CN101315975A - Battery anode and lithium ion battery using the same and their production method - Google Patents

Abstract

The invention provides a lithium ion battery anode, comprising a conductive substrate and an anode material which is coated and/or filled on the conductive substrate; the anode material comprises an anode active matter, a conductive agent and a bonding agent; the anode active matter contains LiCoO2 and a LiFePO4; wherein, the total weight of the anode active matter is taken as a benchmark, and the content of the LiCoO2 is 10-90% according to the weight; the content of the LiFePO4 is 10-90% according to the weight. The battery prepared by the anode which is prepared by the anode active matter, simultaneously has high discharging specific capacity, excellent circulation performance and large current discharging performance.

Description

Anode and this anodal lithium ion battery of use and their preparation method

Technical field

The invention relates to a kind of anode and use this anodal battery and their preparation method, specifically, the invention relates to a kind of anode and use this anodal lithium ion battery and their preparation method.

Background technology

Lithium ion battery is as a kind of chemical power source, refers to respectively the secondary cell that constitutes as both positive and negative polarity with two compounds that can reversibly embed with the removal lithium embedded ion.When battery charge, lithium ion takes off embedding from positive pole, in negative pole, embed, otherwise during discharge.

Lithium rechargeable battery is as a kind of battery of green high-capacity, have that voltage height, energy density are big, good cycle, numerous advantages such as operating temperature range is wide, self discharge is little, Wu's memory effect, and be widely used in mobile phone, notebook computer, video camera and various portable power tool and electronic instrument etc.When lithium rechargeable battery is widely used as the energy of each class of electronic devices, people are also more and more higher to its performance demands, no matter be circular batteries with higher capacity, the rectangular lithium ion battery of still suitable each electronic product, people are in the consideration to service time and useful life, all require above when having higher initial capacity as energy supply person-battery, also require these batteries in charge and discharge process repeatedly, to have capability retention preferably, show excellent cycle performance, have long useful life.

Positive active material is the important component part of lithium ion battery, and studying maximum at present is LiCoO₂, LiNiO₂And LiMn₂O₄Wherein, LiCoO₂Be the positive electrode of unique large-scale commercial, research comparative maturity, high comprehensive performance.But cobalt resource is deficient day by day now, furthermore costs an arm and a leg, has toxicity.In order to address this problem, employing is arranged in the prior art with LiCoO₂Be mixed with the method for anode with other materials.For example, CN1832231A discloses a kind of positive electrode, comprises first positive electrode active materials, second positive electrode active materials and the 3rd positive electrode active materials, and wherein, this first positive electrode active materials is the composite oxides that contain lithium, manganese, nickel and cobalt; This second positive electrode active materials is at least a composite oxides that contain lithium and nickel and cobalt; The 3rd positive electrode active materials is to contain lithium and manganese and have the composite oxides of spinel structure and contain phosphorous oxides at least a of lithium and iron, and the weight ratio of each positive electrode active materials is the value in each some A, B by representing in mathematical expression I, C is connected acquisition with D scope, be in the ternary diagram of each positive electrode active materials wherein in vertex, this first positive electrode active materials is x, this second positive electrode active materials is y, and the 3rd positive electrode active materials is z, mathematical expression I is: A (x, y, z)=(0.76,0.04,0.20)

B(x，y，z)＝(0.94，0.05，0.01)

C(x，y，z)＝(0.05，0.94，0.01)

D(x，y，z)＝(0.04，0.76，0.20)。

The battery that adopts the positive pole of the mixture preparation of above-mentioned positive electrode active materials to prepare has the good low-temperature performance.In the specific embodiment of this method, employing LiCoO is also disclosed₂And LiFePO₄Mixture prepare the comparative example of positive pole and battery, positive active material LiCoO in this comparative example as positive active material₂And LiFePO₄Weight ratio be 99: 1, adopt the capacity of the battery that the positive pole of the positive active material preparation of this mixed proportion obtains lower, the cycle performance of battery is also relatively poor.

Summary of the invention

Goal of the invention of the present invention is to overcome existing use LiCoO₂And LiFePO₄The shortcoming of mixture, cycle performance difference not high as the capacity of the lithium ion battery of positive active material, provide a kind of and can make battery have the anode of high power capacity and good circulation performance simultaneously and use this anodal lithium ion battery.

Another object of the present invention provides the preparation method of anode and uses the preparation method of this anodal lithium ion battery.

The invention provides a kind of lithium ion cell positive, this positive pole comprises conducting base and coating and/or is filled in positive electrode on the conducting base, and described positive electrode comprises positive active material, conductive agent and adhesive, and described positive active material contains LiCoO₂And LiFePO₄, wherein, be benchmark with the total weight of positive active material, described LiCoO₂Content be 10-90 weight %, described LiFePO₄Content be 10-90 weight %.

The present invention also provides a kind of preparation method of lithium ion cell positive, this method comprises that the slurry that will contain positive electrode and solvent applies and/or is filled on the conducting base, dry, roll or do not roll, described positive electrode comprises positive active material, conductive agent and adhesive, and described positive active material contains LiCoO₂And LiFePO₄, wherein, be benchmark with the total weight of positive active material, described LiCoO₂Content be 10-90 weight %, described LiFePO₄Content be 10-90 weight %.

The present inventor finds unexpectedly, adopts the LiCoO with certain proportioning of the present invention₂And LiFePO₄Mixture have higher battery specific capacity and good cycle performance simultaneously as the battery that the positive pole of positive active material preparation prepares.Under the preferable case, the heavy-current discharge performance of the battery for preparing at the positive pole that anodal conductive agent of the present invention and described positive active material is used preparation improves, and the cycle performance of battery can be further improved simultaneously.

Embodiment

According to the present invention, described anode comprises conducting base and coating and/or is filled in positive electrode on the conducting base, and described positive electrode comprises positive active material, conductive agent and adhesive, and described positive active material contains LiCoO₂And LiFePO₄, wherein, be benchmark with the total weight of positive active material, described LiCoO₂Content be 10-90 weight %, be preferably 50-70 weight %; Described LiFePO₄Content be 10-90 weight %, be preferably 30-50 weight %.

Conductive agent in the described positive electrode is not particularly limited, and can be the anodal conductive agent of this area routine, such as in conductive carbon black, acetylene black, the electrically conductive graphite one or more.Total weight with positive active material is a benchmark, and the content of described conductive agent is 1-15 weight %, is preferably 2-10 weight %.

Under the preferable case, the conductive agent that the present invention adopts is the mixture of graphite and carbon black, and the average diameter of particles of described graphite is the 1-5 micron, is preferably the 2-4 micron; The average diameter of particles of described carbon black is the 30-100 nanometer, is preferably the 50-80 nanometer; Total weight with described conductive agent is a benchmark, and the content of described graphite is 10-50 weight %, is preferably 25-40 weight %; The content of described carbon black is 50-90 weight %, is preferably 60-75 weight %.

Because agent of bulky grain graphite and positive active material LiCoO have been filled in short grained carbon black conductive agent₂And LiFePO₄Between the slit, the electric conductivity of conductive agent is not fully exerted, thereby has improved battery at the specific discharge capacity at the initial stage of use and the heavy-current discharge performance that can improve battery simultaneously.

The kind of the adhesive in the described positive electrode and content are conventionally known to one of skill in the art, for example one or more in fluorine resin and polyolefin compound such as polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), the butadiene-styrene rubber (SBR).In general, according to the difference of adhesive therefor kind, be benchmark with the weight of positive active material, the content of adhesive is 0.01-10 weight %, is preferably 0.02-5 weight %.

The kind of described anodal conducting base has been conventionally known to one of skill in the art, for example can be selected from aluminium foil, Copper Foil, Punching steel strip.In the specific embodiment of the present invention, use aluminium foil as anodal conducting base.

According to the present invention, the preparation method of described positive pole comprises that the slurry that will contain positive electrode and solvent applies and/or is filled on the conducting base, and drying is rolled or do not rolled, described positive electrode comprises positive active material, conductive agent and adhesive, and described positive active material contains LiCoO₂And LiFePO₄, wherein, be benchmark with the total weight of positive active material, described LiCoO₂Content be 10-90 weight %, described LiFePO₄Content be 10-90 weight %.

The consumption of the kind of solvent, conductive agent and adhesive and consumption and positive active material of the present invention is conventionally known to one of skill in the art in the described slurry.In general, be benchmark with the weight of positive active material, the content of described solvent is 40-90 weight %, is preferably 50-85 weight %.The content of described positive active material, conductive agent and adhesive is the 40-85 weight % of anode sizing agent total weight, is preferably 60-75 weight %.Described solvent can be selected from one or more in N-methyl pyrrolidone (NMP), dimethyl formamide (DMF), diethylformamide (DEF), dimethyl sulfoxide (DMSO) (DMSO), the oxolane (THF); The consumption of solvent can make described pastel have viscosity and flowability, can be coated on the described conducting base to get final product.Wherein, the method for described drying and calendering and condition are conventionally known to one of skill in the art.For example, the temperature of described drying is generally 100-150 ℃.

Lithium ion battery provided by the present invention comprises electrode group and nonaqueous electrolytic solution, and described electrode group and nonaqueous electrolytic solution are sealed in the battery container, and described electrode group comprises positive pole, negative pole and barrier film.Just very adopt the positive pole provided by the invention except described, can use conventional negative pole, barrier film and nonaqueous electrolytic solution.

Described barrier film is arranged between positive pole and the negative pole, has electrical insulation capability and liquid retainability energy.Described barrier film can be selected from various barrier films used in the lithium ion battery, as polyolefin micro porous polyolefin membrane, polyethylene felt, glass mat or ultra-fine fibre glass paper.The position of described barrier film, character and kind are conventionally known to one of skill in the art.

Consisting of of described negative pole is conventionally known to one of skill in the art.In general, negative pole comprises conducting base and coating and/or is filled in negative material on the conducting base that described negative material comprises negative electrode active material and negative pole adhesive.

Described negative electrode active material is not particularly limited, can use embedding of this area routine to disengage the negative electrode active material of lithium, material with carbon element for example, described material with carbon element be selected from non-graphitized charcoal, graphite or the charcoal that obtains by high-temperature oxydation by polyyne family macromolecule material or pyrolytic carbon, coke, organic polymer sinter, active carbon in one or more.Described organic polymer sinter can be by with products therefrom after sintering such as phenolic resins, epoxy resin and the charing.

The kind of described negative pole adhesive and content are conventionally known to one of skill in the art, for example one or more in fluorine resin and polyolefin compound such as polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), butadiene-styrene rubber (SBR), hydroxypropyl methylcellulose, sodium carboxymethylcellulose, hydroxyethylcellulose, the polyvinyl alcohol; In general, according to the difference of adhesive therefor kind, be benchmark with the weight of negative electrode active material, the content of negative pole adhesive is 0.01-10 weight %, is preferably 0.02-5 weight %.

Described negative material can also comprise that conductive agent to increase the conductivity of electrode, reduces the internal resistance of cell.Described conductive agent is not particularly limited, and can be the cathode conductive agent of this area routine, such as in carbon black, nickel powder, the copper powder one or more.Weight with negative electrode active material is benchmark, and the content of described conductive agent is 0-12 weight %, is preferably 2-10 weight %.

The negative pole conducting base can be for negative pole conducting base conventional in the lithium ion battery, as stamped metal, and metal forming, net metal, foamed metal uses Copper Foil as the negative pole conducting base in specific embodiments of the present invention.

The preparation method of described negative pole can adopt conventional preparation method.For example, with negative material and solvent, apply and/or be filled on the described conducting base, drying is rolled or is not rolled, and can obtain described negative pole.Wherein, described solvent can be selected from one or more in N-methyl pyrrolidone (NMP), dimethyl formamide (DMF), diethylformamide (DEF), dimethyl sulfoxide (DMSO) (DMSO), oxolane (THF) and water and the alcohols.The consumption of solvent can make described pastel have viscosity and flowability, can be coated on the described conducting base to get final product.In general, be benchmark with the weight of negative electrode active material, the content 50-150 weight % of described solvent is preferably 70-120 weight %.The content of described negative electrode active material and adhesive is the 40-70 weight % of cathode size total weight, is preferably 45-60 weight %.The consumption of solvent can make described pastel have viscosity and flowability, can be coated on the described conducting base to get final product.Wherein, drying, the method for calendering and condition are conventionally known to one of skill in the art.For example, the temperature of described drying is generally 100-150 ℃.

Described nonaqueous electrolytic solution is the mixed solution of electrolyte lithium salt and nonaqueous solvents, and it is not particularly limited, and can use the nonaqueous electrolytic solution of this area routine.Be selected from lithium hexafluoro phosphate (LiPF such as electrolyte lithium salt₆), in lithium perchlorate, LiBF4, hexafluoroarsenate lithium, lithium halide, chlorine lithium aluminate and the fluorocarbon based sulfonic acid lithium one or more.Organic solvent is selected chain acid esters and ring-type acid esters mixed solution for use, wherein the chain acid esters can be dimethyl carbonate (DMC), diethyl carbonate (DEC), methyl ethyl carbonate (EMC), carbonic acid first propyl ester (MPC), dipropyl carbonate (DPC) and other are fluorine-containing, sulfur-bearing or contain at least a in the chain organosilane ester of unsaturated bond, the ring-type acid esters can be ethylene carbonate (EC), propene carbonate (PC), vinylene carbonate (VC), gamma-butyrolacton (γ-BL), sultone and other are fluorine-containing, sulfur-bearing or contain at least a in the ring-type organosilane ester of unsaturated bond.The injection rate of electrolyte is generally 1.5-4.9 gram/ampere-hour, the concentration of electrolyte be generally 0.1-2.0 rub/liter.

According to the preparation method of lithium ion battery provided by the invention, except described positive pole prepared according to method provided by the invention, other step was conventionally known to one of skill in the art.In general, positive pole and negative pole winding are separated formation electrode group, electrode group and the electrolyte that obtains is sealed in the battery case, can obtain lithium ion battery provided by the invention by membrane layer.The method for winding of the membrane layer between positive pole and negative pole is conventionally known to one of skill in the art, does not repeat them here.

To the present invention be described in more detail by embodiment below.

Embodiment 1

This embodiment illustrates positive pole provided by the invention and contains this anodal lithium ion battery and their preparation method.

(1) Zheng Ji preparation

With 70 weight portion positive active material LiCoO₂, 30 weight portion LiFePO₄, 5 weight portion adhesive polyvinylidene fluoride (PVDF), 4 weight portion conductive agent acetylene blacks join in the 80 weight portion N-methyl pyrrolidones (NMP), in de-airing mixer, stir then and form uniform anode sizing agent.

This slurry is coated on wide 400 millimeters, the thick 20 microns aluminium foil equably, 120 ℃ of oven dry then, under the pressure of 1.6 MPas, on cutting machine, cut after the roll-in and obtain being of a size of 385 millimeters * 42 millimeters * 135 microns positive pole, wherein contain 6.3 gram positive active materials.

(2) preparation of negative pole

100 weight portion negative electrode active material native graphites, 5 weight portion adhesive polytetrafluoroethylene (PTFE)s, 4 weight portion conductive agent carbon blacks are joined in 120 parts by weight of deionized water, in de-airing mixer, stir then and form cathode size stable, homogeneous.

This slurry is coated on wide 400 millimeters, the thick 10 microns Copper Foil equably, after 120 ℃ of oven dry, rolling, on cutting machine, cuts and obtain being of a size of 43 millimeters * 355 millimeters * 135 microns negative pole, wherein contain 2.87 gram negative electrode active materials.

(3) assembling of battery

With LiPF₆Be configured to LiPF with ethylene carbonate (EC) and diethyl carbonate (DEC)₆Concentration is the solution (wherein, the volume ratio of EC and DEC is 1: 1) of 1.0 mol, obtains nonaqueous electrolytic solution.The negative pole that positive pole, membrane layer polyethylene (PE), (2) that (1) is obtained obtain is successively with the stacked electrode group that is wound into scroll of up-coiler, the electrode group that obtains is put into the battery case of an end opening, and inject above-mentioned nonaqueous electrolytic solution with the amount of 3.8g/Ah, make lithium ion battery A1 after the sealing.

Embodiment 2

This embodiment illustrates positive pole provided by the invention and contains this anodal lithium ion battery and their preparation method.

Prepare anode sizing agent, anode and battery according to the method identical with embodiment 1, different is, described anodal conductive agent is the 1 weight portion graphite (KS-6 that Te Migao company in Changzhou produces, particle diameter is 3 microns) and the 3 weight portion carbon blacks (SUPPER-P that Te Migao company in Changzhou produces, particle diameter is 60 nanometers), prepare lithium rechargeable battery A2.

Embodiment 3

This embodiment illustrates positive pole provided by the invention and contains this anodal lithium ion battery and their preparation method.

Prepare anode sizing agent, anode and battery according to the method identical with embodiment 1, different is, described anodal conductive agent is the 1.6 weight portion graphite (KS-6 that Te Migao company in Changzhou produces, particle diameter is 3 microns) and the 2.4 weight portion carbon blacks (SUPPER-P that Te Migao company in Changzhou produces, particle diameter is 60 nanometers), prepare lithium rechargeable battery A3.

Embodiment 4

This embodiment illustrates positive pole provided by the invention and contains this anodal lithium ion battery and their preparation method.

Prepare anode sizing agent, anode and battery according to the method identical with embodiment 1, different is, described anodal conductive agent is the 2 weight portion graphite (KS-6 that Te Migao company in Changzhou produces, particle diameter is 3 microns) and the 2 weight portion carbon blacks (SUPPER-P that Te Migao company in Changzhou produces, particle diameter is 60 nanometers), prepare lithium rechargeable battery A4.

Embodiment 5

This embodiment illustrates positive pole provided by the invention and contains this anodal lithium ion battery and their preparation method.

Prepare anode sizing agent, anode and battery according to the method identical with embodiment 1, different is, described anodal conductive agent is the 3 weight portion graphite (KS-6 that Te Migao company in Changzhou produces, particle diameter is 3 microns) and the 1 weight portion carbon black (SUPPER-P that Te Migao company in Changzhou produces, particle diameter is 60 nanometers), prepare lithium rechargeable battery A5.

Embodiment 6

This embodiment illustrates positive pole provided by the invention and contains this anodal lithium ion battery and their preparation method.

Prepare anode sizing agent, anode and battery according to the method identical with embodiment 1, different is that described positive active material is 50 weight portion LiCoO₂With 50 weight portion LiFePO₄, prepare lithium rechargeable battery A6.

Embodiment 7

This embodiment illustrates positive pole provided by the invention and contains this anodal lithium ion battery and their preparation method.

Prepare anode and battery according to the method identical with embodiment 6, different is, described anodal conductive agent is the 1 weight portion graphite (KS-6 that Te Migao company in Changzhou produces, particle diameter is 2 microns) and 2 weight portion carbon blacks (SUPPER-P that Te Migao company in Changzhou produces, particle diameter is 70 nanometers) prepare lithium rechargeable battery A7.

Embodiment 8

This embodiment illustrates positive pole provided by the invention and contains this anodal lithium ion battery and their preparation method.

Prepare anode and battery according to the method identical with embodiment 1, different is that described positive active material is 60 weight portion LiCoO₂With 40 weight portion LiFePO₄, prepare lithium rechargeable battery A8.

Embodiment 9

This embodiment illustrates positive pole provided by the invention and contains this anodal lithium ion battery and their preparation method.

Prepare anode and battery according to the method identical with embodiment 1, different is that described positive active material is 80 weight portion LiCoO₂With 20 weight portion LiFePO₄, prepare lithium rechargeable battery A9.

Embodiment 10

This embodiment illustrates positive pole provided by the invention and contains this anodal lithium ion battery and their preparation method.

Prepare anode and battery according to the method identical with embodiment 1, different is that described positive active material is 90 weight portion LiCoO₂With 10 weight portion LiFePO₄, prepare lithium rechargeable battery A10.

Embodiment 11

This embodiment illustrates positive pole provided by the invention and contains this anodal lithium ion battery and their preparation method.

Prepare anode and battery according to the method identical with embodiment 10, different is, described anodal conductive agent is the 1 weight portion graphite (KS-6 that Te Migao company in Changzhou produces, particle diameter is 4 microns) and the 3 weight portion carbon blacks (SUPPER-P that Te Migao company in Changzhou produces, particle diameter is 75 nanometers), prepare lithium rechargeable battery A11.

Embodiment 12

This embodiment illustrates positive pole provided by the invention and contains this anodal lithium ion battery and their preparation method.

Prepare anode and battery according to the method identical with embodiment 1, different is that described positive active material is 40 weight portion LiCoO₂With 60 weight portion LiFePO₄, prepare lithium rechargeable battery A12.

Embodiment 13

This embodiment illustrates positive pole provided by the invention and contains this anodal lithium ion battery and their preparation method.

Prepare anode and battery according to the method identical with embodiment 1, different is that described positive active material is 25 weight portion LiCoO₂With 75 weight portion LiFePO₄, prepare lithium rechargeable battery A13.

Comparative Examples 1

This Comparative Examples illustrates that reference is anodal and contains this anodal reference lithium ion battery and their preparation method.

Ratio according to the method identical with embodiment 1 and each material prepares the anodal and lithium ion battery AC1 of reference, and different is that described positive active material is 99 weight portion LiCoO₂With 1 weight portion LiFePO₄

Comparative Examples 2

This Comparative Examples illustrates that reference is anodal and contains this anodal reference lithium ion battery and their preparation method.

Ratio according to the method identical with embodiment 1 and each material prepares the anodal and lithium ion battery AC2 of reference, and different is that described positive active material is 100 weight portion LiCoO₂

Comparative Examples 3

This Comparative Examples illustrates that reference is anodal and contains this anodal reference lithium ion battery and their preparation method.

Ratio according to the method identical with embodiment 1 and each material prepares the anodal and lithium ion battery AC3 of reference, and different is that described positive active material is 100 weight portion LiFePO₄

Comparative Examples 4

This Comparative Examples illustrates that reference is anodal and contains this anodal reference lithium ion battery and their preparation method.

Method according to the disclosed embodiment 4-1 of CN1832231A prepares reference lithium ion battery AC4.The positive active material of this lithium ion battery is LiMn_0.2Ni_0.6Co_0.2O₂, LiCoO₂And LiFePO₄Mixture, the weight ratio of described three kinds of materials is 5: 94: 1.

Embodiment 14-26

This embodiment illustrates the performance of battery.

The method of testing of battery capacity, cycle performance of battery and heavy-current discharge performance below adopting is carried out battery performance test to the lithium ion battery A1-A13 that embodiment 1-13 obtains respectively.

(1) battery capacity method of testing: charge with constant voltage charging method, the restriction electric current is 0.1C (65mA), and final voltage is 4.2 volts; Discharge in the constant-current discharge mode, discharging current is 1C (650mA), and the cut-ff voltage of discharge is 3.0 volts.

The result is as shown in table 1.

(2) cycle performance of battery method of testing: under 23 ℃ of conditions, battery respectively with 1C current charges to 4.2 volt, is risen to 4.2 volts of backs with constant-potential charge at voltage, cut-off current is 0.05C, shelves 10 minutes; Battery was shelved 5 minutes with 1C current discharge to 3.0 volt, and the discharge capacity first of record battery.Repeat above-mentioned steps, when the discharge capacity of battery drop to discharge capacity first 85% the time, the cycle-index of record battery.

The result is as shown in table 1.

(3) heavy-current discharge performance method of testing: battery is placed on test respectively cashier's office in a shop, carries out constant current charge with the 0.2C electric current earlier, the charging upper voltage limit is 4.2 volts, and constant voltage charge is 2.5 hours then; After shelving 20 minutes, be discharged to 3.0 volts with the electric current of 1C and 3C from 4.2 volts respectively, the ratio of the discharge capacity when writing down the discharge capacity of each battery and calculating respectively with the 0.2C discharge, that is:

C_1C/ C_0.2C: with the electric current of 1C from 4.2 volts be discharged to 3.0 volts discharge capacity with the electric current of 0.2C from 4.2 volts of ratios that are discharged to 3.0 volts discharge capacity;

C_3C/ C_0.2C: with the electric current of 3C from 4.2 volts be discharged to 3.0 volts discharge capacity with the electric current of 0.2C from 4.2 volts of ratios that are discharged to 3.0 volts discharge capacity.

The result is as shown in table 1.

Comparative Examples 5-8

The performance of this Comparative Examples explanation reference cell.

Method according to embodiment 14-26 is measured battery capacity, cycle performance of battery and heavy-current discharge performance, and different is the reference lithium ion battery AC1-AC4 that the battery of test obtains for the method that adopts Comparative Examples 1-4.

The result is as shown in table 1.

Table 1

The embodiment numbering	The battery numbering	Specific discharge capacity (MAH/gram)	Cycle-index	C1C/C0.2CMultiplying power (%)	C3C/C0.2CMultiplying power (%)
						Embodiment 14	A1	129.5	587	93.5	75.0
Embodiment 15	A2	132.3	657	96.7	80.1
						Embodiment 16	A3	133.2	663	97.0	80.5
Embodiment 17	A4	131.6	646	95.6	79.7
						Embodiment 18	A5	130.5	618	94.7	77.4
Embodiment 19	A6	128.1	639	95.2	78.3
						Embodiment 20	A7	129.8	642	95.9	79.0
Embodiment 21	A8	128.6	626	93.2	73.5
						Embodiment 22	A9	130.9	553	92.8	72.6
Embodiment 23	A10	131.8	532	92.3	72.0
						Embodiment 24	A11	133.2	548	93.0	73.0
Embodiment 25	A12	126.3	633	94.6	78.0
						Embodiment 26	A13	125.2	647	95.0	78.9
Comparative Examples 5	AC1	133.4	477	91.7	69.4
						Comparative Examples 6	AC2	134.2	445	91.5	69.4
Comparative Examples 7	AC3	120.9	880	94.5	78.4
						Comparative Examples 8	AC4	127.8	405	90.5	68.3

Data from last table 1 adopt the specific capacity of the battery that positive pole of the present invention prepares higher as can be seen, all at 125 MAHs/more than the gram.Under 23 ℃, when the discharge capacity of battery drop to discharge capacity first 85% the time, the cycle-index of battery all can reach more than 500 times, the cycle performance of battery is also very superior.In addition, the C of battery_1C/ C_0.2CAnd C_3C/ C_0.2CHeavy-current discharge performance also better.In addition, battery A2-A5, A7 for preparing as embodiment 15-18,20 and 24 and the C of A11_1C/ C_0.2CAnd C_3C/ C_0.2CThe multiplying power discharging property data as can be known, the positive pole of above-mentioned battery is and adopts the preferred anodal conductive agent of the present invention to prepare, with under the same conditions, the battery that adopts conventional anodal conductive agent to prepare is compared, and it is more outstanding that battery has the cycle performance and the heavy-current discharge performance of higher capacity and battery.The reference cell that the method for employing Comparative Examples prepares then can not possess higher capacity and excellent cycle performance simultaneously.In sum, the battery that adopts positive pole provided by the invention to prepare has higher specific discharge capacity, excellent cycle performance and heavy-current discharge performance simultaneously, and battery has good comprehensive electrochemical.

Claims (9)

1, a kind of lithium ion cell positive, this positive pole comprise conducting base and coating and/or be filled in positive electrode on the conducting base, and described positive electrode comprises positive active material, conductive agent and adhesive, and described positive active material contains LiCoO₂And LiFePO₄, it is characterized in that, be benchmark with the total weight of positive active material, described LiCoO₂Content be 10-90 weight %, described LiFePO₄Content be 10-90 weight %.

2, positive pole according to claim 1 wherein, is a benchmark with the total weight of positive active material, described LiCoO₂Content be 50-70 weight %, described LiFePO₄Content be 30-50 weight %.

3, positive pole according to claim 1, wherein, described conductive agent comprises graphite and carbon black, and the average diameter of particles of described graphite is the 1-5 micron, and the average diameter of particles of described carbon black is the 30-100 nanometer; Total weight with described conductive agent is a benchmark, and the content of described graphite is 10-50 weight %, and the content of described carbon black is 50-90 weight %.

4, positive pole according to claim 3, wherein, the average diameter of particles of described graphite is the 2-4 micron, the average diameter of particles of described carbon black is the 50-80 nanometer; Total weight with described conductive agent is a benchmark, and the content of described graphite is 25-40 weight %, and the content of described carbon black is 60-75 weight %.

5, the preparation method of the described lithium ion cell positive of claim 1, this method comprises that the slurry that will contain positive electrode and solvent applies and/or is filled on the conducting base, dry, roll or do not roll, described positive electrode comprises positive active material, conductive agent and adhesive, and described positive active material contains LiCoO₂And LiFePO₄, it is characterized in that, be benchmark with the total weight of positive active material, described LiCoO₂Content be 10-90 weight %, described LiFePO₄Content be 10-90 weight %.

6, method according to claim 5 wherein, is a benchmark with the total weight of positive active material, described LiCoO₂Content be 50-70 weight %, described LiFePO₄Content be 50-70 weight %.

7, method according to claim 5, wherein, described conductive agent comprises graphite and carbon black, and the average diameter of particles of described graphite is the 1-5 micron, and the average diameter of particles of described carbon black is the 30-100 nanometer; Total weight with described conductive agent is a benchmark, and the content of described graphite is 10-50 weight %, and the content of described carbon black is 50-90 weight %.

8, method according to claim 7, wherein, the average diameter of particles of described graphite is the 2-4 micron, the average diameter of particles of described carbon black is the 50-80 nanometer; Total weight with described conductive agent is a benchmark, and the content of described graphite is 25-40 weight %, and the content of described carbon black is 60-75 weight %.

9, a kind of lithium ion battery, this battery comprises electrode group and nonaqueous electrolytic solution, and described electrode group and nonaqueous electrolytic solution are sealed in the battery container, and described electrode group comprises positive pole, negative pole and barrier film, it is characterized in that any described positive pole among the described just very claim 1-4.