JP2728448B2 - Rechargeable battery - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a secondary battery, and more particularly, to a small-sized secondary battery having stable high capacity.

(Prior art) A secondary battery in which the main component of the positive electrode body is a transition metal chalcogen compound such as TiS ₂ or MoS ₂ and the negative electrode body is Li or an alkali metal mainly composed of Li has a high energy density. Therefore, commercialization efforts are being made.

Secondary batteries using a conductive polymer such as polyacetylene for the positive electrode and Li or an alkali metal mainly composed of Li for the negative electrode body have also been studied.

(Problems to be Solved by the Invention) However, in such a secondary battery, the negative electrode body is
There is a problem based on the fact that it is a Li foil or an alkali metal foil mainly containing Li.

In other words, when the battery is discharged, Li becomes Li ions from the negative electrode body and moves into the electrolytic solution, and when charged, these Li ions become metallic Li and are deposited again on the negative electrode body, but this charge / discharge cycle is repeated. And the metal Li deposited therewith becomes dendritic. This dendritic Li
Is an extremely active substance, which breaks down the electrolyte,
As a result, there arises a disadvantage that the charge / discharge cycle characteristics of the battery deteriorate. When this further grows, finally, the dendrite-like metal Li deposit penetrates through the separator and reaches the positive electrode body, causing a problem that a short-circuit phenomenon occurs. In other words, there is a problem that the charge / discharge cycle life is short.

In order to avoid such a problem, an attempt has been made to constitute the negative electrode body by using a carbonaceous material obtained by calcining an organic compound as a support and carrying Li or an alkali metal mainly composed of Li on the support.

The use of such an anode body has prevented the precipitation of Li dendrite, but on the other hand, batteries incorporating this anode body have a much higher discharge capacity than primary batteries of the same size. And the magnitude of self-discharge was not necessarily reduced to a satisfactory level.

An object of the present invention is to provide a secondary battery having a larger battery capacity and improved self-discharge characteristics under such circumstances.

[Constitution of the Invention] (Means for Solving the Problems) The present inventors have conducted intensive studies on the negative electrode body in order to solve the above problems, and as a result, have found that a carbonaceous material having a specific structure obtained by carbonizing crystalline cellulose is obtained. The present inventors have found that it is effective to achieve the above-mentioned object when used as a carrier for a negative electrode, and have arrived at the present invention.

That is, the secondary battery of the present invention includes a negative electrode body including an active material and a support for supporting the active material. (1) The active material is lithium or an alkali metal mainly containing lithium. (2) the carrier is made of a carbonaceous material obtained by carbonizing crystalline cellulose particles, and the carbonaceous material has (a) an atomic ratio of hydrogen / carbon of less than 0.10; and (b) an X-ray wide angle The interplanar spacing (d ₀₀₂ ) of the (002) plane by the diffraction method is 3.37 ° or more; and the crystallite size (Lc) in the c-axis direction is 150 ° or less.

The battery of the present invention is characterized in that the negative electrode body has the above-described configuration, and other elements may be the same as the conventional secondary battery.

In the negative electrode body according to the present invention, the active material is Li or Li.
The active material enters and exits the negative electrode body in response to charging and discharging of the battery.

The active material carrier constituting the negative electrode body in the present invention,
It is composed of a carbonaceous material obtained by carbonizing crystalline cellulose particles.

The crystalline cellulose particles used herein are obtained by hydrolyzing purified pulp with a mineral acid, washing and removing non-crystalline regions, and then pulverizing.

In the present invention, those having a volume average particle size of 300 μm or more, preferably 500 μm to 2.5 mm, more preferably 700 μm to 2.0 mm, are used.

When the volume average particle size of the crystalline cellulose particles thus obtained is 300 μm or less, a water-soluble polymer compound such as carboxymethyl cellulose is further used as a binder, and the average volume particle size in the above range is obtained. Granules or granules can also be used. Granulation can be performed by dispersing crystalline cellulose in water to which a binder has been added, followed by spray drying, a spray drier method or the like.

By using particles having a volume average particle diameter in the above-mentioned range, the fluidity of the carbonaceous material obtained by carbonizing the particles in the electrode forming step can be favorably maintained.

Further, the particles of the crystalline cellulose used in the present invention,
The ash content is preferably 0.25% by weight or less, more preferably 0.1% by weight.
It is at most 20% by weight, particularly preferably at most 0.08% by weight.

Further, as other elements that can be contained in the particles of the crystalline cellulose used in the present invention, Cu, Pb is preferably each
Less than 10 ppm, more preferably less than 1 ppm, particularly preferably less than 0.1 ppm, Fe is preferably less than 10 ppm, more preferably less than 5 ppm, Ca is preferably 300 ppm
Less, more preferably less than 200 ppm, particularly preferably
Less than 100 ppm.

In the present invention, the carbonaceous material constituting the support of the negative electrode body, the above-described particles of crystalline cellulose, under an inert gas flow or under vacuum, at a temperature of 350 ° C ~ 3000 ° C, thermal decomposition,
Obtained by carbonization. Usually, carbonization is performed in two stages.

That is, as the first step, an inert gas such as nitrogen or argon is used at a flow rate of 0.1 / hr or more, preferably 0.5 l / hr or more, more preferably 1.5 l / hr or more and 200 l / hr or less per kg of crystalline cellulose. While flowing helium or the like, at a temperature of 350 ° C or more and 1000 ° C or less, preferably at a temperature of 500 ° C or more and 1000 ° C or less, more preferably 700 ° C or more and 100 ° C or less.
Bake at a temperature of 0 ° C or less. Firing is 2 ℃ / hr or more and 500 ℃ / hr
min or less, preferably 10 ° C./hr or more and 50 ° C./min or less, more preferably 20 ° C./hr or more and 10 ° C./min or less at a heating rate, and further heated at this temperature for 1 minute From 10
Time, preferably from 10 minutes to 5 hours, more preferably
Perform by holding for 20 minutes to 2 hours.

Next, in the second stage, the material having undergone the first-stage thermal sintering is heated to a temperature exceeding 1000 ° C. under an inert gas flow or vacuum.
The carbonization is carried out at a temperature of 00 ° C or lower, preferably at a temperature of 1500 ° C or higher and 2800 ° C or lower, more preferably at a temperature of 1700 ° C or higher and 2500 ° C or lower. At this time, the oxygen concentration in the system is 100p
pm or less, preferably 50 ppm or less, particularly preferably 20 ppm
Hold so that:

The carbonization may be performed by raising the temperature to the above-mentioned temperature at an arbitrary heating rate, but is usually 20 ° C./hr or more, preferably 100 ° C.
/ hr or more and 200 ° C / min or less, more preferably 500 ° C / hr or more
The temperature is raised to the above-mentioned temperature at a heating rate of 60 ° C./min or less, and at that temperature for 1 minute to 10 hours, preferably 5 minutes to 5 minutes.
It can be carried out by holding for not more than time, more preferably not less than 10 minutes and not more than 3 hours.

The carbonaceous material constituting the support of the negative electrode body thus obtained according to the present invention is characterized by having the following characteristics.

(B) the atomic ratio of hydrogen / carbon (H / C) is less than 0.10; and (b) the plane spacing (d ₀₀₂ ) of the (002) plane by X-ray wide-angle diffraction is 3.37 ° or more; and the c-axis. The crystallite size in the direction (Lc) is 150 ° or less; In the carbonaceous material, other atoms, for example, atoms of nitrogen, oxygen, halogen and the like are preferably at most 7 mol%, more preferably at most 4 mol%, particularly preferably at most 2 mol%.
It may be present in a proportion of at most mol%.

H / C is preferably less than 0.07, more preferably less than 0.05, particularly preferably 0.04 or less.

The spacing (d ₀₀₂ ) of the (002) plane is preferably 3.39.
~ 3.75 °, more preferably 3.41 to 3.70 °, particularly preferably 3.45 to 3.70 °; the crystallite size Lc in the c-axis direction is preferably 5 to 150 °, more preferably 10 to 80 °, particularly preferably 12 °. It is ~ 70Å.

If any of these parameters, i.e., H / C, d ₀₀₂ and Lc, deviates from the above range, the overvoltage at the time of charging and discharging in the negative electrode body increases, and as a result, gas is generated from the negative electrode body. Not only does the safety of the battery significantly deteriorate, but also the charge / discharge cycle characteristics deteriorate.

Further, the carbonaceous material used for the support of the negative electrode body according to the present invention preferably has the following characteristics.

That is, in Raman spectrum analysis using an argon ion laser beam having a wavelength of 5145 °, the following formula: Is preferably less than 2.5, more preferably less than 2.0, particularly preferably 0.2 or more
It is less than 1.2.

Here, the G value refers to the above-mentioned carbonaceous material at a wavelength of 5145 °.
In the spectrum intensity curve recorded in the chart when the Raman spectrum analysis was performed using the argon ion laser light of the above, the integrated value (area intensity) of the spectrum intensity within the range of the wave number of 1580 ± 100 cm ⁻¹ was calculated as the wave number of 1360 ± 1. 100cm ^-1
, And corresponds to a measure of the degree of graphitization of the carbonaceous material.

That is, the carbonaceous material has a crystalline portion and an amorphous portion, and the G value is a parameter indicating the ratio of the crystalline portion in the carbonaceous structure.

Further, the carbonaceous material used for the support of the negative electrode body according to the present invention preferably satisfies the following conditions.

That is, the distance a ₀ (= 2d ₁₁₀ ), which is twice the spacing (d ₁₁₀ ) of the (110) plane in the X-ray wide-angle diffraction analysis, is preferably 2.38 ° to 2.47 °, more preferably 2.39 ° to 2.46 °; a
The size La of the crystallite in the axial direction is preferably 10 ° or more, more preferably 15 ° to 150 °, and particularly preferably 19 ° to 70 °.
It is.

The carbonaceous material described above has a volume average particle size of preferably 200
μm or less, more preferably 0.5 μm or more and 150 μm or less,
It is particularly preferably adjusted by pulverization or the like so that the particles have a size of 5 μm or more and 100 μm or less.

Such carbonaceous material particles have pores therein, and the total pore volume is preferably 1.5 × 10 ⁻³ ml / g or more, more preferably 2.0 × 10 ⁻³ ml / g or more, More preferably 3.0 × 10 ^-3 ml / g or more, more preferably 4.0 × 10 ^-3 ml
/ g or more.

The average pore radius (γ _p ) of the above-mentioned carbonaceous material is 8
~ 100 °, more preferably 10 ~ 80
Å, more preferably 12 to 60Å, particularly preferably 14 to
40Å.

The total pore volume and average pore radius are determined by measuring the amount of gas adsorbed on the sample under equilibrium pressure using a constant volume method.

That is, in the present invention, the total pore volume and the average pore radius mean those determined as follows.

The total pore volume is the relative pressure P / P ₀ determined using the constant volume method, assuming that the pores are filled with, for example, liquid nitrogen.
= 0.995 determine the total volume (VADS) nitrogen gas adsorbed in [P:: vapor pressure of adsorbed gas (mmHg), P ₀ the saturated vapor pressure of adsorbed gas at cooling temperature (mmHg)], then the following equation, Wherein, P _a is the atmospheric pressure (kgf / cm ^2), T is the measured temperature (K), V _m is the molecular volume of the gas adsorbed (cm ³ / mol; N ₂
Is 34.7), and V _liq is the liquid nitrogen volume (cm ³ )], and is converted to the amount of liquid nitrogen (V _liq ) filled in the pores.

Next, the average pore radius (γ _p ) is calculated from the following equation based on V _liq obtained from the above equation (1) and the value of the BET specific surface area (S) of the sample. Converted by The pores are assumed to be cylindrical.

Furthermore particles of the carbonaceous material described above, BET specific surface area is preferably 1 m ² / g or more, more preferably 2m ² / g or more 100 m ² /
g, particularly preferably 3 m ² / g or more and 50 m ² / g or less.

The active material carrier constituting the negative electrode body according to the present invention,
By mixing a metal that can be alloyed with the active material and / or an alloy of the active material with the specific carbonaceous material described above, the electrode capacity can be further improved.

Therefore, a metal that can be alloyed with such an active material and an alloy of the active material will be described.

As described above, since the active material is Li or an alkali metal mainly composed of Li, usually, a metal alloyable with Li or
It is preferable to use an alloy of Li.

As such a metal, for example, aluminum (A
l), lead (Pb), zinc (Zn), tin (Sn), bismuth (B
i), indium (In), magnesium (Mg), gallium (Ga), cadmium (Cd), silver (Ag), silicon (S
i), boron (B), gold (Au), platinum (Pt), palladium (Pd), antimony (Sb), etc., or an alloy thereof, and preferably Al, Pb, In, Bi and Cd. And more preferably Al, Pb and In.

The alloy has a composition (molar composition) of, for example, Li _x M (where x
Is the molar ratio to the metal M). As the other metal used as M, the above-mentioned metal that can be alloyed with Li can be used.

In Li _x M, x preferably satisfies 0 ≦ x ≦ 9, more preferably 0.1 ≦ x ≦ 5, further preferably 0.5 ≦ x ≦ 3, and particularly preferably 0.7 ≦ x ≦ 2.
It is.

One or more of the above metals can be used as the metal that can be alloyed with the active material, and one or two or more alloys can be used as the alloy (Li _x M) of the active material.

In addition, some metals that can be alloyed with Li or alloys of Li include
In addition to the above metals, other elements may be contained in a range of 50 mol% or less.

When the carrier constituting the negative electrode body according to the present invention is a material obtained by mixing a metal capable of being alloyed with the active material and / or an alloy of the active material with the carbonaceous material described above, the carbon in the mixed material may be used. The proportion of the substance is preferably 30 to 95% by weight, more preferably 50 to 90% by weight, particularly preferably
60-85% by weight.

The proportion of the metal which can be alloyed with the active material in the mixed material is preferably from 3% by weight to less than 60% by weight, more preferably from 5% by weight to less than 40% by weight, particularly preferably from 7% by weight to less than 30% by weight. The proportion of the alloy of the active material in the mixed material is preferably 3% by weight or more and less than 60% by weight,
It is more preferably at least 5% by weight and less than 40% by weight, particularly preferably at least 7% by weight and less than 30% by weight.

As a method for obtaining a mixture of the above-mentioned carbonaceous material particles, a metal that can be alloyed with the active material, and / or an alloy of the active material, for example, a powder of carbonaceous material, a metal that can be alloyed with the active material, and / or
Alternatively, a method of uniformly and mechanically mixing an active material alloy powder, a metal and / or an active material alloy that can be alloyed with the molten active material, and a carbonaceous material powder, and then cooling and solidifying. If necessary, there is a method of further pulverizing this.

The carrier constituting the negative electrode body according to the present invention may contain a conductive agent, a binder and the like in addition to the above-mentioned carbonaceous material.

As the conductive agent, expanded graphite, metal powder and the like can be added usually in an amount of less than 50% by weight, preferably in an amount of less than 30% by weight.

Further, the binder may be added with a powder such as a polyolefin resin in an amount of less than 50% by weight, preferably less than 30% by weight, more preferably 5% by weight or more and less than 10% by weight.

The carrier constituting the negative electrode body according to the present invention is manufactured, for example, as follows.

A method in which the above-mentioned carbonaceous material is directly added or a binder or the like is added thereto, and molded by compression molding, or a method in which the above-mentioned carbonaceous material is mixed with a binder dissolved or suspended in a solvent, and collected. A method in which the composition is applied to a body wire net or the like and molded is used.

Examples of a method for supporting the active material on the negative electrode body including the support obtained as described above include a chemical method, an electrochemical method, and a physical method.
A method of immersing the carrier, which is the powder compact described above, in an electrolytic solution containing Li ions or alkali metal ions, and electrolytically impregnating the carrier with lithium as the counter electrode to make the carrier an anode. A method of immersing the carrier in the electrolyte while lithium is in electrical contact with the carrier, a method of mixing lithium powder in the process of obtaining a molded body of the carrier, and the like can be applied.

By doing so, Li ions or alkali metal ions are doped into the carbonaceous material of the support and supported there. The supporting of the active material may be performed not only on the support of the negative electrode body but also on the support of the positive electrode body or on both electrodes.

The amount of the active material carried on the carrier of the negative electrode according to the present invention,
Preferably, (1) 1 to 20% by weight, more preferably 3 to 10% by weight, based on the carbonaceous material; and (2) a metal which can be alloyed with an active material in the carbonaceous material; /
Alternatively, when an alloy of an active material is mixed, a metal which can be alloyed with the active material and / or an alloy of the active material is 1 to 80%.
Mol%, more preferably 5 to 60 mol%, particularly preferably 10 to 50 mol%, and most preferably 20 to 50 mol%.

When the supported amount of the active material in the negative electrode body is smaller than the range defined in the above (1) and (2), the supported amount of the active material is too small to decrease the capacity of the battery. The change in the volume of the negative electrode body due to the discharge is increased, which results in poor current collection, and facilitates the formation of lithium dendrite, thereby shortening the charge / discharge cycle life.

Next, the configuration of the secondary battery of the present invention will be described with reference to the drawings. In the figure, the positive electrode can (1) also serves as the positive electrode terminal
A positive electrode body (2) is set in and housed at the bottom of the positive electrode can (1). The cathode body is not particularly limited, but is preferably made of, for example, a metal chalcogen compound which releases or acquires an alkali metal cation such as Li ion along with a charge / discharge reaction. Such metal chalcogen compounds include vanadium oxides, vanadium sulfides,
Molybdenum oxides, molybdenum sulfides, manganese oxides, chromium oxides, titanium oxides, titanium sulfides, composite oxides thereof, composite sulfides, and the like can be given. _{Preferably, Cr 3 O 8, V 2} O 5, V 6 O 13, VO 2, Cr 2 O 5,
MnO ₂ , TiO ₂ , MoV ₂ O ₈ , TiS ₂ , V ₂ S ₅ , MoS ₂ , MoS ₃ , VS ₂ , C
r _0.25 V _0.75 S ₂ , Cr _0.5 V _0.5 S ₂ and so on. Also, LiCoO ₂ , W
O oxide such as _{3, CuS, Fe 0.25 V 0.75} S 2, Na 0.1 CrS sulfides such as _2, NiPS _3, FePS ₃ like phosphorous, sulfur compounds, VSe _2, Nb
A selenium compound such as Se ₃ can also be used.

The negative electrode body (4) faces the positive electrode body (2) and the separator (3).

The separator (3) holding the electrolytic solution is made of a material having excellent liquid retaining properties, for example, a nonwoven fabric of a polyolefin resin. The separator (3) is provided with an aprotic organic solvent such as propylene carbonate, 1,3-dioxolan, 1,2-dimethoxyethane, or the like, with LiClO ₄ , LiBF ₄ , LiAsF ₅ ,
It is impregnated with a non-aqueous electrolyte of a predetermined concentration in which an electrolyte such as LiPF ₆ is dissolved.

Further, a solid electrolyte which is a conductor of Li or an alkali metal ion can be interposed between the positive electrode body and the negative electrode body.

The negative electrode body (4) is obtained by supporting an active material on a support made of a carbonaceous material having the above-described characteristics, and is mounted in a negative electrode can (5) also serving as a negative electrode terminal.

The positive electrode body (2), the separator (3), and the negative electrode body (4) constitute a power generating element as a whole. Then, the power generation element is incorporated in a battery container including the positive electrode can (1) and the negative electrode can (5), and a battery is assembled.

Reference numeral 6 denotes an insulating packing for separating the positive and negative electrode bodies. The battery is sealed by bending the opening of the positive electrode can (1) inward.

In the secondary battery of the present invention, release of Li ions (or alkali metal ions mainly composed of Li) carried at the time of discharging occurs in the negative electrode body, and at the time of charging, the release of Li ions to the carbonaceous material in the carrying body occurs. By doping, Li ions are carried on the carrier of the negative electrode.

The charging / discharging cycle of the battery is repeated by carrying and releasing such Li ions.

The secondary battery of the present invention can support a large amount of the active material on the negative electrode body by using the support made of the above-mentioned carbonaceous material for the negative electrode body. Since it is possible to repeat loading and discharging, excellent charge / discharge characteristics can be exhibited with a large capacity, which has never existed before.

In the present invention, each measurement of elemental analysis and X-ray wide-angle diffraction was performed by the following methods.

“Elemental analysis” The sample was dried under reduced pressure at 120 ° C. for about 15 hours, and then dried at 100 ° C. for 1 hour on a hot plate in a dry box. Then, sampling is performed on an aluminum cup in an argon atmosphere, and the carbon content is determined from the weight of CO ₂ gas generated by combustion, and the hydrogen content is determined from the weight of H ₂ O generated. In the examples of the present invention described later, the measurement was performed using a Perkin Elmer 240C elemental analyzer.

"X-Ray Wide Angle Diffraction" (1) Spacing between ( ₀₀₂ ) planes (d ₀₀₂ ) and (110) plane (d ₁₁₀ ) When the carbonaceous material is a powder, as it is Powdered in a mortar, about 15% by weight of the sample, high-purity silicon powder for X-ray standard as an internal standard substance was added and mixed, filled in a sample cell, and a monochromatized CuKα ray with a graphite monochromator was used as a radiation source. A wide-angle X-ray diffraction curve is measured by a reflection type diffractometer method.
For the correction of the curve, the following simple method is used without correcting so-called Lorentz, polarization factor, absorption factor, atomic scattering factor and the like. That is, the base line of the curve corresponding to the (002) and (110) diffractions is drawn, and the substantial intensity from the base line is re-plotted to obtain a correction curve for the (002) plane and the (110) plane. The midpoint of the line where the line parallel to the angle axis drawn to two-thirds of the peak height of this curve intersects the diffraction curve is determined, the angle of the midpoint is corrected by the internal standard, and this is repeated. twice the precious obtains the d ₀₀₂ and d ₁₁₀ from the wavelength of the CuKα line λ by the Bragg equation follows.

λ: 1.5418Å θ, θ ': diffraction angle corresponding to d ₀₀₂ , d ₁₁₀ (2) Crystallite size in c-axis and a-axis directions: Lc; La Peak height in the corrected diffraction curve obtained in the preceding section C axis and a using a so-called half width β at half the position of
The size of the crystallite in the axial direction is determined by the following equation.

Although there are various arguments about the shape factor K, K = 0.90 was used. λ. θ and θ ′ have the same meaning as in the previous section.

(Examples) Hereinafter, the present invention will be described with reference to examples.

Example (1) Production of Positive Electrode Body 5 g of MnO ₂ powder fired at 470 ° C. and 0.5 g of powdered polytetrafluoroethylene were kneaded, and the obtained kneaded product was roll-formed into a sheet having a thickness of 0.4 mm. .

One side of this sheet was pressed against a 60-mesh stainless steel net having a wire diameter of 0.1 mm as a current collector to form a positive electrode.

(2) Production of negative electrode body The purified pulp was hydrolyzed with a mineral acid and then filtered. The residue is washed with water, pulverized, purified, and dried by a conventional method. A crystalline cellulose powder (average particle size of 40 μm) is dispersed in water to which carboxymethylcellulose is added, and then spray-dried to obtain a volume average particle size of about 1 mm. Was granulated.

The crystalline cellulose powder had an ash content of 0.08% by weight or less and a heavy metal content of 20 ppm or less.

Set the granulated particles of the crystalline cellulose into an electric furnace, under a stream of N ₂ at a rate of crystalline cellulose 1kg per 100l / hr, the temperature was raised to 1000 ° C. at a heating rate of 250 ° C. / hr, further 1000 C. for 1 hour and allowed to cool.

Further, the heat-treated product is set in another electric heating furnace, and while flowing N ₂ gas, 1700 at a heating rate of 1000 ° C / hr.
The temperature was raised to 0 ° C., and the temperature was maintained for another hour to fire.

The carbonized material thus obtained was placed in a 250 ml agate container, and one 30 mm diameter agate ball, three 25 mm diameter agate balls, and eight 20 mm diameter agate balls were set in a ball mill, Milled for 3 minutes.

As a result of analysis such as elemental analysis, X-ray wide-angle diffraction, particle size distribution, and specific surface area (BET method) measurement, the carbonaceous material had the following characteristics.

Hydrogen / carbon (atomic ratio) = 0.04 d ₀₀₂ = 3.60Å, Lc = 21Å a ₀ (2d ₁₁₀ ) = 2.41Å, La = 24Å, volume average particle size = 36.7 μm, specific surface area (BET) = 7.8 m ² / g, angle of repose = 46 ° After mixing 7% by weight of polyethylene powder having an average particle size of 5 µm with the carbonaceous material powder, compression molding is performed and the thickness is 0.5 m.
m-shaped pellet-shaped support.

(3) the cathode can made of assembled stainless steel cell, a positive electrode as described above and clamped by and the current collector down after placing the polypropylene nonwoven fabric as a separator thereon, concentration LiClO ₄ therein 1
A non-aqueous electrolyte dissolved in propylene carbonate at mol / l was impregnated. Then, the above-mentioned negative electrode body was mounted thereon to form a power generating element.

Prior to the incorporation into the battery, the negative electrode support pellet was immersed in a 1 mol / l Li-ion electrolytic solution, and subjected to electrolytic treatment using the pellet as an anode and metallic Li as a cathode. The electrolytic treatment was performed under the conditions of a bath temperature of 20 ° C. and a current density of 0.5 mA / cm ² , and 12.0 mAh of Li was carried on the carrier to obtain a negative electrode body.

Prior to assembling the positive electrode into the battery, the positive electrode was immersed in a 1 mol / l Li-ion electrolyte, and the positive electrode was used as the anode.
It was subjected to electrolytic treatment using metal Li as a cathode. The electrolysis treatment was performed under the conditions of a bath temperature of 20 ° C., a current density of 0.5 mA / cm ² , and an electrolysis time of 7 hours, and loaded 2.0 mAh of Li on the positive electrode body.

Thus, a button type secondary battery as shown in the figure was manufactured.

(4) Characteristics of Battery The battery manufactured in this manner was repeatedly charged and discharged at a constant current of 250 μA and a battery voltage in the range of an upper limit of 3.2 V and a lower limit of 1.8 V, and cycle evaluation was performed. 50th cycle, 20
Table 1 shows the battery performance at the 0th cycle.

Furthermore, when the charge of the 51st cycle was completed incorrectly, the circuit was opened and left for 90 days, and then the discharge was performed.
Compare the second cycle battery performance with the 50th cycle
It is shown in the table.

Comparative Example (1) Production of Positive Electrode Body A positive electrode body was produced in the same manner as in Example.

(2) Production of negative electrode body The mesoface pitch was heated to 2600 ° C under N ₂ flow,
Thereafter, the temperature was kept at 2500 ° C. for 1 hour.

This mesoface pitch was placed in a 250 ml agate container, 15 agate balls having a diameter of 20 mm were placed in a ball mill, and ground for 10 minutes.

As a result of the same analysis as in the example, the obtained carbonaceous material had the following characteristics.

Hydrogen / carbon (atomic _{ratio) = 0.03 d 002 = 3.40Å,} Lc = 87Å a 0 (2d 110) = 2.41Å, La = 81Å, volume average particle size = 27.3μm, specific surface area (BET) = 10.1 m ² / g After mixing 7% by weight of polyethylene powder having an average particle size of 5 μm with the powder of the carbonaceous material, the mixture is compression-molded to a thickness of 0.5 m.
m-shaped pellet-shaped support.

(3) Battery assembly A battery was assembled in the same manner as in the example.

(4) Battery Characteristics The battery characteristics were measured under the same conditions as in the examples, and the results are shown in Tables 1 and 2.

[Effects of the Invention] As is clear from the above description, the secondary battery of the present invention has a long charge-discharge cycle life, and has a stable active material of Li or an alkali metal mainly composed of Li during charging. Since the battery can be fixed to the carrier in a stable form, stable high capacity, that is, large current discharge is possible, and the battery has good self-discharge characteristics and high reliability, so that its industrial value is great.

Although the description so far has been made with respect to a secondary battery having a button-shaped structure, the technical idea of the present invention is not limited to this structure, and for example, a cylindrical shape, a flat shape, a rectangular shape, etc. It can also be applied to secondary batteries.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a button type secondary battery according to an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1 ... Positive electrode can, 2 ... Positive electrode body 3 ... Separator 4, ... Negative electrode body 5 ... Negative electrode can, 6 ... Insulating packing

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Hiroshi Yui 1 Tohocho, Yokkaichi-shi, Mie Mitsubishi Oil Chemicals Co., Ltd. New Materials Research Laboratories (72) Inventor Katsuharu Ikeda 3-4-1-10 Minamishinagawa, Shinagawa-ku, Tokyo Toshiba Battery Co., Ltd. (72) Inventor Kuniaki Inada 3-4-1, Minamishinagawa, Shinagawa-ku, Tokyo Toshiba Battery Co., Ltd. (72) Yuji Mochizuki 3-4-1, Minamishinagawa, Shinagawa-ku, Tokyo No. Toshiba Battery Co., Ltd. (72) Inventor Tsuchiyama et al. Toshiba Battery Co., Ltd. 3-4-1-10 Minamishinagawa, Shinagawa-ku, Tokyo (56) References JP-A-63-193462 (JP, A) JP-A-63-193462 Hei 1-255165 (JP, A)

Claims (1)

(57) [Claims] 1. A secondary battery comprising a negative electrode body comprising an active material and a carrier for supporting the active material, wherein (1) the active material is lithium or an alkali metal mainly composed of lithium; 2) The support is made of a carbonaceous material obtained by carbonizing particles of crystalline cellulose, and the carbonaceous material has (a) an atomic ratio of hydrogen / carbon of less than 0.10; and (b) a wide-angle X-ray diffraction method. 002) A secondary battery having a plane spacing (d ₀₀₂ ) of 3.37 ° or more; and a crystallite size (Lc) in the c-axis direction of 150 ° or less.