JP2013058405A - Lithium ion oxygen cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lithium ion oxygen cell which obtains a large cell capacity.SOLUTION: A lithium ion oxygen cell 1 includes: a positive electrode 2 using oxygen as an active material and including a lithium source; a negative electrode 3 including a material capable of absorbing or discharging lithium ions; and an electrolyte layer 4 sandwiched between the positive electrode 2 and the negative electrode 3 and transmitting the lithium ions. The lithium ion oxygen cell 1 is sealed and housed in a housing 5. The positive electrode 2 includes an oxygen storage material and a lithium compound, and the negative electrode 3 includes silicon. The lithium ion oxygen cell 1 includes a solid electrolyte interface layer 11 between the negative electrode 3 and the electrolyte layer 4.

Description

  The present invention relates to a lithium ion oxygen battery.

Conventionally, a lithium ion secondary comprising a positive electrode containing lithium iron phosphate (LiFePO ₄ ) as an active material, a negative electrode containing graphite as an active material, and an electrolyte layer sandwiched between the positive electrode and the negative electrode and capable of conducting lithium ions. Batteries are known. In the lithium ion secondary battery, the lithium ion is occluded or released (intercalation or deintercalation) in lithium iron phosphate or graphite in accordance with charge / discharge in the positive electrode or the negative electrode, thereby acting as a battery. .

  However, since the lithium iron phosphate cannot maintain the crystal structure when the amount of lithium released (deintercalated) increases, the theoretical capacity is 150 mAh / g. The capacity is considered to be 120-140 mAh / g. On the other hand, the graphite has a theoretical capacity of 372 mAh / g, and has a capacity of about three times the capacity normally considered to be available in the lithium iron phosphate.

  Therefore, when the lithium ion battery is configured, it is necessary to make the mass of the positive electrode active material about 3 times the mass of the negative electrode active material, and sufficiently increase the energy density per mass. There is a problem that can not be.

  In order to solve the above problems, a positive electrode containing oxygen as an active material and containing lithium oxide or lithium peroxide, a negative electrode containing graphite as an active material, and an electrolyte sandwiched between the positive electrode and the negative electrode and capable of conducting lithium ions A lithium ion oxygen battery including a layer has been proposed (see, for example, Patent Document 1). In the lithium ion oxygen battery, the positive electrode includes activated carbon fibers and is open to the atmosphere, and oxygen in the atmosphere is oxidized by the activated carbon fibers.

  In the lithium ion oxygen battery, at the time of discharging, as shown in the following formula, metallic lithium occluded (intercalated) in the negative electrode is ionized to generate lithium ions and electrons. And the produced | generated lithium ion is discharge | released from the said graphite (deintercalation), permeate | transmits the said electrolyte layer, and moves to a positive electrode.

  On the other hand, in the positive electrode, oxygen taken in from the atmosphere receives electrons and becomes oxygen ions, and reacts with the lithium ions to generate lithium oxide or lithium peroxide. Therefore, electrical energy can be taken out by connecting the negative electrode and the positive electrode with a conductive wire.

(Negative electrode) 4Li → 4Li ⁺ + 4e ⁻
(Positive electrode) O ₂ + 4e ⁻ → 2O ²⁻
4Li ⁺ + 2O ²⁻ → 2Li ₂ O
2Li ⁺ + 2O ²⁻ → Li ₂ O ₂
Moreover, at the time of charge, as shown in the following formula, lithium ions, electrons, and oxygen are generated from lithium oxide or lithium peroxide in the positive electrode, and the generated lithium ions pass through the electrolyte layer and move to the negative electrode. In the negative electrode, the lithium ions receive electrons and are deposited as metallic lithium. The deposited metallic lithium is occluded (intercalated) into the graphite.

(Positive electrode) 2Li ₂ O → 4Li ⁺ + O ₂ + 4e ⁻
Li ₂ O ₂ → 2Li ⁺ + O ₂ + 4e ⁻
(Negative electrode) 4Li ⁺ + 4e ⁻ → 4Li
According to the lithium ion oxygen battery, since the positive electrode uses oxygen in the atmosphere as an active material, the mass of the positive electrode active material is not restricted and the energy density per mass can be increased.

Japanese Patent Laid-Open No. 2005-166585

  However, in the conventional lithium ion oxygen battery, since the positive electrode is open to the atmosphere, moisture and carbon dioxide contained in the atmosphere enter the battery, and each component deteriorates, resulting in reduced performance. There's a problem.

  In order to solve the above problem, in the conventional lithium ion oxygen battery, the positive electrode, the negative electrode, and the electrolyte layer are sealed and accommodated in a casing, and the positive electrode includes an oxygen storage material and lithium oxide or lithium peroxide. It is possible to do so. When doing so, the required oxygen is supplied from the oxygen storage material in the positive electrode, and each component of the lithium ion oxygen battery is not deteriorated by moisture or carbon dioxide contained in the atmosphere. It is expected that a lithium-ion oxygen battery having a large capacity can be obtained by avoiding the decrease of the battery.

  However, in the conventional lithium ion oxygen battery, if the negative electrode is made of graphite, the theoretical capacity is 372 mAh / g as described above, so that the battery capacity is limited, and lithium ions having a larger battery capacity are available. An oxygen battery is desired.

  In view of such circumstances, an object of the present invention is to provide a lithium ion oxygen battery capable of obtaining a large battery capacity.

  To achieve this object, a lithium ion oxygen battery of the present invention includes a positive electrode containing oxygen as an active material and a lithium source, a negative electrode containing a material capable of inserting or extracting lithium ions, and the positive electrode and the negative electrode. A positive electrode, a negative electrode, and an electrolyte layer are sealed and accommodated in a casing, and the positive electrode includes an oxygen storage material, the lithium A lithium compound as a source, and the negative electrode contains silicon as a material capable of inserting or extracting lithium ions.

  In the lithium ion oxygen battery of the present invention, since the positive electrode, the negative electrode, and the electrolyte layer are sealed and accommodated in a casing, each component is not deteriorated by moisture or carbon dioxide contained in the atmosphere, A lithium ion oxygen battery having a large capacity can be obtained. The lithium ion oxygen battery of the present invention includes silicon having a theoretical capacity of about 4000 mAh / g, which is larger than that of graphite, as a material capable of inserting or extracting lithium ions into the negative electrode, so that a larger battery capacity can be obtained. Can do.

  The lithium ion oxygen battery of the present invention further includes a solid electrolyte interface layer between the electrolyte layer and the negative electrode. According to the lithium ion oxygen battery of the present invention having the solid electrolyte interface layer, it is possible to maintain stable charge and discharge by eliminating irreversible capacity as a difference between charge capacity and discharge capacity, and excellent cycle performance. Can be obtained.

  The negative electrode includes a positive electrode made of a material containing silicon and capable of occluding or releasing lithium ions, a negative electrode made of metallic lithium, and an electrolyte layer sandwiched between the positive electrode and the negative electrode made of metallic lithium and capable of conducting lithium ions. Of a material containing silicon and capable of occluding or releasing lithium ions by repeatedly applying and removing lithium ions to and from the material containing silicon and capable of inserting or extracting lithium ions. Those having the solid electrolyte interface layer formed on the surface can be used.

  At this time, the solid electrolyte interface layer can be formed by repeating the insertion and removal of lithium ions from the material containing silicon and capable of inserting or extracting lithium ions until the irreversible capacity disappears. .

  In the lithium ion oxygen battery of the present invention, it is preferable that the oxygen storage material is made of a composite metal oxide containing yttrium and manganese. The oxygen storage material is composed of the composite oxide, and has a function of occluding or releasing the oxygen. The oxygen storage material can adsorb and desorb oxygen on the surface and act as a catalyst for a chemical reaction in the positive electrode. be able to.

  Therefore, in the lithium ion oxygen battery of the present invention, by using the oxygen storage material made of a composite metal oxide containing yttrium and manganese for the positive electrode, the theoretical capacity of the silicon contained in the negative electrode can be effectively utilized. And a larger battery capacity can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS Explanatory sectional drawing which shows the example of 1 structure of the lithium ion oxygen battery of this invention. Explanatory sectional drawing which shows the structure of the battery used for the repetitive operation of insertion and detachment of lithium ions from the negative electrode of the lithium ion oxygen battery of the present invention The graph which shows the charging / discharging curve of the 1st cycle in the battery shown in FIG. The graph which shows the charging / discharging curve of the 2nd cycle and the 3rd cycle in the battery shown in FIG. The graph which shows the charging / discharging curve of the 5th cycle when charging / discharging is repeated in the lithium ion oxygen battery shown in FIG.

  Next, embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

  As shown in FIG. 1 (a), a lithium ion oxygen battery 1 according to this embodiment includes a positive electrode 2, a negative electrode 3, and an electrolyte layer 4 disposed between the positive electrode 2 and the negative electrode 3. 2, the negative electrode 3, and the electrolyte layer 4 are hermetically housed in a case 5.

  The case 5 includes a cup-shaped case body 6 and a lid body 7 that closes the case body 6, and an insulating resin 8 is interposed between the case body 6 and the lid body 7. The positive electrode 2 includes a positive electrode current collector 9 between the top surface of the lid 7 and the negative electrode 3 includes a negative electrode current collector 10 between the bottom surface of the case body 6.

  In the lithium ion oxygen battery 1, the positive electrode 2 includes an oxygen storage material, a conductive material, and a binder, and includes a lithium compound. The oxygen storage material has a function of occluding and releasing oxygen, and at the same time, can adsorb and desorb oxygen on the surface thereof. Here, the oxygen storage material accompanies generation and dissociation of chemical bonds with oxygen when storing and releasing oxygen, but only intermolecular force is used when adsorbing and desorbing oxygen on the surface. Acts and does not involve chemical bond formation or dissociation.

  Therefore, the adsorption and desorption of oxygen to the surface of the oxygen storage material is performed with lower energy than when the oxygen storage material occludes and releases oxygen, and the cell reaction involves the surface of the oxygen storage material. Oxygen adsorbed on is preferentially used. As a result, a decrease in reaction rate and an increase in overvoltage can be suppressed.

It is preferable that the oxygen storage material has a function of occluding or releasing oxygen, can adsorb and desorb oxygen on the surface, and also functions as a catalyst for a chemical reaction in the positive electrode 2. Examples of such an oxygen storage material include a composite oxide containing Y and Mn such as YMnO ₃ .

  Examples of the conductive material include carbonaceous materials such as ketjen black. Examples of the binder include polytetrafluoroethylene (PTFE).

Examples of the lithium compound include lithium oxides such as lithium peroxide (Li ₂ O ₂ ) and lithium oxide (Li ₂ O).

  Next, the negative electrode 3 contains silicon as a material that can occlude or release lithium ions. Here, since silicon is a nonconductor, the negative electrode 3 preferably contains a conductive material and a binder together with silicon. Examples of the conductive material include carbonaceous materials such as ketjen black. Moreover, a polyimide etc. can be mentioned as said binder.

  In the negative electrode 3, the silicon, the conductive material, and the binder are dispersed in a dispersant such as N-methyl-2-pyrrolidone (NMP) or pure water, and the resulting dispersion is added to the negative electrode current collector 10. It can be formed by coating and drying.

  Next, the electrolyte layer 4 may be, for example, a nonaqueous electrolyte solution immersed in a separator, or may be a molten salt or a solid electrolyte.

As the non-aqueous electrolyte solution, for example, a lithium salt dissolved in a non-aqueous solvent can be used. Examples of the lithium salt include lithium hexafluorophosphate (LiPF ₆ ). Examples of the non-aqueous solvent include a carbonate ester solvent, an ether solvent, and an ionic liquid.

  Examples of the carbonate solvent include ethylene carbonate, propylene carbonate, dimethyl carbonate, and diethyl carbonate. Two or more of the carbonate ester solvents can be used in combination.

  Examples of the ether solvent include dimethoxyethane, dimethyl trigram, polyethylene glycol, and the like. Two or more of the ether solvents can be used in combination.

  Examples of the ionic liquid include cation such as imidazolium, ammonium, pyridinium, and peridium, bis (trifluoromethylsulfonyl) imide (TTSI), bis (pentafluoroethylsulfonyl) imide (BETI), tetrafluoroborate, park, and the like. Examples thereof include salts with anions such as lorate and halogen anions.

  Examples of the separator include glass fiber, glass paper, polypropylene nonwoven fabric, polyimide nonwoven fabric, polyphenylene sulfide nonwoven fabric, and polyethylene porous film.

  Examples of the solid electrolyte include an oxide solid electrolyte and a sulfide solid electrolyte.

Examples of the oxide solid electrolyte include Li ₇ La ₃ Zr ₂ O ₁₂ , which is a composite oxide of lithium, lanthanum, and zirconium, glass ceramics mainly composed of lithium, aluminum, silicon, titanium, germanium, and phosphorus. Can be mentioned. Li ₇ La ₃ Zr ₂ O ₁₂ replaces part of lithium, lanthanum, and zirconium with other metals such as strontium, barium, silver, yttrium, bismuth, lead, tin, antimony, hafnium, tantalum, and niobium. It may be what was done.

  Next, examples of the positive electrode current collector 9 include those made of mesh such as titanium, stainless steel, nickel, and aluminum. Further, examples of the negative electrode current collector 10 include metal foils such as copper, titanium, and stainless steel that are not alloyed with lithium.

  Moreover, it is preferable that the lithium ion oxygen battery 1 of this embodiment is provided with the solid electrolyte interface layer 11 between the negative electrode 3 and the electrolyte layer 4 as shown in FIG.1 (b). The solid electrolyte interface layer 11 is formed on the surface of the negative electrode 3 by repeating insertion and removal of lithium ions from the negative electrode 3. The solid electrolyte interface layer 11 may be naturally formed by repeating charge and discharge in the lithium ion oxygen battery 1 shown in FIG. It may be formed by performing an operation of repeating desorption (aging).

  The solid electrolyte interface layer 11 is formed by performing the aging on the negative electrode 3 in advance, so that the irreversible capacity can be eliminated.

  For example, as shown in FIG. 2, the aging can be performed by incorporating the silicon-containing material 3 a forming the negative electrode 3 in the battery 21 and repeating charge and discharge as the positive electrode 22. The battery 21 shown in FIG. 2 includes a positive electrode 22 made of a silicon-containing material 3a, a negative electrode 23 made of metallic lithium, and an electrolyte layer 24 disposed between the positive electrode 22 and the negative electrode 23. 23 and the electrolyte layer 24 are hermetically accommodated in the case 25. The case 25 has a configuration similar to that of the case 5 shown in FIG. 1A, and includes a cup-shaped case main body 26 and a lid 27 that closes the case main body 26. The case main body 26 and the lid Insulating resin 28 is interposed between 27 and 27. A current collector 29 is disposed between the positive electrode 22 and the top surface of the lid body 27.

  The silicon-containing material 3a that forms the negative electrode 3 is incorporated in the battery 21 and can be charged and discharged repeatedly until the irreversible capacity disappears, thereby forming the solid electrolyte interface layer 11 on the surface thereof. The silicon-containing material 3a on which the solid electrolyte interface layer 11 is formed is taken out from the battery 21 and used as the negative electrode 3 of the lithium ion oxygen battery 1 shown in FIG.

  In the lithium ion oxygen battery 1 of the present embodiment, at the time of charging, lithium ions and oxygen ions are generated from the lithium peroxide or lithium oxide as the lithium compound at the positive electrode 2 as shown in the following formula. Here, the lithium ions permeate through the electrolyte layer 4 and move to the negative electrode 3, and the oxygen ions are stored by generating a chemical bond in the oxygen storage material or adsorbed on the surface thereof. The

  On the other hand, in the negative electrode 3, the lithium ions that have moved from the positive electrode 2 are occluded by the silicon by receiving electrons and forming a lithium-silicon alloy.

(Positive electrode) Li ₂ O → 2Li ⁺ + O ²⁻
Li ₂ O ₂ → 2Li ⁺ + 2O ⁻
(Negative electrode) Si + 4.4Li ⁺ + 4.4e ⁻ → Li _4.4 Si
Further, at the time of discharging, as shown in the following formula, the lithium-silicon alloy is decomposed in the negative electrode 3 to generate lithium ions and electrons. The generated lithium ions are released from the silicon and move to the positive electrode 2 through the electrolyte layer 4. On the other hand, in the positive electrode 2, oxygen released from the oxygen storage material by dissociation of chemical bonds or taken out by desorption from the surface thereof receives electrons together with the lithium ions transferred from the negative electrode 3. Thus, lithium peroxide or lithium oxide is produced.

(Negative electrode) Li _4.4 Si → Si + _4.4 Li ⁺ + 4.4e ⁻
(Positive electrode) 4Li ⁺ + O ₂ + 4e ⁻ → 2Li ₂ O
2Li ⁺ + O ₂ + 2e ⁻ → Li ₂ O ₂
Therefore, electrical energy can be taken out by connecting the negative electrode 3 and the positive electrode 2 with a conducting wire (not shown).

  At this time, since the voids are formed in the positive electrode 2 by ionizing lithium peroxide or lithium oxide at the time of charging, the lithium peroxide or lithium oxide formed at the time of discharging is precipitated in the voids. can do. As a result, volume increase in the positive electrode 2 can be suppressed.

  Further, as shown in FIG. 1B, the lithium ion oxygen battery 1 includes the solid electrolyte interface layer 11 between the negative electrode 3 and the electrolyte layer 4, so that the electrolyte contacts the negative electrode 3. Therefore, the electrolyte is not decomposed by the reaction on the surface of the negative electrode 3. Therefore, according to the lithium ion oxygen battery 1 including the solid electrolyte interface layer 11, stable charge / discharge can be maintained without irreversible capacity, and excellent cycle performance can be obtained.

  Next, examples and comparative examples are shown.

[Example 1]
In this example, first, yttrium nitrate pentahydrate, manganese nitrate hexahydrate, and malic acid were pulverized and mixed in a molar ratio of 1: 1: 6 to obtain a composite metal oxide. A mixture of materials was obtained. Next, the resulting mixture of composite metal oxide materials was reacted at a temperature of 250 ° C. for 30 minutes, and further reacted at a temperature of 300 ° C. for 30 minutes and at a temperature of 350 ° C. for 1 hour. Next, the mixture of reaction products was pulverized and mixed, and then fired at a temperature of 1000 ° C. for 1 hour to obtain a composite metal oxide represented by the chemical formula YMnO ₃ .

Next, 40 parts by mass of the obtained YMnO _3, 50 parts by mass of ketjen black (manufactured by Lion Corporation) as a conductive material, and 10 parts by mass of polytetrafluoroethylene (manufactured by Daikin Industries, Ltd.) as a binder, Further, lithium peroxide as a lithium compound was added and mixed. The lithium peroxide had a mass twice that of silicon used for the negative electrode 3. And the obtained mixture was crimped | bonded to the positive electrode collector 9 which consists of Al meshes with the pressure of 5 MPa, and the positive electrode 2 of diameter 15mm and thickness 1mm was formed.

  Next, 90 parts by mass of silicon (manufactured by Kojundo Chemical Laboratory Co., Ltd.), 5 parts by mass of Ketjen Black (manufactured by Lion Corporation) as a conductive material, and 5 parts by mass of polyimide as a binder are N- Disperse in methyl-2-pyrrolidone and mix. Then, the obtained dispersion was applied on a copper foil having a thickness of 12.5 μm with an applicator, dried, and then punched by a press to form a silicon-containing material 3a having a diameter of 14 mm and a thickness of 100 μm.

  Next, the silicon-containing material 3a was incorporated into the battery 21 shown in FIG. First, the battery 21 was prepared by placing a negative electrode 23 made of metallic lithium having a diameter of 14 mm inside a bottomed cylindrical SUS case body 26 having an inner diameter of 17 mm, and a glass fiber separator having the same diameter (Japan). Plate glass). Next, the silicon-containing material 3a obtained as described above was superposed on the separator so as to be in contact with the separator, whereby a positive electrode 22 was obtained. The positive electrode 22 (silicon-containing material 3a) includes the copper foil as a current collector 29 on the surface opposite to the separator. Next, a non-aqueous electrolyte solution was injected into the separator to form an electrolyte layer 24.

As the non-aqueous electrolyte solution, lithium hexafluorophosphate (LiPF ₆ ) was dissolved as a supporting salt at a concentration of 1 mol / liter in a mixed solution in which 30 parts by mass of ethylene carbonate and 70 parts by mass of diethyl carbonate were mixed. The solution (made by Kishida Chemical Co., Ltd.) was used.

  Next, the laminate including the negative electrode 23, the electrolyte layer 24, the positive electrode 22, and the current collector 29 housed in the case main body 26 was sealed with a bottomed cylindrical SUS lid body 27 having an inner diameter of 17 mm. At this time, by disposing a ring-shaped insulating resin 28 made of polytetrafluoroethylene having an outer diameter of 70 mm, an inner diameter of 40 mm, and a thickness of 0.3 mm between the case body 26 and the lid body 27, FIG. The battery 21 shown was obtained.

Next, the battery 1 is mounted on an electrochemical measuring apparatus (manufactured by Toho Giken Co., Ltd.), and a current of 0.5 mA is applied between the positive electrode 22 and the negative electrode 23 per 1 cm ^{2 of} the negative electrode 23 to cut off the battery 1. Charging / discharging was repeated 3 cycles with the potential set at 0V and 2.0V. Thereby, operation (aging) which repeats insertion and detachment | desorption of lithium ion with respect to the positive electrode 22 (silicon-containing material 3a) was performed.

  The charge / discharge curve of the first cycle is shown in FIG. 3, and the charge / discharge curves of the second and third cycles are shown in FIG. In charge / discharge of the first cycle shown in FIG. 3, there is a difference between the discharge capacity (insertion of lithium ions with respect to the positive electrode 22) and the charge capacity (desorption of lithium ions from the positive electrode 22), and irreversible capacity is generated. ing. On the other hand, in the charge / discharge of the second cycle shown in FIG. 4, there is no difference between the discharge capacity and the charge capacity, and it is clear that the irreversible capacity disappears. The disappearance of the irreversible capacity indicates that the solid electrolyte interface layer 11 is formed on the surface of the positive electrode 22 (silicon-containing material 3a).

  Further, in the charge / discharge at the third cycle shown in FIG. 4, the charge / discharge capacity equivalent to that at the charge / discharge at the second cycle is maintained, and the positive electrode 22 (silicon-containing material 3a) in which the solid electrolyte interface layer 11 is formed. It is clear that excellent cycle performance can be obtained by using.

  Next, the battery 21 is disassembled, the silicon-containing material 3a subjected to the aging is taken out together with the current collector 29, and the current collector 29 is placed inside the bottomed cylindrical SUS case body 6 having an inner diameter of 17 mm. The negative electrode 3 was formed so as to be in contact with the bottom surface of the case body 6. At this time, the current collector 29 becomes the negative electrode current collector 10.

  Next, a glass fiber separator (manufactured by Nippon Sheet Glass Co., Ltd.) having a diameter of 17 mm was overlaid on the negative electrode 3. Next, the positive electrode 2 and the positive electrode current collector 9 obtained as described above were superimposed on the separator so that the positive electrode 2 was in contact with the separator. Next, a non-aqueous electrolyte solution was injected into the separator to form an electrolyte layer 4.

As the non-aqueous electrolyte solution, lithium hexafluorophosphate (LiPF ₆ ) as a supporting salt was dissolved at a concentration of 1 mol / liter in a mixed solution in which 50 parts by mass of ethylene carbonate and 50 parts by mass of diethyl carbonate were mixed. The solution (made by Kishida Chemical Co., Ltd.) was used.

  Next, a laminated body composed of the negative electrode current collector 10, the negative electrode 3, the electrolyte layer 4, the positive electrode 2, and the positive electrode current collector 9 housed in the case body 6 is formed into a bottomed cylindrical SUS lid body 7 having an inner diameter of 17 mm. Closed. At this time, by disposing a ring-shaped insulating resin 8 made of polytetrafluoroethylene having an outer diameter of 70 mm, an inner diameter of 40 mm, and a thickness of 0.3 mm between the case main body 6 and the lid body 7, FIG. The lithium ion oxygen battery 1 shown in b) was obtained.

Next, the lithium ion oxygen battery 1 obtained in this example was mounted on an electrochemical measurement device (manufactured by Toho Giken Co., Ltd.), and between the negative electrode 3 and the positive electrode 2, 0 per 1 cm ^{2 of} the negative electrode 3. A current of 0.1 mA was applied and the cut-off potential was set to 2.0 V and 4.0 V, or the charge / discharge capacity was 2500 mAh / g, and charge / discharge was repeated 5 cycles. FIG. 5 (a) shows the relationship between the cell voltage and the charge capacity in the fifth cycle, and FIG. 5 (b) shows the relationship between the cell voltage and the discharge capacity.

[Comparative Example]
In this comparative example, first, 40 parts by mass of lithium iron phosphate (LiFePO ₄ ), 50 parts by mass of Ketjen Black (manufactured by Lion Corporation) as a conductive material, and 10 parts by mass of carboxymethyl cellulose as a binder, Dispersed in water and mixed. Then, the obtained dispersion was applied on an Al foil having a thickness of 12.5 μm with an applicator, dried, and then punched out by a press to form a positive electrode having a diameter of 15 mm and a thickness of 100 μm. The positive electrode includes the Al foil as a positive electrode current collector.

In this comparative example, a lithium ion oxygen battery having the same configuration as that shown in FIG. 1A was obtained except that the positive electrode was used and the negative electrode 3 was not aged. In the lithium ion oxygen battery of this comparative example, as the non-aqueous electrolyte solution, a mixed solution in which 30 parts by mass of ethylene carbonate and 70 parts by mass of diethyl carbonate were mixed, and lithium hexafluorophosphate (LiPF) was used as a supporting salt. ₆ ) A solution (made by Kishida Chemical Co., Ltd.) in which 1) was dissolved at a concentration of 1 mol / liter was used.

  Next, except for using the lithium ion oxygen battery obtained in the present comparative example, charging / discharging was repeated 5 cycles in exactly the same manner as in the above example. FIG. 5 (a) shows the relationship between the cell voltage and the charge capacity in the fifth cycle, and FIG. 5 (b) shows the relationship between the cell voltage and the discharge capacity.

From FIG. 5, according to the lithium ion oxygen battery 1 (Example) including the positive electrode 2 including the oxygen storage material made of YMnO ₃ and the negative electrode 3 including silicon, the positive electrode including lithium iron phosphate and the negative electrode 3 including silicon. It is clear that a remarkably large charge / discharge capacity (battery capacity) can be obtained as compared with a lithium ion oxygen battery (comparative example) comprising

  DESCRIPTION OF SYMBOLS 1 ... Lithium ion oxygen battery, 2 ... Positive electrode, 3 ... Negative electrode, 4 ... Electrolyte layer, 5 ... Case, 11 ... Solid electrolyte interface layer

Claims (5)

Lithium ion oxygen comprising a positive electrode including oxygen as an active material and a lithium source, a negative electrode including a material capable of inserting or extracting lithium ions, and an electrolyte layer sandwiched between the positive electrode and the negative electrode and capable of conducting lithium ions In batteries,
The positive electrode, the negative electrode, and the electrolyte layer are sealed and accommodated in a casing, the positive electrode includes an oxygen storage material and a lithium compound as the lithium source, and the negative electrode can occlude or release lithium ions. A lithium ion oxygen battery comprising silicon as a material. Lithium ion oxygen comprising a positive electrode including oxygen as an active material and a lithium source, a negative electrode including a material capable of inserting or extracting lithium ions, and an electrolyte layer sandwiched between the positive electrode and the negative electrode and capable of conducting lithium ions In batteries,
The positive electrode, the negative electrode, and the electrolyte layer are sealed and accommodated in a casing, the positive electrode includes an oxygen storage material and a lithium compound as the lithium source, and the negative electrode can occlude or release lithium ions. A lithium ion oxygen battery comprising silicon as a material and having a solid electrolyte interface layer between the electrolyte layer and the negative electrode.   3. The lithium ion oxygen battery according to claim 2, wherein the negative electrode includes a positive electrode made of a material containing silicon and capable of occluding or releasing lithium ions, a negative electrode made of metallic lithium, and a negative electrode made of the positive electrode and the metallic lithium. A current is applied to a battery including an electrolyte layer that is sandwiched and can conduct lithium ions, and insertion and desorption of lithium ions are repeated with respect to a material that contains silicon and can absorb or release lithium ions, thereby A lithium ion oxygen battery characterized in that the solid electrolyte interface layer is formed on the surface of a material that can contain or release lithium ions.   4. The lithium ion oxygen battery according to claim 3, wherein the insertion and release of lithium ions with respect to the material containing silicon and capable of inserting or extracting lithium ions is repeated until the irreversible capacity disappears. Ion oxygen battery.   5. The lithium ion oxygen battery according to claim 1, wherein the oxygen storage material is composed of a composite metal oxide containing yttrium and manganese. 6.

Images