JP3318767B2 - Negative electrode material, method for producing the same, and nonaqueous electrolyte battery using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a negative electrode material comprising a compound containing carbon, phosphorus and oxygen as main components and doped with and dedoped with lithium, and a method for producing the same. The present invention relates to a non-aqueous electrolyte battery.

[0002]

2. Description of the Related Art The electric capacity per unit weight of a carbonaceous material is determined by the doping amount of lithium. Therefore, in order to increase the charge / discharge capacity of a battery, the doping amount of carbon material with respect to lithium must be as large as possible. (Theoretically, the ratio of one Li atom to six carbon atoms is the upper limit.)

Conventionally, as a carbonaceous material used for a negative electrode of this type of battery, for example, as described in Japanese Patent Application Laid-Open No. 62-122066 or Japanese Patent Application Laid-Open No. 62-90863, an organic material is used. Carbonaceous materials obtained by carbonization are known.

[0004]

However, in the above-mentioned carbonaceous materials, the doping amount of lithium is insufficient, which is only about half the theoretical value. Therefore, the present invention has been proposed for the purpose of further improving the carbonaceous material, and an object of the present invention is to provide a negative electrode material having a lithium doping amount which is much larger than that of the conventional carbonaceous material and a method for producing the same. .

Another object of the present invention is to provide a non-aqueous electrolyte battery having a large discharge capacity and excellent cycle life characteristics.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, it has been found that a specific compound composed of carbon, phosphorus and oxygen exhibits good characteristics as a negative electrode material. Of knowledge. And ³¹ P
By conducting structural analysis by nuclear-solid NMR and XPS (X-ray photoelectron spectroscopy), the added phosphorus atom does not exist as an atom alone or as a compound such as an oxide alone, but reacts with carbon or oxygen during the firing process. Thus, it was found that a compound having a bond such as carbon-phosphorus or carbon-oxygen-phosphorus was formed. This means that the effect of adding a phosphorus compound that causes an increase in the lithium doping amount is not a mere doping / dedoping of lithium to a carbon material, but a special compound containing carbon, oxygen, and phosphorus as main components (hereinafter referred to as C-P-
It is called O compound. ) Means expressed.

The negative electrode material of the present invention has been completed on the basis of the above findings, and has carbon, phosphorus and oxygen as main components, and has a phosphorus content of 0.2 to 9.0% by weight. , 31P nuclear-solid NMR spectrum has a peak in the range of ± 100 ppm on the basis of orthophosphoric acid, and the X-ray photoelectron spectroscopy measurement shows that the carbon-carbon bond energy of the carbon atom 1s orbital spectrum is 284.6 eV. A carbon material heat-treated at 700 ° C. or less having a peak of a phosphorus atom 2p orbital spectrum of 135 eV or less
Sintered with phosphorus compound added to raw material or organic material
It is mainly made of coke .

[0008] Further, the manufacturing method of the present invention is characterized in that :
And adding a phosphorus compound in an amount of 0.2 to 32% by weight in terms of phosphorus to an organic material or a carbon material which becomes coke by firing , and firing in an inert atmosphere. Further, the non-aqueous electrolyte battery of the present invention contains carbon, phosphorus, and oxygen as main components and has a phosphorus content of 0.2 to 9.0% by weight.
± 100 pp based on orthophosphoric acid in MR spectrum
m, and in the X-ray photoelectron spectroscopy measurement, when the bond energy between carbon and carbon in the carbon atom 1s orbital spectrum is 284.6 eV, the peak of the phosphorus atom 2p orbital spectrum is 135 eV or less. Have
Carbon materials or organic materials heat-treated at 700 ° C or less
A negative electrode mainly composed of coke , which is obtained by adding phosphorus pentoxide to sintering , a positive electrode containing Li, and a non-aqueous electrolyte.

[0009] The negative electrode material of the present invention is obtained by adding a phosphorus compound to an organic material or a carbon material and baking in an inert atmosphere. The organic material or the carbon material used as a starting material is arbitrary, and for example, (00
2) The surface spacing is 3.70 ° or more, and the true density is 1.70 g.
/ Cm ³ and 7 by differential thermal analysis in an air stream.
An organic material or a carbon material which does not have an exothermic peak at 00 ° C. or more and is a so-called non-graphitizable carbon is preferable.

[0010] The non-graphitizable carbon has a large lithium doping amount as compared with a conventional carbon material, and in combination with the effect of the addition of a phosphorus compound, a negative electrode having a lithium doping amount greatly exceeding the conventional carbonaceous material. Materials can be provided.

As the organic material used as a starting material for the non-graphitizable carbon, furfuryl alcohol or furfural made of a homopolymer or copolymer of furfural is preferable. This is because the carbonaceous material obtained by carbonizing this furan resin has a (002) plane spacing of 3.70 ° or more, a true density of 1.70 g / cc or less, and has no oxidative heat peak at 700 ° C. or more in DTA. This is because they exhibit very good characteristics as a negative electrode material of a battery. .

Other starting materials that become non-graphitizable carbon include those obtained by introducing a functional group containing oxygen into a petroleum pitch having a specific H / C atomic ratio (so-called oxygen crosslinking). Similarly, it exhibits excellent properties when carbonized, so that it can be used. The petroleum pitch is distilled (vacuum distillation, atmospheric distillation, steam distillation) of tars, asphalt, etc. obtained by high-temperature pyrolysis of coal tar, ethylene bottom oil, crude oil, etc., thermal polycondensation, extraction, chemical polycondensation And the like.

At this time, the H / C atomic ratio of the petroleum pitch is important, and the H / C atomic ratio needs to be 0.6 to 0.8 in order to obtain non-graphitizable carbon. The specific means for introducing a functional group containing oxygen into these petroleum pitches is not limited. For example, a wet method using an aqueous solution of nitric acid, mixed acid, sulfuric acid, hypochlorous acid, or the like, or an oxidizing gas (air, oxygen) A dry method, furthermore, a reaction with a solid reagent such as sulfur, ammonium nitrate, ammonium persulfate, and ferric chloride is used.

For example, when oxygen is introduced into petroleum pitch by the above method, the final carbonaceous material can be obtained in a solid phase without melting in the carbonization process (400 ° C. or higher),
It is similar to the formation process of non-graphitizable carbon.

The petroleum pitch into which the functional group containing oxygen is introduced is carbonized by the above-described method to produce a negative electrode material. Regardless of the conditions for carbonization, the (002) plane spacing is 3.70 ° or more, and the true density is reduced. 1.70 g / cc or less and 700 in DTA
If it is set so as to obtain a carbonaceous material that satisfies the characteristic that it does not have an oxidative heat peak at a temperature of not less than ° C., a material having a large lithium doping amount per unit weight is obtained. This is because, for example, by setting the oxygen content of the precursor obtained by oxygen-crosslinking petroleum pitch to 10% by weight or more, the (002) plane spacing can be set to 3.70 ° or more. Therefore, the oxygen content of the precursor is preferably set to 10% by weight or more, and is practically in the range of 10 to 20% by weight.

Further, the organic material for performing the oxygen crosslinking is H.
Since the / C atomic ratio only needs to be 0.6 to 0.8, it can be used by performing a pre-heat treatment such as pitching. Examples of such starting materials include phenolic resins, acrylic resins, vinyl halide resins, polyimide resins, polyamide imide resins, polyamide resins, conjugated resins, selenthrene, anthracene, triphenylene, pyrene, perylene, pentaphene, and pentacene. Cyclic hydrocarbon compounds, other derivatives (eg, carboxylic acids, carboxylic anhydrides, carboxylic imides and the like), various pitches mainly containing a mixture of the above compounds, acenaphthylene, indole, isoindole, quinoline, isoquinoline, quinoxaline, Phthalazine, carbazole, acridine,
Condensed heterocyclic compounds such as phenazine and phenanthridine;
And derivatives thereof.

Alternatively, as a starting material, an organic material or a carbon material which is heat-treated at a temperature of 700 ° C. or less and is fired to become coke may be used. Here, coke is
It is a carbon material that becomes graphitizable when heat-treated at about 3000 ° C., that is, easily graphitizable carbon, and is advantageous in terms of packing density compared to the above non-graphitizable carbon.

That is, in a cylindrical practical battery formed by winding spiral electrodes, the electrode area must be increased in order to charge and discharge at a high rate, but the electrodes must be filled with more active material. Must. However, since a carbon material has a lower true density than an oxide-based active material, a capacity increase due to a phosphorus addition effect occurs in a carbon material having a higher true density, for example, coke (a true density of about 2.0 g / cm ³ ). If it can be achieved, it is expected that the capacity can be further increased as compared with the case where phosphorus is contained in non-graphitizable carbon.

Typical examples of the organic material used as a starting material for the graphitizable carbon include coal and pitch. Pitch can be obtained by distillation (vacuum distillation, atmospheric distillation, steam distillation, etc.) from tar, asphalt, etc. obtained by high-temperature pyrolysis of coal tar, ethylene bottom oil, crude oil, etc., thermal polycondensation, extraction, chemical polycondensation, etc. There are also those obtained by the operation, and other pitches generated during wood carbonization.

The raw material of the high molecular compound includes polyvinyl chloride resin, polyvinyl acetate, polyvinyl butyrate, 3,5-dimethylphenol resin and the like.

These raw materials have a maximum of 400 during the carbonization.
It exists in a liquid state at about ℃, the aromatic rings are condensed by holding at that temperature, polycyclized to be in a laminated orientation state, and then when the temperature becomes about 500 ° C. or more, a solid carbon precursor, that is, semi-coke is formed. Form. Such a process is called a liquid phase carbonization process and is a typical production process of graphitizable carbon.

The above-mentioned raw materials such as coal, pitch, and high molecular compound are naturally subjected to the above-mentioned liquid phase carbonization process when carbonized. In addition, condensed polycyclic hydrocarbon compounds such as naphthalene, phenanthrene, anthracene, triphenylene, pyrene, perylene, pentaphen, and pentacene, and other derivatives (for example, these carboxylic acids,
Carboxylic anhydrides, carboxylic imides, etc.), mixtures of the above compounds, condensed heterocyclic compounds such as acenaphthylene, indole, isoindole, quinoline, isoquinoline, quinoxaline, phthalazine, carbazole, acridine, phenazine, phenanthridine, and derivatives thereof Can also be used as a raw material.

When a carbonaceous material is obtained by using the above raw material organic material, for example, after carbonizing at 300 to 700 ° C. in a nitrogen stream, the temperature is increased in a nitrogen stream at a rate of 1 to 20 ° C. per minute and a temperature of 900 to 900 ° C. What is necessary is just to bake on conditions of 1500 degreeC and the holding time at the ultimate temperature 0-5 hours. Of course, in some cases, the carbonization operation may be omitted. In the present invention, before the raw material organic material is fired, or after the raw material organic material is carbonized to some extent, by adding a phosphorus compound and firing, the lithium doping amount containing carbon, phosphorus and oxygen as main components is obtained. Can be obtained.

Examples of the phosphorus compound include oxides of phosphorus such as phosphorus pentoxide, oxo acids such as orthophosphoric acid, and salts thereof. Phosphorus oxide and phosphoric acid are preferred from the viewpoint of easy handling. is there. In particular, when a raw material that becomes coke (easily graphitizable carbon) after firing is used, a phosphorus oxide such as phosphorus pentoxide is preferable.

In the present invention, upon production, 0.2 to 32% by weight, preferably 1.0 to 15% by weight of the C—P—O compound raw material, that is, an organic material or a carbon material, in terms of phosphorus.
% By weight of a phosphorus compound.
The proportion of phosphorus remaining in the -PO compound is 0.2 to 9.
0% by weight, preferably 0.3 to 5.0% by weight. In particular, in the case of non-graphitizable carbon after firing, CPO
0.2 to 15% by weight in terms of phosphorus based on the raw material of the compound,
Preferably, a phosphorus compound is added at a ratio of 0.5 to 7% by weight, and the ratio of phosphorus remaining in the obtained CPO compound is preferably 0.2 to 5.0% by weight.

If the amount of the phosphorus compound added is less than the above range and the proportion of phosphorus in the CPO compound is too small,
The effect of increasing the doping amount of lithium cannot be expected so much. Conversely, if the amount of the phosphorus compound added is too large,
Even if the proportion of phosphorus in the -O compound is too large, C which substantially contributes to lithium doping by increasing elemental phosphorus, etc.
There is a possibility that the proportion of the -PO compound is reduced and the properties are rather deteriorated.

When the phosphorus compound is added, a CPO compound is basically formed even if it is added to a carbonaceous material, but the amount of remaining phosphorus becomes smaller. The lithium doping amount does not increase much. Therefore, it is preferable to add the phosphorus compound from the starting materials as much as possible. In particular, coke after firing (graphitizable carbon)
In this case, the maximum temperature at which the phosphorus compound is added is 70.
0 ° C. Even if added to a material processed at a temperature higher than that, phosphorus is still contained to some extent, but lithium-doped
There is no effect on undoping. This suggests that the C—P—O bond site in the bulk, which would be formed by the reaction between the raw material and the phosphorus compound in the firing process, participates in lithium doping and undoping.

The CPO compound obtained by calcination is pulverized and classified for use as a negative electrode material. This pulverization may be performed before or after calcination or during the temperature raising process. When the above-mentioned CPO compound is used as a negative electrode of a non-aqueous electrolyte battery, the positive electrode preferably contains a sufficient amount of Li, for example, a general formula LiMO ₂ (where M is at least Co or Ni The composite metal oxide represented by the formula (1), an intercalation compound containing Li, and the like are preferable. Particularly, LiCoO ₂
Good characteristics are exhibited when using such as.

Since the nonaqueous electrolyte battery of the present invention aims at achieving a high capacity, the positive electrode is kept in a steady state (for example, after repeating charge and discharge about 5 times).
-It is necessary to contain Li corresponding to a charge / discharge capacity of 250 mAH or more per 1 g of the PO compound, and desirably contains Li corresponding to a charge / discharge capacity of 300 mAH or more.
It is more preferable to include Li corresponding to a charge / discharge capacity of 0 mAH or more. Note that it is not always necessary to supply all of Li from the positive electrode material. In short, Li is equivalent to a charge / discharge capacity of 250 mAH or more per 1 g of CPO compound in the battery system.
Should exist. The amount of Li is determined by measuring the discharge capacity of the battery.

The non-aqueous electrolyte is prepared by appropriately combining an organic solvent and an electrolyte, and any of these organic solvents and electrolytes can be used as long as they are used in this type of battery. For example, propylene carbonate, ethylene carbonate, diethyl carbonate, dimethyl carbonate, methyl ethyl carbonate, 1,2-dimethoxyethane, 1,2-diethoxyethane, γ-butyrolactone, tetrahydrofuran, 2-methyltetrahydrofuran, 1 , 3-dioxolan, 4-methyl-1,3-dioxofuran, diethyl ether, sulfolane, methylsulfolane, acetonitrile,
Propionitrile, anisole, acetate, butyrate, propionate and the like.

As the electrolyte, LiClO ₄ , LiAs
F ₆ , LiPF ₆ , LiBF ₄ , LiB (C
_{6 H 5) 4, CH 3} SO 3 Li, CF 3 SO 3 Li, L
iCl, LiBr and the like.

[0032]

By adding a phosphorus compound to an organic material or a carbon material and firing in an inert atmosphere, carbon-phosphorus or carbon-carbon containing carbon, phosphorus and oxygen as main components is obtained.
A compound having an oxygen-phosphorus bond is formed. In particular, in the ³¹ P nucleus-solid NMR spectrum, it has a peak in the range of ± 100 ppm based on orthophosphoric acid, and in X-ray photoelectron spectroscopy measurement, the binding energy between carbon and carbon in the carbon atom 1s orbital spectrum is 284.6 eV. A compound having a peak of 2e orbital spectrum of phosphorus atom of 135 eV or less has a larger lithium doping amount than a conventional carbonaceous material. By using this material for a negative electrode, a compound having a large charge / discharge capacity can be obtained. A water electrolyte secondary battery becomes possible.

[0033]

EXAMPLES The present invention will be described below with reference to specific examples, but it goes without saying that the present invention is not limited to these examples. First, a method of measuring the negative electrode capacity, ³¹ P nucleus-solid NMR spectrum and X-ray photoelectron spectroscopy spectrum employed in this example will be described.

Material for measuring the capacity , such as the C—O—P compound obtained after firing, was crushed in a mortar, classified with a mesh to 38 μm or less, and evaluated using a test cell. In preparing the test cell, first, the classified powder was subjected to a pre-heat treatment in an Ar atmosphere immediately before the preparation of the negative electrode mix, under the conditions of a heating rate of about 30 ° C./min, a reaching temperature of 600 ° C., and a reaching temperature holding time of 1 hour. Thereafter, 10% by weight of polyvinylidene fluoride was added as a binder, mixed with dimethylformamide as a solvent, and dried to prepare a negative electrode mix. Thereafter, 37 mg thereof was formed into a pellet having a diameter of 15.5 mm together with a Ni mesh as a current collector to prepare a working electrode. The configuration of the test cell is as follows.

<Cell Configuration> Coin-type cell (diameter 20 mm, thickness 2.5 mm) Counter electrode: Li metal Separator: Porous polypropylene membrane Electrolyte: Propylene carbonate and 1,2-
Li mixed solvent of dimethoxyethane (1: 1 by volume ratio)
One in which ClO ₄ is dissolved at a rate of 1 mol / l.

Current collector: copper foil

With respect to the test cell having the above configuration, CP-
The capacity per 1 g of the O compound was measured. Lithium doping into the working electrode (charging: Strictly speaking, in this test method, the process of doping the CPO compound is not charging but discharging, but for the sake of convenience according to the actual situation in an actual battery, The process is referred to as charging, and the undoping process is referred to as discharging.) Is a process in which charging is performed for 1 hour and resting for 2 hours at a current density of 0.53 mA / cm ² , and the equilibrium potential at rest is 3 mV (Li / Li ⁺ ). I went until it became. The discharge (de-doping process) was repeated at a current density of 0.53 mA / cm ² for 1 hour / discharge for 2 hours, and a terminal voltage of 1.5 V was used as a cutoff voltage.

It has been found that the amount of discharged electricity obtained by the present method is smaller than the amount of charged electricity in any material, and this undischarged electric capacity is referred to as capacity loss for convenience. In a practical battery, the value of the capacity loss is also important in evaluating the negative electrode material.

[0039] - a mixture of ^<31 P nuclear solid high decomposition NMR Measurement> powder sample and the weight of KCl, and the sealed filled into the sample tube was measured under the following conditions. ³¹ P nucleus-solid high-resolution NMR measurement conditions Apparatus JEOL GSX270 (solid probe: GSH27T6) Measurement nucleus ³¹ P Measurement frequency 109.25 MHz Measurement mode MASGHD Reference substance diammonium hydrogen phosphate (1.
6 ppm) Sample tube rotation speed About 5000 Hz Measurement temperature Room temperature Diluent KCl (2 to 3 times)

<XPS (X-ray Photoelectron Spectroscopy)> Using a powder sample, a spectrum of a phosphorus atom and a 2p orbit was measured under the following conditions. XPS (X-ray Photoelectron Spectroscopy) Measurement Conditions Equipment SSIM M-PROBE Vacuum at the time of measurement After evacuation at 1 × 10 ^-9 torr, introduce argon gas and measure at 2 × 10 ^-7 torr Neutralization electron 2.0 eV pass Energy 50 eV Photoelectron take-up angle 35 ° Charge uniformity Ni mesh Standard Carbon-carbon bond 284.6 eV Waveform processing Gaussian 80% + Lorentzi
an 20%

<Standard compound> In a carbon material that has been heat-treated at a high temperature, the existence of an alkyl chain is difficult to consider, so it is appropriate to think that the terminal to which phosphorus is bonded is a benzene ring.
The chemical shift value of NMR and the binding energy of XPS were compared with the measured values of the aromatic phosphorus compound, and the state of phosphorus was identified.

The fact that the aromatic phosphorus compound may be used as a standard compound was confirmed by a simulation using molecular orbital calculations and the like to show that the increase in the number of benzene rings bonded to the phosphorus compound was not affected. Table 1 shows the chemical shift value in the ³¹ P nucleus-solid NMR spectrum and the binding energy in the XPS-P (2p) spectrum of each phosphorus compound.

[0043]

[Table 1]

Experiment 1 This experiment is an example in which non-graphitizable carbon was examined.

<Preliminary Experiment 1> First, using a furan resin as an organic material, the effect of adding phosphorus was examined. FIG.
Refers to a continuous chargeable / dischargeable capacity of a battery using a furfuryl alcohol resin (polymerization catalyst: maleic anhydride) 1200 ° C. calcined (hereinafter abbreviated as PFA-C) phosphoric acid at the time of calcining and using this as a negative electrode. Shows that the addition of phosphoric acid during baking is very effective in expanding the charge / discharge capacity.
As shown in FIG. 2, the added phosphorus remained in the CPO compound obtained according to the added amount. The quantification of phosphorus was performed by inductively coupled plasma emission spectroscopy.

Further, PFA-C is 700 in DTA.
It has no exothermic peak above ℃ and (002)
The interplanar spacing also shows a large value of 3.85 °. However, even if phosphoric acid is added during firing to obtain PFA-C,
As shown in FIG. 4, these characteristics hardly change. For example, even when 10% by weight of phosphoric acid is added, the exothermic peak in DTA is about 680 ° C., and the (002) plane spacing is 3.70 ° or more. there were.

<Preliminary Experiment 2> First, a petroleum pitch (H / C
(Atomic ratio 0.6-0.8), and the oxygen content is 15.
A 4% by weight carbon precursor was prepared, and various phosphorus compounds [orthophosphoric acid, phosphoric anhydride (phosphorous pentoxide), various phosphates] were added thereto.
Heat treated for hours.

Next, the precursor after the heat treatment was pulverized in a mill, charged in a crucible, heated in a nitrogen atmosphere at a rate of 5 ° C./min, a maximum temperature of 1100 ° C., and a holding time at the maximum temperature of 1 hour. It was fired under the condition of time. After cooling, the mixture was pulverized in a mortar, classified with a mesh to 38 μm or less, and evaluated using a test cell according to the above-described capacity measurement method.

As a result, the discharge capacity was improved by adding any of the phosphorus compounds, but the effect of the addition was anhydrous> phosphoric acid>
The order was monobasic acid salt> dibasic acid salt. FIG. 5 is a characteristic diagram showing the relationship between the amount of the phosphorus compound (phosphorus pentoxide and orthophosphoric acid) added to the carbon precursor and the discharge capacity.
In the case of orthophosphoric acid, the discharge capacity was maximized by adding about 5% by weight, and became substantially constant thereafter. On the other hand, in the case of phosphorus pentoxide, the maximum was obtained at about 10% by weight, and the discharge capacity was rather lowered thereafter. When comparing orthophosphoric acid and phosphorus pentoxide, it can be said that the latter is more effective.

Table 2 shows the discharge capacity when a typical phosphorus compound was added.

[0051]

[Table 2]

When used as a negative electrode of a non-aqueous electrolyte battery, the (002) spacing determined by X-ray diffraction and the temperature of the exothermic peak appearing in the DTA curve in an air atmosphere are closely related to the battery characteristics. It is considered to have. Then, what changes appeared in the (002) plane spacing and the DTA peak temperature due to the addition of the phosphorus compound, and how the changes corresponded to the characteristics were examined.

FIGS. 6 and 7 show the results.
The amount of change of each parameter due to the addition of the phosphorus compound was not so large, and it was presumed that the improvement of the characteristics and the change of these parameters did not uniquely correspond, and that the contribution of another factor was large.

Further, it was examined how much phosphorus remains when the phosphorus compound is added. The measurement of the residual amount of phosphorus is the same as in the preliminary experiment 1. The result is shown in FIG. As the amount of the phosphorus compound added increases, the amount of phosphorus remaining in the CPO compound naturally increases, but the remaining amount of phosphorus tends to be saturated at about 3% by weight. Was done.

Therefore, the amount of remaining phosphorus is 0.2 to 5
%, More preferably 0.5 to 3% by weight.

Further, an analysis was conducted on the state of the remaining phosphorus, which is also important in investigating the cause of the effect of the addition of the phosphorus compound. The measurement sample was a petroleum pitch (H
/ C atomic ratio of 0.6-0.8) and the oxygen content is 1
Phosphorous pentoxide is added to 10% by weight of a carbon precursor of 5.4% by weight.
% By weight, heat-treated at 500 ° C. for 5 hours in a nitrogen stream, and further, the precursor after the heat treatment was pulverized by a mill, charged into a crucible, and heated at a rate of 5 ° C. in a nitrogen stream. / Min, and holding time at the maximum attained temperature of 1 hour, the maximum attained temperature is 800, 1100, and 1300 ° C.
The presence of phosphorus was analyzed by ³¹ P nucleus-solid high-resolution NMR and XPS (X-ray photoelectron spectroscopy) measurement using the above four types.

FIG. 9 shows the analysis result by ³¹ P nucleus-solid high-resolution NMR, and FIG. 10 shows the XPS (phosphorus atom, 2p orbital) spectrum. First, according to the NMR results, at a calcination temperature of 500 ° C., the main peak of phosphorus pentoxide was found at 0 ppm and the side band was found at about ± 50 ppm, and a considerable amount remained. In addition, peaks are found at about -10 ppm and about 20 ppm as shoulders of the main peak. Also, a peak is observed at about 40 ppm.

Next, at 800 ° C., the peak of phosphorus pentoxide disappears, and the main peak is about -10 ppm.
The peak at 500 ° C. also remains small. Next, at 1100 ° C., the main peak did not change and the intensity was 80%.
Considering almost the same as 0 ° C., it is considered that the remaining amount of phosphorus is also substantially equal. The other peaks disappeared except that the rise of the side band was observed on both sides of the main peak.

At 1300 ° C., the position and shape of the main peak are not different from 1100 ° C., but it is considered that the intensity is reduced and the residual amount of phosphorus is also reduced. From the above results, 800 ° C
It is considered that the main peak existing thereafter is derived from a compound generated by the reaction between the carbon material and phosphorus during firing. This about-
The peak at 10 ppm corresponds to the (C ₆ H ₅ ) ₃ P −
8.9 ppm -12 of or _{(C 6 H 5 O) 2} P (= O) (OH),.
Although 7 ppm was closest, the peak was broad and could not be clearly distinguished.

Looking at the XPS phosphorus atom 2p orbital binding energies of the phosphorus compounds narrowed down by NMR, there is a difference of about 4 eV, and the oxidation state is greatly different. all right.

Next, the results of XPS will be described. FIG.
FIG. 11 shows the XPS spectrum of 0 subjected to further waveform processing (curve fitting), and Table 3 shows the compounds identified thereby and the P / C atomic ratio.

[0062]

[Table 3]

The P / C atomic ratio decreases greatly from 500 ° C. to 800 ° C., which corresponds to the disappearance of the phosphorus pentoxide peak in the NMR spectrum. Further, it does not change up to 1100 ° C., but decreases greatly at 1300 ° C. As a compound, (C ₆ H ₅ O) ₂ P (= O) (OH) is most present at the time of 500 ° C., and (C ₆ H ₅ )
The presence of ₃ P was not observed. As the firing temperature rises, the compound changes to a compound in which carbon and phosphorus are directly bonded, and eventually phosphorus itself is reduced to (C ₆ H ₅ ) ₃ P and further to P (element). confirmed.

From the result of XPS, at 500 ° C., (C
_The absence of ₆ H ₅ ) ₃ P results in about −10 in NMR.
It was found that the ppm peak was derived from (C ₆ H ₅ O) ₂ P (= O) (OH).

In the industrial production of phosphorus, 1100 to 1
At 400 ° C, carbon reacts with the oxygen of phosphoric acid to remove and reduce oxygen in the form of carbon monoxide gas.
It can be seen that phosphorus is more easily reduced on the surface,
From the result of NMR, which is information on the bulk, it was confirmed by XPS that the composition did not change even if the firing temperature changed, while phosphorus reduction occurred on the outermost surface.

From the above results, the above-mentioned negative electrode material is mainly composed of a compound having a carbon-oxygen-phosphorus bond, and the surface composition is further reduced in addition to the carbon-oxygen-phosphorus bond. It can be proved that the compound is a special compound consisting of a compound having a phosphorus bond.

Based on the preliminary experiments described above, a phosphorus compound was added to an organic material or a precursor in which the oxygen content of petroleum pitch was increased, and a nonaqueous electrolyte secondary battery was assembled using a fired body. Its characteristics were investigated.

<Study on Petroleum Pitch> A petroleum pitch appropriately selected from an H / C atomic ratio in the range of 0.6 to 0.8 was pulverized and oxidized in an air stream to obtain a carbon precursor. Quinoline-insoluble matter of this carbon precursor (JIS centrifugation: K24
25-1983) was 80%, and the oxygen content (by organic element analysis) was 15.4% by weight.

Phosphorus pentoxide (P ₂ O ₅ ) was added to this carbon precursor.
6% by weight was added, and kept at 500 ° C. for 5 hours in a nitrogen stream, and then heated to 1100 ° C. and heat-treated for 1 hour. The following battery was constructed using the CPO compound thus obtained.

The C—P—O compound was pulverized in a mortar, classified by a sieve, and used under 390 mesh. 100 mg of polyvinylidene fluoride as a binder was added to 1 g of this powder, made into a paste form using dimethylformamide, applied to a stainless steel net, and dried at 5 tons / ton.
Crimping was performed with a pressure of cm ² . This was punched out to form a negative electrode, and the net active material at this time was 32.4 mg.

On the other hand, the positive electrode is made of LiNi as an active material._0.2
Co_o.8O_TwoUsing the LiNi _0.2Co_o.8O_Two9
1 g of graphite powder 6 g, polytetrafluoroethylene
Add 3 g of ren, mix well and take 1 g
2 tons / cm in mold ^TwoCompression at pressure
To form a disk-shaped electrode.

Using the above-mentioned positive electrode and negative electrode, one of propylene carbonate and 1,2-dimethoxyethane was used as an electrolytic solution.
LiClO ₄ at 1: 1 (volume ratio) mixed solvent at 1 mol / l
And a separator made of polypropylene non-woven fabric, respectively, and a coin-shaped battery (Example 1)
Was prototyped. The battery was configured such that the amount of active material used was an electrochemical equivalent, that is, the positive electrode >> the negative electrode, so that the negative electrode was regulated.

A coin-type battery (Comparative Example 1) was produced in the same manner as in Example 1 except that phosphorus pentoxide was not added.

First, a discharge curve was drawn for Example 1 and Comparative Example 1. The result is shown in FIG. In the figure, the solid line shows the discharge curve of Example 1, and the broken line shows the discharge curve of Comparative Example 1. From FIG. 12, it was also found that the calcination with the addition of the phosphorus compound was much better in terms of capacity.

Next, cycle characteristics of Example 1 and Comparative Example 1 were examined. In the charge / discharge test, the current density was set to a constant current of 0.53 mA / cm ² for both charge and discharge, and the cutoff voltage for discharge was set to 1.5V.
FIG. 13 shows the result. In FIG. 13, line a represents the cycle characteristics when Example 1 was charged at 360 mAH / g.
Line b shows the cycle characteristics when Comparative Example 1 was charged at 360 mAH / g, and line c shows the cycle characteristics when Comparative Example 1 was charged at 320 mAH / g.

In Example 1, good cycle characteristics are exhibited even when charged at 360 mAH / g, but Comparative Example 1 has a very short life. In Comparative Example 1, the cycle characteristics were good when charged at 320 mAH / g, but the discharge capacity was small.

<Study with Novolak Phenol Type Resin> 10 g of pure water and 1 g of ethanol were added to 10 g of novolak phenol resin powder (manufactured by Gunei Chemical Co., Ltd., trade name: XPGA 4552B), mixed and wetted, and 85% phosphorus was added. 500 mg of an aqueous acid solution was added and mixed well. This was kept at 500 ° C. for 5 hours in a nitrogen atmosphere, and then heated to 1200 ° C. and heat-treated for 1 hour. The properties of the obtained compound are as follows.

(002) Spacing 3.75 A True density 1.60 g / cm ³ DTA exothermic peak 631 ° C. Phosphorus content about 0.8% by weight Chemical shift of peak at −11 ppm in ³¹ P nucleus-solid NMR spectrum by XPS Surface composition / abundance ratio of phosphorus (C ₆ H ₅ O) ₂ P (= O) (OH) /17.7% (C ₆ H ₅ ) ₂ P (= O) (OH) /35.9% (C _{6 H 5) 3 P = O} /26.0% (C 6 H 5) 3 P /20.4%

Using the CPO compound powder thus obtained as a negative electrode active material, a battery (Example 2) having the same configuration as in Example 1 was produced. The net negative electrode active material is 32.
It was 5 mg. As a result of conducting a charge / discharge cycle test with various charge / discharge capacities, it was found that stable charge / discharge can be performed with a charge amount of 360 mAH / g or less.

FIG. 14 is a solid line showing a discharge curve when charging / discharging at 360 mAH / g.

Next, a battery (Comparative Example 2) was prepared in exactly the same manner as in Example 2 except that phosphoric acid was not added to the novolak type phenol resin powder, and a charge / discharge cycle test was performed at various charge / discharge capacities. Was. As a result, stable charge and discharge can be performed only at a charge amount of at most about 210 mAH / g.

A discharge curve when charging is performed at 210 mAH / g is shown by a broken line in FIG.

Experiment 2 In this experiment, the effect of phosphorus content in graphitizable carbon was examined.

<Preliminary Experiment> Acenaphthylene (C ₁₂ H ₈ :
Wako Pure Chemical Co., Ltd.) as raw material, raw material state and 200 ~
P ₂ O ₅ was added to the material that had been heat-treated at 650 ° (constant addition amount: 5% by weight), and the change in capacity with respect to the heat treatment temperature (for convenience, referred to as the addition temperature) was examined. The phosphorus content was determined by inductively coupled plasma emission spectroscopy (IC
The quantification was performed according to P).

Here, the sample was prepared as follows. That is, after the temperature of acenaphthylene was raised to the addition temperature, the temperature was once lowered, pulverized, and P ₂ O ₅ was added and mixed.
The temperature was raised again to the addition temperature. Then, after holding for 1 hour, carbonized at 530 ° C., and further baked at 1100 ° C.
What passed 90 mesh was used as a sample. The heating rate was 100 ° C./hour before carbonization and 5 ° C./minute during firing.

FIG. 15 shows the change in the capacity and the capacity loss with respect to the addition temperature, and FIG. 16 shows the change in the phosphorus content. The capacity was almost constant up to the addition temperature of 430 ° C., but then decreased, and at 600 to 700 ° C., the capacity was almost the same as that without P ₂ O ₅ added. On the other hand, the phosphorus content decreases at an addition temperature of 300 ° C. or higher, as is clear from FIG. 16, but when considered in conjunction with FIG. It has been found that a great effect can be obtained on the expansion of.

<Study with Acenaphthylene> 25 g of acenaphthylene (C ₁₂ H ₈ : a reagent manufactured by Wako Pure Chemical Industries, Ltd.) was heated to 430 ° C. at 100 ° C./hour in a nitrogen stream, and then cooled and pulverized to obtain a sample. P ₂ O ₅ was added to the obtained sample, mixed and maintained at 430 ° C. for 1 hour, and then heated to 530 ° C. to obtain a solid precursor. This was further pulverized, heated to 1100 ° C. and heat-treated for 1 hour, and after cooling, a powder sample was obtained.

The amount of P ₂ O ₅ added was 3% by weight (Example A),
5% by weight (Example B), 10% by weight (Example C), 15%
% (Example D) and 20% (Example E)
The phosphorus content, volume and volume loss were measured. The quantification of phosphorus in the powder sample was performed by ICP. The (002) diffraction peak plane spacing (d002) which is a structural parameter
The crystallite thickness (Lc002) was measured by powder X-ray diffraction, and the true density was also measured.

A powder sample (Comparative Example A) was prepared in exactly the same manner as in Examples AE except that P ₂ O ₅ was not added to acenaphthylene, and its capacity, d002, Lc002 and true density were measured. Table 4 summarizes the above results.
It is.

[0090]

[Table 4]

FIG. 17 shows the change in the capacity with respect to the phosphorus content, and FIG. 18 shows the change in the phosphorus content with the added amount of P ₂ O ₅ . 19 to 24 show charge / discharge curves of Comparative Example A and Examples A to E at the time of capacity measurement.
Here, the solid line indicates the closed circuit voltage when energized,
The mark indicates the equilibrium potential after rest.

Next, using the powder samples of Example D and Comparative Example A, a cell for a cycle test was prepared and evaluated.
The cell manufacturing method and test conditions are shown below. For the negative electrode,
A molded electrode prepared using the C—O—P compound powder sample as an active material and manufactured in the same manner as in the capacity test method was used. LiCoO ₂ was used as the active material for the positive electrode. 6 g of graphite and 3 g of polytetrafluoroethylene were added to 91 g of the LiCoO ₂ , mixed thoroughly, and 1 g of the mixture was put into a mold, and a pressure of 2 ton / cm ² was applied. To obtain a disk-shaped electrode.

Using the above-mentioned positive electrode and negative electrode, one of propylene carbonate and 1,2-dimethoxyethane was used as an electrolytic solution.
A coin-type battery was trial-produced by dissolving LiPF ₆ in a 1: 1 (volume ratio) mixed solvent at a rate of 1 mol / l and using polypropylene non-woven fabric as a separator. This battery uses the amount of active material used as the electrochemical equivalent
>> It is configured to be the negative electrode, and the negative electrode is regulated.

The charge / discharge cycle test was performed under the conditions that the charge was 320 mAh per gram of the negative electrode active material and the discharge was performed to a cutoff of 2.5 V. The results are shown in FIG. 25, and the phosphorus contained more favorable cycle characteristics.

Next, using the samples of Examples A to E, the presence state of phosphorus was analyzed by ³¹ P nucleus-solid high-resolution NMR and XPS measurement. For Example C, in addition to the 1100 ° C fired product, 500 ° C
The measurement was also performed on the fired product and the 1300 ° C. fired product.
FIG. 26 shows the NMR spectra of Examples A to E, FIG. 27 shows the XPS spectra, and Table 5 shows a summary of the composition of each compound.

[0096]

[Table 5]

As a result, even if the added amount of P ₂ O ₅ is increased, NM
The main peak of R showed about -10 ppm. On the other hand, X
In the PS spectrum, in addition to the compound in which the benzene ring and phosphorus were bonded, elemental phosphorus and a component having a lower binding energy (a component having an electron-rich bond than the element) were present. Components with lower binding energy than phosphorus element
Usually, compounds of phosphorus and other metals are listed, but the constituent elements are carbon, oxygen, phosphorus and some hydrogen, and other metals do not exist. Therefore, this phenomenon can be considered as follows. In other words, a low binding energy means that the electrons are excessive, and it can be considered that the effect is such that electrons are donated. Since such a phenomenon did not occur with non-graphitizable carbon containing phosphorus, the graphitizable carbon had a more developed graphite structure, and the influence of its π electrons was part of elemental phosphorus. It is considered that the peak shifted and appeared in the spectrum as a component having low binding energy. (This peak is indicated as electron rich P because it is attributed to the electron rich element phosphorus.) This phenomenon can be said to be a characteristic of graphitizable carbon such as coke containing phosphorus.

FIG. 28 shows an NMR spectrum, FIG. 29 shows an XPS spectrum, and Table 6 shows a summary of each compound composition with respect to changes in the firing process.

[0099]

[Table 6]

From the NMR spectrum, at 500 ° C., a main peak of phosphorus pentoxide was found at 0 ppm and a side band was found at about ± 50 ppm, and a considerable amount remained. In addition, peaks are found at about -10 ppm and about 20 ppm as shoulders of the main peak. Also, about -30pp
m also has a peak. Next, at 1100 ° C., about −
A main peak appears at 10 ppm, and no other peaks are found except that a rise like a side band is observed.

Finally, at 1300 ° C., the position and shape of the main peak are not different from those at 1100 ° C., but it is considered that the intensity is reduced and the residual amount of phosphorus is also reduced. The peak at about -10 ppm is (C ₆ H
₅ ) −8.9 ppm of ₃ P or −C of (C ₆ H ₅ O) ₂ P (= O) (OH)
Although 12.7 ppm was closest, the peak was too broad to be clearly distinguished.

On the other hand, in the XPS spectrum, P ₂ O ₅ is the largest at 500 ° C., (C ₆ H ₅ O) ₂ P () O) (OH) is also present in a large amount, and (C ₆ H ₅ ) ₃ The presence of P was not observed. 1100 ° C
In (C ₆ H ₅ ) ₃ P, the presence of (C ₆ H ₅ ) ₃ P was also recognized, but intermediate (C ₆ H ₅ O) ₂ P (= O) (OH) and (C ₆ H ₅ ) ₃ P It was found that there is a process where phosphorus is gradually reduced in the presence of = O.

From the results of XPS, at 500 ° C., (C
_The absence of ₆ H ₅ ) ₃ P results in about −10 in NMR.
ppm peak was found to be _{(C 6 H 5 O) 2} P (= O) (OH). In an industrial process for producing phosphorus, 1100 to 140
The fact that carbon reacts with oxygen of phosphoric acid at 0 ° C. to remove and reduce oxygen in the form of carbon monoxide indicates that phosphorus is more easily reduced at the surface, so from the NMR results that are bulk information The composition did not change even when the firing temperature changed, while XPS confirmed that phosphorus reduction had occurred on the outermost surface.

From the above results, the internal composition of the negative electrode material of this example is mainly a compound having a carbon-oxygen-phosphorus bond, and the surface composition is further reduced in addition to the carbon-oxygen-phosphorus bond. It has been proved to be a special compound consisting of a compound having a carbon-phosphorus bond.

<Study with Petroleum Coke> Next, a similar experiment was performed using petroleum coke instead of acenaphthylene. That is, petroleum coke was pulverized to 200 mesh or less, 10 g of the coke was mixed with 1 g of P ₂ O ₅ , and then heat-treated under the same conditions as in Example A.
The powder was fired at 0 ° C. for 1 hour to obtain a powder sample (Example F). And about the obtained sample, the phosphorus content, capacity, and capacity loss were measured.

On the other hand, a heat treatment was conducted in the same manner as in Example F except that P ₂ O ₅ was not added to petroleum coke to obtain a powder sample (Comparative Example B). And about the obtained sample, the phosphorus content, capacity, and capacity loss were measured. Table 7 summarizes the above results. 30 and 31 show charge / discharge curves of Example F and Comparative Example B at the time of capacity measurement, respectively. In addition,
Again, the solid line shows the closed circuit voltage when energized,
The mark indicates the equilibrium potential after rest.

[0107]

[Table 7]

Using the powder samples of Example F and Comparative Example B, cells similar to those of Example D and Comparative Example A were prepared and subjected to a cycle test. In the charge / discharge cycle test, 320 mAh was charged per 1 g of the negative electrode active material, and the cutoff was 2.5 V.
The discharge was performed under the condition that the battery was discharged until the discharge. The results are shown in FIG. 32, and it can be seen that the inclusion of phosphorus shows better cycle characteristics.

Next, for the sample of Example F, ³¹ P nucleus
The result of having analyzed the presence state of phosphorus by solid high-resolution NMR and XPS measurement is shown. Chemical shift of peak in ³¹ P nucleus-solid NMR spectrum: -11 ppm Surface composition of phosphorus by XPS (abundance ratio): (C ₆ H ₅ O) ₂ P (= O) (OH) 12.9%: (C _{6 H 5) 2 P (= O} ) (OH) 15.5%: (C 6 H 5) 3 P = O 23.0%: (C 6 H 5) 3 P 22.3%: P 7.5% : P having an electron-rich bond 18.7%

Although the present invention has been described with reference to specific embodiments, the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the present invention. .

[0111]

As is clear from the above description, phosphatization
A carbon compound containing carbon, phosphorus and oxygen as main components.
Form phosphorus or a compound with a carbon-oxygen-phosphorus bond
Negative electrode material with large lithium doping
Can be provided. That is, the negative electrode material of the present invention
Has an internal composition of (C₆H_FiveO)_TwoP (= O) (O
H), but the surface composition is (C₆H_FiveO)_TwoP (= O)
(OH) and further reduced (C₆H_Five)_TwoP (= O)
(OH), (C₆H_Five)_ThreeP = O, (C₆H _Five)_ThreeP
It is a special compound consisting of And this special structure
Increase lithium doping only by having
This is an effect.

Further, according to the production method of the present invention, a negative electrode material having excellent characteristics can be produced by a simple operation, and it is possible to produce a negative electrode material such as a lithium secondary battery without increasing production cost or deteriorating productivity. Suitable negative electrode materials can be manufactured. Furthermore, in the nonaqueous electrolyte battery of the present invention, since a negative electrode material having a large lithium doping amount is used, a charge / discharge capacity that exceeds the theoretical value when graphite is used as the negative electrode can be realized, and It is possible to provide a battery having excellent cycle characteristics. By using this material, a non-aqueous electrolyte secondary battery having a large charge / discharge capacity can be obtained.

[Brief description of the drawings]

FIG. 1 is a characteristic diagram showing a relationship between a charged amount of phosphoric acid and an amount of electricity that can be continuously charged and discharged in a polyfurfuryl alcohol fired body obtained.

FIG. 2 is a characteristic diagram showing a relationship between a charged amount of phosphoric acid and a residual ratio of phosphorus in a fired body of polyfurfuryl alcohol resin.

FIG. 3 is a characteristic diagram showing a temperature change of a DTA peak according to a charged amount of phosphoric acid in a fired body of polyfurfuryl alcohol resin.

FIG. 4 is a characteristic diagram showing a change in d ₀₀₂ according to a charged amount of phosphoric acid in a fired body of polyfurfuryl alcohol resin.

FIG. 5 is a characteristic diagram showing the relationship between the amount of orthophosphoric acid and phosphorus pentoxide added to oxygen-crosslinked petroleum pitch and the discharge capacity.

FIG. 6 is a characteristic diagram showing a change in d ₀₀₂ due to the addition of a phosphorus compound in a petroleum pitch fired product crosslinked with oxygen.

FIG. 7 is a characteristic diagram showing a temperature change of a DTA peak due to the addition of a phosphorus compound in an oxygen-crosslinked petroleum pitch fired body.

FIG. 8 is a characteristic diagram showing the relationship between the amount of a phosphorus compound added and the amount of residual phosphorus in an oxygen-crosslinked petroleum pitch fired body.

FIG. 9 is a ³¹ P nuclear-solid NMR spectrum.

FIG. 10 is a 2p orbital spectrum of a phosphorus atom by XPS.

11 is a diagram obtained by subjecting the spectrum of FIG. 10 to waveform processing.

FIG. 12 is a characteristic diagram showing discharge curves of Example 1 and Comparative Example 1.

FIG. 13 is a characteristic diagram showing cycle characteristics of Example 1 and Comparative Example 1.

FIG. 14 is a characteristic diagram showing discharge curves of Example 2 and Comparative Example 2.

FIG. 15 is a characteristic diagram showing the relationship between the addition temperature of phosphorus pentoxide, the capacity, and the capacity loss in acenaphthylene.

FIG. 16 is a characteristic diagram showing the relationship between phosphorus pentoxide addition temperature and phosphorus content in acenaphthylene.

FIG. 17 is a characteristic diagram showing a relationship between phosphorus content and capacity and capacity loss in acenaphthylene.

FIG. 18 is a characteristic diagram showing a relationship between an added amount of phosphorus pentoxide and a phosphorus content in acenaphthylene.

FIG. 19 is a characteristic diagram showing a charge / discharge curve of Comparative Example A.

FIG. 20 is a characteristic diagram showing a charge / discharge curve of Example A.

FIG. 21 is a characteristic diagram showing a charge / discharge curve of Example B.

FIG. 22 is a characteristic diagram showing a charge / discharge curve of Example C.

FIG. 23 is a characteristic diagram showing a charge / discharge curve of Example D.

FIG. 24 is a characteristic diagram showing a charge / discharge curve of Example E.

FIG. 25 is a characteristic diagram showing cycle characteristics of batteries using Example D and Comparative Example A.

FIG. 26 is a characteristic diagram showing a difference in ³¹ P nucleus-solid NMR spectrum depending on the amount of phosphorus pentoxide added to acenaphthylene.

FIG. 27 is a characteristic diagram showing a difference in an XPS spectrum depending on an added amount of phosphorus pentoxide in acenaphthylene.

FIG. 28 is a characteristic diagram showing a difference in ³¹ P nucleus-solid NMR spectrum depending on a sintering temperature after adding phosphorus pentoxide to acenaphthylene.

FIG. 29 is a characteristic diagram showing a difference in XPS spectrum depending on a sintering temperature after adding phosphorus pentoxide to acenaphthylene.

FIG. 30 is a characteristic diagram showing a charge / discharge curve of Example F.

FIG. 31 is a characteristic diagram showing a charge / discharge curve of Comparative Example B.

FIG. 32 is a characteristic diagram showing cycle characteristics of batteries using Example F and Comparative Example B.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-137010 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01M 4/02-4/58

Claims (3)

(57) [Claims] 1. A carbon, phosphorus and oxygen as main components, the content of phosphorus is 0.2 to 9.0 ^{wt%, 31} P nuclei - in the range of ± 100ppm with orthophosphoric acid standards in solid state NMR spectrum It has a peak, and in X-ray photoelectron spectroscopy measurement, the binding energy between carbon and carbon in the carbon atom 1s orbital spectrum is 284.6.
When eV, the phosphorus atom 2p orbital spectrum is 13
Heat-treated at 700 ° C. or less with a peak of 5 eV or less
Phosphorus compound added to the carbon or organic material
Anode material mainly composed of coke . 2. Heat treatment at 700 ° C. or lower and firing
Carbon, phosphorus, characterized in that 0.2 to 32% by weight of a phosphorus compound in terms of phosphorus is added to an organic material or a carbon material to be used as a raw material, and the mixture is fired in an inert atmosphere.
A method for producing a negative electrode material containing oxygen as a main component. Wherein carbon, phosphorus, the phosphorus content is a principal component of the oxygen is between 0.2 to 9.0 ^{wt%, 31} P
In a nuclear-solid NMR spectrum, it has a peak in the range of ± 100 ppm based on orthophosphoric acid, and in the X-ray photoelectron spectroscopy measurement, when the bond energy between carbon and carbon in the carbon atom 1s orbital spectrum is 284.6 eV, A carbon material heat-treated at 700 ° C. or less having a phosphorus atom 2p orbital spectrum having a peak of 135 eV or less
Or coke fired by adding a phosphorus compound to an organic material
A non-aqueous electrolyte battery comprising a negative electrode mainly composed of lithium, a positive electrode containing Li, and a non-aqueous electrolyte.