JP4876531B2 - Negative electrode for lithium secondary battery and method for producing lithium secondary battery - Google Patents

Description

  The present invention relates to a negative electrode for a lithium secondary battery and a method for producing a lithium secondary battery.

  In recent years, negative electrode materials containing elements such as silicon (Si) and tin (Sn) have attracted attention in order to increase the capacity of non-aqueous electrolyte secondary batteries. For example, the theoretical discharge capacity of Si is about 4199 mAh / g, which is about 11 times the theoretical discharge capacity of graphite.

  However, these negative electrode materials are known to have problems with cycle characteristics. Therefore, it is attempted to improve cycle characteristics by using oxides, nitrides or oxynitrides of Si or Sn instead of these negative electrode materials.

  However, Si, Sn, or their oxides and nitrides have a problem of large irreversible capacity. In other words, since a large proportion of lithium ions released from the positive electrode during the initial charge remains occluded in the negative electrode, the battery capacity becomes smaller than the theoretical capacity of these negative electrode materials. In order to avoid this irreversible capacity, a technique is disclosed in which lithium corresponding to the irreversible capacity is inserted in the negative electrode in advance, and then a battery is assembled and charging / discharging is started (see, for example, Patent Documents 1 to 4). By using these methods, lithium ions released from the positive electrode during the first charge can be recovered from the negative electrode at a high rate, and the battery capacity is increased.

  Patent Document 1 includes a negative electrode mixture layer containing a negative electrode active material containing at least one selected from the group consisting of Si, Sn, and Si—Ti alloys, and covers the surface of the negative electrode mixture layer. Discloses forming a metal lithium layer by vapor deposition or sputtering.

  Patent Document 2 discloses a method in which a lithium oxide layer is formed on a silicon oxide thin film formed on a current collector, a metal lithium layer is further formed, and lithium is supplemented with silicon oxide. Yes.

  Patent Document 3 discloses a method of co-evaporating silicon and lithium when a second layer made of silicon or the like is formed after a first layer mainly composed of carbon is provided on a current collector. ing.

Patent Document 4 discloses the production of a negative electrode comprising a step of forming a negative electrode mixture layer capable of inserting and extracting light metals, and a step of forming a light metal layer on the negative electrode mixture layer by a dry film forming method. The law is disclosed.
Japanese Patent Laying-Open No. 2005-063805 Japanese Patent Laid-Open No. 2003-162997 JP 2002-358594 A JP 2005-038720 A

  In order to increase the capacity of the battery, it is desirable to make the irreversible capacity as small as possible. For that purpose, it is necessary to apply lithium having the same amount of electricity as the irreversible capacity. Generally, in the negative electrode active material layer formed on the current collector, there is a weight variation in the electrode surface due to process fluctuations at the time of forming the negative electrode active material layer. In addition, when lithium is applied to the electrode surface, for example, when a vapor deposition method or the like is used as a lithium application method, the state of the lithium application source (for example, evaporation area, temperature, vapor flight path, etc.) is completely controlled. The variation in weight exists in the electrode surface for the reason that it is very difficult to suppress the non-uniformity with time due to. For this reason, when lithium having substantially the same amount of electricity as the irreversible capacity is applied, excessive application of lithium locally occurs.

  Excessive lithium is deposited without reacting with the active material layer. When a battery is configured using such an electrode plate, the electric field concentrates on the portion where lithium is deposited, and therefore lithium deposition proceeds with repeated charge and discharge. As a result, a short circuit occurs between the positive electrode and the negative electrode separated by the separator or the electrolyte layer, thereby causing a defect.

  In addition, as described in Patent Document 4, it takes a certain amount of time for lithium provided to the active material layer to be occluded in the active material layer. Accordingly, when lithium is applied to the negative electrode active material layer formed on the long current collector (continuous production), it cannot be wound into a hoop until the applied lithium is occluded. . Although depending on the amount of lithium applied, if the required time is long, there is a problem that the production efficiency is reduced, for example, the production facility needs to be increased accordingly.

  The present invention solves the above-mentioned conventional problems, and while reducing the irreversible capacity as much as possible by applying lithium, it is easy to prevent problems such as short-circuiting of the battery due to application of local excess lithium. An object of the present invention is to provide a manufacturing method of a negative electrode for a battery (hereinafter also referred to as a negative electrode) and a manufacturing method of a lithium secondary battery (hereinafter also referred to as a battery).

In order to solve the above-described conventional problems, the negative electrode manufacturing method of the present invention includes a silicon simple substance on a current collector, a silicon alloy, a compound containing silicon and oxygen, a compound containing silicon and nitrogen, a simple substance of tin, and tin. A first step of providing a first active material layer containing at least one selected from the group consisting of an alloy, a compound containing tin and oxygen, and a compound containing tin and nitrogen; and on the first active material layer A second step of applying lithium in a vacuum process, and a single element of silicon, a silicon alloy, a compound containing silicon and oxygen, a compound containing silicon and nitrogen, and a simple substance of tin on the first active material layer provided with lithium And a third active material layer including at least one selected from the group consisting of a tin alloy, a compound containing tin and oxygen, and a compound containing tin and nitrogen (hereinafter also referred to as an active material group). Including processes First electrical quantity corresponding to the amount of lithium to be applied in the second step, based on the sum of the first irreversible capacity and a second irreversible capacity possessed by the second active material layer having a first active material layer, 80 % Or more and 100% or less .

  This production method facilitates the production of a negative electrode capable of reducing irreversible capacity as much as possible by applying lithium and preventing local application of excess lithium.

The battery manufacturing method of the present invention includes a positive electrode capable of inserting and extracting lithium ions, a negative electrode capable of inserting and extracting lithium ions, a separator disposed between the positive electrode and the negative electrode, and lithium ions. A first step of providing a first active material layer including at least one selected from an active material group on a current collector of a negative electrode, and A second step of applying lithium to the active material layer by a vacuum process; and a second active material layer including at least one selected from an active material group on the first active material layer to which lithium is applied The first electric quantity corresponding to the amount of lithium applied in the second process includes the first irreversible capacity of the first active material layer and the second irreversible capacity of the second active material layer. 80% of the total And equal to or less than the upper 100%.

  This manufacturing method facilitates the manufacture of a battery that can reduce the irreversible capacity as much as possible by applying lithium, and that can prevent the application of local excess lithium.

  According to the method for producing a negative electrode and the method for producing a battery of the present invention, a negative electrode capable of improving battery performance, particularly cycle characteristics, by reducing irreversible capacity and preventing local application of excess lithium. The battery can be manufactured easily. This makes it possible to use an active material that theoretically absorbs or releases a large amount of lithium ions but has a large irreversible capacity, for example, at least one selected from the group of active materials. In addition, continuous production in which lithium is continuously applied while moving the negative electrode active material layer formed on the long current collector is also possible.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

(Embodiment 1)
FIG. 1 is a schematic diagram showing an example of a method for producing a negative electrode in the first embodiment. In FIG. 1, the inside of the vacuum chamber 2 is exhausted by an exhaust pump 1. The long battery electrode 4 unwound from the unwinding roll 3 in the vacuum layer 2 travels along the peripheral surfaces of the conveying roller 5 and the cylindrical first can 6 and the second can 7, and the winding roll 8 is wound up. In the battery electrode 4, a first active material layer (not shown) including at least one selected from an active material group is formed on a current collector in advance (first step). Although the 1st active material layer should just be formed in the surface facing the surface which contacts the 1st can 6 of a collector, you may be formed in the surface which contacts the 1st can 6 of a collector.

  The battery electrode 4 that has undergone the first step receives the application of lithium from the lithium supply source 9 in a state along the first can 6 (second step). The lithium application source 9 is composed of, for example, a crucible and lithium disposed inside the crucible, and is heated by a heating device (not shown) such as a resistance heating device, an induction heating device, or an electron beam heating device, and the lithium is supplied. Evaporate. At this time, the amount and range of applying lithium can also be adjusted by optimizing the heating condition of lithium, the gap between the shielding plates 10, the distance between the shielding plate 10 and the lithium applying source 9, and the like.

  After the second step, the second active material layer is applied from the active material applying source 31 with the battery electrode 4 along the second can 7 (third step). The active material application source 31 is composed of, for example, a crucible and an active material disposed inside the crucible, and is heated by a heating device (not shown) such as a resistance heating device, an induction heating device, or an electron beam heating device, The active material evaporates. At this time, the amount and range of applying the active material can be adjusted by optimizing the gap between the shielding plates 10 and the distance between the shielding plate 10 and the active material application source 31. In addition, when the active material is provided, the active material can be a compound containing oxygen or nitrogen by supplying oxygen gas or nitrogen gas.

  After completion of the third step, the battery electrode 4 is taken up by the take-up roll 8. Note that the steps from the first step to the third step may be repeated a plurality of times as unit steps.

  Moreover, it is preferable that the lithium provided in the second step is occluded in the first active material layer before the battery electrode 4 reaches the first transport roller 5a after the end of the second step.

  The manufacturing method of Embodiment 1 includes a first step of providing a first active material layer including at least one selected from an active material group on a current collector, and a vacuum process on the first active material layer. Including a second step of providing lithium, and a third step of providing a second active material layer including at least one selected from the active material group on the first active material layer to which lithium is applied. It is characterized by. According to this manufacturing method, the lithium applied on the first active material layer in order to reduce the irreversible capacity is excessive even before the lithium is completely occluded in the first active material layer. Even if it is deposited on the first active material layer, the second active material layer is formed on the first active material layer, so that excess lithium does not exist on the surface of the negative electrode. Accordingly, a negative electrode capable of improving battery performance, particularly cycle characteristics, can be easily manufactured by reducing irreversible capacity and preventing local application of excess lithium. In addition, continuous production in which lithium is continuously applied while moving the negative electrode active material layer formed on the long current collector is also possible.

  Moreover, the negative electrode of the present invention is often produced using an apparatus including a step of winding and running a battery electrode having a negative electrode active material layer formed on a long current collector. In the case of such a device, process fluctuations such as uneven running speed exist, so the distribution of lithium deposition occurs in-plane due to the process fluctuations, and as a result, a part of excess lithium is given. There is a case. When the amount of lithium applied is small relative to the irreversible capacity of the active material layer, all of the applied lithium is occluded in the active material layer, so that partial lithium deposition does not occur. However, when the amount of lithium applied is increased, excessive lithium is partially applied, and as a result, precipitation of lithium occurs. Such a situation depends on the accuracy of the process of winding and running the electrode plate and the reactivity between the active material and lithium, but the precipitation of lithium generally occurs when 80% or more of the irreversible capacity is applied. Therefore, the first amount of electricity corresponding to the amount of lithium applied in the second step is the sum of the first irreversible capacity of the first active material layer and the second irreversible capacity of the second active material layer. It is preferably 80% or more and 100% or less. This is because a negative electrode free from lithium deposition with almost 100% irreversible capacity is obtained.

  The first active material layer and the second active material layer are silicon simple substance, silicon alloy, compound containing silicon and oxygen, compound containing silicon and nitrogen, tin simple substance, tin alloy, compound containing tin and oxygen, And at least one selected from the group consisting of compounds containing tin and nitrogen may be the same active material or different materials. In particular, since the degree of irreversible capacity is as large as, for example, 5 to 70% with respect to the initial charge capacity, an oxide-based material such as Si or Sn needs a large amount of applied lithium. Therefore, there is a tendency that uneven distribution of lithium in the surface becomes large. Therefore, the improvement degree by the manufacturing method of this invention is remarkable.

  From the viewpoint of reactivity with lithium, the active material is preferably amorphous or low crystalline. The term “low crystallinity” as used herein refers to a region where the crystal grain size is 50 nm or less. Note that the grain size of the crystal grains is calculated by the Scherrer equation from the half-value width of the peak with the highest intensity in the diffraction image obtained by X-ray diffraction analysis. The term “amorphous” means that a diffraction peak obtained by X-ray diffraction analysis has a broad peak in the range of 2θ = 15 ° to 40 °.

  The ratio between the first active material layer and the second active material layer is not particularly limited, but the ratio of the first active material layer is preferably 80% or more from the viewpoint of preventing highly reactive lithium from being in a metallic state as much as possible.

  Lithium deposition becomes particularly noticeable when 92% or more of the irreversible capacity is imparted, and therefore, a fourth step of further imparting lithium may be provided following the third step. Such a case will be described below.

(Embodiment 2)
FIG. 2 is a schematic diagram showing another example of the method for producing a negative electrode in the second embodiment. The manufacturing method in the second embodiment is the same as the manufacturing method in the first embodiment except that the fourth step described above is included.

  2, the same reference numerals are used for the same components as in FIG. In FIG. 2, the inside of the vacuum chamber 2 is exhausted by the exhaust pump 1. The long battery electrode 4 unwound from the unwinding roll 3 in the vacuum layer 2 travels along the peripheral surfaces of the transport roller 5 and the cylindrical first can 6, second can 7 and third can 32. Then, it is wound on the winding roll 8. In the battery electrode 4, a first active material layer (not shown) including at least one selected from an active material group is formed on a current collector in advance (first step). Although the 1st active material layer should just be formed in the surface facing the surface which contacts the 1st can 6 of a collector, you may be formed in the surface which contacts the 1st can 6 of a collector.

  The battery electrode 4 that has undergone the first step receives the application of lithium from the lithium supply source 9 in a state along the first can 6 (second step). After the second step, the second active material layer is applied from the active material applying source 31 with the battery electrode 4 along the second can 7 (third step). After completion of the third step, lithium is applied from the lithium supply source 9a with the battery electrode 4 along the third can 32 (fourth step). After completion of the fourth step, the battery electrode 4 is taken up by the take-up roll 8. The steps from the first step to the third step are the same as the steps described in FIG. 1, and the fourth step is the same as the second step. Note that the steps from the first step to the third step or the fourth step may be repeated a plurality of times as a unit step.

  The sum of the first electric amount corresponding to the amount of lithium applied in the second step and the second electric amount corresponding to the amount of lithium applied in the fourth step is the first irreversible capacity of the first active material layer. It is preferable that it is 80% or more and 100% or less with respect to the sum total with the 2nd irreversible capacity | capacitance which a 2nd active material layer has. The ratio of the amount of lithium applied in the second step and the fourth step is arbitrary, but in the second step, 100% of the first irreversible capacity is given, and the rest is given in the fourth step. This is preferable from the viewpoint of improving the reactivity of lithium into the active material layer.

  Note that the lithium applied in the second step is preferably occluded in the first active material layer before the battery electrode 4 reaches the first transport roller 5a after the end of the second step. Moreover, it is preferable that the lithium provided in the fourth step is occluded in the second active material layer before the battery electrode 4 reaches the first transport roller 5b after the fourth step.

  In addition, it is desirable that the second negative electrode active material application in the third step is performed without breaking the vacuum after the lithium application in the second step in order to prevent inadvertent reaction of excess lithium. Absent.

  In each of the embodiments described above, it is desirable that each of the transport rollers 5, 5a, and 5b be made of a material that does not alloy with lithium. This is because even when unreacted lithium is present, it is possible to prevent the lithium from reacting with the roller, contaminating the roller, or bonding the roller and the electrode plate to cause poor running. Any material that does not form an alloy with lithium may be used, but from the viewpoint of roller shape and ease of processing into the roller surface layer, and from the viewpoint of cost, copper, nickel, chromium, stainless steel, fluorine, or fluorine-containing resin may be used. It is desirable to use such a material. When these materials are used in a portion in contact with the electrode plate, reaction with lithium in that portion can be prevented, and stable travel of the electrode plate can be ensured.

  As the current collector that can be used in the present invention, a sheet-like metal foil containing copper, nickel, or the like can be used. The thickness of the foil is preferably 4 to 30 μm, more preferably 5 to 10 μm from the viewpoints of strength, volumetric efficiency as a battery, and ease of handling. The surface of the foil may be smooth, but in order to increase the adhesion strength with the active material layer, a concavo-convex foil of about Ra = 0.1 to 4 μm can be used. The unevenness of the foil also has the effect of forming voids between the particles constituting the active material layer. From the viewpoints of adhesion, cost, etc., Ra is more preferably 0.4 to 2.5.

  As a method for forming the first active material layer, a wet process having steps of refining, coating, and pressing, or a dry process such as a vapor deposition method, a sputtering method, and a CVD method can be used. In order to form the active material layer by a wet process, a negative electrode active material particle is appropriately mixed with a binder and a conductive auxiliary agent to form a paste, which is applied to an appropriate thickness by a doctor blade or the like and dried. Then press as necessary. The negative electrode active material particles used generally have a particle size of 0.1 μm or more and 50 μm or less. Further, the binder only needs to have an adhesive force for binding the current collector to the negative electrode active material and be electrochemically inactive in a potential range where the battery operates. For example, styrene-butylene copolymer rubber, polyvinylidene fluoride, polytetrafluoroethylene, carboxymethylcellulose, or the like is used alone or in combination. As the conductive auxiliary agent, a material mainly composed of carbon such as graphite, carbon black, or carbon nanotube is used.

  When the first active material layer is formed by a dry process, a vapor deposition method, a sputtering method, a CVD method, or the like can be used. Among these, the vapor deposition method is particularly desirable from the viewpoint of efficiently forming the active material layer. As the vapor deposition method, electron beam vapor deposition may be used, or resistance heating vapor deposition may be performed. When depositing oxides or nitrides of Si or Sn, oxides or nitrides may be used as evaporation materials, and oxygen gas, nitrogen gas, or these gases are ionized while Si or Sn is evaporated. Alternatively, reactive vapor deposition may be performed by directing a radicalized product.

  As the lithium application method performed in the second step or the fourth step, it is desirable to use a thin film process. Among these, vacuum deposition is desirable because lithium can be applied at high speed. By using a thin film process, lithium can be applied thinly and uniformly on the negative electrode plate with high accuracy. As a result, uneven distribution of lithium can be reduced, so that lithium can be applied up to 100% of the irreversible capacity. Considering the high activity of lithium, it is desirable to perform all of these series of processes continuously in a vacuum.

  The electrode plate may be heated to promote the reaction with the active material layer during or after the application of lithium. The electrode plate may be heated using the heating means 30 shown in FIGS. 1 and 2, for example. In particular, in Embodiment 2, when the lithium applied in the fourth step is wound without being sufficiently occluded in the active material layer, lithium transfer to the back surface occurs. It is important that the lithium applied to the negative electrode active material layer finishes the reaction before winding, and the longer the time after winding of lithium and the higher the electrode plate temperature, the more the reaction between lithium and the negative electrode active material. Is perfect. Although it does not specifically limit as the heating means 30, For example, heater heating, light heating, induction heating, and other methods can be used.

(Embodiment 3)
A battery using the negative electrode obtained by the method described in each of the above embodiments will be described with reference to the drawings.

  FIG. 3 is a schematic cross-sectional view showing an example of a battery according to the present invention. In FIG. 3, one end of a positive electrode lead 14 made of, for example, aluminum is connected to a current collector of the positive electrode 11 manufactured to a predetermined size. For example, one end of a negative electrode lead 15 made of nickel is connected to the current collector of the negative electrode 12 obtained by the method shown in the first or second embodiment. The electrode plate group 20 can be configured by winding the positive electrode 11 and the negative electrode 12 through a separator 13 wider than both electrode plates. As the separator 13, for example, a polyethylene resin microporous film having a thickness of 20 μm is applicable, but is not limited thereto.

  The obtained electrode plate group 20 is vacuum-dried at 60 ° C. for 10 hours in a dry atmosphere having a dew point temperature of −60 ° C., for example, to drive out moisture contained in the electrode plate group 20. It is preferable to sufficiently dry the separator 13 and other battery members in advance to reduce moisture brought into the battery. An outer surface of the electrode plate group is interposed by a separator 13. The electrode plate group 20 is provided with an upper insulating ring 16 and a lower insulating ring 17 on the upper and lower sides thereof, and is accommodated in an inner space of a battery can 18 made of, for example, iron and nickel-plated on the surface.

The electrode plate group is impregnated with a non-aqueous electrolyte (not shown). The other end of the positive electrode lead 14 is welded to the back surface of a sealing plate 19 having an insulating packing 21 disposed on the periphery. The other end of the negative electrode lead 15 is welded to the inner bottom surface of the battery can 18. By closing the opening of the battery can 18 with the sealing plate 19, a cylindrical lithium ion secondary battery can be produced. As the non-aqueous electrolyte, for example, a non-aqueous electrolyte solution in which LiPF ₆ is dissolved at a concentration of 1 mol / L in a mixed solvent of ethylene carbonate and propylene carbonate in a volume ratio of 1: 1 can be used, but the invention is not limited thereto. It is not a thing.

Examples of the positive electrode active material used for the positive electrode 11 include, but are not limited to, LiCoO ₂ , LiNiO ₂ , LiMn ₂ O ₄ that can occlude and release lithium ions.

  The present invention can be applied to non-aqueous electrolyte secondary batteries having various shapes such as a cylindrical shape, a flat shape, a coin shape, and a square shape, and the shape of the battery is not particularly limited. INDUSTRIAL APPLICABILITY The present invention is applicable to batteries of various sealing forms, including batteries that contain power generation elements such as battery electrodes and electrolytes in metal battery cans and laminated film cases. The form is not particularly limited.

  As described above, according to the present invention, it is theoretically possible to use an active material such as a metal such as Si or Sn, or an oxide or nitride having a large irreversible capacity, although it can absorb or release a large amount of ions. It is said.

  In addition, the manufacturing method of the negative electrode and battery of this invention is not limited to the active material of this invention, It can apply to all the active material materials with a large irreversible capacity | capacitance. Moreover, it can apply to batteries other than a lithium ion secondary battery, and the electrode plate which has the subject accompanying an irreversible reaction.

  The present invention provides an electrode plate and a battery manufacturing method for effectively extracting the energy density of an active material having a large degree of irreversible capacity. The electrode plate obtained by the production method of the present invention is not limited to the battery industry field and can be applied to all electrochemical devices.

The schematic diagram which shows the manufacturing method of the electrode plate in Embodiment 1 of this invention. The schematic diagram which shows the manufacturing method of the electrode plate in Embodiment 2 of this invention. Schematic sectional view showing a battery according to Embodiment 3 of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Exhaust pump 2 Vacuum tank 3 Unwinding roll 4 Battery electrode 5 Conveyance roller 6 1st can 7 2nd can 8 Winding roll 9, 9a Lithium supply source 10 Shielding plate 11 Positive electrode 12 Negative electrode 13 Separator 14 Positive electrode lead 15 Negative electrode lead 16 Upper insulating ring 17 Lower insulating ring 18 Battery can 19 Sealing plate 20 Electrode plate group 21 Insulating packing 30 Heating means 31 Negative electrode active material application source 32 Third can

Claims (6)

From a simple substance of silicon on a current collector, a silicon alloy, a compound containing silicon and oxygen, a compound containing silicon and nitrogen, a simple substance of tin, a tin alloy, a compound containing tin and oxygen, and a compound containing tin and nitrogen A first step of providing a first active material layer containing at least one selected from the group consisting of:
A second step of applying lithium on the first active material layer by a vacuum process;
On the first active material layer provided with lithium, silicon simple substance, silicon alloy, compound containing silicon and oxygen, compound containing silicon and nitrogen, simple substance tin, tin alloy, tin and oxygen are included. And a third step of providing a second active material layer containing at least one selected from the group consisting of a compound and a compound containing tin and nitrogen,
The first quantity of electricity corresponding to the amount of lithium applied in the second step is a sum of the first irreversible capacity of the first active material layer and the second irreversible capacity of the second active material layer. The manufacturing method of the negative electrode for lithium secondary batteries which is 80% or more and 100% or less . Following the third step, further comprising a fourth step of applying lithium,
The manufacturing method of the negative electrode for lithium secondary batteries of Claim 1 characterized by these. The sum of the first electric amount corresponding to the amount of lithium applied in the second step and the second electric amount corresponding to the amount of lithium applied in the fourth step is the first active material layer has. 80% or more and 100% or less of the total of the irreversible capacity and the second irreversible capacity of the second active material layer;
The method for producing a negative electrode for a lithium secondary battery according to claim 2. A lithium secondary battery comprising: a positive electrode capable of inserting and extracting lithium ions; a negative electrode capable of inserting and extracting lithium ions; a separator disposed between the positive electrode and the negative electrode; and an electrolyte having lithium ion conductivity. A method for manufacturing a secondary battery, comprising:
On the current collector of the negative electrode, silicon simple substance, silicon alloy, compound containing silicon and oxygen, compound containing silicon and nitrogen, tin simple substance, tin alloy, compound containing tin and oxygen, and tin and nitrogen A first step of providing a first active material layer containing at least one selected from the group consisting of containing compounds;
A second step of applying lithium on the first active material layer by a vacuum process;
On the first active material layer provided with lithium, silicon simple substance, silicon alloy, compound containing silicon and oxygen, compound containing silicon and nitrogen, simple substance tin, tin alloy, tin and oxygen are included. And a third step of providing a second active material layer containing at least one selected from the group consisting of a compound and a compound containing tin and nitrogen,
The first quantity of electricity corresponding to the amount of lithium applied in the second step is a sum of the first irreversible capacity of the first active material layer and the second irreversible capacity of the second active material layer. , 80% or more and 100% or less of a method for producing a lithium secondary battery. Following the third step, further comprising a fourth step of applying lithium,
The method for producing a lithium secondary battery according to claim 4. The sum of the first electric amount corresponding to the amount of lithium applied in the second step and the second electric amount corresponding to the amount of lithium applied in the fourth step is the first active material layer has. 80% or more and 100% or less of the total of the irreversible capacity and the second irreversible capacity of the second active material layer;
The method for producing a lithium secondary battery according to claim 5.