KR101009623B1 - Composition for negative electrode of non-aqueous secondary battery and non-aqueous secondary battery prepared by using same - Google Patents

Abstract

The present invention relates to a negative electrode material for a nonaqueous secondary battery and a nonaqueous secondary battery using the same, wherein the negative electrode material for a nonaqueous secondary battery includes a lithium oxide such as Li ₂ CO ₃ and a vanadium compound such as V ₂ O ₅ such as an organic acid such as (COOH) ₂ . Lithium vanadium oxide prepared by firing with an organic acid salt formed by mixing with a precursor.

The negative electrode material for a non-aqueous secondary battery according to the present invention may have a uniform composition to improve charge and discharge characteristics of the non-aqueous secondary battery.

Non-rechargeable secondary battery, negative electrode material, charge and discharge characteristics.

Description

NON-AQUEOUS SECONDARY BATTERY AND NON-AQUEOUS SECONDARY BATTERY PREPARED BY USING SAME

The present invention relates to a negative electrode material for a non-aqueous secondary battery, such as a lithium ion secondary battery, and a non-aqueous secondary battery using the same. More preferably, the present invention provides a non-aqueous secondary battery that can improve the charge and discharge characteristics of the non-aqueous secondary battery. It relates to a negative electrode material and a non-aqueous secondary battery using the same.

The conventional nonaqueous secondary battery is formed by immersing a positive electrode and a negative electrode capable of occluding and desorbing lithium ions in a nonaqueous electrolyte (Japanese Patent Laid-Open No. 2003-68305 (claims 3 to 11 and 10). ). The negative electrode includes lithium vanadium oxide as a negative electrode material, and the lithium vanadium oxide is formed by mixing a lithium source such as lithium hydroxide and a vanadium source such as vanadium trioxide in a solid phase method and then baking at a temperature of 650 ° C. or higher.

During charging of the non-aqueous secondary battery, the negative electrode is negatively charged, and lithium ions occluded in the positive electrode are detached and stored in the negative electrode. When discharging the non-aqueous secondary battery, lithium ions stored in the negative electrode are detached and stored in the positive electrode.

1 is a view showing charge and discharge characteristics of a lithium vanadium oxide which is a conventional anode material.

The test cell used for the measurement used the lithium metal as a counter electrode, and measured the lithium reference | standard open potential using the sample of the conventional lithium vanadium oxide manufactured by the solid-state method as a counter electrode. The vertical axis is potential (unit: V), and the horizontal axis is capacity (unit: mAh / g). The sample was dry mixed with lithium hydride and vanadium trioxide, and then calcined at 1100 ° C. under a nitrogen atmosphere.

In FIG. 1, A11 represents one time of occlusion of lithium ions, and B11 represents one time of detachment of lithium ions. A12 represents 10 times of occlusion of lithium ions, and B12 represents 10 times of desorption of lithium ions.

According to FIG. 1, a flat portion having a potential variation of 0.05 V or less at one time of desorption (A11) and occlusion (B11) of lithium ions is less than 25% of the entire section (corresponding to the horizontal axis) where the reaction takes place. It is included. Namely, it has a so-called flat dislocation at the time of detachment and occlusion at one time. In the meantime, the flat portion is not formed at the time of lithium ion desorption 10 times (A12) and at the time of occlusion (B12), indicating that ideal charge and discharge characteristics are not obtained.

That is, when lithium vanadium oxide is manufactured by the dry method, since the composition of the target substance is not uniform and a stable crystal structure cannot be maintained, there is a problem that the potential is not stabilized when charge and discharge are repeated, resulting in deterioration of the charge and discharge characteristics. .

It is an object of the present invention to provide a negative electrode material for a non-aqueous secondary battery and a nonaqueous secondary battery using the same, which can improve charge and discharge characteristics.

In order to achieve the above object, the present invention is within 0.05V in the range of 25% or more with respect to the entire section in which the open potential when charging and discharging with lithium as a counter electrode occurs when occlusion or desorption of lithium ions occurs. The flat portion has a flat portion, and the flat portion provides a negative electrode material for a non-aqueous battery comprising lithium vanadium oxide having an average potential of 0.20 to 0.25V when lithium ions are occluded and having an average potential of 0.23 to 0.27V when the lithium ion is detached.

The negative electrode material for a non-aqueous secondary battery according to the present invention may have a uniform composition to improve charge and discharge characteristics of the non-aqueous secondary battery.

The present invention is a negative electrode material for a non-secondary battery containing lithium vanadium oxide, the lithium vanadium oxide is formed by firing an organic acid salt containing lithium and vanadium.

For example, the non-aqueous lithium vanadium oxide contained in the secondary battery negative electrode material, include Li _a V _b O _d and so on obtained by firing the organic acid salt such as _{Li a V b O d (C} 2 O 4) as a precursor . Here, a, b and d are numerical values determined according to Scheme 1 below.
Scheme 1
0.22Li ₂ CO ₃ + V ₂ O ₅ + X (COOH) ₂ → Li _a V _b O _d (C ₂ O ₄ ) + Y (COOH) ₂
In addition, the present invention is characterized in that, in the negative electrode material for a non-aqueous secondary battery of the above structure, the organic acid salt is formed by mixing a lithium compound and a vanadium compound with an organic acid. According to the constitution, the organic acid salts such as Li _a V _b O _d (C ₂ O ₄ ) are mixed with lithium compounds such as Li ₂ CO ₃ and vanadium compounds such as V ₂ O ₅ with organic acids such as (COOH) ₂ . Is formed.

delete

In the negative electrode material prepared by the above method, the peak intensity ratio of the (104) plane to the (003) plane is preferably 0.2 to 0.8, more preferably 0.3 to 0.6. If the peak intensity ratio is less than 0.2, it is undesirable because only the basal plane is developed and the prismatic plane is less developed. If the peak intensity ratio is greater than 0.8, it is not preferable because other phases other than the layer plane are not developed. not.

In addition, the present invention is characterized in that in the negative electrode material for a non-aqueous secondary battery having the above constitution, the molar ratio of lithium and vanadium contained in the lithium compound and vanadium compound mixed with the organic acid salt is set to 1.2: 1 to 1.24: 1. have.

Further, the present invention is characterized in that, in the negative electrode material for a non-aqueous secondary battery of each of the above structures, the organic acid is present at a molar amount of 1.5 to 5 times the molar amount reacting with the lithium compound and the vanadium compound during the reaction.

According to this structure, an organic acid salt is formed by the chemical reaction shown by following Reaction Formula 1, for example. The amount of organic acid used in the reaction is X-Y mole, and the amount of organic acid present in the reaction is X mole. Z is an arbitrary value.

Scheme 1

0.22Li ₂ CO ₃ + V ₂ O ₅ + X (COOH) ₂ → Li _a V _b O _d (C ₂ O ₄ ) + Y (COOH) ₂

In addition, in the negative electrode material for a non-aqueous secondary battery of each of the above structures, the lithium vanadium oxide is a section in which an open potential is reacted when lithium ions are occluded and desorbed when charging and discharging with lithium as a counter electrode. The flat portion has a flat portion within 0.05V in a range of 25% or more with respect to the whole, the flat portion is characterized in that the average potential at the time of occlusion of lithium ions is 0.20 to 0.25V, the average potential at the time of desorption of lithium ions.

According to this structure, the charge / discharge characteristic can be measured in the test cell which arrange | positions the negative electrode material containing lithium vanadium oxide as a counter electrode, and arrange | positions the metallic lithium as a counter electrode. At this time, the test cell has a so-called flat potential having an open potential of 0.20 to 0.25V upon occlusion of lithium ions. It also has a flat potential of 0.23 to 0.27V when the lithium ions are released. The flat potential is formed in a flat portion having a variation in the potential of 0.05 V or less in the range of 25% or more with respect to the entire section where the reaction is carried out upon occlusion and desorption of lithium ions.

In addition, in the negative electrode material for a non-aqueous secondary battery of the above structure, in the charge and discharge characteristics after storing and desorbing lithium ions once, the flat portion is formed in a range of 25% or more with respect to the entire section where the reaction is performed. I make it a characteristic. According to this configuration, in the charge and discharge characteristics when the charge / discharge is repeated two or more times in the Tess cell, the potential of the dislocation is in the range of 25% or more for the entire section in which the reaction is performed when occluding and desorbing lithium ions. The flat part with a variation within 0.05V appears. In addition, after the capacity deteriorates to the extent regarded as the lifetime, the case where the flat portion is not 25% or more of the entire section where the reaction is performed is included.

In addition, in the negative electrode material for a non-aqueous secondary battery of the above structure, in the charge / discharge characteristics after storing and desorbing lithium ions once, the flat portion is formed in a range of 40% or more with respect to the entire section where the reaction is performed. It features. According to this configuration, in the charge / discharge characteristics when the charge and discharge are repeated two or more times in the test cell, the potential is changed in a range of 40% or more for the entire section where the reaction is carried out at the time of occlusion and desorption of lithium ions. The flat part within this 0.05V appears. It also includes the case where the flat portion is not more than 40% of the entire section where the reaction takes place after the capacity is deteriorated to the extent considered to be the life.

In addition, the present invention is a negative electrode material for a non-secondary battery containing a lithium vanadium oxide, the charge and discharge characteristics of the lithium vanadium oxide when the charge and discharge when lithium as a counter electrode reacts when the lithium ion is occluded and released It has a flat portion within 0.05V in the range of 25% or more with respect to the entire section to be performed, wherein the flat portion has an average potential of 0.20 to 0.25V when the lithium ion is occluded, and an average potential of 0.23 to 0.27V when the lithium ion is detached. In the charge-discharge characteristics after occluding and desorbing lithium ions once, the flat portion is formed in a range of 25% or more with respect to the entire section in which the reaction is performed.

In addition, the non-aqueous secondary battery of the present invention is characterized by consisting of a negative electrode, a positive electrode and an electrolyte made of a negative electrode material for each non-aqueous secondary battery of the above configuration.

According to the present invention, since the lithium vanadium oxide forming the negative electrode material for a non-aqueous secondary battery is formed by firing an organic acid salt containing lithium and vanadium, the composition is uniform and the crystal structure is stable. As a result, the charge / discharge potential of the non-aqueous secondary battery is stable, thereby improving charge / discharge characteristics. In addition, an inexpensive V ₂ O ₅ containing pentavalent vanadium can be used as a source of vanadium. For this reason, the cost of the negative electrode material for nonaqueous secondary batteries and a nonaqueous secondary battery can be reduced.

According to the present invention, since the organic acid salt is mixed with the lithium compound and the vanadium compound in the organic acid and calcined, the organic acid salt can be easily obtained by the wet method.

According to the present invention, since the molar ratio of lithium and vanadium contained in the organic compound and the vanadium compound is 1.2: 1 to 1.24: 1, a nonaqueous secondary battery having high discharge capacity can be obtained.

In addition, according to the present invention, since the organic acid is present in an excess of 1.5 to 5 times the molar amount of the amount of organic acid reacted with the lithium compound and the vanadium compound during the reaction, a negative electrode material having a high discharge capacity after firing can be obtained.

According to the present invention, since the open potential of the negative electrode material has a flat portion, the flat portion has a mean potential of 0.20 to 0.25V when occluded with lithium ions, and a mean potential of 0.23 to 0.27V upon detachment of lithium ions. It has a flat potential close to the material. Therefore, a nonaqueous secondary battery having high energy density can be obtained by using lithium vanadium oxide having a large capacity per volume instead of the conventional anode material using graphite.

According to the present invention, since the flat portion is formed in a range of 25% or more with respect to the entire section where the reaction is performed in the charge / discharge characteristic after the lithium ion is occluded and desorbed once, the potential remains unchanged even after the charge and discharge of the non-aqueous secondary battery is repeated. It is stable and can improve a charge / discharge characteristic.

According to the present invention, since the flat portion is formed in a range of 40% or more with respect to the entire section where the reaction is performed in the charging characteristic after the lithium ion is occluded and desorbed once, the potential is remarkably stable even after repeated charging and discharging of the non-aqueous secondary battery. You can.

Hereinafter, a nonaqueous secondary battery according to one embodiment of the present invention will be described with reference to the drawings.

2 is a vertical cross-sectional view showing a non-aqueous secondary battery according to one embodiment of the present invention. The nonaqueous secondary battery 1 consists of a spiral cylindrical lithium secondary battery. The center pin 6 is provided in the non-aqueous secondary battery 1, and the laminate 10 formed by sandwiching the separator 5 between the positive electrode 3 and the negative electrode 4 is overlapped with the center pin 6. It is wound. Accordingly, the laminate 10 has a cylindrical structure.

The positive electrode 3 is formed by the positive electrode mixture 3a containing the positive electrode active material, having two layers between the front and rear surfaces of the positive electrode current collector 3b interposed therebetween. The negative electrode 4 is formed by the negative electrode mixture 4a containing the negative electrode active material, having two layers on the front and rear surfaces of the negative electrode current collector 4b at a time. The cylindrical laminate 10 is housed in a casing 2 of a hollow park mold and is immersed in an electrolyte (not shown). The case 2 is connected to the positive electrode 3 and the positive electrode terminal 7 with the lower end protruding is formed.

Insulation plates 9b and 9a are provided above and below the laminate 10, respectively. The positive electrode current collector 3b penetrates through the insulating plate 9a and is connected to the positive electrode terminal 7 by the positive electrode lead 11. On the insulating plate 9b on the opening side of the case 2, a safety plate 13 having a convex shape in the direction of the insulating plate 9b is provided. A cap-shaped negative electrode terminal 8 having a convex shape in the opposite direction to the safety plate 13 is formed above the safety plate 13. The negative electrode current collector 4b penetrates through the insulating plate 9b and is connected to the negative electrode terminal 8 by the negative electrode lead 12. The edges of the safety plate 13 and the negative electrode terminal 8 are sealed by the gasket 14 and are separated from the positive electrode terminal 7.

As the positive electrode active material and the electrolyte, known materials may be used as the positive electrode active material and the electrolyte of the non-aqueous secondary battery. For example, lithium transition metal oxides such as lithium cobalt oxide can be used as the positive electrode active material. In addition to the electrolyte may be used that containing a solute composed of a lithium salt such as _{LiPF 6, Li 2 SiF 6,} LiTiF 6, LiBF 4 in a solvent such as ethylene carbonate and diethylene carbonate.

The negative electrode 4 includes a negative electrode material as described above as a negative electrode active material. Specifically, lithium vanadium oxide represented by Li _a V _b M _c O _d is included as _a negative electrode active material. M is at least one or a plurality of elements selected from transition metals, alkali metals and alkaline earth metals, and a, b, c and d are arbitrary values. And the cathode is a negative electrode material; Conductive agents such as acetylene black and the like; And after mixing the binder is formed on the negative electrode current collector (3b) made of copper and press-formed.

The lithium vanadium oxide is formed by firing a precursor made of an organic acid salt represented by Li _a V _b M _c O _d (C ₂ O ₄ ) in an atmosphere such as nitrogen.

For example, the organic acid salt is mixed with lithium carbonate (Li ₂ CO ₃ ) as a lithium compound, vanadium pentoxide (V ₂ O ₅ ) as a vanadium compound, oxalic acid ((COOH ₂ ) as an organic acid, reacted in an aqueous solution, and then evaporated to dryness. You can get it.

Moreover, when using lithium carbonate, vanadium pentoxide, and oxalic acid, the said organic acid salt can be obtained especially easily and easily. Lithium hydroxide, lithium oxalate, or the like may be used as the lithium compound. As the organic acid, acetic acid, citric acid, malic acid, succinic acid and the like may be used in addition to oxalic acid.

According to this production method, lithium vanadium oxide is obtained by firing an organic acid salt in which lithium atoms and vanadium atoms are mixed in advance. For this reason, compared with the conventional lithium vanadium oxide obtained by mixing and baking a lithium compound and a vanadium compound, it is easy to form the state which a solid solution of a lithium atom and a vanadium atom was made to a micro level. Therefore, lithium vanadium oxide of a uniform composition can be obtained.

Hereinafter, preferred examples and comparative examples of the present invention are described. However, the following embodiments are only preferred embodiments of the present invention, and the present invention is not limited to the following embodiments.

Example  1. Preparation of Lithium Vanadium Oxide

Lithium carbonate (Li ₂ CO ₃ ) as a lithium compound, vanadium pentoxide (V ₂ O ₅ ) as a vanadium compound, and oxalic acid ((COOH) ₂ ) as an organic acid were mixed and reacted in an aqueous solution as shown in the following reaction formula, followed by evaporation to dryness. An organic acid salt of _a V _b O _d (C ₂ O ₄ ), wherein a, b and d are numerical values determined according to the following schemes, was prepared. At this time, the molar ratio of lithium and vanadium contained in lithium carbonate and vanadium pentoxide was 1.22: 1, and the organic acid was added in a molar amount of 1.5 times the molar amount reacted with the lithium carbonate and vanadium pentoxide.
[Scheme]
0.22Li ₂ CO ₃ + V ₂ O ₅ + X (COOH) ₂ → Li _a V _b O _d (C ₂ O ₄ ) + Y (COOH) ₂

Lithium vanadium oxide was prepared by baking the prepared organic acid salt as a precursor at 1100 ° C. under a nitrogen atmosphere.

Example  2. Preparation of Lithium Vanadium Oxide

Lithium vanadium oxide was prepared in the same manner as in Example 1, except that citric acid was used instead of oxalic acid.

Comparative example  One

After mixing 26.35 g of LiOH and 67.5 g of V ₂ O ₃ in a solid phase method, calcining at 650 ° C. to produce lithium vanadium oxide.

X-ray diffraction analysis was performed on the lithium vanadium oxides prepared in Example 1 and Comparative Example 1. The results are shown in FIGS. 3 and 4.

3 is a result of X-ray diffraction analysis of lithium vanadium oxide according to Example 1 and Comparative Example 1 of the present invention, Figure 4 is an enlarged view of the peak corresponding to the (003) plane in FIG.

As shown in Figures 3 and 4, the peak intensity ratio of the (104) plane to the (003) plane of the lithium vanadium oxide according to Example 1 is 0.6, while the (003) plane of the lithium vanadium oxide according to Comparative Example 1 The peak intensity ratio of (104) plane to was 0.3.

Example  3. Manufacturing of Lithium Secondary Battery

80 wt% of the lithium vanadium oxide prepared in Example 1, 10 wt% of acetylene black, and 10 wt% of polyvinylidene fluoride were mixed and coated on a negative electrode current collector made of copper, and then pressed to 1.8 g / cm ^3. A negative electrode was formed.

As a positive electrode active material, 91 wt% of LiCoO ₂ , 3 wt% of acetylene black, and 6 wt% of polyvinylidene fluoride were mixed to form a positive electrode. In addition, a mixed solvent of EC: DEC = 3: 7 (volume ratio) was used as a solvent of the nonaqueous electrolyte, and LiPF ₆ was used as the electrolyte .

Moreover, after inject | pouring electrolyte solution by electrolyte solution pouring process and leaving still for 1 hour, the inlet was sealed and the lithium secondary battery was manufactured.

Example  4. Fabrication of Lithium Secondary Battery

A lithium secondary battery was manufactured by the same method as Example 3, except that lithium vanadium oxide prepared in Example 2 was used.

Except for varying the molar ratio of lithium contained in Li ₂ CO ₃ inserted into (COOH) ₂ and vanadium contained in V ₂ O ₅ , or varying the amount of the organic acid used in Example 1 and A lithium vanadium oxide prepared in the same manner is disposed on the counter electrode, a test cell having a lithium reference open potential in which metal lithium is disposed on the counter electrode is prepared, and the discharge capacity is charged and discharged in the range of 0 to 1.4 V with respect to the cell. Measured. The results are shown in FIGS. 5 and 6.

5 and 6, the vertical axis represents the discharge capacity (unit: mAh / g) of the test cell. 5 represents the molar ratio of lithium contained in Li ₂ CO ₃ inserted into (COOH) ₂ and vanadium contained in V ₂ O ₅ . At this time, the organic acid was added in 1.5 times molar amount of the molar amount reacted with the lithium carbonate and vanadium pentoxide.

According to FIG. 5, when the molar ratio between lithium included in Li ₂ CO ₃ and vanadium included in V ₂ O ₅ is set to 1.2: 1 to 1.24: 1, high discharge capacity can be obtained.

6 represents the amount of (COOH) ₂ present in the reaction of Li ₂ CO ₃ , V ₂ O ₅ and (COOH) ₂ , and the amount of (COOH) ₂ used in the reaction is 1; It is shown by ratio. That is, the organic acid salt represented by Li _a V _b O _d (C ₂ O ₄ ) is represented by, for example, Formula (1), and the amount of (COOH) ₂ used in the reaction is XY moles. 6 is a ratio represented by X / (XY). Z is an arbitrary value.

1.22 Li ₂ CO ₃ + V ₂ O ₅ + X (COOH) ₂ → Li _a V _b O _d (C ₂ O ₄ ) + Y (COOH) ₂ (1)

According to FIG. 6, when (COOH) ₂ is present in the reaction at a molar amount of 1.5 to 5 times the molar amount reacted with Li ₂ CO ₃ and V ₂ O ₅ , high discharge capacity can be obtained.

The charge and discharge characteristics of lithium vanadium oxide, which is a negative electrode material according to Example 1, were measured. The results are shown in FIG.

The test cell used for the measurement arrange | positions metal lithium to a counter electrode, and arrange | positions the lithium vanadium oxide which concerns on Example 1 to a counter electrode, and measures a lithium reference open potential. The vertical axis is potential (unit: V), and the horizontal axis is capacity (unit: mAh / g). In addition, (COOH) with a molar ratio of lithium and vanadium included in the V ₂ O ₅ contained in the Li ₂ CO _3, insert ₂ is 1.22: 1.

In addition, in FIG. 7, A1 has shown the 1st desorption time of lithium ion. B1 has shown the time of the first occlusion of lithium ion. A2 has shown the 10th time of detachment of lithium ion, and B2 has shown the 10th time of occlusion of lithium ion.

As shown in FIG. 7, the test cell using the lithium vanadium oxide according to Example 1 exhibits a shift in potential at the first and tenth desorption times (A1, A2) and occlusion (B1, B2) of lithium ions. The flat part within 0.05V is contained in 70% or more of range with respect to the whole area | region (it corresponds to a horizontal axis) in which reaction is performed. When the lithium ions are occluded, the flat potential of the flat part has a so-called flat potential of about 0.22 V, and when detached, the flat potential of the flat part has a flat potential of about 0.25 V.

As described above with reference to FIG. 1, in the test cell using the conventional lithium vanadium oxide by the solid phase method, the flat portion is included in the first occlusion (A11) and the desorption (B11) of lithium ions. However, the flat part is not formed at the time of occlusion (A12) and desorption (B12) of the 10th time of lithium ion.

This is considered to be because lithium vanadium oxide according to one embodiment of the present invention has a uniform composition in the particles and a stable crystal structure. As a result, the nonaqueous secondary battery 1 having stable charge and discharge potentials can be obtained. Moreover, in the lithium vanadium oxide by the solid-phase method, the flat part is not formed even when the lithium ion is occluded and desorbed at the second time.

In addition, when the molar ratio of lithium contained in Li ₂ CO ₃ inserted into (COOH) ₂ and vanadium contained in V ₂ O ₅ is in the range of 1.2: 1 to 1.24: 1, the flat potential of FIG. 5 is changed. That is, in the range where high discharge capacity can be obtained, the average potential of the flat portion has a flat potential of 0.20 to 0.25 V when the lithium ions are occluded, and the average potential of the flat portion has a flat potential of 0.23 to 0.27 V during detachment.

In addition, the lithium vanadium oxide according to an embodiment of the present invention, the charge and discharge is further repeated, soon the capacity is lowered. In general, at 50% capacity deterioration, which has a lifetime, it has a flat portion of 25% for the entire section in which the reaction is performed. If the flat part has 20% or more of the entire section to be reacted, there is no practical problem, and if it is 25% or more, it has practically sufficient performance. In addition, if the flat part has 40% or more of the entire reaction section, a non-aqueous secondary battery having high stability can be obtained.

According to the exemplary embodiment of the present invention, since the lithium vanadium oxide included in the negative electrode 4 is formed by firing an organic acid salt containing lithium and vanadium, the sintering becomes uniform and the crystal structure is stabilized. As a result, the charge / discharge potential of the non-aqueous secondary battery 1 is stable and the charge / discharge characteristics can be improved.

Since the organic acid salt was prepared by mixing Li ₂ CO ₃ and V ₂ O ₅ in (COOH) ₂ , the organic acid salt Li _a V _b M _c O _d (C ₂ O ₄ ) can be easily obtained by a wet method. Moreover, another lithium compound may be used as a source of lithium, and another vanadium compound may be used as a source of vanadium. Moreover, you may use organic acids other than (COOH) ₂ .

Lithium vanadium oxide it is necessary to use an expensive, such as V ₂ O ₃ or V ₂ O ₄ in the conventional and the conventional method as a source of vanadium because it contains a trivalent or tetravalent vanadium. However, in the wet method according to the embodiment of the present invention, even when using V ₂ O ₅ containing pentavalent vanadium, vanadium is reduced to trivalent or tetravalent. Therefore, it is possible to reduce the cost of the non-aqueous secondary battery negative electrode material and a nonaqueous secondary battery (1) it is possible to use an inexpensive V ₂ O _5.

In addition, since the charge and discharge characteristics of the negative electrode material have a flat portion, the flat portion has a flat potential close to the negative electrode material using graphite because the average potential of lithium ions when occluded is 0.20 to 0.25V, and the average potential of lithium ions is 0.23 to 0.27V. Has a potential. Therefore, a nonaqueous secondary battery having high energy density can be obtained using lithium vanadium oxide having a large capacity per volume instead of the conventional negative electrode material using graphite.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it belongs to the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS The figure which shows the relationship between the capacity | capacitance and electric potential of the negative electrode material for conventional nonaqueous secondary batteries.

Figure 2 is a vertical cross-sectional view showing a non-aqueous secondary battery according to an embodiment of the present invention.

3 is a graph showing the results of X-ray diffraction analysis of lithium vanadium oxide according to Example 1 and Comparative Example 1 of the present invention.

4 is a partially enlarged view of a peak corresponding to the (003) plane in FIG.

5 is a view showing the relationship between the discharge capacity and the ratio of lithium and vanadium inserted at the time of organic acid formation of the negative electrode material for a non-aqueous secondary battery according to the present invention.

6 is a view showing the relationship between the amount of the organic acid and the discharge capacity when forming an organic acid salt of the negative electrode material for a non-secondary battery according to the present invention.

7 is a view showing a relationship between a capacity and a potential of a negative electrode material for a non-aqueous secondary battery according to Example 1 of the present invention.

[Description of main parts of drawing]

1 non-rechargeable battery 2 case

3 anode 4 cathode

5 Separator 6 Center Pin

7 Positive terminal 8 Negative terminal

9a, 9b insulation plate 10 laminate

Claims (18)

The open potential when charging and discharging with lithium as a counter electrode has a flat portion within 0.05 V in the range of 25% or more with respect to the entire charge / discharge curve in which the reaction proceeds at the time of occlusion or desorption of lithium ions to obtain a capacity. And the flat part comprises lithium vanadium oxide having an average potential of 0.20 to 0.25 V when occluded with lithium ions and an average potential of 0.23 to 0.27 V upon detachment of lithium ions. The method of claim 1, In the charge-discharge characteristics after storing and detaching lithium ions once, the flat portion is formed in a range of 25% or more with respect to the entire reaction section, the negative electrode material for a non-aqueous secondary battery. The method of claim 1, In the charge / discharge characteristics after occluding and desorbing lithium ions once, the flat portion is formed in a range of 40% or more with respect to the entire reaction section is a negative electrode material for a non-aqueous secondary battery. The method of claim 1, The lithium vanadium oxide is 0.05 V in the range of 25% or more with respect to the entire charge / discharge curve in which the open potential at the time of charge / discharge with lithium as a counter electrode proceeds upon the reaction of occlusion or desorption of lithium ions to obtain a capacity. It has a flat portion within, the flat portion has an average potential of 0.20 to 0.25V at the time of occlusion of lithium ions, the average potential of 0.23 to 0.27V at the time of desorption of lithium ions, and charge and discharge characteristics after occluding and detaching lithium ions once In the flat portion is a negative electrode material for a non-aqueous secondary battery that is formed in a range of 25% or more with respect to the entire reaction section. The method of claim 1, The lithium vanadium oxide is formed by firing an organic acid salt containing lithium and vanadium negative electrode material for a secondary battery. The method of claim 5, The organic acid salt is a negative electrode material for a non-aqueous battery that is formed by mixing a lithium compound and a vanadium compound with an organic acid. The method of claim 6, A negative electrode material for a non-aqueous secondary battery, wherein a molar ratio of lithium and vanadium contained in the organic compound and the vanadium compound is 1.2: 1 to 1.24: 1. The method of claim 7, wherein The organic acid is a negative electrode material for a non-aqueous secondary battery that is contained in 1.5 to 5 times the molar amount of the molar amount reacted with the lithium compound and the vanadium compound. The method of claim 1, The negative electrode material is a negative electrode material for a non-aqueous secondary battery, the peak intensity ratio of the (104) plane to the (003) plane is 0.2 to 0.8. cathode; anode; And Includes an electrolyte, The negative electrode has a flat portion of 0.05 V or less in a range of 25% or more with respect to the entire section in which the open potential when charging and discharging with lithium as a counter electrode occurs when occlusion or desorption of lithium ions occurs. A non-aqueous secondary battery comprising a negative electrode material containing lithium vanadium oxide having an average potential of 0.20 to 0.25 V when occluded with lithium ions and an average potential of 0.23 to 0.27 V upon detachment of lithium ions. The method of claim 10, In the charge / discharge characteristics after occluding and desorbing lithium ions once, the flat part is formed in a range of 25% or more with respect to the entire reaction section. The method of claim 10, In the charge-discharge characteristics after occluding and desorbing lithium ions once, the flat part is formed in a range of 40% or more of the entire reaction section. The method of claim 10, The lithium vanadium oxide has a flat portion of 0.05 V or less in a range of 25% or more with respect to the entire section in which the open potential when charging and discharging with lithium as a counter electrode occurs during the occlusion and desorption of lithium ions. The flat portion has an average potential of 0.20 to 0.25 V when occluded with lithium ions, and has an average potential of 0.23 to 0.27 V upon desorption of lithium ions. Non-aqueous secondary battery is formed in a range of 25% or more for the entire section. The method of claim 10, The lithium vanadium oxide is formed by firing an organic acid salt containing lithium and vanadium. The method of claim 14, The organic acid salt is a non-aqueous secondary battery formed by mixing a lithium compound and a vanadium compound with an organic acid. The method of claim 15, A non-aqueous secondary battery having a molar ratio of lithium and vanadium contained in the lithium compound and the vanadium compound mixed in the organic acid is 1.2: 1 to 1.24: 1. The method of claim 15, The organic acid is a non-aqueous secondary battery comprising 1.5 to 5 times the molar amount of the molar amount reacted with the lithium compound and the vanadium compound. The method of claim 10, The negative electrode material is a non-aqueous secondary battery having a peak intensity ratio of 0.2 to 0.8 of the (104) plane to the (003) plane.

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