.

[0112] At this time, based on a total of 100 parts by weight, the negative electrode active material may contain 80 to 95 parts by weight of graphite and 1 to 20 parts by weight of silicon (Si)-containing particles. By adjusting the contents of graphite and silicon (Si)-containing particles contained in the negative electrode active material to the above ranges, the present invention can increase the charge capacity per unit mass while reducing lithium consumption and irreversible capacity loss during the initial charge / discharge of the battery.

[0113] In addition, the average thickness of the negative electrode binder layer may be 100 μm to 200 μm, specifically 100 μm to 180 μm, 100 μm to 150 μm, 120 μm to 200 μm, 140 μm to 200 μm, or 140 μm to 160 μm.

[0114] In addition, the negative electrode current collector is not particularly limited as long as it has high conductivity and does not cause chemical changes in the battery. For example, copper, stainless steel, nickel, titanium, calcined carbon, etc. can be used, and in the case of copper or stainless steel, materials with their surfaces treated with carbon, nickel, titanium, silver, etc. can be used. In addition, like the positive electrode current collector, the negative electrode current collector can form fine concavo-convex objects on its surface to strengthen the bonding force with the negative electrode active material, and can take various forms, such as films, sheets, foils, meshes, porous materials, foams, non-woven materials, etc. In addition, considering the conductivity and total thickness of the negative electrode to be manufactured, the average thickness of the negative electrode current collector can be appropriately applied within the range of 3 to 500 μm.

[0115] Additionally, the separator is located between the negative and positive electrodes and uses an insulating film with high ion permeability and mechanical strength. There are no particular limitations on the separator, as long as it is conventionally used in the art; however, specifically, sheets or nonwoven fabrics made of chemically resistant and hydrophobic polypropylene, glass fiber, or polyethylene can be used, and in some cases, composite separators can be used, wherein inorganic / organic particles are coated onto a porous polymer substrate (e.g., sheet or nonwoven fabric) using an organic binder polymer. When a solid electrolyte, such as a polymer, is used as the electrolyte, the solid electrolyte can also serve as the separator. Furthermore, the average pore size of the separator can be from 0.01 to 10 μm, and the average thickness can be from 5 to 300 μm.

[0116] Meanwhile, the positive and negative electrodes can be wound and housed in cylindrical, prismatic, or pouch-shaped batteries in the form of a core, or they can be housed in pouch-shaped batteries in a folded or stacked-folded form, but are not limited thereto.

[0117] Furthermore, the lithium-containing electrolyte of the present invention can be composed of an electrolyte lithium salt, and non-aqueous organic solvents, organic solid electrolytes, and inorganic solid electrolytes can be used as electrolytes.

[0118] Specifically, electrolytes may contain compounds represented by the following chemical formula 3:

[0119] [Chemical Formula 3]

[0120]

[0121] Wherein, R1 is a C1-4 alkylamino group with or without a substituent; a 4-7 membered ring heteroalkyl group with or without a substituent; or a 4-7 membered ring heteroaryl group with or without a substituent, wherein the heteroalkyl and heteroaryl groups contain at least one nitrogen atom (N).

[0122] n is an integer from 1 to 4.

[0123] Specifically, in the compound represented by Formula 3, R1 is dimethylamino, diethylamino, diisopropylamino, pyrrolidinyl, piperidinyl, piperazine, morpholinyl, pyrrolidinyl, or imidazolyl, wherein one or more hydrogens present in the pyrrolidinyl, piperidinyl, piperazine, morpholinyl, pyrrolidinyl, and imidazolyl groups are not substituted or may be substituted by C1-4 alkyl or nitrile groups, and n is 1 or 2.

[0124] As an example, the compound represented by formula 3 can be the compound represented by formula 4:

[0125] [Chemical Formula 4]

[0126]

[0127] The compound represented by Formula 4 strengthens the SEI film formed on the negative electrode surface by including a triple bond at the end, and suppresses side reactions in the electrolyte by adsorbing and removing impurities (such as metallic foreign matter) present in the electrolyte. Furthermore, R1 of this compound uses a nitrogen atom contained in an alkylamine, heteroalkyl, or heteroaryl group to stabilize the lithium salt, thereby suppressing the formation of decomposition products (such as HF and PF5) in the electrolyte. This prevents battery degradation and voltage reduction due to acidic HF, PF5, etc. Most importantly, R1 stabilizes the reaction sites of the positive electrode additives contained in the positive electrode additive layer, preventing a decrease in positive electrode resistance due to the positive electrode additives, while simultaneously improving the battery's charge / discharge capacity.

[0128] As non-aqueous organic solvents, for example, aprotic organic solvents such as N-methyl-2-pyrrolidone, ethylene carbonate, propylene carbonate, butyl carbonate, dimethyl carbonate, diethyl carbonate, γ-butyrolactone, 1,2-dimethoxyethane, tetrahydroxyflavone, 2-methyltetrahydrofuran, dimethyl sulfoxide, 1,3-dioxolane, formamide, dimethylformamide, dioxolane, acetonitrile, nitromethane, methyl formate, methyl acetate, triphosphate, trimethoxymethane, dioxolane derivatives, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolinone, propylene carbonate derivatives, tetrahydrofuran derivatives, ethers, methyl propionate, or ethyl propionate can be used.

[0129] As organic solid electrolytes, for example, polyethylene derivatives, polyethylene oxide derivatives, polypropylene oxide derivatives, phosphate polymers, polylyzed lysine, polyester sulfides, polyvinyl alcohol, polyvinylidene fluoride, and polymer materials including ion-dissociating groups can be used.

[0130] As an inorganic solid electrolyte, nitrides, halides, and sulfates of Li can be used, such as Li3N, LiI, Li5Ni2, Li3N-LiI-LiOH, LiSiO4, LiSiO4-LiI-LiOH, Li2SiS3, Li4SiO4, Li4SiO4-LiI-LiOH, and Li3PO4-Li2S-SiS2.

[0131] Lithium salts are materials that are readily soluble in non-aqueous electrolytes, and for example, LiCl, LiBr, LiI, LiClO4, LiBF4, and LiB can be used. 10 Cl 10 LiPF6, LiCF3SO3, LiCF3CO2, LiAsF6, LiSbF6, LiAlCl4, CH3SO3Li, (CF3SO2)2NLi, lithium chloroborane, lower aliphatic carboxylic acids, lithium tetraphenylborate, and imides, etc.

[0132] In addition, to improve charge / discharge characteristics and flame retardancy, pyridine, triethyl phosphite, triethanolamine, cyclic ethers, ethylenediamine, n-glycol dimethyl ether, triammonium hexaphosphate, nitrobenzene derivatives, sulfur, quinone imine dyes, N-substituted oxazolidinones, N,N-substituted imidazolidines, ethylene glycol dialkyl ethers, ammonium salts, pyrroles, 2-methoxyethanol, and aluminum trichloride can be added to the electrolyte. In some cases, to impart non-flammability, halogenated solvents such as carbon tetrachloride and trifluoroethylene can be further included, and carbon dioxide gas can be further included to improve high-temperature storage characteristics. Fluorinated ethylene carbonate (FEC) and propylene sulpholone (PRS) can also be further included.

[0133] Meanwhile, the positive and negative electrodes can be wound and housed in a cylindrical, prismatic, or pouch-type battery in the form of a core, or they can be housed in a pouch-type battery in a folded or stacked-folded form. For example, the lithium secondary battery of the present invention can be a pouch-type battery.

[0134] Implementation

[0135] The present invention will be described in detail below through examples.

[0136] However, the following embodiments and experimental examples are only used to illustrate the present invention, and the content of the present invention is not limited to the following embodiments and experimental examples.

[0137] Manufacturing example: Manufacturing of lithium secondary batteries

[0138] Weigh 95 parts by weight of LiNi as the positive electrode active material. 0.8 Co 0.1 Mn 0.1 O2, 0.9 parts by weight of Li6Co as a positive electrode additive 0.7 Zn 0.3 O4, 1.6 parts by weight of PVdF as a binder, and 2.5 parts by weight of carbon black as a conductive material were mixed in N-methylpyrrolidone (NMP) solvent to prepare a slurry for the positive electrode binder layer. The binder layer slurry was coated onto aluminum foil, dried, and then rolled to form a positive electrode with a positive electrode binder layer (average thickness: 130 μm).

[0139] 85 parts by weight of natural graphite as carbon-based active material, 5 parts by weight of SiO (silicon oxide) as silicon-based active material, 6 parts by weight of carbon black as conductive material, and 4 parts by weight of PVDF as binder were mixed in N-methylpyrrolidone solvent to prepare a slurry for the negative electrode mixture layer, and then coated on copper foil to prepare a negative electrode with a negative electrode mixture layer (average thickness: 180 μm).

[0140] An electrode assembly is fabricated by laminating a separator (approximately 16 μm thick) made of porous polyethylene (PE) membrane between the manufactured positive and negative electrodes. After placing this electrode assembly inside a battery casing, electrolyte is injected into the casing, and the battery is then left at room temperature for 3 days to allow for full electrolyte impregnation, thus manufacturing a lithium-ion secondary battery. E2DVC containing a compound represented by the following chemical formula 4 is injected as an electrolyte additive to prepare a full-cell type battery cell. At this point, the compound represented by formula 4 is weighed to ensure its content is 1% by weight based on the electrolyte.

[0141] Here, "E2DVC" is a carbonate electrolyte, which refers to a solution obtained by mixing lithium hexafluorophosphate (LiPF6, 1.0M) and ethylene carbonate (VC, 2% by weight) in a mixture of ethylene carbonate (EC): dimethyl carbonate (DMC): diethyl carbonate (DEC) = 1:1:1 (volume ratio).

[0142] [Chemical Formula 4]

[0143]

[0144] Examples 1 to 6: Activation of lithium secondary batteries

[0145] An activation step was performed on the lithium secondary battery manufactured in the manufacturing example. The temperature for each activation step was 55°C. Activation step 1 was performed at 0.2°C and 3.4V, and activation steps 2 to 4 were performed at 1°C and 3.6V. Table 1 shows the time for each activation step, whether a degassing process was performed, and whether a pressurization process was performed during the activation step. Simultaneously, the activation step was performed while the lithium secondary battery was pressurized using a pressurizing fixture, and the gas inside the lithium secondary battery was collected in a gas bag. During the degassing process, the gas collected in the gas bag was removed by puncturing the gas bag's forming hole and applying a negative pressure of -5 to -90 kPa. After the activation step, the lithium secondary battery was aged at 60°C for 24 hours, and the aged lithium secondary battery was degassed.

[0146] Comparative Example 1: Activation of Lithium Secondary Batteries

[0147] The lithium secondary battery manufactured in the example is charged at 0.3C for 10 hours until it reaches 4.3V to perform the secondary battery activation step. After the activation step, a fixture is used to degas the gas in the battery.

[0148] [Table 1]

[0149]

[0150] Experimental Example

[0151] To evaluate the performance differences of lithium secondary batteries caused by activation methods, the following experiments were conducted.

[0152] A) Analyze the amount of gas generated during the activation step.

[0153] The amount of gas generated internally and the total amount of gas during the activation process (formation) of the lithium secondary batteries in the examples and comparative examples were analyzed. The results are shown in Table 2 below.

[0154] [Table 2]

[0155]

[0156] As shown in Table 2, the lithium secondary batteries activated according to the conditions of the Examples have a higher total gas generation compared to the lithium secondary batteries activated according to the Comparative Examples. Furthermore, Example 1, which performed a degassing process after each activation step compared to Examples 2-6, has a higher total gas generation. Moreover, as seen from Examples 2, 4, and 5, which performed a total of two degassing steps in the activation steps, the lithium secondary batteries of Examples 2 and 4, which performed a degassing process after activation step 1, have a greater total gas generation compared to the lithium secondary battery of Example 5. Generally, since SEI formation is most active in activation step 1, the lithium secondary batteries of Examples 2 and 4, which performed a degassing process after activation step 1, appear to have a higher total gas generation compared to the lithium secondary battery of Example 5.

[0157] In the lithium secondary battery activated according to the embodiments, a degassing process can be performed during the activation step to easily remove gases generated in the lithium secondary battery. In particular, it appears that this process prevents gases generated in the secondary battery from interfering with the formation of the SEI or participating in side reactions, thereby improving the performance of the lithium secondary battery.

[0158] B) Evaluation of initial resistance value

[0159] The resistance of each activated lithium secondary battery in the examples and comparative examples was measured while discharging at 2C C rate for 10 seconds at 50% SOC, and the results are shown in Table 3.

[0160] [Table 3]

[0161] Classification Resistance (mΩ) Example 1 0.84 Example 2 0.85 Example 3 0.86 Example 4 0.85 Example 5 0.93 Example 6 0.92 Comparative Example 1 1.04

[0162] As shown in Table 3, in the case of lithium secondary batteries activated according to the examples, the resistance values ​​were confirmed to be lower than those of the comparative examples. In particular, the resistance values ​​of the lithium secondary batteries of Examples 1 to 4, which underwent a degassing process after activation step 1, were lower than those of Examples 5 to 6. This is believed to be due to the removal of side reaction gases inside the lithium secondary battery, thereby increasing the impregnation of the electrolyte and resulting in a more uniform electrode-electrolyte reaction.

[0163] C) Evaluate cycle life performance

[0164] The activated lithium secondary batteries in the examples and comparative examples were discharged to a cutoff voltage of 2V at a discharge current of 0.1C, and the initial charge / discharge capacity per unit mass was measured.

[0165] Then, 100 charge-discharge cycles were repeated at 45°C and 0.3C, while measuring the charge and discharge capacity and calculating the charge / discharge capacity retention rate after 100 charge-discharge cycles. The results are shown in Table 4 below.

[0166] [Table 4]

[0167] Classification Initial charge / discharge capacity [Ah] Capacity retention rate (%) Example 1 102.0 96.2 Example 2 101.9 96.0 Example 3 102.0 95.8 Example 4 101.8 95.7 Example 5 100.5 93.5 Example 6 100.6 93.5 Comparative Example 1 98.7 89.1

[0168] Referring to Table 4, the initial charge / discharge capacity of the lithium secondary battery activated according to the examples is 100 Ah or more, and the capacity retention rate after 100 charge and discharge cycles is 90% or more. However, it was confirmed that the initial charge / discharge capacity and the capacity retention rate after 100 charge / discharge cycles of the lithium secondary battery activated according to the comparative examples are lower than those of the examples.

[0169] In the case of the lithium secondary battery activated according to the embodiment, as the SOC increases during activation, side reaction gases are removed, and an SEI film is stably formed. This SEI film does not decompose due to additional electrolyte decomposition reactions and remains in good condition. On the other hand, in the case of the comparative example, since no degassing process is performed during activation, it appears that the gases generated in the lithium secondary battery during activation interfere with SEI formation or participate in side reactions. Therefore, the lithium secondary battery of the comparative example is expected to have an insignificant SEI film formation reaction, and thus, as the electrolyte decomposition reaction intensifies during cycling, it will lead to cycle degradation.

[0170] These results show that the lithium secondary battery activation method of the present invention has the following advantages: by performing a degassing step at least once during the activation step to remove gas from the internal structure of the secondary battery, the total amount of gas generated during charging and discharging can be reduced, thus improving battery safety. Furthermore, the charge / discharge capacity of the lithium secondary battery and the capacity retention rate after repeated use can be improved.

[0171] Although the above description has been made with reference to preferred embodiments of the invention, those skilled in the art or those of ordinary skill in the art should understand that various changes and modifications can be made thereto without departing from the spirit and scope of the invention as set forth in the appended claims.

[0172] Therefore, the technical scope of this invention should not be limited to the content described in the detailed description of the specification, but should be defined by the claims.

Claims

1. A method of activating a lithium secondary battery, in which an electrode assembly and an electrolyte are accommodated, the electrode assembly including a cathode containing a cathode active material and a cathode additive, the method including an activation step of charging the lithium secondary battery to a state of charge (SOC) of 90% or more, wherein in the activation step, one or more degassing processes for removing a gas inside the secondary battery during charging to an SOC of 90% or more are performed; wherein the activation step includes: activation step 1 of charging the lithium secondary battery to an SOC of 20% or less; activation step 2 of charging the lithium secondary battery subjected to the activation step 1 to an SOC of more than 20% and 40% or less; activation step 3 of charging the lithium secondary battery subjected to the activation step 2 to an SOC of more than 40% and 70% or less; and activation step 4 of charging the lithium secondary battery subjected to the activation step 3 to an SOC of 90% or more; the degassing process is performed after at least one of the activation steps 1 to 3; wherein the cathode additive is a lithium cobalt oxide represented by the following Chemical Formula 1: [Chemical Formula 1] Li p Co (1-q) M 1 q O4 wherein, M 1 is one or more elements selected from the group consisting of W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B, and Mo, and p and q are 5≤p≤7 and 0≤q≤0.5, respectively.

2. The method of claim 1, wherein, the degassing process is performed two or three times.

3. The method of claim 1, wherein, the degassing process is performed after each of the activation steps 1 to 3. 4.The method of claim 1, wherein, in the activation step 1, a low-rate charging is performed under a condition of 0.5C or less, and in the activation steps 2 to 4, a high-rate charging is performed under a condition of more than 0.5C.

5. The method of claim 1, wherein, the activation step further includes pressurizing the lithium secondary battery.

6. The method of claim 1, wherein, the activation step is performed under a temperature condition of 40℃ to 70℃.

7. The method of claim 1, wherein, In Chemical Formula 1, M 1 is a Zn element, and q is 0.2 ≤ q ≤ 0.

4.

8. The method of claim 1, wherein, the content of the cathode additive is 0.1 to 5% by weight, based on the total weight of the cathode mixture layer. 9.The method of claim 1, after the activation step, the method includes an aging step of aging the activated lithium secondary battery at a temperature of 40℃ to 80℃. 10.A lithium secondary battery activated by the method of any one of claims 1 to 9, including an electrode assembly and an electrolyte, the electrode assembly including: a cathode; an anode; a separator interposed between the cathode and the anode, wherein the cathode includes a cathode current collector and a cathode mixture layer on the cathode current collector, the cathode mixture layer containing a cathode active material, a cathode additive represented by the following Chemical Formula 1, a conductive material, and a binder, and the cathode active material is a lithium nickel composite oxide represented by the following Chemical Formula 2: [Chemical Formula 1] Li p Co (1-q) M 1 q O4 [Chemical Formula 2] Li x [Ni y Co z Mn w M 2 v ]O u wherein, M 1 is one or more elements selected from the group consisting of W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B, and Mo, and p and q are 5≤p≤7 and 0≤q≤0.5, respectively, M 2 is at least one element selected from the group consisting of W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B, and Mo, and x, y, z, w, v, and u are 1.0≤x≤1.30, 0.1≤y<0.95, 0.01<z≤0.5, 0.01<w≤0.5, 0≤v≤0.2, 1.5≤u≤4.5, respectively. 11.The battery of claim 10, the anode has an anode current collector and an anode mixture layer on the anode current collector containing an anode active material, and wherein, the anode active material contains a carbon material and a silicon material.

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