CN1717822A - Electrode material comprising silicon and/or tin particles and production method and use thereof - Google Patents

Abstract

The invention provides an electrode material comprising at least one kind of particles from silicon particles, tin particles, silicon compound particles, and stannic compound articles, and carbon fibre. The particles comprises: (1) at least one kind of particles from silicon particles, tin particles, silicon compound particles containing lithium ions which can be inserted and discharged, and tin compound particles containing lithium ions which can be inserted and discharged; or (2) carbon particles containing silicon and/or silicone compound deposited on partial surface of the carbon particles in plumbago structure. Lithium secondary battery adopting the electrode material as a cathode has the advantages of high loading capacity, cycle performance and excellent characteristics under high current load.

Description

The electrode material and manufacture method and the purposes that contain silicon and/or tin particles

The cross reference of related application

The application submits to according to 35 U.S.C. the 111st (a) joint, and under the regulation of 35 U.S.C. the 111st (b) joint, require to enjoy the U.S. Provisional Application of submitting on December 4th, 2002 the 60/430th according to 35 U.S.C. the 119th (e) (1) joint, the priority that No. the 60/432nd, 250, the U.S. Provisional Application of submitting in No. 646 and on December 11st, 2002.

Technical field

The present invention relates to a kind of electrode material and manufacture method thereof and purposes.Especially, the present invention relates to a kind of electrode that forms as the electrode material with negative pole in the nonaqueous electrolytic solution secondary battery of excellent specific property under high power capacity, excellent cycle characteristics and the high current load, its manufacture method, by this material, and the nonaqueous electrolytic solution secondary battery that comprises this electrode.More particularly, the present invention relates to a kind of electrode material, the electrode that forms by this material and lithium secondary battery that comprises this electrode as lithium secondary battery anode.

Background technology

Demand to the lithium secondary battery of high power capacity has appearred in the development of the portable equipment that, light weight little along with size and performance are high.With this demand relatively, the negative material that capacity is surpassed 372mAh/g is studied, this capability value is the theoretical capacity of graphite, graphite is all the time usually as the negative material of making lithium secondary battery.

Especially, proposed to be used for the substitute of the non-material with carbon element (material that for example contains silicon, tin, aluminium and W elements) of more jumbo negative pole as this graphite cathode material.

For example, JP-A-2000-173612 (using term " JP-A " expression Japan special permission publication application number here) discloses a kind of by with siliceous solid solution layer or the first crude granule of intermetallic compounds layer silicon-coating and the carbonaceous material of deposited carbon-containing fiber prepares on the part or all of surface of the particle that applies thus negative material.JP-A-2000-357515 (the 6th, 300, No. 013 United States Patent (USP)) discloses a kind of as the material with carbon element of negative material and the mixture of silicon compound.

Yet, when lithium ion inserts in the described non-carbon negative pole material or therefrom discharges, promptly when lithium ion being mixed or during dedoping, the volume of active material particle can experience great variety, and produce microgap between described active material particle, thereby the part that causes being used for the electrode material of effective store charge quantitatively reduces.Especially, because this change in volume, crackle can appear in the described electrode material, active material particle is by miniaturization, and between the particle of this miniaturization, produce microgap, thereby cause interrupting, and the part that can not participate in the electrode material of electrochemical reaction quantitatively increases by the conductive network that causes of contact between the described particle.Can imagine that this phenomenon can produce the problem that comprises that charging descends and internal resistance increases.

As mentioned above, when lithium ion inserts in the non-carbon negative pole material or therefrom discharges, the volume marked change of described active material particle.Thereby following problem appears in electrode material: owing to charge/discharge cycle repeatedly causes this material obviously impaired, and internal resistance value (particularly under the low temperature) increases.

The disclosed electrode material of JP-A-2000-173612 is deposited on as preparing on the silicon grain of examining by the carbonaceous material that will contain carbon fiber.Therefore, when described electrode material experience charge/discharge cycle, the particle of forming this material is by miniaturization, so each particle can not keep its shape, and described particle is separated from each other, thereby causes for example problem of cycle characteristics and irreversible capacity aspect.

At JP-A-2000-357515 the (the 6th, 300, No. 013 United States Patent (USP)) in the disclosed electrode material, wherein the ratio of the average grain diameter of the average grain diameter of silicon compound particle and material with carbon element particle is adjusted, at the doping/dedoping that carries out in by the granuloplastic particle diameter of described material with carbon element between lithium ion and the silicon compound particle greater than the microgap of silicon compound particle grain size.When this electrode material stood repeatedly charge/discharge cycle, these particles were separated from each other, thereby caused for example problem of cycle characteristics and irreversible capacity aspect.

On the other hand, JP-A-2002-8652 discloses a kind of by being deposited on trickle silicon grain on the powdered graphite and forming the negative material that carbon coating prepares on described powdered graphite.JP-A-2002-255529 discloses and has a kind ofly applied the carbonaceous material that described composite particles prepares by being deposited on the graphite granule and with amorphous carbon by the composite particles that silicon and conductive carbon material form.

Yet the problem of the disclosed electrode material of JP-A-2002-8652 is to be accompanied by charge/discharge cycle, and contacting and can not keep between silicon grain expansion or contraction, described silicon grain and the powdered graphite can be taken place, thereby conductance descends, and causes cycle characteristics to worsen.

In the disclosed carbonaceous material of JP-A-2002-255529, silicon and conductive carbon material (for example carbon black) are applied by amorphous carbon fully.Therefore, this carbonaceous material has following point: conductance is low, and large current characteristic is impaired, and the expansion or the cracking of particle cause the contact between the described particle not keep during owing to charge/discharge, thereby causes cycle characteristics to worsen.

Summary of the invention

The purpose of this invention is to provide a kind ofly be suitable as the excellent specific property, the excellent specific property under high current load that are used to make when having high charge/discharge capacity, charge/discharge cycle, irreversible capacity is little and the electrode material of the negative material of the lithium rechargeable battery that internal resistance value (particularly under the low temperature) is low, and provides a kind of method for preparing this electrode material.

The invention provides following aspect:

1. one kind comprises the particle of siliceous and/or tin and the electrode material of carbon fiber, and wherein said particle is: (1) is contained and is selected from silicon grain, tin particles, contains the particle of the silicon compound that can insert/can discharge lithium ion and contains at least a particle in the particle of the tin compound that can insert/can discharge lithium ion; Perhaps (2) comprise the particle of the carbonaceous material of the siliceous and/or silicon compound on the part surface at least that is deposited on the carbon granule with graphite-structure, and wherein said carbonaceous material obtains by the composition that contains polymer is heat-treated.

2. as top 1 described electrode material, wherein said particle siliceous and/or tin is to contain to be selected from silicon grain, tin particles, to contain the particle of the silicon compound that can insert/can discharge lithium ion and to contain at least a particle in the particle of the tin compound that can insert/can discharge lithium ion, the back is referred to as " particle A ", and described carbon fiber is a gas-phase growth of carbon fibre.

3. as top 2 described electrode materials, the silicon compound of wherein said insertion the/can discharge lithium ion is by formula M _xThe compound that Si represents, wherein M represents to be different from the element of lithium, and x is at least 0.01.

4. as top 3 described electrode materials, wherein M is the element that is selected among B, C, N, O, S, P, Na, Mg, Al, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, Ru, Rh, Pd, Pt, Be, Nb, Nd, Ce, W, Ta, Ag, Au, Cd, Ga, In, Sb and the Ba.

5. as top 2 described electrode materials, the tin compound of wherein said insertion the/can discharge lithium ion is ashbury metal, tin oxide, artificial gold, tin halides or stannide.

6. as top 2 described electrode materials, the amount of wherein said gas-phase growth of carbon fibre is 0.01～20 quality %.

7. as top 2 described electrode materials, every filament of wherein said gas-phase growth of carbon fibre has the cavity along its extension of central axis, and external diameter is 2～1,000nm, and draw ratio is 10～15,000.

8. as top 7 described electrode materials, wherein said gas-phase growth of carbon fibre contains the carbon fiber of branching.

9. as top 2 described electrode materials, wherein based on the particle A of 100 mass parts, the amount of described gas-phase growth of carbon fibre is 0.1～30 mass parts.

10. as top 2 described electrode materials, wherein said gas-phase growth of carbon fibre contains by means of X-ray diffraction method measures average layer spacing (d on (002) face ₀₀₂) be 0.344nm or littler carbon.

11. as top 2 described electrode materials, the average grain diameter of wherein said particle A is 0.3 μ m～70 μ m.

12. as top 11 described electrode materials, it is 0.1 μ m or littler and/or 85 μ m or bigger particle that wherein said particle A is substantially devoid of average grain diameter.

13. as top 2 described electrode materials, the part surface at least of wherein said particle A is coated with carbonaceous material, and the thickness of this carbonaceous material coating is 1～30,000nm.

14. as top 13 described electrode materials, wherein said carbonaceous material can obtain by the composition that contains the polymer that is selected from phenol resin, polyvinyl alcohol resin, furane resins, celluosic resin, polystyrene resin, polyimide resin and epoxy resin is heat-treated.

15. as top 14 described electrode materials, the wherein said composition that contains polymer is the composition that contains phenol resin and drying oil or its derived fatty acid.

16. as top 1 described electrode material, the carbonaceous material and the carbon fiber of the siliceous and/or silicon compound on the part surface at least that it contains carbon granule with graphite-structure, be deposited on described carbon granule, wherein said carbonaceous material obtains by the composition that contains polymer is heat-treated.

17. as top 16 described electrode materials, wherein said carbonaceous material siliceous and/or silicon compound also contains carbon fiber.

18. as top 16 described electrode materials, wherein said carbon granule contains on its surface by the instrumentality of described carbonaceous material and has the silicon that is fine particulate form and/or the carbon granule of silicon compound.

19. as top 16 described electrode materials, wherein said carbon granule contains the carbon granule that has carbon fiber on its surface by the instrumentality of described carbonaceous material.

20. as top 16 described electrode materials, wherein said carbon granule contains on its surface by the instrumentality of described carbonaceous material and has the silicon that is fine particulate form and/or the carbon granule of silicon compound and carbon fiber.

21. as top 16 described electrode materials, the amount of wherein said silicon and/or silicon compound is 1～20 quality %.

22. as top 16 described electrode materials, wherein said polymer contains and is selected from least a of phenol resin, polyvinyl alcohol resin, furane resins, celluosic resin, polystyrene resin, polyimide resin and epoxy resin.

23. as top 16 described electrode materials, the wherein said composition that contains polymer is the composition that contains phenol resin and drying oil or its derived fatty acid.

24. as top 16 described electrode materials, wherein said carbon granule and/or described carbonaceous material with graphite-structure contains boron.

25. as top 16 described electrode materials, wherein said carbon fiber contains by means of X-ray diffraction method measures average layer spacing (d on (002) face ₀₀₂) be 0.344nm or littler carbon.

26. as top 16 described electrode materials, wherein said carbon fiber is a gas-phase growth of carbon fibre, every filament of described carbon fiber comprises the cavity along its extension of central axis, and external diameter is 2～1,000nm, and draw ratio is 10～15,000.

27. as top 26 described electrode materials, wherein said gas-phase growth of carbon fibre contains the carbon fiber of branching.

28. as top 26 described electrode materials, wherein based on the described carbon granule with graphite-structure of 100 mass parts, the amount of described gas-phase growth of carbon fibre is 0.1～30 mass parts.

29. as top 16 described electrode materials, wherein said average grain diameter with carbon granule of graphite-structure is 5 μ m～70 μ m.

30. as top 29 described electrode materials, the average grain diameter that wherein said carbon granule with graphite-structure contains is that the amount of 3 μ m or littler and/or 85 μ m or bigger particle is 5 quality % or still less.

31. as top 16 described electrode materials, wherein said carbon granule with graphite-structure is coated with carbonaceous material, the thickness of this carbonaceous material coating is 1～30,000nm.

32. as top 16 described electrode materials, wherein said silicon compound is to be selected from least a in carborundum, silicon dioxide and the silicon nitride.

33. a method of making electrode material, it comprises:

The composition that will contain polymer is deposited on to comprise and is selected from silicon grain, tin particles, contains the particle of the silicon compound that can insert/can discharge lithium ion and contains step on the part surface at least of particle at least a in the particle of the tin compound that can insert/can discharge lithium ion;

The step that the particle that obtains is mixed with carbon fiber; With

To described particle step of heat treatment.

34. as the method for top 33 described manufacturing electrode materials, wherein said polymer contains the polymer that particle A is shown adhesion.

35. as the method for top 33 described manufacturing electrode materials, wherein said heat treatment step is the combustion step (firing step) that carries out under at least 200 ℃ of temperature.

36. a method of making electrode material, it comprises:

The composition that will contain polymer is deposited on the step on the part surface at least of carbonaceous particle;

Described carbonaceous particle and carbon fiber and silicon and/or silicon compound are mixed, thereby the instrumentality by the described composition that contains polymer is with described carbon fiber and silicon and/or the step of silicon compound deposited on described carbonaceous particle; With

The subsequent step that the carbonaceous particle that obtains is heat-treated.

37. a method of making electrode material, it comprises:

Composition, carbon fiber and silicon and/or the silicon compound that will contain polymer mix, and described carbonaceous particle is mixed with this mixture, thereby the instrumentality by the described composition that contains polymer is with described carbon fiber and silicon and/or the step of silicon compound deposited on described carbonaceous particle; With

The subsequent step that the carbonaceous particle that obtains is heat-treated.

38. as the method for top 36 or 37 described manufacturing electrode materials, wherein said polymer contains the polymer that carbon is shown adhesion.

39. as the method for top 36 or 37 described manufacturing electrode materials, wherein said polymer contains and is selected from least a in phenol resin, polyvinyl alcohol resin, furane resins, celluosic resin, polystyrene resin, polyimide resin and the epoxy resin.

40. as the method for top 36 or 37 described manufacturing electrode materials, wherein said polymer contains phenol resin and drying oil or its derived fatty acid.

41. as the method for top 37 described manufacturing electrode materials, it comprises:

The composition that will contain polymer, carbon fiber and silicon and/or silicon compound is deposited on the carbonaceous particle, wherein said polymer contains phenol resin and drying oil or its derived fatty acid, the step that the described composition that is deposited on this carbonaceous particle is cured subsequently; With

To the carbonaceous particle step of heat treatment that obtains, it carries out after described first step repeats 1～20 time.

42. as the method for top 36 or 37 described manufacturing electrode materials, wherein in described heat treatment step, boron compound is added into described carbonaceous particle.

43. as the method for top 36 or 37 described manufacturing electrode materials, wherein said heat treatment step carries out under at least 2,000 ℃ of temperature.

44. as the method for top 36 or 37 described manufacturing electrode materials; wherein said carbon fiber is a gas-phase growth of carbon fibre; and described gas-phase growth of carbon fibre is mixed with described carbonaceous particle; so that based on the described carbonaceous particle of 100 mass parts, the amount of described gas-phase growth of carbon fibre is 0.1～30 mass parts.

45. by as top 33 to 44 in the electrode material made of each described method.

46. contain electrode paste as each described electrode material in top 1 to 32 and 35 and adhesive.

47. contain electrode as top 46 described electrode pastes.

48. contain secondary cell as top 47 described electrodes.

49. as top 48 described secondary cells, it comprises nonaqueous electrolytic solution solvent and electrolyte, and wherein said nonaqueous electrolytic solution solvent is to be selected from least a in ethylene carbonate, diethyl carbonate, dimethyl carbonate, methyl ethyl carbonate, gamma-butyrolacton and the propylene carbonate.

Describe the present invention below.

[electrode material]

Electrode material of the present invention comprises to contain and is selected from particle at least a in silicon, tin, silicon compound and the tin compound and carbon fiber.Especially, realize that mode of the present invention comprises following two kinds: mode 1 adopts the particle of siliceous and/or tin as nuclear, and mode 2 adopts the carbon granule with graphite-structure as nuclear, and wherein the carbonaceous material with siliceous and/or silicon compound is deposited on the part surface at least of described carbon granule.Respectively dual mode is described in detail.

[1] mode 1

(1-1) as the particle of examining

Particle as nuclear comprises containing and is selected from silicon grain, tin particles, contains the particle of the silicon compound that can insert/can discharge lithium ion and contains particle at least a in the particle of the tin compound that can insert/can discharge lithium ion (back is referred to as " particle A ").This particle can be the particle of above-mentioned particle and the combination of other organic or inorganic compound.

As used herein, insert lithium ion and refer to a kind of like this phenomenon, when battery charge, lithium ion discharges from positive pole in lithium ion battery, in the microgap between the active material particle of the formation of lithium ion insertion subsequently negative material, thereby form compound.This may also be referred to as " doping " phenomenon.Simultaneously, discharge lithium ion and refer to the phenomenon that the lithium that comprises therefrom discharges with the lithium ion form in negative material described in the discharge process.This can be called " dedoping " phenomenon.In the process of using lithium ion battery, this doping/dedoping circulation is carried out repeatedly.

The particle that each particle that contains the silicon compound that can insert/can discharge lithium ion and/or tin compound can be the primary granule that formed by the compound that contains silicon atom, formed by the compound that contains tin atom, by the compound that contains silicon atom with contain the particle that the compound of tin atom forms, perhaps the secondary aggregated particle that is combined to form by these particles.

This particle can be bulk, sheet, spherical or fibrous.Preferably, this particle is taked spherical or block.

Adopt the median particle diameter (D50) of this particle that laser diffraction type particle size distribution measurement mechanism measures to be preferably about 0.3 μ m～about 70 μ m, 0.3 μ m～50 μ m more preferably, further 0.5 μ m～20 μ m more preferably.Preferably, to be substantially devoid of particle diameter be 0.1 μ m or littler and/or 85 μ m or bigger particle to this particle.

Owing to following reason with described particle size adjustment within above-mentioned preferable range.When described particle grain size was big, this particle can react and miniaturization by charge/discharge, thereby caused cycle characteristics to worsen.In contrast, when described particle grain size hour, this particle can not fully participate in the electrochemical reaction with lithium ion, thereby causes capacity to descend, and for example cycle characteristics worsens.

For particle diameter is adjusted, can adopt any known pulverizing or classification technique.The instantiation of the device that is used to pulverize comprises hammer-mill, jaw formula pulverizer and impact grinder.Stage division can be air current classifying or screening.The example that is used for the device of air current classifying comprises turbine type grader and turbo plex.

Described silicon compound can be by formula M _xThe compound that Si represents, wherein M represents to be different from the element of Li, and x is 0.01 or bigger.In the formula, M is B, C, N, O, S, P, Na, Mg, Al, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, Ru, Rh, Pd, Pt, Be, Nb, Nd, Ce, W, Ta, Ag, Au, Cd, Ga, In, Sb or Ba.In the formula, x is preferably 0.1 or bigger, and more preferably 0.3 or bigger.

Described silicon compound for example can be the alloy that is formed by silicon and alkaline-earth metal, transition metal or metalloid.Preferably, this compound is solid solution alloy or eutectic alloy, and it is formed by silicon and Be, Ag, Al, Au, Cd, Ga, In, Sb or Zn.The average grain diameter that constitutes the particle of described alloy is 0.3～70 μ m, is preferably 0.3～40 μ m.

Described silicon compound can be a silicide; The i.e. compound that is formed by silicon and metal, wherein the proportion of composing of component needn't be corresponding with the chemical valence of silicon.The silicide that can adopt comprises CaSi, CaSi ₂, Mg ₂Si, BaSi ₂, Cu ₅Si, FeSi, FeSi ₂, CoSi ₂, Ni ₂Si, NiSi ₂, MnSi, MnSi ₂, MoSi ₂, CrSi ₂, Cr ₃Si, TiSi ₂, Ti ₅Si ₃, NbSi ₂, NdSi ₂, CeSi ₂, WSi ₂, W ₅Si ₃, TaSi ₂, Ta ₅Si ₃, PtSi, V ₃Si, VSi ₂, PdSi, RuSi and RhSi.

Described silicon compound can be SiO for example ₂, SiC or Si ₃N ₄Compound.

Described tin compound can be ashbury metal, tin oxide, artificial gold, tin halides or stannide.Described tin compound comprises the solid solution alloy that is formed by Sn and Zn, Cd, In or Pb; Tin oxide, for example SnO, SnO ₂, Sn ₂O ₃, Sn ₃O ₄, Mg ₂SnO ₄, ZnSnO ₄, CoSnO ₄, Na ₄SnO ₄, K ₂SnO ₃And Na ₂SnO ₃Artificial gold, for example SnS and SnS ₂Tin halides, for example SnX ₂And SnX ₄, wherein X represents halogen atom; And stannide, for example MgSn, Mg ₂Sn, FeSn, FeSn ₂, MoSn and MoSn ₂Described tin compound can be hydrate, for example SnCl _{2 2}H ₂O, SnO ₂NH ₂O and SnOH ₂O.

(1-2) carbonaceous material

In the present invention, the part surface at least of particle A can be applied by described carbonaceous material.The particle that is applied by described carbonaceous material can be deposited on by the composition that will contain polymer on the part surface at least of particle A, carbon fiber (being preferably gas-phase growth of carbon fibre) is sneaked into wherein, heat-treated subsequently and obtain.

The polymer that adopts preferably shows the adhesion to particle A.Can adopt any polymer, as long as this polymer for example shows when (for example mixing, stir, remove solvent or heat treatment) to compression, crooked, the tolerance peeling off, impact, stretch or tear etc., so that this polymer can not cause peeling off from described particle substantially standing any processing.Preferably, this polymer is to be selected from least a in phenol resin, polyvinyl alcohol resin, furane resins, celluosic resin, polystyrene resin, polyimide resin and the epoxy resin.Preferred polymer comprises phenol resin and polyvinyl alcohol resin.

Particularly, form fine and close carbonaceous material when employing during with phenol resin that drying oil or its derived fatty acid are mixed.As if the drying oil modified phenolic resin that this obtains owing to the unsaturated bond generation chemical reaction by phenol resin and drying oil, it can relax decomposition and prevent effervesce during heat treatment (or burning).Except carbon-carbon double bond, drying oil has the ester bond that has quite long alkyl, and it is considered to for example to remove gas in combustion process effectively relevant.

Phenol resin prepares by the reaction between phenol and the aldehyde.The example of the phenol resin that can adopt comprises unmodified phenol resin, for example novolac and fusible phenol resin; And the phenol resin of special modification.If desired, described phenol resin can contain rubber, for example acrylonitrile-butadiene rubber.The example of described phenol comprises phenol, cresols, xylenols and has C20 or be less than the alkylphenol of C20 alkyl.

The described phenol resin that contains drying oil or its derived fatty acid can prepare by following method: at first, phenol and drying oil are carried out addition reaction in the presence of strong acid catalyst, in the reactant mixture that obtains, add base catalyst subsequently, so that this mixture shows alkalescence, carry out formaldehyde addition reaction (formalin addition reaction) afterwards; Perhaps, in the reactant mixture that obtains, add drying oil subsequently with phenol and formolite reaction.

The example of drying oil comprises general known vegetable oil, for example tung oil, Linseed oil, dehydrated castor oil, soybean oil and cashew nut oil.Also can adopt by these drying oil derived fatty acid.When this drying oil is sprawled forming film and when afterwards it being left standstill in air, described drying oil short relatively time inner drying with solidify.

Based on the phenol resin that 100 mass parts obtain by phenol and formaldehyde condensation reaction, the preferred amounts of drying oil or its derived fatty acid is 5～50 mass parts.When the amount of drying oil or its derived fatty acid surpassed 50 mass parts, the carbonaceous material that obtains showed more weak adhesion to particle A.

When with the above-mentioned polymer of solvent (for example acetone, ethanol or toluene) dilution when regulating its viscosity, the polymer that obtains is easy to be deposited on the described particle.

Carry out under the pressure condition that is deposited on atmospheric pressure, elevated pressure or reduction of described polymer.Preferred deposition is carried out under the pressure that reduces, and this is because the affinity between described carbon granule and the polymer is improved.

Be coated with under the situation of carbonaceous material (comprising that whole surface-coated when particle has the situation of carbonaceous material) when the part surface at least of particle A, the coating layer thickness that obtains is 1～30, and 000nm is preferably 5～3,000nm.The coating layer thickness of each part can be different, as long as described particle is applied by described carbonaceous material substantially.

(1-3) mix and remove solvent

In the present invention, gas-phase growth of carbon fibre is mixed with particle A, and the mixture that obtains is stirred, thereby described gas-phase growth of carbon fibre is dispersed among the particle A.Described stirring means is not had special restriction, can adopt for example mixing plants such as ribbon-type blender, screw-kneader, Spartan ryuzer, Lodige mixer, planetary-type mixer or universal mixer.

Do not apply at described particle under the situation of described carbonaceous material, whipping temp and mixing time are not had special restriction, as long as described gas-phase growth of carbon fibre is dispersed in the described particle.Simultaneously, under the situation of the described carbonaceous material of described particle coating, suitably determine whipping temp and mixing time according to the component and the viscosity of for example particle and polymer.Whipping temp is generally about 0 ℃～about 50 ℃, is preferably about 10 ℃～about 30 ℃.

As selection,, regulate incorporation time and use the solvent dilution said composition in order under described mixing temperature, the viscosity of said mixture to be reduced to 500Pas or littler.In this case, can adopt any solvent, as long as this solvent shows good affinity to the compound of described polymer and silicon atoms and/or tin atom.The example of this solvent comprises alcohols, ketone, aromatic hydrocarbon and ester class.Preferred examples comprises methyl alcohol, ethanol, butanols, acetone, methylethylketone, toluene, ethyl acetate and butyl acetate.

After finishing stirring, preferably remove part or all of described solvent.Removing of described solvent can realize for example heated-air drying or vacuumize by means of known technology.

Described baking temperature is according to for example the boiling point and the vapour pressure of solvent for use change.Especially, baking temperature is 50 ℃ or higher, is preferably in 100 ℃～1000 ℃ scopes, in more preferably 150 ℃～500 ℃ scopes.

For heating and curing, can adopt most of known heaters.Yet, consider that from the angle of productivity ratio preferred in process of production employing can processed continuously for example rotary furnace or the device of belt continuous oven.

Adopting under the situation of phenol resin as polymer, based on the particle A of 100 mass parts, the addition of described phenol resin is preferably 2～30 mass parts, 4～25 mass parts more preferably, further 6～18 mass parts more preferably.

Preferably, particle A is coated with described carbonaceous material, and the particle that will so apply subsequently mixes with described gas-phase growth of carbon fibre.Yet particle A, described composition and the gas-phase growth of carbon fibre that contains polymer can mix simultaneously, as long as described gas-phase growth of carbon fibre can not adhere on the particle A.

(1-4) heat-treat condition

When described polymer deposition was on particle A, center that will each particle A was heated to described maximum temperature, as long as described carbonaceous material coating can satisfy actual requirement to the adhesion on particle A surface, strength of coating etc.

Under 200 ℃ or higher temperature, heat-treat having deposited the described particle that contains the composition of polymer on it.This temperature is 200 ℃～2,000 ℃ under the situation that burning is handled, and is preferably 200 ℃～1,200 ℃, is 2,000 ℃～3,000 ℃ under the situation of graphitization processing.Under 200 ℃ or higher temperature, the compound of described silicon atoms and/or tin atom can partly form carborundum, silica, tin oxide etc.Under the situation that adopts known heater that described particle is heat-treated, when the heating rate in this device fell in the scope between the minimum and maximum heating rate, the performance of described particle can not be subjected to appreciable impact.Yet, because described particle exists with powder type, and seldom can cause the problem that for example fracture (for example contingent in moulding material) waits, therefore, preferably adopt high heating rate from the angle consideration of production cost.Described particle is preferably 12 hours or still less from the time that room temperature is heated to described maximum temperature experience, more preferably 6 hours or still less, is preferably 2 hours especially or still less.

Can adopt any known annealing device, for example acheson furnace or directly electric furnace.Consider that from the angle of production cost described device is favourable.Yet, preferred its structure that adopts makes its inside can fill the furnace apparatus of inert gas (for example argon gas or helium), this is owing to the resistance of described particle in the presence of nitrogen may reduce, and the intensity of described carbonaceous material may be owing to being reduced by dioxygen oxidation.The preferred embodiment of described stove comprises that its inside can find time and carry out batch furnace and the continuous oven that the batch furnace, internal atmosphere of gas displacement can be controlled by tube furnace.

The average grain diameter of particle A is preferably 0.3～70 μ m, 0.3～50 μ m more preferably, further 0.5～20 μ m more preferably.Described average grain diameter can be passed through laser diffraction-scattering method and measure.When described average grain diameter during less than 0.3 μ m, it is big that draw ratio is tended to become, and it is big that specific area is tended to become.For example, when making battery electrode, generally negative material is mixed with adhesive making pastel, and the pastel that obtains is put on the collector electrode.When the average grain diameter of the particle that constitutes described negative material during less than 0.3 μ m, described electrode material can contain the fine particle of taking measurements greatly less than 0.1 μ m.Therefore, the viscosity of described pastel increases, and the operability of this pastel descends.

When described negative material contains average grain diameter and is 85 μ m or bigger bulky grain, can on the surface of gained electrode, form a large amount of irregular bodies, thereby be used for causing cut on the dividing plate of battery.Preferred adopt that not contain average grain diameter substantially be that the negative material of 0.1 μ m or littler and 85 μ m or bigger particle forms electrode.

(1-5) carbon fiber

The carbon fiber that uses must show excellent electric conductivity, and the therefore preferred carbon fiber with high-crystallinity that adopts.When the electrode that will be formed by electrode material of the present invention adds in the lithium rechargeable battery, the immediate current of the whole negative pole of need flowing through.Therefore, the crystal growth direction of used carbon fiber is preferably parallel with each filametntary axle of described fiber, and described filament has branch.When described carbon fiber is the carbon fiber of branching, between described particle, sets up electrical connection easily by means of described carbon fiber, thereby improve conductivity.

Used carbon fiber can be by asphalt base carbon fiber, gas-phase growth of carbon fibre etc., preferably contains along the gas-phase growth of carbon fibre of the carbon crystal of each filament axle growth of described fiber, and wherein each filament has branch.

Gas-phase growth of carbon fibre can be for example by following process manufacturing: the organic compound that will gasify infeeds in the high-temperature atmosphere with the iron as catalyst.

Used gas-phase growth of carbon fibre can be the carbon fiber of original preparation (as-produced); The heat treated carbon fiber of process under for example 800 ℃～1,500 ℃ temperature; Or under for example 2,000 ℃～3,000 ℃ temperature through graphited carbon fiber.Yet, the carbon fiber of the original preparation of preferred employing or the heat treated carbon fiber of process under about 1,500 ℃ of temperature.

The gas-phase growth of carbon fibre that uses among the present invention is preferably the branching carbon fiber.Each filament of this branching carbon fiber can have hollow structure, and wherein hollow space extends along whole filament, comprises its branching part.Therefore, the carbon-coating of this filametntary formation shell shows as continual stratiform thing.As used herein, term " hollow structure " refers to the wherein structure of carbon-coating formation shell.The hollow cylinder structure comprises: the carbon-coating that wherein forms shell forms the structure of imperfect shell; The structure that wherein said carbon-coating is partly excised; Two wherein stacked carbon-coatings are configured as the structure of single carbon-coating.The cross section of described shell needn't show as circular completely, and can be ellipse or polygon.Interlamellar spacing (d to the carbon crystal layer ₀₀₂) there is not a special restriction.Interlamellar spacing (the d of the described carbon crystal layer that employing X-ray diffraction method measures ₀₀₂) be preferably 0.344nm or littler, 0.339nm or littler more preferably, further 0.338nm or littler more preferably.Described carbon crystal layer is preferably 40nm or littler at the axial thickness of C (Lc).

The filametntary external diameter of each of used gas-phase growth of carbon fibre is 2～1,000nm, and this filametntary draw ratio is 10～15,000.Preferably, this filametntary external diameter is 10～500nm, and length is 1～100 μ m (being that draw ratio is 2～2,000); Perhaps external diameter is 2～50nm, and length is 0.5～50 μ m (being that draw ratio is 10～25,000).

When after the described carbon fiber of preparation with this gas-phase growth of carbon fibre when heat-treating under 2,000 ℃ or the higher temperature, the degree of crystallinity of this carbon fiber further improves, thereby makes the conductivity raising.In this case, a kind of effective measures are to add boron before the heat treatment in described carbon fiber, and it helps graphitization.

The amount of the gas-phase growth of carbon fibre that comprises in the described electrode material is preferably 0.01～20 quality %, 0.1～15 quality % more preferably, further 0.5～10 quality % more preferably.When the amount of described carbon fiber surpassed 20 quality %, electric capacity descended, and when the amount of described carbon fiber during less than 0.01 quality %, the internal resistance increase under the low temperature (as-35 ℃).

Based on the particle A of 100 mass parts, the amount of described gas-phase growth of carbon fibre is preferably 0.1～30 mass parts, more preferably 1～20 mass parts.

When described gas-phase growth of carbon fibre being inserted in the microgap that forms by particle A, form three-dimensional network by described gas-phase growth of carbon fibre itself or by the entanglement that particle A and size are equal to or less than the carbon fiber wire of particle A.Can imagine that the network as buffering ball (cushion ball) absorption percussion that forms thus can suppress the change in volume of particle A during charge/discharge cycle.Simultaneously, can imagine that by means of the resilience of gas-phase growth of carbon fibre, the resilience of described negative electrode active material increases, and described negative pole shows improved restoration characteristics.Therefore, the change in volume of whole negative pole can be suppressed, thereby cycle characteristics can be improved.

The gas-phase growth of carbon fibre that the present invention uses has a large amount of irregular bodies and coarse part on its surface.Therefore, can imagine, this gas-phase growth of carbon fibre shows the adhesion of enhancing to particle A, therefore, even under the situation of charge/discharge cycle repeatedly, described negative electrode active material and provide the carbon fiber of reagent adhering to each other and be not separated from each other as conductivity, thus keep conductivity, and improve cycle characteristics.

When described gas-phase growth of carbon fibre contained the carbon fiber of a large amount of branching, above-mentioned network can form in an efficient way, thereby obtained high conductivity and thermal conductivity easily.In addition, described carbon fiber can be dispersed in the described active material, with the coating active material, thereby improves the intensity of this negative pole, and set up excellent contact between described particle.

When described gas-phase growth of carbon fibre inserted between the described particle, described negative material showed the effect of the maintenance electrolytic solution of enhancing, and even under cryogenic conditions, lithium ion also can successfully insert described electrode material or therefrom discharge.

(1-6) capacity

The capacity of described electrode material is preferably 400mAh/g or higher, and more preferably 400～2,000mAh/g, further more preferably 400～1,000mAh/g.Described electrode material preferably has high power capacity.Yet when the amount of Si that comprises in the described electrode material or Sn increased, because the change in volume of Si or Sn particle, described particle was by miniaturization, and so the particle of miniaturization is separated from one another, thereby causes cycle characteristics significantly to worsen.In addition, when the amount of Si that comprises in the described electrode material or Sn increased, described negative pole expanded/shrinks during charge/discharge, and this electrode material tends to peel off from copper sheet.

In addition, when the amount of silicon, tin, silicon compound and tin compound being adjusted to based on 80～95 quality % of the whole particle A that form electrode material when obtaining the capacity of 400～600mAh/g, the negative material that obtains shows good Practical Performance; Be cycle characteristics, high power capacity retention rate and the low internal resistance of high power capacity, excellence.

[2] mode 2

(2-1) as the particle of examining

The carbon granule that has a graphite-structure when employing is during as the particle that serves as nuclear and when on the part surface at least at described particle with silicon and/or silicon compound deposited, and this carbon granule is the carbon granule as the negative electrode active material in the secondary cell can developed effectively with graphite-structure.For example, adopt the interlamellar spacing (d of the carbon crystal layer that the X-ray diffraction method measures ₀₀₂) be preferably 0.3395nm or littler, more preferably 0.3354nm～0.3370nm.

Described carbon granule can adopt and can become the carbon granule with graphite-structure and prepare by heat treatment.Hereinafter, described particle and the carbon granule with graphite-structure is called as " carbonaceous particle " sometimes.

Spendable carbonaceous particle comprises organic compound (anthropogenics of sintering or the natural organic-compound of sintering) particle, sintering carbonaceous mesophase spherules, sintering resin particle, the petroleum base coke granule of sintering, the coke granule and graphite (as native graphite or the Delanium) particle of charcoal base.The particle of these types can use separately, also can be used in combination with two or more species.

This particle can be bulk, sheet, spherical or fibrous.Preferably, this particle is taked spherical or block.

The median particle diameter (D50) of the described carbon granule that employing laser diffraction type particle size distribution measurement mechanism measures is preferably about 0.1 μ m～about 100 μ m, more preferably 5 μ m～70 μ m.Preferably, to be substantially devoid of particle diameter be 3 μ m or littler and/or 85 μ m or bigger particle to described carbon granule.

For following reason with described particle size adjustment in above-mentioned preferable range.When the particle diameter of described carbon granule hour, the specific area of this particle increases, and follows the side reaction of charge/discharge to become significantly, thereby causes charge significantly to reduce.In contrast, when the particle diameter of described carbon granule was big, it is big that the space that forms between the described particle becomes, thereby bulk density reduces.In addition, because the contact point decreased number between the adjacent particle, current path quantity reduces, thereby causes the characteristic under the high current load significantly to worsen.Simultaneously, owing to described electrode must be placed in the limited space, so the thickness of negative pole can be restricted.Yet, having in employing under the situation of carbon granule of big particle diameter, the negative pole that obtains may not satisfy the requirement of relevant thickness.

In order to adjust particle diameter, can adopt above-mentioned pulverizing or classification technique.

Need show big discharge capacity and high charge as the material with carbon element of negative electrode active material, this can by 2,000 ℃ or higher temperature down heating realize.

In order to improve discharge capacity and charge, effectively by in described carbon granule, be added with before the heat treatment help graphited material (as boron) improve as described in the degree of crystallinity of carbon granule.

Waiting to deposit to the silicon on the above-mentioned carbon granule and/or the particle (back is referred to as silicon/silicon compound) of silicon compound can be bulk, sheet, spherical or fibrous.Preferably, this silicon/silicon compound particle is taked spherical or block.Described silicon/silicon compound can be the element silicon material, contain the compound of silicon atom and/or contain the mixture of the compound of silicon atom, and can be to be selected from silicon, carborundum, silicon dioxide and the silicon nitride one or more.

For following reason, the median particle diameter (D50) of silicon/silicon compound particle that employing laser diffraction type particle size distribution measurement mechanism measures is preferably about 0.1 μ m～about 10 μ m, more preferably 0.3 μ m～3 μ m.When described particle diameter is big, the miniaturization of this particle by charge/discharge, thus cause cycle characteristics to worsen.

In order to adjust described particle diameter, can adopt any known pulverizing or classification technique.The instantiation of the device that is used to pulverize comprises hammer-mill, jaw formula pulverizer and impact grinder.Stage division can be air current classifying or screening.The example that is used for the device of air current classifying comprises turbine type grader and turboplex.

For following reason, based on whole described carbon granules, the amount of described silicon/silicon compound is preferably 1～20 quality %, 2～15 quality % more preferably, further 3～10 quality % more preferably.When the amount of described silicon/silicon compound increased, although capacity increases, cycle characteristics significantly worsened.

(2-2) carbonaceous material

The part surface at least that is used for carbon granule of the present invention is applied by carbonaceous material.This carbonaceous material can be deposited on by the composition that will contain polymer to the described carbon granule of small part and heat-treat and obtain.

The polymer that adopts preferably shows the adhesion to carbon fiber and silicon/silicon compound.When show adhering polymer be present between described carbon granule and the carbon fiber or between described carbon granule and the silicon/silicon compound so that these materials are when contacting with each other, these materials are bonded together by chemical bond (as covalent bond), Van der Waals force or hydrogen bond or the physical adherence that obtains by the diffusion by similar substance.Can adopt any adhering polymer that shows in the present invention, as long as this polymer shows tolerance to compression, crooked, the active force that causes such as peel off, impact, stretch or tear standing any processing when (for example mixing, stir, remove solvent or heat treatment), thereby this polymer is gone up substantially and can not be caused peeling off from described carbon fiber.

Preferably, this polymer is with mentioned above identical, that is to say to be selected from least a in phenol resin, polyvinyl alcohol resin, furane resins, celluosic resin, polystyrene resin, polyimide resin and the epoxy resin.Preferred polymer comprises phenol resin and polyvinyl alcohol resin.

In these polymer, the known nature of glass carbon that obtains by thermosetting resin (as phenol resin or furfuryl alcohol resin) carbonization shows the excellent impenetrability to electrolytic solution.Therefore, this nature of glass carbon is suitable for being coated on the surface with the high material with carbon element of electrolytic solution reactivity.In addition, this nature of glass carbon ratio for example pitch be easier to handle.In lithium secondary battery, repeating to take place the lithium ion folder is attached in carbon granule, silicon and the silicon compound or the reaction that therefrom discharges, thereby since the folder of lithium ion attached/discharge, described carbon granule, silicon and silicon compound generation volumetric expansion/contraction, thereby cause dropping or separating of silicon and silicon compound, perhaps carbon fiber dropping or peeling off.The polymer that uses among the present invention is suitable for preventing this phenomenon.

Under the situation that adopts phenol resin and drying oil or its derived fatty acid, preferably, the composition that repeats to contain carbon fiber and silicon/silicon compound is deposited on the carbonaceous particle and step 1～20 that subsequently the described composition that is deposited on the carbonaceous particle are cured time, afterwards the carbonaceous particle that obtains is heat-treated, the angle that reduces from the specific area of described carbonaceous particle, the side reaction (it may take place on described particle surface) that is different from charge/discharge reduces, and cycle characteristics improves.

Based on the phenol resin that 100 mass parts obtain by phenol and formaldehyde condensation reaction, the preferred amounts of drying oil or its derived fatty acid can be 5～50 mass parts.When the amount of drying oil or its derived fatty acid surpassed 50 mass parts, adhesiveness descended, and the density of described carbon fiber or silicon/silicon compound reduces.

(2-3) mix and remove solvent

For the instrumentality by the described composition that contains polymer maybe can be by being heat-treated on the particle (carbonaceous particle) for the carbon granule with graphite-structure at the carbon granule with graphite-structure with carbon fiber and silicon/silicon compound deposited, any all feasible in following two kinds of methods:

Above-mentioned carbonaceous particle is mixed the method for also sneaking into carbon fiber and silicon/silicon compound on this particle surface subsequently so that said composition is deposited on the composition that contains polymer; Composition, carbon fiber and the silicon/silicon compound that perhaps will contain polymer mixes and further sneaks into the method for described carbonaceous particle.

Stirring means is not had special restriction, can adopt for example mixing plants such as ribbon blender, screw-kneader, Spartan ryuzer, Lodige mixer, planetary-type mixer or universal mixer.

Component and viscosity according to for example described particle and polymer are suitably determined described whipping temp and mixing time.Described whipping temp is generally about 0 ℃～about 50 ℃, is preferably about 10 ℃～about 30 ℃.As selection,, can regulate incorporation time and use the solvent dilution said composition in order under described mixing temperature, the viscosity of said mixture to be reduced to 500Pas or littler.In this case, can adopt any solvent, as long as this solvent shows good affinity to described polymer, carbon fiber and silicon/silicon compound.The example of this solvent comprises alcohols, ketone, aromatic hydrocarbon and ester class.Preferred examples comprises methyl alcohol, ethanol, butanols, acetone, methylethylketone, toluene, ethyl acetate and butyl acetate.

After finishing stirring, preferably remove part or all of described solvent.Removing of described solvent can be carried out by means of known technology, for example heated-air drying or vacuumize.

Baking temperature is according to for example the boiling point and the vapour pressure of solvent for use change.Especially, baking temperature is 50 ℃ or higher, is preferably in 100 ℃～1000 ℃ scopes, in more preferably 150 ℃～500 ℃ scopes.

For heating and curing, can adopt most of known heaters.Yet, consider that from the angle of productivity ratio preferred in process of production employing can processed continuously for example rotary furnace or the device of belt continuous oven.

Adopting under the situation of phenol resin as polymer; maybe can become the particle of carbon granule with graphite-structure based on the carbon granule with graphite-structure of 100 mass parts; the addition of phenol resin is preferably 2～30 mass parts; 4～25 mass parts more preferably, further 6～18 mass parts more preferably.

(2-4) heat-treat condition

For the charging that the insertion that improves because of lithium ion causes, must improve the degree of crystallinity of described carbon granule.Owing to the degree of crystallinity of carbon generally improves according to the maximum temperature in the thermo-lag (being maximum heat treatment temperature), therefore the angle that improves from battery performance considers that heat treatment is preferably carried out under higher temperature.Heat treatment temperature is preferably 2,000 ℃ or higher, more preferably 2,500 ℃ or higher, further more preferably 2,800 ℃ or higher, is preferably 3,000 ℃ or higher especially.

Preferably, with long-time heating under the maximum temperature of described carbon granule in thermo-lag.Yet because carbon granule to be heated is fine particulate form, therefore when heat conduction reached the center of each particle, described carbon granule showed enough performances basically.Consider preferably short heating time from the angle of production cost.For example, when being the carbonaceous powder of about 20 μ m when heating, after the temperature at each particle center of this powder reaches described maximum temperature, this powder remained on described maximum temperature following 30 minutes or more of a specified duration to having average grain diameter, preferred 10 minutes or more of a specified duration, more preferably 5 minutes or more of a specified duration.

When applying the matrix (as heat treated Delanium of process or native graphite) with high-carbon degree of crystallinity with coating material, this coating material originally needs to experience heat treatment to a certain degree after coating is finished.Heat treatment preferably 2,400 ℃ or higher, more preferably 2,700 ℃ or higher, carry out particularly preferably under 2,900 ℃ or the higher temperature.In this case, the center of described matrix needn't be heated to described maximum temperature, as long as the coating that obtains satisfies actual requirement substantially to the adhesion on described carbonaceous material surface, strength of coating etc.

By adopting under the situation that known heater heat-treats described particle, when the heating rate in this device fell in the scope between the minimum and maximum heating rate, the performance of described particle can not be subjected to appreciable impact.Yet, because described particle exists with powder type, and seldom can cause the problem that for example fracture (for example contingent in moulding material) waits, therefore, preferably adopt high heating rate from the angle consideration of production cost.Described particle is preferably 12 hours or still less from the time that room temperature is heated to described maximum temperature experience, more preferably 6 hours or still less, is preferably 2 hours especially or still less.

Can adopt any known annealing device, for example acheson furnace or directly electric furnace.Consider that from the angle of production cost described device is favourable.Yet, preferred its structure that adopts makes its inside can fill the furnace apparatus of inert gas (for example argon gas or helium), this is owing to the resistance of described particle in the presence of nitrogen may reduce, and the intensity of described carbonaceous material may be owing to being reduced by dioxygen oxidation.The preferred embodiment of described stove comprises that its inside can find time and carry out batch furnace and the continuous oven that the batch furnace, internal atmosphere of gas displacement can be controlled by tube furnace.

In order to improve the degree of crystallinity of described material with carbon element, if desired, can adopt any known graphitization catalyst, for example boron compound, beryllium compound, aluminium compound or silicon compound.

In graphite network crystal structure, carbon atom can be substituted by the boron atom.This when alternative when taking place, it is believed that the reorganization that crystal structure has taken place; Be carbon-carbon bond fracture and reorganization then.Therefore, when the graphite granule with relative low-crystallinity was carried out this reorganization, the particle that obtains can show high-crystallinity.Phrase " carbon coating that contains boron (element boron) " refers to the carbon atom of boron atom in described carbon coating of introducing when a part and forms solid solution and be present on the described carbon-coating surface or the situation between the carbon atomic layer of hexagonal network configuration; Or carbon atom part situation about being substituted by the boron atom.

This boron compound operable boron compound do not had special restriction, as long as can produce boron by heating.The example of operable boron compound comprises boron, boron carbide, boron oxide and organic boron oxide compound.Described boron compound can be solid, liquid or gas form.Instantiation comprises element boron, boric acid (H ₃BO ₃), borate, boron oxide (B ₂O ₃), boron carbide (B ₄C) and BN.

Addition to boron compound does not have special restriction, and it depends on the chemical property and the physical property of this compound.For example, when with boron carbide (B ₄When C) adding in the described carbon granule, based on 100 mass parts described carbon granule to be heated, the amount of boron carbide is preferably 0.05～10 mass parts, more preferably 0.1～5 mass parts.

When under situation about before the heat treatment particle diameter of described carbon granule being adjusted, needn't adjust the particle diameter of described material with carbon element after the heat treatment.Yet, when described material with carbon element has fused or assembled, can slightly pulverize this material, and carry out air current classifying then.Consider from the angle of ease-to-operate, preferably adopt mesh screen to carry out classification by screening.

The average grain diameter of described material with carbon element is 5～70 μ m, is preferably 8～30 μ m, more preferably 10～25 μ m.Average grain diameter can be passed through laser diffraction-scattering method and measure.When described average grain diameter during less than 5 μ m, it is big that draw ratio is tended to become, and it is big that specific area is tended to become.For example, when making battery electrode, generally described material with carbon element is mixed with adhesive, and the pastel that obtains is put on the collector electrode with the formation pastel.When the average grain diameter of described material with carbon element during less than 5 μ m, this material with carbon element contains the fine particle of a large amount of sizes less than 5 μ m.Thereby the viscosity of described pastel increases, and the operability of this pastel descends.

Preferably, the particle diameter that contains of described carbonaceous material is that 3 μ m or littler particle and particle diameter are that the amount of 85 μ m or bigger particle is 5 quality % or still less.In this case, the average grain diameter of described material with carbon element is 8～30 μ m.When described material with carbon element contains average grain diameter and is 85 μ m or bigger bulky grain, on the electrode surface of gained, form a large amount of irregular bodies, thereby produce cut on the dividing plate that causes in battery, using.

(2-5) carbon fiber

The carbon fiber that uses can be preferably gas-phase growth of carbon fibre with mentioned above identical.

When after the described carbon fiber of preparation this gas-phase growth of carbon fibre being heat-treated, the degree of crystallinity of described gas-phase growth of carbon fibre further improves, thus the conductivity raising.Yet, consider from the angle of production cost, in the process of making described material with carbon element, carry out twice or more times heat treatment step is disadvantageous.Therefore, preferably will bond together through pulverizing and the carbon granule raw material of classification, not graphited gas-phase growth of carbon fibre and silicon/silicon compound by polymer, and with the product that obtains 2,000 ℃ or higher temperature be heating down, thereby prepares the electrode material of the gas-phase growth of carbon fibre that contains high-crystallinity.

(2-6) capacity

The capacity of described material with carbon element is preferably 400～1,000mAh/g, 400～800mAh/g more preferably, further 400～600mAh/g more preferably.Preferred described material with carbon element has high power capacity.Yet when the Si content in the described electrode material increased, by miniaturization, and described carbon granule was separated from one another when the secondary cell of gained carries out recharge/discharge cycles for described silicon grain, thereby causes cycle characteristics significantly to worsen.In addition, when the Si content in the described electrode material increased, described negative material expanded/shrinks during charge/discharge, and this electrode material tends to peel off from copper sheet.When the amount of described silicon/silicon compound being adjusted to based on 1～20 mass parts of the described carbon granule of 100 mass parts when obtaining the capacity of 400～600mAh/g, the electrode material that obtains relies on the excellent cycle characteristics and the low bulk/shrinkage character of graphite to show good Practical Performance.

[secondary cell]

Can adopt any known method to make lithium secondary battery by electrode material of the present invention.

In order to be used for electrode of lithium cell, it is long-pending that described electrode material preferably has small specific surface.The specific area that measures the particle that constitutes electrode material of the present invention by the BET method is 3m ²/ g or littler.When described specific area surpasses 3m ²During/g, the surface activity of above-mentioned particle increases, and because for example decomposition of electrolytic solution, coulombic efficiency descends.In order to improve battery capacity, must improve the bulk density of above-mentioned particle.Thereby each particle that constitutes described material with carbon element preferably presents sphere in fact.When representing each coating of particles, this draw ratio is 6 or littler, is preferably 5 or littler with draw ratio (being the length of the length/minor axis of major axis).Described draw ratio can adopt the microphoto of particle for example and obtain.As selection, draw ratio can calculate by following method: the average grain diameter (A) of measuring particle by laser diffraction-scattering method; Measure the average grain diameter (B) of particle by electrical detection method (Coulter counting method); Each particle is considered as a disk, and its basal surface diameter is represented with (A); This disk volume (C) is calculated by following formula: C=4/3 * (B/2) ³π; This disc thickness (T) is calculated by following formula: T=C/ (A/2) ²π; And draw ratio is calculated by A/T.

Under the situation of lithium secondary battery electrode, but when the electrode material that uses showed good filling capacity and has high-bulk-density, the gained electrode showed the high discharge capacity of per unit volume.The bulk density of electrode material of the present invention is 0.8g/cm ³Or bigger, be preferably 0.9g/cm ³Or it is bigger.Described bulk density is measured by following step: the described material with carbon element (6.0g) of predetermined quality is placed in the measuring cell of size 15mm φ; This measuring cell is placed in the vibrating device; With the free fall 400 times under following condition of this measuring cell: height of drop: 46mm, vibration rate: 2 seconds/time; After finishing repetition free fall 400 times, measure the volume of described material with carbon element; The bulk density of described material with carbon element is by the quality and the volume calculation of above-mentioned measurement.

Lithium secondary battery electrode can be by following process manufacturing: use the solvent dilution adhesive, subsequently itself and described electrode material are kneaded with general fashion, and the mixture that obtains is put on the collector electrode (substrate).

The example of operable adhesive comprises known adhesive, as fluoropolymer (as polyvinylidene fluoride and polytetrafluoroethylene) and rubber (as SBR (styrene butadiene rubbers)).Can use any known solvent that is suitable for adhesive to be used.When adopting fluoropolymer, for example adopt toluene or N-methyl pyrrolidone as solvent as adhesive.When adopting SBR, for example adopt water as solvent as adhesive.

Based on the described electrode material of 100 mass parts, the amount of the adhesive of use is preferably 1～30 mass parts, is preferably about 3～about 20 mass parts especially.

Kneading of described negative material and adhesive can adopt any known devices to carry out, for example ribbon blender, screw-kneader, Spartan ryuzer, Lodige mixer, planetary-type mixer and universal mixer etc.

The mixture of kneading thus can put on the collector electrode by means of any known mode.For example, can use scraper, spreading rod or similar device that this mixture is put on the collector electrode, subsequently for example by the collector electrode moulding of roll-in with gained.

The example of operable collector electrode comprises known material, as copper, aluminium, stainless steel, nickel and alloy thereof.

Can use any known dividing plate, but the adhesive-bonded fabric that especially preferably uses polyethylene or polypropylene to make.

In lithium secondary battery of the present invention, described electrolytic solution can be known organic electrolysis solution, and electrolyte can be known inorganic solid electrolyte or copolymer solid electrolyte.Consider preferred organic electrolysis solution from the angle of conductance.

The preferred embodiment that is used to prepare the organic solvent of described organic electrolysis solution comprises ethers, as diethyl ether, butyl oxide, glycol monoethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol dimethyl ether and ethylene glycol phenyl ether; Amide-type, as formamide, N-methylformamide, N, dinethylformamide, N-ethyl-formamide, N, N-diethylformamide, N-methylacetamide, N, N-dimethylacetylamide, N-ethyl acetamide, N, N-diethyl acetamide, N, N-dimethyl propylene acid amides and hexamethyl phosphoramide; Sulfur-containing compound is as dimethyl sulfoxide (DMSO) and sulfolane; Dialkyl ketone is as methylethylketone and methyl second butyl ketone; Cyclic ethers is as oxirane, expoxy propane, oxolane, 2-methoxyl group oxolane, 1,2-dimethoxy-ethane and 1,3-dioxolanes; Carbonic ester is as ethylene carbonate and propylene carbonate; Gamma-butyrolacton; The N-methyl pyrrolidone; Acetonitrile; And nitromethane.The example that is more preferably comprises the ester class, as ethylene carbonate, butylene carbonate, diethyl carbonate, dimethyl carbonate, propylene carbonate, carbonic acid ethenylidene ester and gamma-butyrolacton; Ethers is as dioxolanes, diethyl ether and diethoxyethane; Dimethyl sulfoxide (DMSO); Acetonitrile; And oxolane.Especially, preferably adopt the carbonate group nonaqueous solvents, as ethylene carbonate and propylene carbonate.These solvents can use separately or be used in combination with two or more.

Use may be dissolved in lithium salts in the above-mentioned solvent as solute (electrolyte).The example of general known lithium salts comprises LiClO ₄, LiBF ₄, LiPF ₆, LiAlCl ₄, LiSbF ₆, LiSCN, LiCl, LiCF ₃SO ₃, LiCF ₃CO ₂And LiN (CF ₃SO ₂) ₂

The example of described copolymer solid electrolyte comprises polyethylene oxide derivant and contains the polymer of this derivative, poly propylene oxide derivative and contain polymer, phosphate ester polymer and the polycarbonate derivatives of this derivative and contain the polymer of this derivative.

In containing the lithium secondary battery of negative material of the present invention, preferably, adopt and contain the transition metal oxide of lithium as positive active material.Preferably, described positive active material is for mainly containing lithium and the oxide that is selected from following at least a transition metal: Ti, V, Cr, Mn, Fe, CO, Ni, Mo and W, wherein the mol ratio of lithium and transition metal is 0.3～2.2.More preferably, described positive active material is for mainly containing lithium and being selected among oxide V, Cr, Mn, Fe, Co and the Ni of following at least a transition metal, and wherein the mol ratio of lithium and transition metal is 0.3～2.2.Described positive active material can contain Al, Ga, In, Ge, Sn, Pb, Sb, Bi, Si, P, B etc., and based on all transition metal that exist as main component, it is measured less than 30mol%.In above-mentioned positive active material, preferred material be selected from have spinel structure, by formula Li _xMO ₂Expression (wherein M represents to be selected from least a element among Co, Ni, Fe and the Mn, and x is 0～1.2) or by formula Li _yN ₂O ₄The expression (wherein N comprises Mn at least, and y is 0～2) material at least a.

Particularly preferably, described positive active material is to be selected to contain Li _yM _aD _1-aO ₂Material at least a, wherein M represents to be selected from least a element among Co, Ni, Fe and the Mn; D represents to be selected from least a element among Co, Ni, Fe, Mn, Al, Zn, Cu, Mo, Ag, W, Ga, In, Sn, Pb, Sb, Sr, B and the P, and condition is to get rid of the element corresponding with M; Y is 0～1.2; And a is 0.5～1; Or be selected from and have spinel structure and by formula Li _z(N _bE _1-b) ₂O ₄The expression material at least a, wherein N represents to be selected from Mn; E represents to be selected from least a element among Co, Ni, Fe, Mn, Al, Zn, Cu, Mo, Ag, W, Ga, In, Sn, Pb, Sb, Sr, B and the P; B is 1～0.2; And z is 0～2.

The instantiation of described positive active material comprises Li _xCoO ₂, Li _xNiO ₂, Li _xMnO ₂, Li _xCo _aNi _1-aO ₂, Li _xCo _bV _1-bO _z, Li _xCo _bFe _1-bO ₂, Li _xMn ₂O ₄, Li _xMn _cCo _2-cO ₄, Li _xMn _cNi _2-cO ₄, Li _xMn _cV _2-cO ₄And Li _xMn _cFe _2-cO ₄, wherein x is 0.02～1.2, and a is 0.1～0.9, and b is 0.8～0.98, and c is 1.6～1.96, z is 2.01～2.3.The most preferred example that contains the transition metal oxide of lithium comprises Li _xCoO ₂, Li _xNiO ₂, Li _xMnO ₂, Li _xCo _aNi _1-aO ₂, Li _xMn ₂O ₄And Li _xCo _bV _1-bO _z, wherein x is 0.02～1.2, and a is 0.1～0.9, and b is 0.9～0.98, and z is 2.01～2.3.Value x is the value of measuring before the charge/discharge in beginning, and increases along with charge/discharge or reduce.

Average grain diameter to the particle of described positive active material does not have special restriction, but its average grain diameter is preferably 0.1～50 μ m.Preferably, based on whole volumes of positive active material particle, particle diameter is that the volume of the particle of 0.5～30 μ m is 95% or bigger.More preferably, based on whole volumes of positive active material particle, particle diameter is that the volume of 3 μ m or littler particle is 18% or littler, and based on whole volumes of positive active material particle, particle diameter is that the volume of the particle of 15 μ m～25 μ m is 18% or littler.Specific area to positive active material does not have special restriction, but the specific area of measuring by the BET method is preferably 0.01m ²/ g～50m ²/ g is preferably 0.2m especially ²/ g～1m ²/ g.In the time of in described positive active material (5g) being dissolved in distilled water (100ml), the pH value of the supernatant liquor of gained solution is preferably 7～12.

There is not special restriction to making the required element (except said elements) of battery.

Implement best mode of the present invention

Below with reference to representational embodiment the present invention is explained in more detail, it should not be interpreted as limitation of the present invention.

The method of the phenol resin that preparation is used to deposit

Adopt and pass through the partially modified phenol resin of tung oil as deposition materials.

Tung oil (100 mass parts), phenol (150 mass parts) and nonyl phenol (150 mass parts) are mixed, and the mixture that obtains is remained under 50 ℃.In this mixture, add sulfuric acid (0.5 mass parts), stir the mixture that obtains, progressively heating, and under 120 ℃, kept 1 hour, addition reaction takes place thereby make between tung oil and the described phenol.Subsequently, the temperature of gained reactant mixture is reduced to 60 ℃ or lower, and in this mixture, adds the formalin (100 mass parts) of hexa (6 mass parts) and 37 quality %.The mixture that obtains was reacted about 2 hours down at 90 ℃, then dehydration in a vacuum.The mixture of using the dilution of methyl alcohol (100 mass parts) and acetone (100 mass parts) to obtain afterwards, thus the varnish that viscosity is 20mPas (20 ℃) obtained.This varnish of back also is referred to as " varnish A ".

The cell evaluation method:

(1) preparation of pastel

In carbon raw material (1 mass parts), add KF polymer L1320 (a kind of N-methyl pyrrolidone (NMP) solution goods that contain 12 quality %PVDF, Kureha Chemical IndustryCo., Ltd. product) (0.1 mass parts), and adopt planetary-type mixer that the mixture that obtains is kneaded, thereby preparation pure reagent.

(2) formation of electrode

NMP is joined in this pure reagent, to regulate the viscosity of this reagent.By scraper the mixture that obtains is put on the highly purified Copper Foil, to obtain the thickness of 250 μ m.At vacuum, 120 ℃ dry products therefrom 1 hour down, subsequently it is carried out punching press, have 18mm φ electrodes sized thereby form.The electrode holder that forms is thus suppressed between the pressing plate that high-speed steel is made then, so that 1 * 10 ³～3 * 10 ³Kg/cm ²Pressure put on this electrode.Afterwards, with the electrode that obtains in Minton dryer in 120 ℃ dry 12 hours down, and be used for estimating.

(3) manufacturing of battery

Make three-electrode battery in the following manner.Following process is carried out under-80 ℃ or the lower dry argon gas atmosphere at dew point.

In the battery with nut (the about 18mm of internal diameter) of polypropylene system, dividing plate (microporous barrier of polypropylene system, Celgard 2400) is clamped in the above carbon electrode with Copper Foil (positive pole) and the metallic lithium foil (negative pole) that forms in (2), thereby forms laminate.Subsequently, the metallic lithium foil of serving as reference electrode is carried out lamination in mode similar to the above.Afterwards, in this battery, add electrolytic solution, and use the battery that obtains to test.

(4) electrolytic solution

EC electrolytic solution: by will be as electrolytical LiPF ₆(1 mol) is dissolved in the mixture of EC (ethylene carbonate) (8 mass parts) and DEC (diethyl carbonate) (12 mass parts) and prepares.

(5) charge/discharge cycle test

In current density is 0.2mA/cm ²Carry out the charge/discharge test of constant-current constant-voltage under the condition of (corresponding to 0.1C).At 0.2mA/cm ²Under carry out constant current (CC) charging (being about to lithium ion inserts in the carbon), meanwhile voltage increases to 0.002V from electrostatic potential.Subsequently, under 0.002V, carry out constant voltage (CV) charging, and when described current value is reduced to 25.4 μ A, stop charging.

At 0.2mA/cm ²Carry out CC discharge (being that lithium ion discharges) under (corresponding to 0.1C) from carbon, and cut off during for 1.5V at voltage.

Embodiment 1

Silicon materials are pulverized and classification, thereby preparation average grain diameter (D50) is the silicon grain of 20 μ m.Independently, in varnish A, add ethanol and stir the mixture that obtains, thereby varnish A is dissolved in the described ethanol fully.The solution of gained is added in the above-mentioned silicon grain that makes (100g),, and the mixture of gained was kneaded 30 minutes by planetary-type mixer so that the amount of described modified phenolic resin solid becomes 10 quality % based on all silicon grains.In the mixture that this obtains, be added in 2,800 ℃ (the filametntary average diameter of this carbon fiber is 150nm through graphited gas-phase growth of carbon fibre down, described filametntary average aspect ratio is 100) (0.1 quality %), and stir the mixture that obtains thus.In Minton dryer in 80 ℃ of following mixtures 2 hours of dry gained, thereby remove described ethanol.Subsequently, dried mixture is placed in the heating furnace thus, and this furnace interior of finding time is filled argon gas then.Subsequently, this stove of heating under argon gas stream.Furnace temperature kept 10 minutes down at 2,900 ℃, then with this stove cool to room temperature.Afterwards, the sieve that adopts 63 μ m mesh sieves heat treated product thus, thereby obtains the negative material sample less than 63 μ m sizes.When electron microscope (SEM) down observation obtain thus the negative material sample time, find that the filament of gas-phase growth of carbon fibre is dispersed in around each silicon grain.By single pond cell evaluation device, the negative material sample that obtains thus of embodiment 1 is carried out cell evaluation.Adopt the EC electrolytic solution to carry out cell evaluation.In the charge/discharge cycle test, measure the capacity of the 1st circulation time and the capacity of the 50th circulation time.The result is as shown in table 1.

Embodiment 2

Repeat the process of embodiment 1, the addition of different is gas-phase growth of carbon fibre becomes 3 quality %, thereby obtains the negative material sample.With with the identical mode of embodiment 1 sample, by single pond cell evaluation device, the above-mentioned sample that obtains is carried out cell evaluation.Adopt the EC electrolytic solution to carry out cell evaluation.In the charge/discharge cycle test, measure the capacity of the 1st circulation time and the capacity of the 50th circulation time.The result is as shown in table 1.

Embodiment 3

Repeat the process of embodiment 1, the addition of different is gas-phase growth of carbon fibre becomes 10 quality %, thereby obtains the negative material sample.With with the identical mode of embodiment 1 sample, by single pond cell evaluation device, the above-mentioned sample that obtains is carried out cell evaluation.Adopt the EC electrolytic solution to carry out cell evaluation.In the charge/discharge cycle test, measure the capacity of the 1st circulation time and the capacity of the 50th circulation time.The result is as shown in table 1.

Embodiment 4

Repeat the process of embodiment 1, different is to adopt the silicon-carbide particle that is adjusted to average grain diameter (D50) 1 μ m to replace silicon grain, thereby obtains the negative material sample.When electron microscope (SEM) down observation obtain thus the negative material sample time, the filament of finding gas-phase growth of carbon fibre be dispersed in each silicon-carbide particle around.By single pond cell evaluation device, the negative material sample that obtains thus of embodiment 4 is carried out cell evaluation.Adopt the EC electrolytic solution to carry out cell evaluation.In the charge/discharge cycle test, measure the capacity of the 1st circulation time and the capacity of the 50th circulation time.The result is as shown in table 1.

Embodiment 5

Preparation average grain diameter (D50) is the silicon grain of 20 μ m.In the silicon grain of preparation thus, add gas-phase growth of carbon fibre (the filametntary average diameter of this carbon fiber is 150nm, and described filametntary average aspect ratio is 100) (0.1 quality %), and stir the mixture of gained, to obtain negative material.By single pond cell evaluation device the negative material that obtains is thus carried out cell evaluation.Adopt the EC electrolytic solution to carry out cell evaluation.In the charge/discharge cycle test, measure the capacity of the 1st circulation time and the capacity of the 50th circulation time.The result is as shown in table 1.

Embodiment 6

Obtain the negative material sample by the mode identical with embodiment 1, different is that the tin particles that adopts average grain diameter (D50) to be adjusted to 20 μ m replaces silicon grain.Mode by identical with embodiment 1 adopts single pond cell evaluation device that the negative material that obtains is thus carried out cell evaluation.Adopt the EC electrolytic solution to carry out cell evaluation.In the charge/discharge cycle test, measure the capacity of the 1st circulation time and the capacity of the 50th circulation time.The result is as shown in table 1.

The comparative example 1

Preparation average grain diameter (D50) is the silicon grain of 20 μ m.Independently, (10g) is dissolved in the isopropyl alcohol with phenol resin, thereby makes solution.This solution is added in the above-mentioned silicon grain that makes,, and fully stir the mixture of gained, remove solvent subsequently so that described solids content becomes 10 quality % based on all silicon grains.Afterwards, under the condition that does not add gas-phase growth of carbon fibre, the mixture of gained is heat-treated and sieved, thereby form composite particles in the mode identical with embodiment 1.The particulate samples that forms is thus mixed with carbon black (1g), thereby obtain negative material.

By single pond cell evaluation device the negative material that obtains is thus carried out cell evaluation.Adopt the EC electrolytic solution to carry out cell evaluation.In the charge/discharge cycle test, measure the capacity of the 1st circulation time and the capacity of the 50th circulation time.The result is as shown in table 1.

The comparative example 2

Preparation average grain diameter (D50) is the silicon grain of 20 μ m, and this silicon grain is used as negative material.By single pond cell evaluation device this negative material is carried out cell evaluation.Adopt the EC electrolytic solution to carry out cell evaluation.In the charge/discharge cycle test, measure the capacity of the 1st circulation time and the capacity of the 50th circulation time.The result is as shown in table 1.

The comparative example 3

Preparation average grain diameter (D50) is the tin particles of 20 μ m, and as negative material.By single pond cell evaluation device this negative material is carried out cell evaluation.Adopt the EC electrolytic solution to be used for cell evaluation.In the charge/discharge cycle test, measure the capacity of the 1st circulation time and the capacity of the 50th circulation time.The result is as shown in table 1.

Table 1

	Capacity (mAh/g) (the 1st circulation)	Capacity (mAh/g) (the 50th circulation)	Capacity retention rate (%)
				Embodiment 1	831	322	39
Embodiment 2	824	428	52
				Embodiment 3	804	589	73
Embodiment 4	486	388	80
				Embodiment 5	1050	180	17
Embodiment 6	710	360	51
				The comparative example 1	833	92	11
The comparative example 2	1058	83	8
				The comparative example 3	900	100	10

As shown in table 1, in the situation of embodiment 1～6, to compare with comparative example 1～3 situation, the capacity of described the 50th circulation time is higher.Comparison shows that between the embodiment 1～3, the amount of the gas-phase growth of carbon fibre of adding is big more, and the capacity retention rate is high more, and the capacity of the 1st circulation time descends slightly.In the situation of embodiment 1～6, to compare with comparative example 1～3 situation, capacity retention rate (i.e. capacity * 100 of capacity/the 1st of the 50th circulation time circulation) is significantly higher.Can imagine that in embodiment 1～6, in the contact that keeps during the charge/discharge cycle containing between the particle of silicon atoms and/or tin atom compound, and the expansion of described particle or contraction be suppressed, and therefore obtained high power capacity retention rate and high power capacity.

Embodiment 7

Native graphite is pulverized and classification, thereby preparation average grain diameter (D50) is the carbon granule of 20 μ m.The carbon granule (100g) of preparation is thus mixed with carborundum (10g).Independently, in varnish A, add ethanol and stir the mixture of gained, thereby varnish A is dissolved in the ethanol fully.The solution of gained is added in the mixture of above-mentioned acquisition,, and the mixture of gained was kneaded 30 minutes by planetary-type mixer so that the quantitative change of modified phenolic resin solid becomes 10 quality %.In the mixture of gained, be added in 2,800 ℃ down through graphited gas-phase growth of carbon fibre (d ₀₀₂Be 0.339nm, the filametntary mean outside diameter of this carbon fiber is 150nm, and described filametntary average aspect ratio is 200) (3 quality %), and the mixture that obtains thus kneaded.In Minton dryer in 80 ℃ of down dry mixtures of obtaining 2 hours kneaded thus, thereby remove described ethanol.Subsequently, dry thus product is placed in the heating furnace, this furnace interior of finding time is filled argon gas then.Subsequently, this stove of heating under argon gas stream.Furnace temperature kept 10 minutes down at 2,900 ℃, yet this stove is cooled to room temperature.Afterwards, the sieve that adopts 63 μ m mesh sieves heat treated product thus, thereby obtains the powder formed carbon material of the present invention less than 63 μ m sizes.When electron microscope (SEM) down observation obtain thus material with carbon element the time, find that the carbonaceous powder has carbon fiber (being gas-phase growth of carbon fibre) on its particles of powder surface.By single pond cell evaluation device, described powder formed carbon material is carried out cell evaluation.Adopt the EC electrolytic solution to carry out cell evaluation.In the charge/discharge cycle test, measure the capacity of the 1st circulation time and the capacity of the 50th circulation time.The result is as shown in table 2.

Embodiment 8

Repeat the process of embodiment 7, the addition of different is carborundum becomes 5g.With with the identical mode of embodiment 7 samples, by single pond cell evaluation device, the sample that obtains is thus carried out cell evaluation.Adopt the EC electrolytic solution to carry out cell evaluation.In the charge/discharge cycle test, measure the capacity of the 1st circulation time and the capacity of the 50th circulation time.The result is as shown in table 2.

Embodiment 9

Repeat the process of embodiment 7, the addition of different is carborundum becomes 3g.With with the identical mode of embodiment 7 samples, by single pond cell evaluation device, the sample that obtains is thus carried out cell evaluation.Adopt the EC electrolytic solution to carry out cell evaluation.In the charge/discharge cycle test, measure the capacity of the 1st circulation time and the capacity of the 50th circulation time.The result is as shown in table 2.

The comparative example 4

(10g) is dissolved in the isopropyl alcohol with phenol resin, thereby makes solution.Independently, the carborundum (2g) that average grain diameter (D50) is adjusted to 2 μ m mixes with carbon black (1g).The mixture of gained is added in the above-mentioned solution that makes, fully stir the mixture of gained, from this mixture, remove solvent subsequently.Afterwards, under argon gas, 1,000 ℃, the product of gained is heat-treated 180 minutes, thereby obtain composite particles.

Subsequently, the above-mentioned composite particles that obtains (5g) is joined average grain diameter (D50) adjust in the native graphite (95g) of 20 μ m and and mix, and the mixture of gained and isopropyl alcohol are carried out wet mixing close with it.With the mixture of gained with mix by in isopropyl alcohol, dissolving the solution that phenol resin (10g) prepares, make the isopropyl alcohol volatilization subsequently, thereby obtain the native graphite composite particles.

The native graphite composite particles that obtains is thus heat-treated under 1,000 ℃, and the product that employing is handled thus is the sample of embodiment 4 as a comparison.In the charge/discharge cycle test, measure the capacity of the 1st circulation time and the capacity of the 50th circulation time.The result is as shown in table 2.

Table 2

Sample	Capacity (mAh/g)		Capacity retention rate (%)
				The 1st circulation	The 50th circulation
	Embodiment 7	425				382	91
Embodiment 8			390	355	91
	Embodiment 9	380				350	91
The comparative example 4			425	297	70

As shown in table 2, in the situation of embodiment 7～9, to compare with comparative example 4 situation, the capacity of the 50th circulation time is higher.Comparison shows that between the embodiment 7～9, the addition of carborundum is big more, and capacity is big more.In the situation of embodiment 7～9, to compare with comparative example 4 situation, capacity retention rate (i.e. capacity * 100 of capacity/the 1st of the 50th circulation time circulation) is higher.Can imagine that under the situation of embodiment 7～9, in the contact that keeps during the charge/discharge cycle between the described carbon granule, and the expansion of described particle or contraction be suppressed, thereby obtain high power capacity retention rate and high power capacity.

Industrial applicability

Adopt electrode material of the present invention to have high discharge capacity as the nonaqueous electrolytic solution secondary battery of negative pole, the charge-discharge characteristics under cycle characteristics and the large electric current is excellent.

Compare with the situation of the electrode material of gassiness phase grown carbon fiber not, comprise gas-phase growth of carbon fibre and contain following at least a particle and can between described particle, keep conductive path as the electrode material of mixture of the particle of nuclear, described at least a particle is selected from silicon grain, tin particles, contain the particle of the silicon compound that can insert/can discharge lithium ion and contain can insert/can discharge the particle of the tin compound of lithium ion, thereby reduce the resistance of the electrode that is formed by this electrode material, and increase discharge voltage. The interpolation of gas-phase growth of carbon fibre has reached following effect: even in the abundant contact of repeatedly carrying out also can keeping under the charge/discharge situation between the described particle, and improve cycle characteristics. Except above-mentioned reason, because the smooth migration of electric charge and the increase of internal resistance value are suppressed, the cycle characteristics under the low temperature also is improved.

Usually, the problem of siliceous negative material is low than graphite-based negative material of discharge voltage. Yet, use contains the carbon granule of the conduct nuclear with graphite-structure and comprises at least part of lip-deep silicon that is deposited on described carbon granule and/or the electrode material of silicon compound and carbon fiber can keep conductive path between the described particle, the resistance of the electrode that reduction is formed by described material with carbon element increases discharge voltage. The carbon fiber that comprises in the described material with carbon element has following effect: even under charge/discharge situation repeatedly, also can keep abundant contact between the described particle and the cycle characteristics that improves secondary cell.

Claims (49)

1. one kind comprises the particle of siliceous and/or tin and the electrode material of carbon fiber, and wherein said particle is: (1) is contained and is selected from silicon grain, tin particles, contains the particle of the silicon compound that can insert/can discharge lithium ion and contains at least a particle in the particle of the tin compound that can insert/can discharge lithium ion; Perhaps (2) comprise the particle of the carbonaceous material of the siliceous and/or silicon compound on the part surface at least that is deposited on the carbon granule with graphite-structure, and wherein said carbonaceous material obtains by the composition that contains polymer is heat-treated.

2. electrode material as claimed in claim 1, wherein said particle siliceous and/or tin is to contain to be selected from silicon grain, tin particles, to contain the particle of the silicon compound that can insert/can discharge lithium ion and to contain at least a particle in the particle of the tin compound that can insert/can discharge lithium ion, the back is referred to as " particle A ", and described carbon fiber is a gas-phase growth of carbon fibre.

3. electrode material as claimed in claim 2, the silicon compound of wherein said insertion the/can discharge lithium ion is by formula M _xThe compound that Si represents, wherein M represents to be different from the element of lithium, and x is at least 0.01.

4. electrode material as claimed in claim 3, wherein M is the element that is selected among B, C, N, O, S, P, Na, Mg, Al, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, Ru, Rh, Pd, Pt, Be, Nb, Nd, Ce, W, Ta, Ag, Au, Cd, Ga, In, Sb and the Ba.

5. electrode material as claimed in claim 2, the tin compound of wherein said insertion the/can discharge lithium ion is ashbury metal, tin oxide, artificial gold, tin halides or stannide.

6. electrode material as claimed in claim 2, the amount of wherein said gas-phase growth of carbon fibre are 0.01～20 quality %.

7. electrode material as claimed in claim 2, every filament of wherein said gas-phase growth of carbon fibre has the cavity along its extension of central axis, and external diameter is 2～1,000nm, draw ratio is 10～15,000.

8. electrode material as claimed in claim 7, wherein said gas-phase growth of carbon fibre contains the carbon fiber of branching.

9. electrode material as claimed in claim 2, wherein based on the particle A of 100 mass parts, the amount of described gas-phase growth of carbon fibre is 0.1～30 mass parts.

10. electrode material as claimed in claim 2, wherein said gas-phase growth of carbon fibre contain by means of X-ray diffraction method measures average layer spacing (d on (002) face ₀₀₂) be 0.344nm or littler carbon.

11. electrode material as claimed in claim 2, the average grain diameter of wherein said particle A are 0.3 μ m～70 μ m.

12. it is 0.1 μ m or littler and/or 85 μ m or bigger particle that electrode material as claimed in claim 11, wherein said particle A are substantially devoid of average grain diameter.

13. electrode material as claimed in claim 2, the part surface at least of wherein said particle A is coated with carbonaceous material, and the thickness of this carbonaceous material coating is 1～30,000nm.

14. electrode material as claimed in claim 13, wherein said carbonaceous material can obtain by the composition that contains the polymer that is selected from phenol resin, polyvinyl alcohol resin, furane resins, celluosic resin, polystyrene resin, polyimide resin and epoxy resin is heat-treated.

15. electrode material as claimed in claim 14, the wherein said composition that contains polymer are the compositions that contains phenol resin and drying oil or its derived fatty acid.

16. electrode material as claimed in claim 1, the carbonaceous material and the carbon fiber of the siliceous and/or silicon compound on the part surface at least that it contains carbon granule with graphite-structure, be deposited on described carbon granule, wherein said carbonaceous material obtains by the composition that contains polymer is heat-treated.

17. electrode material as claimed in claim 16, wherein said carbonaceous material siliceous and/or silicon compound also contains carbon fiber.

18. containing on its surface by the instrumentality of described carbonaceous material, electrode material as claimed in claim 16, wherein said carbon granule have the silicon that is fine particulate form and/or the carbon granule of silicon compound.

19. electrode material as claimed in claim 16, wherein said carbon granule contains the carbon granule that has carbon fiber on its surface by the instrumentality of described carbonaceous material.

20. containing on its surface by the instrumentality of described carbonaceous material, electrode material as claimed in claim 16, wherein said carbon granule have the silicon that is fine particulate form and/or the carbon granule of silicon compound and carbon fiber.

21. electrode material as claimed in claim 16, the amount of wherein said silicon and/or silicon compound are 1～20 quality %.

22. containing, electrode material as claimed in claim 16, wherein said polymer be selected from least a of phenol resin, polyvinyl alcohol resin, furane resins, celluosic resin, polystyrene resin, polyimide resin and epoxy resin.

23. electrode material as claimed in claim 16, the wherein said composition that contains polymer are the compositions that contains phenol resin and drying oil or its derived fatty acid.

24. electrode material as claimed in claim 16, wherein said carbon granule and/or described carbonaceous material with graphite-structure contains boron.

25. containing by means of X-ray diffraction method, electrode material as claimed in claim 16, wherein said carbon fiber measure average layer spacing (d on (002) face ₀₀₂) be 0.344nm or littler carbon.

26. electrode material as claimed in claim 16, wherein said carbon fiber is a gas-phase growth of carbon fibre, and every filament of described carbon fiber comprises the cavity along its extension of central axis, and external diameter is 2～1,000nm, and draw ratio is 10～15,000.

27. electrode material as claimed in claim 26, wherein said gas-phase growth of carbon fibre contains the carbon fiber of branching.

28. electrode material as claimed in claim 26, wherein based on the described carbon granule with graphite-structure of 100 mass parts, the amount of described gas-phase growth of carbon fibre is 0.1～30 mass parts.

29. electrode material as claimed in claim 16, wherein said average grain diameter with carbon granule of graphite-structure are 5 μ m～70 μ m.

30. electrode material as claimed in claim 29, the average grain diameter that wherein said carbon granule with graphite-structure contains are the amount of 3 μ m or littler and/or 85 μ m or bigger particle is 5 quality % or still less.

31. electrode material as claimed in claim 16, wherein said carbon granule with graphite-structure is coated with carbonaceous material, and the thickness of this carbonaceous material coating is 1～30,000nm.

32. electrode material as claimed in claim 16, wherein said silicon compound are to be selected from least a in carborundum, silicon dioxide and the silicon nitride.

33. a method of making electrode material, it comprises:

The composition that will contain polymer is deposited on to comprise and is selected from silicon grain, tin particles, contains the particle of the silicon compound that can insert/can discharge lithium ion and contains step on the part surface at least of particle at least a in the particle of the tin compound that can insert/can discharge lithium ion;

The step that the particle that obtains is mixed with carbon fiber; With

To described particle step of heat treatment.

34. the method for manufacturing electrode material as claimed in claim 33, wherein said polymer contains the polymer that particle A is shown adhesion.

35. the method for manufacturing electrode material as claimed in claim 33, wherein said heat treatment step are the combustion steps that carries out under at least 200 ℃ of temperature.

36. a method of making electrode material, it comprises:

The composition that will contain polymer is deposited on the step on the part surface at least of carbonaceous particle;

Described carbonaceous particle and carbon fiber and silicon and/or silicon compound are mixed, thereby the instrumentality by the described composition that contains polymer is with described carbon fiber and silicon and/or the step of silicon compound deposited on described carbonaceous particle; With

The subsequent step that the carbonaceous particle that obtains is heat-treated.

37. a method of making electrode material, it comprises:

Composition, carbon fiber and silicon and/or the silicon compound that will contain polymer mix, and described carbonaceous particle is mixed with this mixture, thereby the instrumentality by the described composition that contains polymer is with described carbon fiber and silicon and/or the step of silicon compound deposited on described carbonaceous particle; With

The subsequent step that the carbonaceous particle that obtains is heat-treated.

38. as the method for claim 36 or 37 described manufacturing electrode materials, wherein said polymer contains the polymer that carbon is shown adhesion.

39. as the method for claim 36 or 37 described manufacturing electrode materials, wherein said polymer contains and is selected from least a in phenol resin, polyvinyl alcohol resin, furane resins, celluosic resin, polystyrene resin, polyimide resin and the epoxy resin.

40. as the method for claim 36 or 37 described manufacturing electrode materials, wherein said polymer contains phenol resin and drying oil or its derived fatty acid.

41. the method for manufacturing electrode material as claimed in claim 37, it comprises:

The composition that will contain polymer, carbon fiber and silicon and/or silicon compound is deposited on the carbonaceous particle, wherein said polymer contains phenol resin and drying oil or its derived fatty acid, the step that the described composition that is deposited on this carbonaceous particle is cured subsequently; With

To the carbonaceous particle step of heat treatment that obtains, it carries out after described first step repeats 1～20 time.

42., wherein in described heat treatment step, boron compound is added into described carbonaceous particle as the method for claim 36 or 37 described manufacturing electrode materials.

43. as the method for claim 36 or 37 described manufacturing electrode materials, wherein said heat treatment step carries out under at least 2,000 ℃ of temperature.

44. method as claim 36 or 37 described manufacturing electrode materials; wherein said carbon fiber is a gas-phase growth of carbon fibre; and described gas-phase growth of carbon fibre is mixed with described carbonaceous particle; so that based on the described carbonaceous particle of 100 mass parts, the amount of described gas-phase growth of carbon fibre is 0.1～30 mass parts.

45. by the electrode material of making as each described method in the claim 33 to 44.

46. contain electrode paste just like each described electrode material and adhesive in claim 1 to 32 and 35.

47. contain the electrode of electrode paste as claimed in claim 46.

48. contain the secondary cell of electrode as claimed in claim 47.

49. secondary cell as claimed in claim 48, it comprises nonaqueous electrolytic solution solvent and electrolyte, and wherein said nonaqueous electrolytic solution solvent is to be selected from least a in ethylene carbonate, diethyl carbonate, dimethyl carbonate, methyl ethyl carbonate, gamma-butyrolacton and the propylene carbonate.