JP2013225437A - Negative electrode for lithium ion secondary battery and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive negative electrode for a lithium ion secondary battery which has excellent charge/discharge cycle characteristics and can be manufactured by a low cost method, and also to provide a method of manufacturing the same.SOLUTION: A current collection plate is made of metal foil having particulate tin plating on at least one surface. A negative electrode for a lithium ion secondary battery is characterized in that an average diameter in the current collection plate surface direction of the particulate tin plating is 0.5 μm or more and 20 μm or less, a lower part of the particulate tin plating forms an alloy layer with metal constituting a current collection plate, the area coverage ratio of the current collection plate formed by tin plating is 60% or more and 90% or less, the total attached amount of tin plating exceeds 3 g/mand is 20 g/mor less, and the attached mount of alloyed tin is 0.2 g/mor more and 2 g/mor less.

Description

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

  Until now, graphite has been used as a negative electrode active material for lithium ion secondary batteries, but its theoretical capacity density is 372 mAh / g, which is sufficient for the demand for batteries for driving electric vehicles, which have been rapidly increasing in recent years. I can not respond to. Therefore, a high-capacity negative electrode material for secondary batteries exceeding graphite has been demanded, and tin and silicon are cited as promising candidates as negative electrode active materials. Since the maximum capacity density of tin is expected to be 994 mAh / g and the maximum capacity density of silicon is 4200 mAh / g, if these active materials can be put to practical use, the energy density of the lithium ion secondary battery will be significantly higher than conventional ones. It is possible to increase.

  Patent Document 1 discloses a negative electrode in which a smooth tin film having crystal grains of 1 μm or less is laminated on a current collector surface by electroplating with a thickness of 10 μm or more and 300 μm or less. The reason why the crystal grain size of tin is 1 μm or less is for the smoothness, stability, strength, etc. of the film, and the thickness of the tin film is 10 μm or more and 300 μm or less. The effect is small, and conversely, if it exceeds 300 μm, the negative electrode utilization factor (the ratio of the portion that functions as the negative electrode in the tin film) is reduced.

  However, the use of such a smooth tin plating for the negative electrode of a lithium ion secondary battery has the following problems. At the time of charging, lithium ions in the electrolyte are reduced to become metallic lithium, and at that time, alloyed with tin, which is the negative electrode active material, is taken in, so that the volume of tin in the negative electrode expands nearly three times. On the other hand, since lithium ions are eluted from the negative electrode into the electrolyte during discharge, the negative electrode contracts. Therefore, when charging / discharging is repeated, the tin of the negative electrode repeatedly expands and contracts, and it cannot withstand the large volume change, so that the tin becomes fine or coarse or peels from the current collector. The capacity of the lithium ion secondary battery becomes extremely low with the discharge cycle.

  In order to improve the charge / discharge cycle characteristics, fine irregularities are provided on the surface of the negative electrode current collector copper foil, a microcrystalline silicon film is formed on the surface, and it is formed by the first and subsequent charge / discharge in the thickness direction. A technique is disclosed in which a change in volume during charge / discharge is relaxed and absorbed by being separated into a columnar shape by a cut, and the silicon film is prevented from peeling from the copper foil (Patent Document 2). However, in this case, it is not a negative electrode having the characteristics required at the time of production of the lithium ion secondary battery, and the cut formed by the charge and discharge after the first time on the silicon film affects its performance. The problem remains that the product cannot be shipped. Further, the method of forming a silicon thin film on the surface of the copper foil has a problem that it must be a high-cost method such as a CVD method, a sputtering method, a thermal spraying method, or a vacuum deposition method.

  In Patent Document 3, silicon or tin that can be alloyed with Li is applied to the surface of a sheet-like current collector by a screen printing method, an ink jet method, a spray method, a gravure printing method, a thermal transfer method, a relief printing method, an intaglio printing method. In addition, there is disclosed a technique in which dots are dotted in a method such as an offset printing method. According to the ball transfer method, it is possible in principle to directly attach an active material made of a metal such as tin to the surface of the current collector, but it requires a process of manufacturing very fine metal balls in advance. Since the fine metal ball has a large surface area relative to its volume, that is, there are many portions that oxidize in the atmosphere, it is difficult to metal-bond it to the current collector at a practical cost. In other methods such as printing, it is necessary to disperse the active material in an ink-like liquid, and it is not suitable for attaching only an active material made of metal such as tin to the surface of the current collector.

  Patent Document 4 discloses a plated steel plate for a welding can subjected to granular tin plating and a method for manufacturing the same. However, Patent Document 4 differs from the present invention in its purpose, application, and configuration, and does not disclose any information or characteristics necessary for using granular tin plating as a negative electrode of a lithium ion battery.

JP 2001-68094 A JP 2002-83594 A JP 2005-50681 A JP-A-11-131285

  As described above, application of tin, silicon, and the like to the negative electrode active material of the lithium ion secondary battery has been widely studied, but various problems remain in practical use. An object of the present invention is to provide an inexpensive negative electrode for a lithium ion secondary battery that has excellent charge / discharge cycle characteristics and can be manufactured by a low cost method.

  The inventor has intensively studied the above problems, and has constructed a negative electrode for a lithium ion secondary battery excellent in cycle characteristics and a method for producing the same, and has reached the present invention.

That is, the main point of the present invention is that
(1) A current collector plate made of a metal foil having discontinuous granular tin plating on at least one surface, wherein the average diameter of the granular tin plating in the current collector plate surface direction is 0.5 μm or more and 20 μm or less, and The lower part of the granular tin plating forms an alloy layer with the metal constituting the current collector plate, the coverage area ratio of the current collector plate by the granular tin plating is 60% or more and 90% or less, The total adhesion amount of granular tin plating exceeds 3 g / m ² and is 20 g / m ² or less, and the adhesion amount of alloyed tin is 0.2 g / m ² or more and 2 g / m ² or less. Negative electrode for lithium ion secondary battery,
(2) It is a current collector plate made of a metal foil having discontinuous granular tin plating on at least one surface, and the average diameter in the current collector plate surface direction of the granular tin plating is 0.5 μm or more and 20 μm or less, and The lower part of the granular tin plating forms an alloy layer with the metal constituting the current collector plate, and the coverage area ratio of the current collector plate by the granular tin plating is 60% or more and 90% or less. A negative electrode for a lithium ion secondary battery having an adhesion amount exceeding 3 g / m ² and 20 g / m ² or less, of which the adhesion amount of alloyed tin is 0.2 g / m ² or more and 2 g / m ² or less is manufactured. A method comprising: at least one surface of a current collector plate made of metal foil containing 0.1 to 0.6 mol / L of an acid component and 0.1 to 0.7 mol / L of a tin (II) ion; Using a plating bath consisting of an acidic aqueous solution that does not contain any organic additives, After applying granular tin plating by cathodic electrolysis at a current density of 5 to 60 A / dm ^2, anode method of manufacturing a lithium ion secondary battery, characterized by performing heat treatment temperature reached 180 ° C. to 240 ° C.,
(3) The method for producing a negative electrode for a lithium ion secondary battery according to (2), wherein the plating bath contains an antioxidant,
It is.

  According to the present invention, an inexpensive negative electrode for a lithium ion secondary battery that has excellent charge / discharge cycle characteristics and can be manufactured by a low cost method can be provided.

The present invention is described in detail below.
The current collector plate made of the metal foil used in the present invention is suitably a copper plate, a copper alloy plate, or a steel plate that can be easily tin-plated and easily alloyed with tin by heat treatment. Although the thickness is not limited, the thickness of a practical current collector plate substrate is about 15 μm.

  The negative electrode for a lithium ion secondary battery of the present invention is a current collecting plate made of a metal foil having discontinuous granular tin plating on at least one surface, and the average diameter of the granular tin plating in the current collecting plate surface direction is 0.00. It is 5 micrometers or more and 20 micrometers or less, and the granular tin plating lower part forms the alloy layer with the metal which comprises a current collecting plate, It is the characteristics.

  Since tin is a negative electrode active material, the granular tin-plated surface should be on the electrolyte solution and separator side when incorporated into the battery. Tin plating is not necessary on the opposite surface, but granular or smooth tin plating may be adhered by the back of the electroplating process.

  Since the granular tin plating can be manufactured by electroplating as described later, it is suitable for mass production, and the manufacturing cost can be kept low. The difference in performance from normal smooth tin plating is as follows.

  When smooth tin plating is used as a negative electrode active material of a lithium ion secondary battery, most of the peeling occurs from the current collector plate only by repeating deep charge / discharge several times. Tin, the negative electrode active material, is alloyed with up to 4.4 atoms of lithium per atom during charging and expands about 3 times in volume. When discharging, lithium is released and contracts, but expands in the plane direction of the current collector plate. Since there is no space to do so, it expands in the height direction while deforming greatly, so it is thought that the distortion increases.

  On the other hand, when granular tin plating is used for the negative electrode, there is also a space that is alloyed with lithium at the time of charging and expands in volume, so that in the planar direction of the current collector plate, initial charge and discharge several times like smooth plating Hard to peel. However, since granular tin plating has a small contact area with the base metal, adhesion is difficult, and repeated volume changes due to charging / discharging cause the granular tin plating to peel off gradually, reducing the charge / discharge capacity. come.

  The granular tin plating of the negative electrode for a lithium ion secondary battery of the present invention has dramatically improved adhesion because the lower part (contact part with the current collector plate) forms an alloy layer with the metal constituting the current collector plate. It is difficult to peel off even if the charge / discharge cycle is repeated. The alloy layer under the granular tin plating is strongly bonded to both the tin plating and the current collector plate base, so that adhesion is ensured. When there is no alloy layer, the adhesion is not sufficient.

  The average diameter of the granular tin plating in the direction of the current collector plate is 0.5 μm or more and 20 μm or less. When the thickness is less than 0.5 μm, it is difficult to ensure the charge / discharge capacity per unit area of the current collector plate. This is considered to be because the area of the portion not covered with granular tin becomes relatively large. On the other hand, when the thickness exceeds 20 μm, the volume expansion is large and easily collapses particularly when the lithium is taken in and alloyed during charging. A more preferable average diameter is 0.5 μm or more and 10 μm or less. This is because, as described above, the larger the grain, the greater the distortion caused by the outer volume change.

  Here, the average diameter is a length obtained as follows. The distribution of tin on the surface of the current collector plate subjected to granular tin plating is taken into a computer as an image using an electron beam microanalyzer (EPMA), and an average diameter is calculated by image processing. For example, a stable value can be obtained by taking five visual fields in the field of view of 60 μm × 80 μm and further averaging the five average diameters calculated for each visual field.

  The current collector plate covering area ratio of the granular tin plating is 60% or more and 90% or less. If it is less than 60%, the amount of the active material per unit area of the current collector plate is too small, and a sufficient charge / discharge capacity cannot be obtained. On the other hand, if it exceeds 90%, when lithium is alloyed and expands during charging, it contacts with the adjacent granular tin plating and expands in the vertical direction of the current collector plate. turn into. Moreover, adjacent granular tin plating fuse | melts and coarsens, and it becomes easy to collapse | disintegrate by a subsequent charging / discharging cycle.

  The collector plate coverage area ratio of the granular tin plating is more preferably 60% or more and 80% or less. If the amount of tin adhesion is about the same, more excellent charge / discharge cycle characteristics can be obtained when the covering area ratio is 80% or less. As described above, tin is alloyed with lithium during charging, and the volume expands up to about 3 times. In terms of calculation, the expansion of the area is about twice, so that the coverage of tin is preferably 50% or less, but actually, good charge / discharge cycle characteristics can be obtained with the above-mentioned coverage area. Here, the covering area ratio of tin plating refers to the area ratio of tin occupying the current collector plate surface, which is obtained as follows. Similar to the average diameter, the distribution of tin on the surface of the current collector plate coated with granular tin is taken into a computer as an image using an electron beam microanalyzer (EPMA), and the area ratio occupied by tin is calculated by image processing and covered. Considered area ratio. For example, a stable value can be obtained by further averaging five area ratios calculated for each field by taking five fields of view in the range of 60 μm × 80 μm.

The total adhesion amount of the granular tin plating exceeds 3 g / m ² and is 20 g / m ² or less, of which the adhesion amount of alloyed tin is 0.2 g / m ² or more and 2 g / m ² or less. If the total tin adhesion amount is 3 g / m ² or less, the amount of the active material per unit area of the current collector plate is too small, and a sufficient charge / discharge capacity cannot be obtained. On the other hand, when the adhesion amount exceeds 20 g / m ² , the granular tin plating easily collapses due to the volume change accompanying charging / discharging. The more preferable amount of granular tin plating is 5 g / m ² or more and 20 g / m ² or less. Within this range, a more preferable charge / discharge capacity per unit area of the current collector plate can be obtained. If the adhesion amount of alloyed tin is less than 0.2 g / m ² , the effect of increasing the adhesion between the current collector plate base material and the granular tin plating is insufficient. On the other hand, if it exceeds ² g / m ² , the properties of the alloy layer which are hard and easy to break will appear, and the adhesion will deteriorate. The adhesion amount of alloyed tin is preferably 0.4 g / m ² or more and 0.7 g / m ² or less. Within this range, improved adhesion between the current collector base material and the granular tin plating can be obtained.

  The amount of tin deposited can be determined as follows. The total tin adhesion amount is calculated by measuring the fluorescent X-ray intensity of tin on the surface of the current collector plate and using a previously prepared tin calibration curve. The amount of tin alloy is Fluorescent X of alloy tin remaining in the negative electrode current collector plate after anodic constant potential electrolysis of the negative electrode current collector plate by applying 0.4 V with SUS304 as the cathode in 5% sodium hydroxide solution. The line intensity is measured and calculated using a calibration curve prepared in advance.

Next, the manufacturing method of a granular tin plating negative electrode is explained in full detail.
At least one surface of a current collector plate made of metal foil is subjected to granular tin plating by electroplating using a plating bath made of an acidic aqueous solution containing tin (II). The plating bath comprising the acidic aqueous solution contains an acid component in an amount of 0.1 to 0.6 mol / L, tin (II) ions in an amount of 0.1 to 0.7 mol / L, and does not contain an organic additive having a leveling action. It is.

  The bath temperature is preferably in the range of 35 to 60 ° C. because it is easy to operate and a good granular tin-plated negative electrode is obtained. As the acid component, phenolsulfonic acid, methanesulfonic acid, and sulfuric acid are preferable in terms of cost and ease of handling. Further, by using these acid components, good plating can be obtained with relatively high cathode current efficiency. If the concentration of the acid component is less than 0.1 mol / L, it is better to avoid tin (II) ions in the plating bath as hydroxides and precipitate easily. On the other hand, if it exceeds 0.6 mol / L, the rate at which hydrogen ions are reduced on the surface of the current collector plate, which is the cathode during electrolysis, and hydrogen gas is generated becomes high, and the current efficiency of plating becomes low. It is disadvantageous. A more preferable acid component concentration is 0.3 to 0.6 mol / L.

  The tin (II) ion concentration is 0.1 to 0.7 mol / L. When it is lower than 0.1 mol / L, tin (II) ions are insufficient in the vicinity of the surface of the current collector plate that is a cathode during electrolysis, and so-called plating burn is likely to occur. On the other hand, even if it becomes higher than 0.7 mol / L, there is no improvement in the performance of the obtained plating, and the amount of tin (II) ions that are brought out by adhering to the current collector plate is increased, which is economically disadvantageous. . A more preferable tin (II) ion concentration is 0.2 to 0.6 mol / L.

  It is preferable that the plating bath does not substantially contain an organic additive having a leveling action (also referred to as “smoothing agent”). The leveling action is an action of smoothing the deposited metal. When an organic additive having this action is contained in the plating bath, the tin plating is smoothed and hardly forms a granular plating.

  The plating bath may contain an antioxidant. The purpose of the addition of the antioxidant is to suppress the oxidation activity of dissolved oxygen in the plating bath and prevent the tin (II) ions from being oxidized and precipitated as tin (IV) oxide or hydroxide. . Preferred antioxidants are organic compounds having two or more phenolic hydroxy groups, and their positional relationship is o-position or p-position, for example, hydroquinone, catechol, gallic acid, n-propyl gallate, pyrogallol Etc.

The current collector plate is immersed in the plating bath and subjected to cathodic electrolysis at a cathode current density of 5 to 60 A / dm ² , thereby applying granular tin plating to at least one surface of the current collector plate. If it is less than 5 A / dm ² , plating nucleation is small, and a small number of grains grow large, so that the coverage area ratio with tin becomes small. On the other hand, electrolysis exceeding 60 A / dm ² produces many plating nuclei, resulting in very small granular tin, so that it is difficult to obtain a granular tin plating adhesion amount sufficient to ensure a sufficient charge / discharge capacity. A more preferable cathode current density is 20 to 60 A / dm ² .
The electrolysis time is not particularly limited, but is preferably 0.8 seconds to 100 seconds in order to obtain an appropriate amount of tin plating.

After performing granular tin plating by the electroplating method, the current collector plate is subjected to a heat treatment at an ultimate temperature of 180 ° C. to 240 ° C. Thereby, the lower part of the granular tin is alloyed with a part of the current collector plate base material, and the adhesion of the granular tin is improved. When the ultimate temperature is less than 180 ° C., alloying does not progress much. On the other hand, when the ultimate temperature exceeds 240 ° C., the melting point of tin is 232 ° C., so that the melting proceeds, the amount of alloy tin is excessively increased, and the shape of the granular tin is easily broken. A more preferable reached temperature is 200 ° C to 230 ° C.
The heating time is not particularly limited, but in order to obtain an appropriate amount of alloy, it is preferable that the time of 180 ° C. or higher is 0.2 seconds or longer and the time of 200 ° C. or higher is 200 seconds or shorter.

  Hereinafter, the present invention will be described in more detail by way of examples.

  A steel foil having a thickness of 15 μm was used as a current collector plate. As a pretreatment for plating, electrolytic degreasing was carried out in a 10 mass% sodium hydroxide solution, followed by pickling with 5 mass% dilute sulfuric acid.

  Next, granular tin plating was performed on one surface of the current collector plate by an electroplating method using a plating bath made of an acidic aqueous solution. A platinum-plated titanium plate was used as the plating anode. The tin plating bath contained tin (II), and a phenolsulfonic acid bath, a methanesulfonic acid bath, or a sulfuric acid bath was used. The concentration of tin (II) was 40 g / L (0.34 mol / L). The acid component was 0.5 mol / L. To prevent oxidation of tin (II) ions, 1 g / L of hydroquinone was added to the methanesulfonic acid bath and the sulfuric acid bath. The plating bath temperature was 45 ° C. for all.

The electrolysis conditions in plating were a current density of 5 to 60 A / dm ² and an electrolysis time of 2.5 to 30 seconds.

  The current collector plate made of the metal foil thus subjected to granular plating was punched out to 14 mmφ, and this was used as the negative electrode.

  For comparison, a negative electrode plated with conditions outside the above range was also produced.

  The total tin adhesion amount was calculated by measuring the fluorescent X-ray intensity of tin on the surface of the current collector plate and using a previously prepared tin calibration curve. The amount of tin alloy is Fluorescent X of alloy tin remaining in the negative electrode current collector plate after anodic constant potential electrolysis of the negative electrode current collector plate by applying 0.4 V with SUS304 as the cathode in 5% sodium hydroxide solution. The line intensity was measured and calculated using a calibration curve prepared in advance.

  The distribution image of tin on the surface of the current collector plate by an electron beam microanalyzer (EPMA) was captured in a computer with five fields of view with a field of 60 μm × 80 μm, and the five average diameters and the coating area ratio of the granular plating obtained for each field by image processing Were further averaged to calculate the average diameter and coverage area ratio of the granular tin plating.

The negative electrode produced as described above was evaluated in a two-electrode cell using metallic lithium as a counter electrode. As the electrolytic solution, a solution obtained by dissolving LiPF _{6 in an amount} of 1.0 mol / L in a solvent obtained by mixing ethylene carbonate and diethyl carbonate at 50:50 vol% was used. As the separator, a polyolefin microporous film having a thickness of 25 μm was used.

These were assembled in a coin-shaped battery can, and a charge / discharge test was conducted using a continuous charge / discharge device in a constant temperature room at 25 ° C. The charge / discharge current density was 0.5 mA / cm ² and 5 mA / cm ^2, and after charging to 0 V (vs Li ⁺ / Li), the battery was discharged to 1.5 V (vs Li ⁺ / Li). Repeated.

The discharge capacity per unit area of the current collector plate in 50 charge / discharge cycles at a current density of 0.5 mA / cm ² is 0.20 mAh / cm ² or more, and less than 0.20 mAh / cm ² is ×, The overall evaluation D (failed) regardless of other evaluation results.

When the current density is 0.5 mA / cm ² , the discharge capacity is 600 mAh / g (Sn) at 50 cycles and the discharge capacity is 90% or more of the discharge capacity at the first cycle, and the discharge capacity is 500 mAh / g (Sn). A discharge capacity of 80% or more of the discharge capacity of the first cycle is maintained, and a case where the above does not apply to ◯, ○, a discharge capacity of 450 mAh / g (Sn) or more and a discharge capacity of 70% or more of the discharge capacity of the first cycle The case where the capacity was maintained and the case where the above-mentioned ◎ and ○ were not satisfied was Δ, and the case where the discharge capacity was less than 450 mAh / g (Sn) or less than 70% of the discharge capacity at the first cycle was rated as x.

When the current density is 5 mA / cm ² , the discharge capacity of 500 mAh / g (Sn) in 30 cycles and the discharge capacity of 80% or more of the discharge capacity in the first cycle are maintained as ◎, and the discharge capacity is 400 mAh / g (Sn) or more. A discharge capacity of 70% or more of the discharge capacity of the first cycle is maintained, a case where the above is not true, ○, a discharge capacity of 350 mAh / g (Sn) or more and a discharge capacity of 60% or more of the discharge capacity of the first cycle In the case where the discharge capacity was not maintained as 、 or ◯, the case where the discharge capacity was less than 350 mAh / g (Sn) or less than 60% of the discharge capacity at the first cycle was evaluated as x.

From these results, comprehensive evaluation was determined according to the following criteria. Among the discharge capacity per unit area of the current collector plate at 50 cycles of charge and discharge cycles at a current density of 0.5 mA / cm ² those evaluation of ○, both current density 0.5 mA / cm ² and 5 mA / cm ² In the charge / discharge test of ◎, A is evaluated as A (excellent), one is ◎ or ○ and the other is ○ B (good), one is ◎ or ○ and the other is C (good), both △ or at least one of × is D (poor), A, B and C are acceptable levels, and D is an unacceptable level.

  Table 1 shows detailed negative electrode preparation conditions, and Table 2 shows charge / discharge cycle evaluation results.

  In each of Examples 1 to 82 of the present invention, the overall evaluation was A to C, which was an acceptable level.

  Comparative Example 1 is an example in which the tin plating was smooth, not granular, and the coverage area ratio was high as a result of adding a smoothing agent to the tin plating bath and plating. The decay of tin plating occurred due to the charge / discharge cycle, and the capacity retention rate was low.

  Comparative Example 2 is an example in which the current density of the granular tin plating is high, the granular tin plating is fine, the size in the surface direction of the current collector plate, and the tin plating coverage is small. The discharge capacity per unit area was small.

  Comparative Example 3 is an example in which the size in the surface direction of the current collector plate was large as a result of electrolysis at a low current density for a long time and granular tin plating. The decay of tin plating occurred due to the charge / discharge cycle, and the capacity retention rate was low.

  Comparative Example 4 is an example in which the electrolytic time of granular tin plating was short and the amount of tin adhesion was small. The amount of active material per unit area of the current collector plate was small, and the charge / discharge capacity per unit area was insufficient.

  Comparative Example 5 is an example in which the electrolytic time of granular tin plating was long and the amount of tin deposited was large. The decay of tin plating occurred due to the charge / discharge cycle, and the capacity retention rate was low.

  Comparative Example 6 is an example in which no heat treatment was performed after granular tin plating. The alloy layer was hardly formed, and the tin plating collapsed by the charge / discharge cycle, and the capacity retention rate was low.

  Comparative Example 7 is an example in which the temperature reached by heating after the granular tin plating was low. The amount of the alloy layer was small, the tin plating collapsed by the charge / discharge cycle, and the capacity retention rate was low.

  Comparative Example 8 is an example in which the temperature reached by heating after the granular tin plating was high. The amount of the alloy layer was large, the tin plating collapsed by the charge / discharge cycle, and the capacity retention rate was low.

Claims (3)

A current collector plate made of a metal foil having discontinuous granular tin plating on at least one side,
The average diameter in the direction of the current collector plate of the granular tin plating is 0.5 μm or more and 20 μm or less, and the lower part of the granular tin plating forms an alloy layer with the metal constituting the current collector plate;
The coverage area ratio of the current collector plate by the granular tin plating is 60% or more and 90% or less,
The total adhesion amount of the granular tin plating is more than 3 g / m ² and not more than 20 g / m ² , and the adhesion amount of alloyed tin is not less than 0.2 g / m ^{2 and not} more than 2 g / m ^2. A negative electrode for a lithium ion secondary battery. It is a current collector plate made of a metal foil having discontinuous granular tin plating on at least one surface, the average diameter of the granular tin plating in the current collector plate surface direction is 0.5 μm or more and 20 μm or less, and granular tin plating The lower part forms an alloy layer with the metal constituting the current collector plate, the coverage area ratio of the current collector plate by the granular tin plating is 60% or more and 90% or less, and the total amount of the granular tin plating is It is a method for producing a negative electrode for a lithium ion secondary battery that exceeds 3 g / m ² and is 20 g / m ² or less, of which the adhesion amount of alloyed tin is 0.2 g / m ² or more and 2 g / m ² or less. In addition, at least one surface of a current collector plate made of metal foil contains 0.1 to 0.6 mol / L of an acid component and 0.1 to 0.7 mol / L of tin (II) ions, and an organic additive having a leveling action Cathode current using a plating bath consisting of an acidic aqueous solution containing no agent After applying granular tin plating by cathodic electrolysis in degrees 5 to 60 A / dm ^2, method for producing a negative electrode for a lithium ion secondary battery, characterized by performing heat treatment temperature reached 180 ° C. to 240 ° C..   The method for producing a negative electrode for a lithium ion secondary battery according to claim 2, wherein the plating bath contains an antioxidant.