JP5718734B2 - Secondary battery electrode material and manufacturing method thereof - Google Patents

Description

  The present invention relates to an electrode material for a secondary battery and a method for manufacturing the same, and more particularly to an electrode material used for a secondary battery such as a lithium ion secondary battery and a method for manufacturing the same.

  A lithium ion secondary battery is a type of non-aqueous electrolyte secondary battery that uses lithium, a lithium alloy, or a material capable of occluding lithium as a negative electrode active material, and has a high voltage, light weight, and high energy density. It is used as a secondary battery for information devices such as mobile phones. In recent years, demand for lithium ion secondary batteries has increased as secondary batteries for large power vehicles such as secondary batteries for hybrid vehicles. In order to further reduce the size and weight, the energy density of lithium ion secondary batteries has increased. Various studies have been conducted on improvement (high capacity).

  Conventionally, as a negative electrode material of a lithium ion secondary battery, a carbonaceous material such as non-graphitizable carbon or graphite having a relatively high capacity and good charge / discharge cycle characteristics has been widely used. There is a problem of further increasing the capacity of the negative electrode material of the battery.

  However, it is known that even if the capacity of the negative electrode material is increased in order to increase the capacity of the lithium ion secondary battery, the graphite-based carbonaceous material has a theoretical limit of a discharge capacity of 372 mAh / g. Approaching the limit. On the other hand, the non-graphite-based carbonaceous material has a drawback that although the discharge capacity is large, the irreversible capacity is large and a large loss occurs at the stage of battery design.

  In addition, a large-capacity negative electrode material that can be used as a substitute for a carbonaceous material has also been proposed, and as a negative electrode material that can have a higher capacity than a carbonaceous material, a certain metal is electrochemically alloyed with lithium and reversibly formed. The use of materials that generate and decompose has been studied. For example, although negative electrode materials such as Li—Al alloys and Si alloys have been reported, these alloys expand and contract with charge / discharge, and thus have a problem that charge / discharge cycle characteristics are extremely poor.

  In order to solve this problem, a method of obtaining a negative electrode material in which Sn is combined with various elements such as Co, Fe, Ni, V, Cu, and Cr has been proposed. For example, by mixing a Sn compound, a transition metal compound, a mixed solution containing a complexing agent and a reducing agent, and then oxidizing the reducing agent to synthesize an Sn alloy, Sn alloy powder can be used as a negative electrode material for a secondary battery. A method of obtaining (for example, refer to Patent Document 1), rapid solidification such as strip casting method (roll quench method), gas atomization method, water atomization method, rotating electrode method, etc. A method of obtaining a negative electrode material powder by pulverizing a material treated by the method as necessary (see, for example, Patent Document 2), a mixed powder of Sn powder and Co powder was treated in a ball mill for 25 hours or more in argon gas A method for obtaining an alloyed metal material of 75 μm or less by classification (for example, see Patent Document 3), adding a metal raw material containing Sn. The molten metal obtained by melting is heat treated as a flake by the melt spinning method and then pulverized by a cup mill to obtain a powder having an average particle size of 15 μm (see, for example, Patent Document 4). There has been proposed a method for obtaining a powder having an average particle size of 0.5 to 2.3 μm by treating with a pot mill for 1 week in a gas (see, for example, Patent Document 5).

JP 2001-332254 A (paragraph numbers 0013 and 0017) JP 2006-236835 A (paragraph numbers 0010 and 0035) JP 2001-143761 A (paragraph number 0044) JP 2004-111202 A (paragraph number 0050) JP 2010-161078 A (paragraph number 0029)

  However, in the method of Patent Document 1, it is necessary to provide many tanks for the reaction, and it is necessary to carry out the reaction in an inert gas atmosphere in the tanks. Further, since a complexing agent and a reducing agent are required in addition to the metal raw material, there is a problem that the manufacturing cost is increased and the productivity is poor. In the methods of Patent Documents 2 and 4, it is necessary to suppress oxidation by performing each process from melting metal to obtaining a powder in an inert gas atmosphere. Atomizing equipment is required, and there is a problem that equipment costs increase. Further, the methods of Patent Documents 3 and 5 have a problem that the processing time becomes long and the productivity is poor because the alloy is mechanically alloyed using a mill.

  Moreover, since the specific surface area of the electrode material for a secondary battery increases as the average particle size decreases, and the efficiency of the battery reaction can be improved, a secondary battery electrode material with a small average particle size is desired. ing.

  Accordingly, in view of such conventional problems, the present invention provides a secondary battery electrode material having a high capacity, good charge / discharge cycle characteristics and a small average particle size, and the secondary battery electrode at low cost. It aims at providing the method which can be manufactured with high productivity.

  As a result of diligent research to solve the above-mentioned problems, the inventors of the present invention mixed a solution in which Sn and transition metal are dissolved with an alkali solution to produce hydroxide particles of Sn and transition metal. After drying the hydroxide particles, they are heated in a reducing gas atmosphere to produce a secondary battery electrode material with high capacity, good charge / discharge cycle characteristics and a small average particle size at low cost and high production. The present invention has been completed.

  That is, in the method for producing an electrode material for a secondary battery according to the present invention, a solution in which Sn and transition metal are dissolved and an alkali solution are mixed to produce hydroxide particles of Sn and transition metal, and water obtained The oxide particles are dried and then heated in a reducing gas atmosphere.

  In this method of manufacturing a secondary battery electrode material, the solution in which Sn and the transition metal are dissolved is at least one selected from the group consisting of Sn salt and Co, Ni, Fe, Cu, Cr, In, Ag, and Ti. A solution prepared by dissolving a salt of a transition metal or more in a solvent is preferable. Moreover, it is preferable that the temperature of a heating is 210-600 degreeC.

  The electrode material for a secondary battery according to the present invention is a metal powder of Sn and at least one transition metal element selected from the group consisting of Co, Ni, Fe, Cu, Cr, In, Ag and Ti. The average particle size is 10 to 500 nm.

  In this secondary battery electrode material, the metal powder is SnAx (A is at least one transition metal element selected from the group consisting of Co, Ni, Fe, Cu, Cr, In, Ag and Ti, x is preferably an Sn alloy powder having a composition of 0.2 to 3.0). Moreover, it is preferable that the crystallite diameter of the electrode material for secondary batteries is 50 nm or less, and it is preferable that oxygen concentration is 0.6 mass% or less. The average particle diameter of the secondary battery electrode material is preferably 300 nm or less, more preferably 200 nm or less, and most preferably less than 100 nm.

  According to the present invention, an electrode material for a secondary battery having a high capacity, good charge / discharge cycle characteristics and a small average particle size can be produced at low cost and high productivity.

It is a figure which shows the X-ray-diffraction pattern of the CoSn alloy powder obtained by the Example and the comparative example.

  In the embodiment of the method for producing a secondary battery electrode material according to the present invention, a solution in which Sn and transition metal are dissolved and an alkali solution are mixed to produce hydroxide particles of Sn and transition metal. After drying the hydroxide particles, they are heated in a reducing gas atmosphere.

  The solution in which Sn and transition metal are dissolved dissolves Sn salt and at least one transition metal salt selected from the group consisting of Co, Ni, Fe, Cu, Cr, In, Ag and Ti in a solvent. To obtain. The ratio between the amount of Sn salt and the amount of transition metal salt may be adjusted according to the composition of the Sn alloy powder to be produced. It is preferable to use water as the solvent in consideration of cost and environment. The total metal concentration of Sn and transition metal in the solution is preferably 0.01 to 10 mol / L. When the metal concentration exceeds 10 mol / L, the productivity is excellent, but the alloy concentration is too high, and there is a risk that it is difficult to form a fine precursor, and the metal concentration is 0.01 mol / L. When it is less than L, the productivity is deteriorated.

  The alkaline solution can be obtained by dissolving an alkali hydroxide such as NaOH or KOH, a carbonate such as sodium carbonate, ammonia or the like in a solvent. It is preferable to use water as the solvent in consideration of cost and environment.

  By mixing a solution in which Sn and transition metal are dissolved and an alkali solution, a slurry containing Sn and transition metal hydroxide particles is obtained. The temperature of the solution immediately after mixing is preferably 10 to 60 ° C. If the temperature of the solution immediately after mixing exceeds 60 ° C., the particle diameter of the precursor becomes too large, and there may be a problem that the alloy particles and crystallite diameter after reduction also increase. Moreover, when the temperature of the solution immediately after mixing is lower than 10 ° C., a cooling device for controlling the reaction temperature is required, which is not preferable from the viewpoint of productivity. Moreover, it is preferable to stir the solution during and after mixing.

  A slurry of Sn and transition metal hydroxide can be obtained by solid-liquid separation of the slurry containing Sn and transition metal hydroxide particles thus obtained. This solid-liquid separation can be performed by a known method such as filtration using a Buchner funnel or centrifugal separation. The obtained cake may be washed with pure water or the like. Thereafter, the cake is dried to obtain a powder of Sn and transition metal hydroxide. This drying can be performed by a known method such as heat drying or vacuum drying.

  The Sn alloy powder can be obtained by heating the thus obtained powder of Sn and transition metal hydroxide in a reducing gas atmosphere. As the reducing gas, hydrogen, a mixed gas of nitrogen and hydrogen, carbon monoxide, or the like can be used. In particular, it is preferable to use hydrogen gas in consideration of reducing power and safety.

  The heating temperature is preferably 210 to 600 ° C. If the heating temperature is lower than 210 ° C., the hydroxide powder may not be sufficiently reduced. If the heating temperature exceeds 600 ° C., particle growth proceeds and the particle size and crystallite size increase. May decrease. In order to obtain an Sn alloy powder having a small average particle size, the heating temperature is preferably 210 to 500 ° C, more preferably 250 to 300 ° C. The heating time is preferably 0.5 hours or longer. If the heating time is shorter than 0.5 hour, the target product phase may not be obtained without sufficient reduction.

  At least one or more transition metal elements selected from the group consisting of Sn and Co, Ni, Fe, Cu, Cr, In, Ag, and Ti according to the embodiment of the method for manufacturing the electrode material for a secondary battery described above. A secondary battery electrode material (negative electrode material) having an average particle diameter of 10 to 500 nm, a crystallite diameter of 50 nm or less, and an oxygen concentration of 0.6% by mass or less.

  The secondary battery electrode material (negative electrode material) is selected from the group consisting of Sn, which is an element alloyed with Li, and Co, Ni, Fe, Cu, Cr, In, Ag, and Ti, which are difficult to alloy with Li. It consists of a metal powder with at least one transition metal element. In a secondary battery using only Sn, which is an element alloyed with Li, as a metal element constituting the negative electrode material, a large volume change is caused when Sn is alloyed with Li, so that charge / discharge cycle characteristics are poor. There is a problem, but in a secondary battery using a negative electrode material containing a metal material in which a transition metal element difficult to alloy with Li coexists with Sn, volume change as the negative electrode material is suppressed, and charge / discharge cycle characteristics are reduced. Deterioration can be prevented.

  The metal powder of Sn and the transition metal element is SnAx (A is at least one transition metal element selected from the group consisting of Co, Ni, Fe, Cu, Cr, In, Ag and Ti, and x is A Sn alloy powder having a composition of 0.2 to 3.0) is preferred. If the Sn alloy powder x is less than 0.2, the Sn ratio is too large, and the volume change of the negative electrode material during charging / discharging cannot be sufficiently suppressed. As a result, the charge / discharge cycle characteristics of the battery used may deteriorate. On the other hand, when x exceeds 3.0, the ratio of Sn is too small, and the capacity of a battery using the Sn alloy powder as a negative electrode material may be small. In addition, it is more preferable that x is 0.5 to 1.5.

  In the Sn alloy powder, the transition metal element preferably contains Co. By including Co, it is possible to obtain a negative electrode material of a metal element which is difficult to be alloyed with Li and has high conductivity. The Sn alloy powder mainly includes an alloy phase, but may include a plurality of types of alloy phases and may include Sn and a transition metal in a single phase.

  The average particle size of the metal powder (preferably Sn alloy powder) of Sn and the transition metal element is preferably 10 to 500 nm or less. When the average particle size exceeds 500 nm, the efficiency of the battery reaction may be lowered when Sn alloy powder is used as the negative electrode material. On the other hand, when the average particle size is smaller than 10 nm, there is a risk that problems such as inconvenience in handling and occurrence of side reaction with the electrolyte may occur. Considering the efficiency of the battery reaction when the metal powder is used as the negative electrode material, the average particle size is preferably 300 nm or less, more preferably 200 nm or less, and most preferably 100 nm or less.

  The crystallite diameter of the metal powder (preferably Sn alloy powder) of Sn and the transition metal element is preferably 50 nm or less. The smaller the crystallite diameter, the better. On the other hand, when the crystallite diameter exceeds 50 nm, the volume change of the negative electrode material during charge / discharge cannot be sufficiently suppressed, and the charge / discharge cycle characteristics of the battery using the metal powder as the negative electrode material deteriorate. There is.

  The oxygen concentration (oxygen content) of the metal powder (preferably Sn alloy powder) of Sn and the transition metal element is preferably 0.6% by mass or less. When this oxygen concentration is high, when a lithium ion secondary battery is manufactured using the metal powder as a negative electrode material, there is a risk that problems such as an increase in irreversible capacity during the initial charge of the battery may occur.

  The negative electrode for lithium ion secondary batteries can be manufactured by a well-known method using the metal powder mentioned above. For example, an appropriate binder is mixed with the above-described metal powder, and an appropriate conductive powder is mixed as necessary to improve conductivity. A solvent in which the binder is dissolved is added to this mixture, and if necessary, the mixture is sufficiently stirred with a known stirrer to form a slurry. The slurry is applied to an electrode substrate (current collector) such as a rolled copper foil with a doctor blade or the like, dried, and then consolidated by roll rolling or the like to produce a negative electrode for a non-aqueous electrolyte secondary battery.

  Although it is preferable to produce a lithium ion secondary battery using the negative electrode thus produced, other nonaqueous electrolyte secondary batteries can also be produced. The lithium ion secondary battery includes a negative electrode, a positive electrode, a separator, and a non-aqueous electrolyte as a basic structure, but uses a negative electrode manufactured as described above and a known positive electrode, separator, and electrolyte. A lithium ion secondary battery can be manufactured.

  Examples of the secondary battery electrode material and the method for manufacturing the same according to the present invention will be described below in detail.

[Example 1]
An aqueous solution containing Co and Sn by dissolving 17.57 g of cobalt sulfate heptahydrate (CoSO ₄ .7H ₂ O) and 14.10 g of tin (II) chloride (SnCl ₂ .2H ₂ O) in 400 g of pure water. Produced. Moreover, 20.6 g of 48.5 mass% sodium hydroxide aqueous solution was added to 200 g of pure water, and sodium hydroxide aqueous solution was produced. The aqueous sodium hydroxide solution is heated to 40 ° C. and stirred, and the aqueous solution containing Co and Sn is heated to 40 ° C. and added to the aqueous sodium hydroxide solution to obtain a hydroxide of Co and Sn. A slurry containing was obtained. The slurry was filtered and washed with pure water to obtain a Co and Sn hydroxide cake. The Co and Sn hydroxide cake was dried in the atmosphere at 140 ° C. for 3 hours and then reduced in a hydrogen atmosphere at 300 ° C. for 3 hours to obtain a CoSn alloy powder.

  About the obtained CoSn alloy powder, the range of 20 to 70 ° / 2θ was measured with a Cu radiation source (40 kV / 30 mA) using an X-ray diffractometer (XRD-6100 manufactured by Shimadzu Corporation), and X-ray diffraction (XRD) Was evaluated. An X-ray diffraction pattern of the CoSn alloy powder obtained in this example is shown in FIG. From this X-ray diffraction pattern, it was confirmed that the CoSn alloy powder obtained in this example was a single phase of CoSn.

  Further, by using the half width β of the (2, 0, 1) plane of the CoSn phase obtained from the X-ray diffraction pattern, the crystallite diameter is calculated from Scherrer's equation D = (K · λ) / (β · cos θ). When (Dx) was calculated, the crystallite diameter (Dx) was 24.1 nm. In the Scherrer equation, D is the crystallite diameter (nm), λ is the measured X-ray wavelength (nm), β is the diffraction width spread by the crystallite, θ is the Bragg angle of the diffraction angle, and K is the Scherrer constant. In this equation, the measurement X-ray wavelength λ is 1.54 nm, and the Scherrer constant K is 0.9.

  Further, the major axis diameter of each of the 50 CoSn particles was measured from a 50,000 times scanning electron micrograph (SEM image) of the CoSn alloy powder obtained in this example, and the average value was calculated as the average of the CoSn alloy powder. The particle size was taken. As a result, the average particle size of the obtained CoSn alloy powder was 116.9 nm. The “major axis diameter” means that the minimum distance when a particle image is sandwiched between two parallel lines is the minor axis diameter, and the particle image is sandwiched between two parallel lines orthogonal to the minor axis diameter. The interval.

  In addition, the CoSn alloy powder obtained in this example was sealed in a sealed container in an inert gas atmosphere, and the oxygen concentration of the CoSn alloy powder was measured using a simultaneous oxygen / nitrogen analyzer (TC-436 manufactured by LECO). Was 0.52% by mass.

  These results are shown in Table 1.

[Example 2]
A CoSn alloy powder was produced in the same manner as in Example 1 except that the reduction temperature was set to 400 ° C., and evaluation by X-ray diffraction pattern, calculation of crystallite diameter, calculation of average particle diameter, and measurement of oxygen concentration were performed. went. An X-ray diffraction pattern of the CoSn alloy powder obtained in this example is shown in FIG. From this X-ray diffraction pattern, it was confirmed that the CoSn alloy powder obtained in this example was a single phase of CoSn. The crystallite size was 31.6 nm, the average particle size was 162.1 nm, and the oxygen concentration was 0.21% by mass. These results are shown in Table 1.

[Example 3]
A CoSn alloy powder was produced in the same manner as in Example 1 except that the reduction temperature was changed to 500 ° C., and evaluation by X-ray diffraction pattern, calculation of crystallite diameter, calculation of average particle diameter, and measurement of oxygen concentration were performed. went. An X-ray diffraction pattern of the CoSn alloy powder obtained in this example is shown in FIG. From this X-ray diffraction pattern, it was confirmed that the CoSn alloy powder obtained in this example was a single phase of CoSn. The crystallite size was 48.6 nm, the average particle size was 262.5 nm, and the oxygen concentration was 0.33 mass%. These results are shown in Table 1.

[Example 4]
An aqueous solution containing Co and Sn by dissolving 28.11 g of cobalt sulfate heptahydrate (CoSO ₄ · 7H ₂ O) and 35.06 g of tin (IV) chloride (SnCl ₄ · 5H ₂ O) in 400 g of pure water. Produced. Moreover, 54.43g of 48.5 mass% sodium hydroxide aqueous solution was added to 200g of pure water, and sodium hydroxide aqueous solution was produced. The aqueous sodium hydroxide solution is heated to 40 ° C. and stirred, and the aqueous solution containing Co and Sn is heated to 40 ° C. and added to obtain a slurry containing Co and Sn hydroxides. It was. This slurry was filtered and washed with pure water to obtain a cake of Co and Sn hydroxide (SnCo (OH) ₆ ). The Co and Sn hydroxide cake was dried in the atmosphere at 140 ° C. for 3 hours and then reduced in a hydrogen atmosphere at 285 ° C. for 4 hours to obtain a CoSn alloy powder.

  With respect to the obtained CoSn alloy powder, evaluation by an X-ray diffraction pattern, calculation of crystallite diameter, calculation of average particle diameter, and measurement of oxygen concentration were performed in the same manner as in Example 1. An X-ray diffraction pattern of the CoSn alloy powder obtained in this example is shown in FIG. From this X-ray diffraction pattern, it was confirmed that the CoSn alloy powder obtained in this example was a single phase of CoSn. The crystallite size was 20.1 nm, the average particle size was 98.2 nm, and the oxygen concentration was 0.11% by mass. These results are shown in Table 1.

[Example 5]
A CoSn alloy powder was produced by the same method as in Example 4 except that the reduction temperature was changed to 275 ° C., and evaluated by an X-ray diffraction pattern, calculation of crystallite diameter, average grain size by the same method as in Example 1. The diameter was calculated and the oxygen concentration was measured. An X-ray diffraction pattern of the CoSn alloy powder obtained in this example is shown in FIG. From this X-ray diffraction pattern, it was confirmed that the CoSn alloy powder obtained in this example was a single phase of CoSn. The crystallite diameter was 18.3 nm, the average particle diameter was 95.1 nm, and the oxygen concentration was 0.18% by mass. These results are shown in Table 1.

[Example 6]
An aqueous solution containing Co and Sn by dissolving 28.11 g of cobalt sulfate heptahydrate (CoSO ₄ · 7H ₂ O) and 35.06 g of tin (IV) chloride (SnCl ₄ · 5H ₂ O) in 400 g of pure water. Produced. Moreover, 54.43g of 48.5 mass% sodium hydroxide aqueous solution was added to 200g of pure water, and sodium hydroxide aqueous solution was produced. The aqueous solution containing Co and Sn is heated to 40 ° C. and stirred, and the aqueous sodium hydroxide solution is heated to 40 ° C. and added to the aqueous solution containing Co and Sn. A slurry containing hydroxide was obtained. The slurry was filtered to obtain a cake of Co and Sn hydroxide (SnCo (OH) ₆ ). The Co and Sn hydroxide cake was dried in the atmosphere at 140 ° C. for 3 hours and then reduced in a hydrogen atmosphere at 300 ° C. for 3 hours to obtain a CoSn alloy powder. In addition, about the hydroxide of Co and Sn after drying, when it evaluated by the X-ray-diffraction pattern by the method similar to Example 1, it became an amorphous phase. Further, the Co and Sn hydroxides after drying were dissolved in an acid, and the molar ratio of Co and Sn was calculated from the measurement result by ICP emission spectroscopic analysis. The molar ratio (Co: Sn) was 1. 0: 1.0.

  With respect to the obtained CoSn alloy powder, evaluation by an X-ray diffraction pattern, calculation of crystallite diameter, calculation of average particle diameter, and measurement of oxygen concentration were performed in the same manner as in Example 1. An X-ray diffraction pattern of the CoSn alloy powder obtained in this example is shown in FIG. From this X-ray diffraction pattern, it was confirmed that the CoSn alloy powder obtained in this example was a single phase of CoSn. The crystallite size was 22.6 nm, the average particle size was 110.1 nm, and the oxygen concentration was 0.25% by mass. These results are shown in Table 1.

[Example 7]
An aqueous solution containing Co and Sn by dissolving 18.78 g of cobalt sulfate heptahydrate (CoSO ₄ · 7H ₂ O) and 46.84 g of tin (IV) chloride (SnCl ₄ · 5H ₂ O) in 400 g of pure water. Produced. Moreover, 60.6 g of 48.7 mass% sodium hydroxide aqueous solution was added to 200 g of pure water, and sodium hydroxide aqueous solution was produced. The aqueous sodium hydroxide solution is heated to 40 ° C. and stirred, and the aqueous solution containing Co and Sn is heated to 40 ° C. and added to the aqueous sodium hydroxide solution to obtain a hydroxide of Co and Sn. A slurry containing was obtained. The slurry was filtered and washed with pure water to obtain a Co and Sn hydroxide cake. The Co and Sn hydroxide cake was dried in the atmosphere at 140 ° C. for 3 hours and then reduced in a hydrogen atmosphere at 350 ° C. for 6 hours to obtain a CoSn ₂ alloy powder. In addition, when the hydroxide of Co and Sn after drying was dissolved in an acid and the molar ratio of Co and Sn was calculated from the measurement result by ICP emission spectroscopic analysis, the molar ratio (Co: Sn) was 1. 0: 2.0.

For the obtained CoSn ₂ alloy powder, evaluation by an X-ray diffraction pattern, calculation of crystallite diameter, calculation of average particle diameter, and measurement of oxygen concentration were performed in the same manner as in Example 1. An X-ray diffraction pattern of the CoSn ₂ alloy powder obtained in this example is shown in FIG. From this X-ray diffraction pattern, it was confirmed that the CoSn ₂ alloy powder obtained in this example had a CoSn ₂ phase and a slight CoSn phase. The crystallite diameter was 32.6 nm, the average particle diameter was 174.8 nm, and the oxygen concentration was 0.60 mass%. These results are shown in Table 1. In this example, the half width β of the (2,1,1) plane of the CoSn ₂ phase was used as the half width β used when calculating the crystallite diameter.

[Example 8]
An aqueous solution containing Co and Sn by dissolving 28.11 g of cobalt sulfate heptahydrate (CoSO ₄ · 7H ₂ O) and 35.06 g of tin (IV) chloride (SnCl ₄ · 5H ₂ O) in 400 g of pure water. Produced. Further, a sodium hydroxide aqueous solution was prepared by using 54.22 g of a 48.7 mass% sodium hydroxide aqueous solution and 200 g of pure water. The aqueous solution containing Co and Sn is heated to 40 ° C. and stirred, and the aqueous sodium hydroxide solution is heated to 40 ° C. and added to the aqueous solution containing Co and Sn. A slurry containing hydroxide was obtained. Moreover, 3.49 g of copper sulfate pentahydrate (CuSO ₄ .5H ₂ O) was dissolved in 60 g of pure water to prepare a copper sulfate aqueous solution. This aqueous copper sulfate solution was heated to 40 ° C., added to the slurry containing Co and Sn hydroxides, and stirred to obtain a slurry containing Co, Sn and Cu hydroxides. The slurry containing Co, Sn and Cu hydroxide was filtered and washed with pure water to obtain a Co, Sn and Cu hydroxide cake. The Co, Sn, and Cu hydroxide cake was dried in the atmosphere at 140 ° C. for 3 hours and then reduced in a hydrogen atmosphere at 300 ° C. for 6 hours to obtain a CoSnCu _0.14 alloy powder. In addition, the hydroxide of Co, Sn, and Cu after drying was dissolved in an acid, and the molar ratio of Co, Sn, and Cu was calculated from the measurement result by ICP emission spectroscopic analysis. The molar ratio (Co: Sn : Cu) was 1.0: 1.0: 0.14.

With respect to the obtained CoSnCu _0.14 alloy powder, evaluation by an X-ray diffraction pattern, calculation of crystallite diameter, calculation of average particle diameter, and measurement of oxygen concentration were performed in the same manner as in Example 1. The X-ray diffraction pattern of the CoSnCu _0.14 alloy powder obtained in this example is shown in FIG. From this X-ray diffraction pattern, it was confirmed that the CoSnCu _0.14 alloy powder obtained in this example had a CoSn phase and a Sn ₅ Cu ₆ phase. The crystallite size was 31.3 nm, the average particle size was 99.5 nm, and the oxygen concentration was 0.22% by mass. These results are shown in Table 1.

[Example 9]
A CoSnCu _0.14 alloy powder was produced by the same method as in Example 8 except that the reduction temperature was 350 ° C. and the reduction time was 3 hours, evaluation by X-ray diffraction pattern, calculation of crystallite diameter, average The particle size was calculated and the oxygen concentration was measured. In addition, the hydroxide of Co, Sn, and Cu after drying was dissolved in an acid, and the molar ratio of Co, Sn, and Cu was calculated from the measurement result by ICP emission spectroscopic analysis. The molar ratio (Co: Sn : Cu) was 1.0: 1.0: 0.14. The X-ray diffraction pattern of the CoSnCu _0.14 alloy powder obtained in this example is shown in FIG. From this X-ray diffraction pattern, it was confirmed that the CoSnCu _0.14 alloy powder obtained in this example had a CoSn phase and a Sn ₅ Cu ₆ phase. The crystallite size was 19.2 nm, the average particle size was 92.9 nm, and the oxygen concentration was 0.43% by mass. These results are shown in Table 1.

[Example 10]
CoSnCu was prepared in the same manner as in Example 8 except that the amount of copper sulfate pentahydrate (CuSO ₄ .5H ₂ O) was 7.49 g, the reduction temperature was 350 ° C., and the reduction time was 3 hours. _{A 0.3} alloy powder was produced, and evaluation by an X-ray diffraction pattern, calculation of crystallite diameter, calculation of average particle diameter, and measurement of oxygen concentration were performed. In addition, the hydroxide of Co, Sn, and Cu after drying was dissolved in an acid, and the molar ratio of Co, Sn, and Cu was calculated from the measurement result by ICP emission spectroscopic analysis. The molar ratio (Co: Sn : Cu) was 1.0: 1.0: 0.3. The X-ray diffraction pattern of the CoSnCu _0.3 alloy powder obtained in this example is shown in FIG. From this X-ray diffraction pattern, it was confirmed that the CoSnCu _0.3 alloy powder obtained in this example had a CoSn phase and a Sn ₅ Cu ₆ phase. The crystallite size was 24.2 nm, the average particle size was 95.4 nm, and the oxygen concentration was 0.31% by mass. These results are shown in Table 1.

[Example 11]
CoSnCu was prepared in the same manner as in Example 8 except that the amount of copper sulfate pentahydrate (CuSO ₄ .5H ₂ O) was 15.0 g, the reduction temperature was 400 ° C., and the reduction time was 3 hours. _{A 0.6} alloy powder was produced, and evaluation based on an X-ray diffraction pattern, calculation of crystallite diameter, calculation of average particle diameter, and measurement of oxygen concentration were performed. In addition, the hydroxide of Co, Sn, and Cu after drying was dissolved in an acid, and the molar ratio of Co, Sn, and Cu was calculated from the measurement result by ICP emission spectroscopic analysis. The molar ratio (Co: Sn : Cu) was 1.0: 1.0: 0.6. The X-ray diffraction pattern of the CoSnCu _0.6 alloy powder obtained in this example is shown in FIG. From this X-ray diffraction pattern, it was confirmed that the CoSnCu _0.6 alloy powder obtained in this example had a Sn ₅ Cu ₆ phase. The crystallite size was 26.6 nm, the average particle size was 88.1 nm, and the oxygen concentration was 0.80% by mass. These results are shown in Table 1. In this example, the half-value width β of the (1,1, -3) plane of the Sn ₅ Cu ₆ phase was used as the half-value width β used when calculating the crystallite diameter.

[Example 12]
Cobalt sulfate heptahydrate _{(CoSO 4 · 7H 2 O)} 28.11g tin chloride _{(IV) (SnCl 4 · 5H} 2 O) 35.06g copper sulfate pentahydrate _(CuSO 4 · _5H 2 O ) 3.49 g was dissolved in 400 g of pure water to prepare an aqueous solution containing Co, Sn and Cu. Moreover, 56.75 g of 48.7 mass% sodium hydroxide aqueous solution was added to 200 g of pure water, and sodium hydroxide aqueous solution was produced. The aqueous solution containing Co, Sn and Cu is heated to 40 ° C. and stirred, and the aqueous sodium hydroxide solution is heated to 40 ° C. and added to the aqueous solution containing Co, Sn and Cu. A slurry containing Co, Sn and Cu hydroxide was obtained. The slurry containing Co, Sn, and Cu hydroxide was filtered and washed with pure water to obtain a Co, Sn, and Cu hydroxide cake. The Co, Sn, and Cu hydroxide cake was dried in the atmosphere at 140 ° C. for 3 hours and then reduced in a hydrogen atmosphere at 320 ° C. for 6 hours to obtain a CoSnCu _0.14 alloy powder. In addition, the hydroxide of Co, Sn, and Cu after drying was dissolved in an acid, and the molar ratio of Co, Sn, and Cu was calculated from the measurement result by ICP emission spectroscopic analysis. The molar ratio (Co: Sn : Cu) was 1.0: 1.0: 0.14.

With respect to the obtained CoSnCu _0.14 alloy powder, evaluation by an X-ray diffraction pattern, calculation of crystallite diameter, calculation of average particle diameter, and measurement of oxygen concentration were performed in the same manner as in Example 1. The X-ray diffraction pattern of the CoSnCu _0.14 alloy powder obtained in this example is shown in FIG. From the X-ray diffraction pattern, it was confirmed that the CoSnCu _0.14 alloy powder obtained in this example had a CoSn phase and a Sn ₅ Cu ₆ phase. The crystallite size was 14.8 nm, the average particle size was 80.2 nm, and the oxygen concentration was 0.27% by mass. These results are shown in Table 1.

[Example 13]
The amount of copper sulfate pentahydrate (CuSO ₄ .5H ₂ O) was 1.75 g, 45.5% by mass of a 5% sodium hydroxide aqueous solution was added, and the reduction temperature was 300 ° C. A CoSnCu _0.07 alloy powder was produced in the same manner as in Example 12, and evaluation by X-ray diffraction pattern, calculation of crystallite diameter, calculation of average particle diameter, and measurement of oxygen concentration were performed. In addition, the hydroxide of Co, Sn, and Cu after drying was dissolved in an acid, and the molar ratio of Co, Sn, and Cu was calculated from the measurement result by ICP emission spectroscopic analysis. The molar ratio (Co: Sn : Cu) was 1.0: 1.0: 0.07. The X-ray diffraction pattern of the CoSnCu _0.07 alloy powder obtained in this example is shown in FIG. In this X-ray diffraction pattern, a CoSn phase was confirmed, but a peak attributed to the Sn ₅ Cu ₆ phase could not be confirmed. This is probably because the Cu content was low. The crystallite size was 21.0 nm, the average particle size was 91.0 nm, and the oxygen concentration was 0.26% by mass. These results are shown in Table 1.

[Comparative Example 1]
The obtained powder was evaluated by an X-ray diffraction pattern in the same manner as in Example 1 except that the reduction temperature was 200 ° C. The X-ray diffraction pattern of the powder obtained in this comparative example is shown in FIG. From the X-ray diffraction pattern, in the powder obtained in this comparative example, the SnCo X-ray diffraction peak could not be confirmed. . Moreover, when the oxygen concentration was measured for the powder obtained in this Comparative Example by the same method as in Example 1, it was 12% by mass. These results are shown in Table 1.

Claims (8)

A solution in which Sn and transition metal are dissolved and an alkali solution are mixed to produce Sn and transition metal hydroxide particles. The obtained hydroxide particles are dried and then heated in a reducing gas atmosphere. The manufacturing method of the electrode material for secondary batteries characterized by the above-mentioned. The solution in which Sn and transition metal are dissolved uses Sn salt and at least one transition metal salt selected from the group consisting of Co, Ni, Fe, Cu, Cr, In, Ag and Ti as a solvent. The method for producing an electrode material for a secondary battery according to claim 1, wherein the solution is a dissolved solution. The method for producing an electrode material for a secondary battery according to claim 1 or 2, wherein the heating temperature is 210 to 600 ° C. Sn Ax (A is at least one transition metal element selected from the group consisting of Co, Ni, Fe, Cu, Cr, In, Ag and Ti , and x is 0.2 to 3.0) An electrode material for a secondary battery comprising an Sn alloy powder having a mean particle size of 10 to 500 nm and an oxygen concentration of 0.6% by mass or less . The electrode material for a secondary battery according to claim 4 , wherein a crystallite diameter of the electrode material for the secondary battery is 50 nm or less. Characterized in that said average particle diameter is 300nm or less, the secondary battery electrode material according to claim 4 or 5. Characterized in that said average particle diameter is 200nm or less, the secondary battery electrode material according to claim 4 or 5. Characterized in that said average particle size is less than 100 nm, secondary battery electrode material according to claim 4 or 5.

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