JP5581488B2 - Method for producing spherical carbon material, method for producing spherical phenol resin - Google Patents

Description

The present invention relates to a method for producing a spherical carbon material, a method for producing a spherical phenol resins.

  It is known that carbon materials have various uses such as adsorbents for gas components and odor components, additives for organic synthetic products, toner materials for copying machines, and electrode materials for power storage devices. Among these, carbon materials for electrodes of power storage devices can be broadly classified into graphite materials (crystalline) having a specific layer structure and activated carbon materials having no specific layer structure. Graphite is used when intercalation of electrolyte ions is used, and activated carbon is used when adsorption is used.

An example of the carbon material for an electrode of the power storage device is described in Patent Document 1. That is, spherical activated carbon having an average particle diameter of 1 to 10 μm and a pore volume of 1.5 cm ³ / g or less is used for an electrode of an electric double layer capacitor. The spherical activated carbon can be produced by heating and curing phenols and aldehydes in a solvent in the presence of a catalyst and a suspension stabilizer while stirring, to obtain a spherical phenol resin. It is described that a spherical activated carbon is obtained by carbonization and activation. It is also described that the particle size can be controlled by changing the synthesis conditions such as the stirring conditions and the concentration of the suspension stabilizer.

  Patent Document 2 describes an ultrafine spherical carbon material having a diameter of 30 to 500 nm using resorcinol-based polymer particles as a precursor. The spherical carbon material has a morphological feature of a spherical structure having a layered structure having a resorcinol / formaldehyde copolymer as a skeleton component as a structural unit. Since it has a layered structure as a structural unit, it is recognized as a graphite-like spherical carbon material. According to the photograph of FIG. 1B published in Patent Document 2, the spherical carbon material is one in which individual particles are not separated and independent, but the particles are partially bonded. In the production method, a resorcinol monomer and an aldehyde are mixed with a solution in which one or more surfactants selected from the group consisting of alkylammonium salts and alkylamines and water are mixed at a specific molar ratio in the presence of a basic condensing agent. A spherical polymer product obtained by adding one or more monomers selected from the above and reacting them is baked in an inert atmosphere.

JP 2001-143973 A JP 2007-39263 A

  As described in Patent Document 1, an activated carbon spherical carbon material is known, but its average particle diameter is 1 to 10 μm, which is relatively large. In addition, since the activated carbon on the market is activated and mechanically pulverized and refined, it has not only a large particle size but also an irregularly crushed shape (indefinite shape). Therefore, even if these conventional activated carbons are used for the electrodes of the power storage device, a dramatic improvement in performance cannot be expected.

  For example, in the case of an electric double layer capacitor, in order to increase the energy density (increase in the amount of energy that can be stored), it is necessary to fill activated carbon with a large capacitance into a predetermined volume at a high density. Since the capacitance is determined by the amount of ions adsorbed on the activated carbon, in order to increase the capacitance per unit weight, it is necessary to increase the effective surface area and facilitate diffusion of ions into the micropore. It is important to shorten the diffusion path as much as possible. However, the larger the particle size of activated carbon, the more disadvantageous it is for increasing the surface area and shortening the diffusion path. Moreover, if activated carbon is an irregular crushing shape, even if it fills predetermined volume, the space | gap between particles will become large and a packing density will become low. That is, it is disadvantageous for an increase in capacitance per unit volume.

  On the other hand, the spherical carbon material described in Patent Document 2 is not activated carbon, but its particle size is small. However, as described above, the individual particles are not separated and independent, and the particles are partially bonded. Therefore, even if this is used as an electrode material, it is necessary to grind the spherical carbon material. And even if it grind | pulverizes, since the particle | grains obtained do not necessarily become spherical shape and large diameter particle | grains are contained, the big increase in the said electrostatic capacitance and packing density cannot be desired.

  Therefore, the present invention provides a carbon material that can be used for various applications such as an adsorbent and a toner material for a copying machine, and that can increase the energy density when used as an electrode material for a power storage device. This is the issue.

One aspect of the present invention is a method for producing a spherical carbon material comprising spherical activated carbon particles having an average particle diameter of 100 nm or more and 850 nm or less .

This spherical carbon material is activated carbon, and its average particle size is very small and spherical with submicron order, so it can be used in various applications such as adsorbent, copier toner material, power storage device electrode material, etc. Quality can be improved.

In good preferable embodiment, the activated carbon particles is in the individually independent spherical particles. Thereby, the said spherical carbon material can be utilized without requiring a mechanical grinding | pulverization, and the amorphous form by crushing can be avoided. Therefore, it is possible to increase the packing density when the spherical carbon material is used in a predetermined volume, which is advantageous for improving the product quality.

  For example, in a power storage device using the spherical carbon material as an active material, since the average particle diameter of each activated carbon particle is very small, the capacitance per unit weight is increased by increasing the surface area and shortening the diffusion path. Becomes larger, and high-density filling becomes possible, which is advantageous for increasing the energy density.

Hereinafter, the manufacturing method of the said spherical carbon material is demonstrated concretely. It consists of a step of preparing a reaction solution comprising a mixture of phenols, aldehydes, a surfactant, a curing agent, and an acid catalyst, and heating the reaction solution to advance a polymerization reaction. A step of preparing a spherical phenol resin having an average particle diameter of 1 μm or less, which is a raw material precursor, a step of heat-curing the carbon material precursor, a step of heating and carbonizing the obtained cured product, and And a step of steam-activating the carbonized product.

  Here, the acid catalyst is at least one selected from hydrogen halide, nitric acid and sulfuric acid, and the addition ratio of the acid catalyst to the phenols is 0.01 to 0.15 in terms of molar ratio.

In the polymerization reaction, the reaction solution is reacted at a heat treatment temperature of 75 ° C. or higher and 110 ° C. or lower . The reaction solution may be stirred at the heat treatment temperature for several hours to several tens of hours. In the heat curing, the carbon material precursor (spherical phenol resin) is cured in a temperature atmosphere of 110 ° C. or higher and 300 ° C. or lower . For example, the precursor may be heated in an inert gas atmosphere and held at the temperature for 0.5 hours to 5 hours. In the carbonization, the cured spherical phenol resin is carbonized in a temperature atmosphere of 600 ° C. or higher and 900 ° C. or lower . For example, what is necessary is just to heat in inert gas atmosphere and hold | maintain at the said temperature about 1 hour. Furthermore, in the steam activation, the carbonized material may be heated in a nitrogen gas atmosphere containing saturated steam and kept at a temperature of about 900 ° C. for about 1 hour.

  By this production method, a spherical carbon material made of spherical activated carbon particles having an average particle diameter of 100 nm or more and 850 nm or less can be obtained. This production method is characterized in that a surfactant and an acid catalyst are used for spheroidization and refinement of a phenol resin.

  That is, it is known that a thermoplastic resin called novolak can be obtained by condensation polymerization of phenols and aldehydes in the presence of an acid catalyst. However, when no surfactant is added, the resulting phenolic resin becomes an irregularly shaped lump. On the other hand, in the present invention, the condensation polymerization reaction proceeds in each micelle of the surfactant. Therefore, a large number of spherical phenol resins separated and independent from each other are obtained. At that time, the presence of the acid catalyst reduces the micelle size, so that the particle diameter of the resulting spherical phenol resin is considered to be small.

It relates proportion of the added acid catalyst with respect to the upper notated phenol compound, when the molar ratio is less than 0.01, the condensation polymerization reaction hardly proceeds, and, at a molar ratio greater than 0.15, obtaining a spherical phenol resin It becomes difficult.

  Moreover, it is preferable to use at least one of a cationic surfactant and an anionic surfactant as the surfactant.

Another aspect of the present invention is a process for the preparation of novel spherical phenolic resin average particle size of 300nm or more 1000nm or less. According to this spherical phenol resin, this is cured by heating, the obtained cured product is heated and carbonized, and the resulting carbonized product is steam-activated, whereby a spherical particle having an average particle diameter of 100 nm or more and 850 nm or less is obtained. The above-mentioned spherical carbon material made of the activated carbon particles can be obtained. Moreover, this spherical phenol resin can be used as a raw material for battery electrodes, grindstones, fillers, molding materials, and the like, so that the quality of related products can be improved.

Hereinafter, the manufacturing method of the spherical phenol resin whose said average particle diameter is 300 to 1000 nm is demonstrated concretely. It includes a step of preparing a mixed solution of phenols, aldehydes, a surfactant, a curing agent, and an acid catalyst, and heating the mixed solution to a heat treatment temperature of 75 ° C. or higher and 110 ° C. or lower to perform a polymerization reaction. And a step of advancing.

Here, the acid catalyst is a hydrogen halide, you at least one selected from among nitric acid and sulfuric acid. The addition ratio of the acid catalyst to phenols you 0.01 to 0.15 in molar ratio. When the molar ratio is less than 0.01, the condensation polymerization reaction is difficult to proceed, and when the molar ratio exceeds 0.15, it is difficult to obtain a spherical phenol resin. Moreover, it is preferable to use at least one of a cationic surfactant and an anionic surfactant as the surfactant. In the polymerization reaction, the reaction solution may be stirred at the heat treatment temperature for several hours to several tens of hours.

  As is apparent from the explanation of the method for producing the spherical carbon material described above, according to the production method, a spherical phenol resin having an average particle diameter of 300 nm or more and 1000 nm or less can be obtained.

According to the method for producing a spherical carbon material according to the present invention , phenols, aldehydes, a curing agent and an acid catalyst (hydrogen halide having a molar ratio of 0.01 to 0.15 in terms of addition ratio to the phenols, A surfactant is added to a mixed solution of at least one selected from nitric acid and sulfuric acid) , and a spherical phenol resin having an average particle diameter of 1 μm or less, which is a carbon material precursor, is prepared by a condensation polymerization reaction. Since carbonization and water vapor activation are performed, a spherical carbon material made of spherical activated carbon particles having an average particle diameter of 100 nm or more and 850 nm or less can be obtained.

In addition, according to the method for producing a spherical phenol resin according to the present invention, phenols, aldehydes, surfactants, curing agents, and acid catalysts (addition ratio to the phenols in 0.01 molar ratio). A step of preparing a mixed solution of at least one selected from hydrogen halide, nitric acid, and sulfuric acid of 0.15 or less, and heating the mixed solution to a heat treatment temperature of 75 ° C. to 110 ° C. for polymerization. And a step of advancing the reaction, a spherical phenol resin having an average particle size of 300 nm or more and 1000 nm or less can be obtained.

It is explanatory drawing which shows roughly the preparation method of the spherical phenol resin which concerns on this invention. It is explanatory drawing which shows a mode that a phenol resin is superposed | polymerized and produced within a micelle. It is a scanning electron micrograph of the spherical phenol resin which concerns on this invention. It is a graph which shows the particle size distribution of each spherical phenol resin from which an acid catalyst addition amount differs. It is a graph which shows the particle size distribution of each spherical phenol resin from which the kind of acid catalyst differs. It is a graph which shows the particle size distribution of each spherical phenol resin from which the kind of surfactant differs. It is explanatory drawing which shows roughly the preparation method based on this invention which obtains a spherical carbon material from spherical phenol resin. It is a scanning electron micrograph of the spherical carbon material which concerns on this invention. It is a scanning electron micrograph of a conventional powder carbon material. It is a graph which shows the particle size distribution of the spherical phenol resin which concerns on this invention, and each spherical carbon material obtained from this. It is a graph which shows the relationship between the molar ratio of an acid catalyst, and the average particle diameter of each of spherical phenol resin and spherical carbon material. It is a graph which shows the nitrogen adsorption isotherm of each of spherical carbon material SAC concerning this invention, and conventional powder carbon material AC. It is explanatory drawing which shows the structure of a coin-type electric double layer capacitor. It is a graph which shows the electrode capacity per unit weight with respect to the discharge current density of each of spherical carbon material SAC and conventional powder carbon material AC according to the present invention. It is a graph which shows the electrode capacity | capacitance per unit volume with respect to the discharge current density of the electric double layer capacitor which used each of the spherical carbon material SAC concerning this invention, and conventional powder carbon material AC. It is a graph which shows the charging / discharging cycle test result of the battery using each of spherical carbon material SAC which concerns on this invention, and conventional powder carbon material AC. It is the graph which compared the discharge capacity after 20 cycles of the said battery. It is a graph which shows the test result of the rate characteristic of the said battery.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. It should be noted that the following description of the preferred embodiment is merely illustrative in nature, and is not intended to limit the present invention, its application, or its use.

<Preparation of spherical phenol resin>
FIG. 1 schematically shows the preparation method. That is, a surfactant and a curing agent are mixed in water, and a reaction solution (mixed solution) is prepared by adding and mixing phenol, formaldehyde, and an acid catalyst. The reaction solution is stirred for 24 hours while being heated to a temperature of 95 ° C. (polymerization reaction). Thereafter, the reaction solution is centrifuged, and the resulting product is washed with water and methanol to obtain a spherical phenol resin which is a precursor of the spherical carbon material. The obtained spherical phenol resin is heated under an argon gas atmosphere and kept at a temperature of 270 ° C. for 2 hours to be cured.

  In this case, as shown in FIG. 2, surfactant micelles are formed in the aqueous phase, phenol is introduced into the micelles, and the condensation polymerization reaction proceeds in the presence of an acid catalyst. A spherical phenol resin is obtained by the progress of the polymerization reaction in the micelle. In addition, the surfactant can be dispersed by the acid catalyst, and as a result, the micelle size becomes small, so that the resulting spherical phenol resin has a small particle size. That is, a spherical phenol resin having an average particle diameter of 300 nm or more and 1000 nm or less can be obtained.

  FIG. 3 is an SEM (scanning electron microscope) image of the obtained spherical phenol resin. This uses CTAB (cetyltrimethylammonium bromide; cationic surfactant) as a surfactant, hydrochloric acid as an acid catalyst, and hexamethylenetetramine as a curing agent. The addition amount per mole of phenol is 0.28 mole of CTAB, 0.02 mole of hydrochloric acid, and 0.034 mole of curing agent. FIG. 3 shows that the obtained spherical phenol resin has high sphericity. The average particle diameter was 0.82 μm.

-Effect of addition amount of acid catalyst-
In the preparation of the spherical phenol resin, the influence of the amount of acid catalyst (hydrochloric acid) added on the particle size of the resulting spherical phenol resin was examined. The raw material addition ratio is as shown in Table 1. FIG. 4 shows the particle size distribution (frequency distribution) of the obtained spherical phenol resin.

  The larger the amount of hydrochloric acid added, the smaller the particle size of the resulting spherical phenol resin. Moreover, as shown in FIG. 4, the dispersion degree of the particle diameter decreases as the amount of hydrochloric acid added increases. On the other hand, as shown in Table 1, in the sample 5 having a large amount of hydrochloric acid added (0.18 in molar ratio), the spherical phenol resin was not obtained. This is presumably because if the amount of hydrochloric acid added is too large, most of the surfactant (CTAB) binds to protons and cannot form micelles. From the above, it can be seen that the particle size of the spherical phenol resin can be controlled by the addition amount of the acid catalyst.

-Influence of the type of acid catalyst-
In the preparation of the spherical phenol resin, the effect of the type of acid catalyst on the particle size of the obtained spherical phenol resin was examined. As the acid catalyst, inorganic acids of HBr, HI, HNO ₃ and H ₂ SO ₄ were prepared. The raw material addition ratio is the same as Sample 2 in Table 1. That is, in any inorganic acid, the molar ratio to phenol was 0.02 mol%. Even when any inorganic acid was used, a spherical phenol resin could be obtained. The particle size distribution (frequency distribution) of these spherical phenol resins is shown in FIG. 5 together with the result of the previous sample 2 (acid catalyst; hydrochloric acid HCl). In any of HBr, HI, HNO ₃ and H ₂ SO ₄ , the average particle diameter of the spherical phenol resin is smaller than that of HCl, and the degree of dispersion of the particle diameter is small. From the above, it can be seen that the particle size of the spherical phenol resin can be controlled by the type of the acid catalyst.

-Effect of surfactant type-
In the preparation of the spherical phenol resin, the effect of the type of surfactant on the particle size of the obtained spherical phenol resin was examined. That is, SDS (sodium dodecyl sulfate) was prepared as an anionic surfactant. The raw material addition ratio was the same as Sample 2 in Table 1. The particle size distribution (frequency distribution) of the obtained spherical phenol resin is shown in FIG. 6 together with the result of the previous sample 2 (cationic surfactant; CTAB). In the case of SDS, the particle size is a little larger than the CTAB of sample 2 and the dispersion of the particle size is also a little larger, but the anionic surfactant has the same particle size as in the case of the cationic surfactant. It turns out that a comparatively small spherical phenol resin is obtained.

<Preparation of spherical carbon material>
FIG. 7 schematically shows a preparation method for obtaining a spherical carbon material from the spherical phenol resin obtained by the above preparation method. That is, the above-described cured spherical phenol resin is heated in an argon gas atmosphere and held at a temperature of 800 ° C. for 1 hour. This is a carbonization treatment of a spherical phenol resin. Next, the carbonized product is heated in a nitrogen gas atmosphere containing saturated water vapor and held at a temperature of 900 ° C. for 55 minutes. This is a steam activation treatment.

  FIG. 8 is an SEM image of a spherical carbon material composed of a number of spherical activated carbon particles obtained by subjecting the spherical phenol resin of Sample 2 in Table 1 to the carbonization treatment and the steam activation treatment. FIG. 9 is an SEM image of a powdered carbon material obtained by subjecting the bulk phenol resin prepared without adding a surfactant to the carbonization treatment and the steam activation treatment and pulverization.

  In the case of the spherical phenol resin of sample 2, the spherical shape of the particles is maintained even after carbonization and steam activation. That is, each activated carbon particle has a spherical shape that is separated and independent from each other. FIG. 10 shows the particle size distribution (frequency distribution) of sample 2 before carbonization and after carbonization / steam activation. The spherical phenol resin has a reduced particle size due to carbonization and steam activation, and the degree of dispersion of the particle size is also reduced. The average particle diameter after carbonization and steam activation is 0.33 μm (330 nm).

  In addition to the spherical phenol resins of Samples 1 to 4, a spherical phenol resin having an average particle diameter of 0.32 μm was prepared by a method for preparing the spherical phenol resin with a molar ratio of hydrochloric acid of 0.13. And the spherical carbon material was obtained by the said preparation method from each of the spherical phenol resin of samples 1-4, and the spherical phenol resin with an average particle diameter of 0.32 micrometer. The average particle diameters before carbonization and after carbonization / steam activation are shown in FIG. A spherical carbon material having an average particle diameter of 100 nm to 400 nm is obtained from a spherical phenol resin having an average particle diameter of 320 nm to 930 nm. In addition, each sample of FIG. 11 is one Example obtained by the above-mentioned conditions, and when the preparation conditions are different (however, within the range specified in claim 4 of the present application), a spherical shape having a relatively large average particle diameter. Carbon material is obtained. Specifically, each sample in FIG. 11 has the smallest average particle diameter, and a sample in the bar range shown in FIG. 11 is obtained depending on the conditions. The maximum was 850 nm. From the above, it can be seen that a spherical carbon material having an average particle size of 100 nm to 850 nm can be obtained from a spherical phenol resin having an average particle size of 300 nm to 1000 nm.

-Pore properties-
Each of the spherical carbon material SAC in FIG. 8 and the powder carbon material AC in FIG. 9 was cooled to 77.4 K (the boiling point of nitrogen), nitrogen gas was introduced, and the adsorption amount of nitrogen gas was measured. At this time, the pressure P of the nitrogen gas to be introduced is gradually increased, and the value obtained by dividing by the saturated vapor pressure P ₀ of the nitrogen gas is set as the relative pressure P / P ₀ , and the amount of adsorption with respect to each relative pressure is plotted in FIG. The indicated nitrogen adsorption isotherm was obtained. Then, the specific surface area of each carbon material is obtained by the BET method, the total pore volume is obtained based on the measurement result of the nitrogen gas adsorption amount, and the mesopore volume ratio (pore diameter relative to the total pore volume is 2 nm or more and less than 50 nm by the BJH method. The ratio of mesopore volume) was determined, and the average pore diameter was determined using the specific surface area and the total pore volume. The results are shown in Table 2.

  The spherical carbon material SAC according to the embodiment has substantially the same pore characteristics as the powder carbon material AC obtained by conventional crushing. The spherical carbon material SAC according to the embodiment is considered to have a very small average particle diameter despite being spherical.

<Application to electric double layer capacitors>
The characteristics when each of the samples SAC and AC shown in Table 2 was used as the active material of the electric double layer capacitor were examined. FIG. 13 shows the structure of a coin-type electric double layer capacitor. In the figure, 1 is a current collector, 2 is an electrode, 3 is a separator, and 4 is an electrolytic solution. Platinum was used as the current collector 1, PVDF (polyvinylidene fluoride) was used as the separator 3, and 1 molar Et ₄ NBF ₄ / PC (tetraethylammonium tetrafluorobromide) was used as the electrolytic solution 4. The electrode 2 was composed of a mixture of 95% by mass of a carbon material (SAC or AC) and 5% by mass of PTFE (polytetrafluoroethylene).

Thus, each of the case using the spherical carbon material SAC and the case using the powder carbon material AC as the active material is charged to a voltage of 3V with a constant current of 10 mA, and then to 0 V under a constant current of 1 to 50 mA. After discharging, the electrode capacity (capacitance) C (g) per unit weight and the electrode capacity C (v) per unit volume were determined by the following equations. Here, I is a current value, Δt is a voltage drop time, ΔV is a voltage drop value, (M ₁ + M ₂ ) is an active material mass (g) for _two electrodes, and (V ₁ + V ₂ ) is for two electrodes. It is an active material volume (cm ³ ).

C (g) = I × Δt / (ΔV × (M ₁ + M ₂ ))
C (v) = I × Δt / (ΔV × (V ₁ + V ₂ ))

  First, the electrode density and electrical conductivity are as shown in Table 3. In the case of the spherical carbon material SAC, the electrode density is about twice that of the powder carbon material AC, and the electric conductivity is about 50 times that of the powder carbon material AC.

  FIG. 14 shows the electrode capacity per unit weight with respect to the discharge current density, and FIG. 14 shows the electrode capacity per unit volume with respect to the discharge current density. In any case, the spherical carbon material SAC shows a higher value. In particular, regarding the electrode capacity per unit volume in FIG. 15, the spherical carbon material SAC is more than twice the powder carbon material AC. This is considered to be due to the spherical carbon material SAC being filled at a higher density than the powder carbon material AC.

<Application to batteries>
Spherical carbon material SAC3 types (their average particle diameters are 300 nm, 200 nm, and 100 nm) of the acid catalyst molar ratios 0.04, 0.09, and 0.13 shown in FIG. For AC (average particle diameter 5000 nm), coin batteries (CR2032) each having a negative electrode material were prepared and the characteristics were compared.

The positive electrode material of the coin battery was lithium metal, and a solution obtained by mixing Li electrolyte LiPF ₆ in a mixed solvent of propylene carbonate and dimethyl carbonate was used as the electrolyte. And the charge / discharge cycle test (room temperature 25 degreeC) was done in the constant current of 1 mA and the voltage range of -3.0--0.01V. The results are shown in FIG. Table 4 shows the initial charge / discharge efficiency (= (discharge capacity / charge capacity) × 100).

  In the case of the spherical carbon material SAC according to the present invention, the initial charge / discharge efficiency is higher than that of the conventional carbon material AC. In the case of the charge / discharge cycle, the discharge capacity decreases as the number of cycles increases. However, when the discharge capacity decreases, the spherical carbon material SAC according to the present invention has a decrease degree compared to the conventional carbon material AC. Is small. FIG. 17 compares the discharge capacities after 20 cycles. It can be seen that the spherical carbon material SAC according to the present invention maintains a large discharge capacity even after 20 cycles. Moreover, it can be seen from Table 4 and FIGS. 16 and 17 that the discharge capacity increases as the average particle diameter of the spherical carbon material SAC decreases.

-Rate characteristics-
For each coin battery (CR2032) using the above-mentioned three types of spherical carbon material SAC and the conventional carbon material AC according to the present invention, the rate (applied current change) at a constant current of 1 mA and a voltage range of -3.0 to -0.01V. ) Test (room temperature 25 ° C.) was conducted. That is, the change in the discharge capacity retention rate due to the increase in the discharge rate was measured when the discharge capacity at a discharge rate of 0.5 C (2 hour rate) was 100%. The results are shown in FIG. In any case, although the discharge capacity maintenance rate decreases with an increase in discharge rate (increase in applied current), the three types of spherical carbon materials SAC according to the present invention have a higher discharge than the conventional carbon materials AC. Capacity maintenance rate is high. In addition, the discharge capacity retention rate increases as the average particle diameter of the spherical carbon material SAC decreases.

  That is, the lithium battery is considered to be vulnerable to a large current. However, in the case of the spherical carbon material SAC according to the present invention, the particle diameter is small, and the diffusion and entry of Li ions into the micropores is easy (the diffusion path is short). Therefore, even when the current becomes large, it is recognized that the maintenance rate of the discharge capacity is increased. In other words, in the case of the conventional carbon material AC, since the particle diameter is large, it takes time to diffuse Li ions inside the micropore, and it is not possible to cope with a large current, that is, the carbon material that is not used has increased. It is accepted.

  The spherical carbon material has various uses such as an adsorbing material, a toner material of a copying machine, and an electrode material of a power storage device. The spherical phenol resin can be used as a raw material for granular activated carbon, battery electrodes, grindstones, fillers, molding materials and the like.

DESCRIPTION OF SYMBOLS 1 Current collector 2 Electrode 3 Separator 4 Electrolyte

Claims (4)

A method for producing a spherical carbon material comprising spherical activated carbon particles having an average particle diameter of 100 nm or more and 850 nm or less,
Phenols, aldehydes, surfactants, curing agents, and at least selected from hydrogen halide, nitric acid, and sulfuric acid having a molar ratio of 0.01 to 0.15 in terms of molar ratio. Preparing a mixed solution with a kind of acid catalyst;
A step of preparing a spherical phenol resin having an average particle diameter of 1 μm or less, which is a carbon material precursor, by reacting the mixed solution at a heat treatment temperature of 75 ° C. or higher and 110 ° C. or lower;
Curing the carbon material precursor in a temperature atmosphere of 110 ° C. or higher and 300 ° C. or lower;
A step of carbonizing the obtained cured product in a temperature atmosphere of 600 ° C. or higher and 800 ° C. or lower;
And a step of steam activation of the obtained carbonized product. A method for producing a spherical carbon material. In claim 1 ,
A method for producing a spherical carbon material, wherein at least one of a cationic surfactant and an anionic surfactant is used as the surfactant. A method for producing a spherical phenol resin having an average particle size of 300 nm or more and 1000 nm or less,
Phenols, aldehydes, surfactants, curing agents, and at least selected from hydrogen halide, nitric acid, and sulfuric acid having a molar ratio of 0.01 to 0.15 in terms of molar ratio. Preparing a mixed solution with a kind of acid catalyst;
And a step of heating the mixed solution to a heat treatment temperature of 75 ° C. or higher and 110 ° C. or lower to advance a polymerization reaction. In claim 3 ,
A method for producing a spherical phenol resin, wherein at least one of a cationic surfactant and an anionic surfactant is used as the surfactant.