CN101616870A

CN101616870A - Island-covered lithium cobaltite oxides

Info

Publication number: CN101616870A
Application number: CN200880003464A
Authority: CN
Inventors: 珍斯·马丁·鲍尔森; 托马斯·劳
Original assignee: Umicore NV SA
Current assignee: Umicore NV SA
Priority date: 2007-01-29
Filing date: 2008-01-17
Publication date: 2009-12-30
Anticipated expiration: 2028-01-17
Also published as: CN101616870B

Abstract

Cathode active material is disclosed and with its method of low cost production.Cathode powder comprises modification LiCoO ₂With possible second mutually, it is LiM ' O ₂, wherein M ' is Mn, Ni, Co, has stoichiometric ratio Ni: Mn 〉=1.Modification LiCoO ₂Comprise Ni and Mn, and have low and high Mn content zone, wherein have the high Mn content zone and be positioned at lip-deep island.Cathode material has high cyclical stability, very high speed ability and good high-temperature storge quality.

Description

Island-covered lithium cobaltite oxides

The present invention relates to a kind of powder lithium transition-metal oxide, wherein comprise the LiCoO that particular type has Mn and Ni ₂This cathode powder can be used technology scale operation at a low price.More particularly, described preparation is the mixture sintering thing that contains cobalt precursors, contains cobalt precursors such as LiCoO ₂, contain the Ni-Mn-Co precursor, as mixed hydroxides MOOH and Li ₂CO ₃The enough high LiCoO of sintering temperature to allow to form ₂And cationic exchange between the Li-Ni-Mn-Co oxide compound phase, this generation has the very specific form of different transiting metal component gradients.Described lithium transition-metal oxide powder can be as the cathode active material in the chargeable lithium cell.

Some inherent limitations such as security are relatively poor, cost is high, LiCoO although have ₂Remain the chargeable lithium cell cathode material of maximum application.The human consumer need increase the energy density of chargeable lithium cell strongly.A kind of method of improving energy density is to increase charging voltage, and this needs can be at the firm cathode material of high-voltage charge more.Charging voltage occurs or more serious problem is if increase

(a) security is low,

(b) during the high temperature storage rechargeable battery storage performance relatively poor and

(c) cyclical stability is relatively poor.Disclosing a lot of methods is used to address these problems.Realize the part improvement, but fully do not solved basic problem.

Except that requiring to increase the energy density, require rechargeable cell to satisfy energy requirement.This means battery generally and particularly active cathode material itself have enough high speed performances.

There is popular tendency in this.Scrutinize the open result of cathode material, with better understanding based on LiCoO ₂The defective of chargeable lithium cell.

A basic defect derives from a surface-area difficult problem.Can satisfy the performance (being superpower) that gathers way by increasing surface-area, because can reduce solid-state lithium diffusion length; This causes improving speed ability.Yet high surface area has increased the zone that undesirable side reaction between ionogen and the charged cathode wherein occurs.These side reactions are processes that security under high pressure is relatively poor, cyclical stability is relatively poor, and the storage performance of charged cathode is relatively poor when high temperature.In addition, high surface area material often has low storage density, and this has reduced volume energy density.

Another basic defect derives from the cobalt stoichiometry.Lithium Magno oxidation cobalt-based cathode material is (as LiMn _1/3Ni _1/3Co _1/3O ₂) have a LiCoO of ratio ₂The stability of reacting between higher potential resistance to electrolyte contamination and the negative electrode, and material cost is lower, but these materials are subjected to low volume energy density puzzlement, and these materials have lower lithium diffusion constant usually.

Can sum up and wherein have basic restriction:

-surface-area: wish that the low surface area cathode material has high security at memory period, the density of improvement and high stability; Yet, the performance because this will underspeed, surface-area can not too reduce.

-composition:, wish LiMO if M mainly is a cobalt ₂Negative electrode obtains high lithium rate of diffusion and high volume energy density; Yet the high-content cobalt causes security relatively poor, and it is relatively poor to increase cost and high-voltage stability.

A kind of method that solves this difficult problem is to increase diffusion constant.Increase D and will reduce surface-area, do not lose speed ability.

LiMO was before disclosed ₂, M=Ni-Mn-Co wherein, Ni: Mn＞1.US6 for example, 040,090 (Sanyo) discloses the multiple LiMO of comprising ₂, and the LiMO of Ni: Mn＞1 ₂(M=Mn, Ni Co) form.This patent application discloses the have high-crystallinity LiMO of (small peak HWFM in the X-ray diffractogram) ₂Patent US7 discloses the LiCoO that for example is doped with Ni and Mn in 078,128 ₂US7,078,128 discloses the LiCoO that preferred use is doped with equivalent Ni and Mn ₂

European patent application EP 1716609 A1 disclose a kind of LiMO ₂The base active cathode material, wherein granulometric composition depends on particle size, particularly along with the reduction of particle size, particulate cobalt content reduces.Because the core-shell structure particles cobalt contents reduces, and wherein contains the Mn-Ni shell and has identical thickness, is covered with LiCoO ₂Nuclear.As a result, little as fruit granule, LiCoO ₂Examine for a short time, the cobalt contents of whole particle is lower.

European patent application EP 1556915 A1 disclose a kind of LiMO with transiting metal component gradient ₂This gradient is obtained from the mixed hydroxides shell, is covered with to have the nuclear that obvious different metal is formed.The optimal way center is LiCoO ₂Behind the sintering, the transition metal composition gradient that acquisition has the stoichiometry radial variations, and LiMO ₂Shell covers LiCoO ₂Base nuclear.During the sintering, cobalt is from LiCoO ₂Atomic scatterring is to LiMO ₂Shell.Simultaneously, still less Ni from LiMO ₂Shell diffuses into LiCoO ₂Nuclear.Therefore, shell swelling and LiCoO ₂Nuclear shrinks.The swelling shell that covers retract produces the space usually between shell and nuclear.These spaces are very undesirable.

The objective of the invention is to define a kind of cathode material, and reveal the high stability that prolongs cycle period at the high charge voltmeter with high speed performance.Improved the high-temperature storage performance in addition.With comprising the LiCoO that contains Mn and Ni ₂Particulate powder lithium transition-metal oxide is realized this point, and described particle has Mn and Ni enrichment island in its surface, and described island comprises 5mol% at least, the preferred Mn of 10mol% at least.

Mn and Ni enrichment island preferably have the thickness of 100nm at least, and cover less than 70%, preferably less than 50% the described LiCoO that contains Mn and Ni ₂Particle surface.In addition, in the described island Mn concentration preferably than the described LiCoO that contains Mn and Ni ₂The high at least 4mol% of Mn concentration in the particle body, preferably high at least 7mol%.

In another embodiment, the described LiCoO that contains Mn and Ni of Ni concentration ratio in described Mn and the Ni enrichment island ₂The high at least 2mol% of Ni concentration in the particle body, preferably high at least 6mol%.The LiCoO that preferably contains Mn and Ni ₂Particle comprises 3mol% at least, more preferably 10mol%Ni and Mn at least.In a preferred embodiment, the described LiCoO that contains Mn and Ni ₂Particulate lattice parameter a and c are respectively 2.815+/0.002 and 14.05+/-0.01.

The LiCoO that preferably contains Mn and Ni in addition ₂Particle is a monoblock, and inside does not have hole.In addition, the described LiCoO that preferably contains Mn and Ni ₂The particulate distribution of sizes has the d50 greater than 10 μ m, is preferably greater than 15, most preferably greater than 20 μ m.

In another preferred embodiment, the powder lithium transition-metal oxide comprises the LiCoO of described Mn of containing of 30wt% to 95wt% and Ni ₂Particle.

The present invention also comprises a kind of lithium transition-metal oxide, and it has the LiCoO by described Mn of containing and Ni ₂First phase that particle constitutes comprises second no island phase: the Li with following general formula in addition _1+aM _{' 1-a}O _{2 ± b}, wherein-0.03＜a＜0.05, and b＜0.02, M '=Ni _mMn _nCo _1-m-n, m 〉=n wherein, 0.1＜m+n＜0.9.Then this powder lithium transition-metal oxide preferably has Li _xM _yO _{2 ± δ}Total composition, 0.97＜x＜1.03,0.97＜y＜1.03 wherein, x+y=2, δ＜0.05, and M=Co _1-f-gNi _fMn _g, 0.05＜f+g＜0.5 wherein, f 〉=g.Preferred in addition 0.98＜x/y＜1.00.In another preferred embodiment, described oxide compound only constitutes mutually by two, and first is the LiCoO of described Mn of containing and Ni mutually ₂Particle, second is described no island phase mutually.

The lattice parameter a ' of preferred in addition described no island phase and c ' with reference to lithium transition-metal (M _Ref) the lattice parameter a " and c " of corresponding no island phase of oxide compound has following relationship, wherein has identical composition Li _xM _yO _{2 ± δ}, and by pure LiCoO ₂Particle constitutes mutually with described corresponding no island:

0.980＜a '/a "＜0.998 and 0.9860＜c '/c "＜0.9985,

Preferred 0.990＜a '/a "＜0.997,0.9920＜c '/c "＜0.9980.

If for example from Co precursor and composition M "=Ni _mMn _nCo _1-m-nMixed metal hydroxides prepare material LiMO of the present invention ₂, then lattice parameter a " and c " is meant and has composition LiM " O ₂Reference material, different lattice parameter a ' and c ' show at LiCoO ₂Base first mutually and do not have island second and enough cationic exchange occur between mutually.

No island preferably has secondary granule mutually, and it has the size distribution of 2 to 10 microns d50, and described secondary granule is made of the elementary crystal grain agglomerate of agglomerating 0.5 to 2 μ m d50 size distribution.In another preferred embodiment, described Mn further comprises Ti with Ni enrichment island mutually with described no island, and wherein Ti content is less than oxide compound Li _xM _yθ _{2 ± δ}The M of middle 10mol%.

More preferably, at oxide compound Li _xM _yO _{2 ± δ}In, the powder lithium transition-metal oxide further comprises less than one or more of 5mol%M and is selected from the hotchpotch of Al and Mg, and is selected from the hotchpotch of Be, B, Ca, Zr, S, F and P less than one or more of 1mol%M.

For simplicity, in this specification sheets, contain the LiCoO of Mn and Ni ₂Particle is commonly referred to ' mutually 1 ' or be also referred to as ' modification LiCoO ₂Phase ', have general formula Li _1+aM ' _1-aO _{2 ± b}No island be called mutually lithium transition-metal oxide ' LiM ' O ₂' (M '=Ni-Mn-Co) mutually or ' mutually 2 ', be also referred to as ' cathode material '.

Surprisingly, if the invention discloses to cause during the sintering at LiCoO ₂And LiM ' O ₂Between these mixtures of the mutual thermal treatment of method (co-sintering) of exchange cation, can significantly improve LiCoO ₂(mutually 1) and have Ni: the LiM ' O of Mn ratio＞1 ₂(M '=Ni-Mn-Co) speed ability of the mixture of (phase 2),

generation phase

1 and 2 particulate composition distribution mutually.Obtain 1 particle (LiCoO mutually simultaneously ₂) specific modality.With containing manganese LiM ' O ₂Sheet material partly covers described particle.The author claims that this form is " island " form.Simultaneously, surprisingly, equally significantly improved high-voltage stability.

The form of modification LiCoO has the intensive modification LiCoO that sinters to ₂The island of body produces the partial gradient of transition metal chemistry metering.Described island comprises high density manganese.LiCoO ₂And LiM ' O ₂Particle has the distribution of composition.In addition, LiM ' O ₂Particle has the form that depends on cobalt contents.The size of elementary crystal grain increases along with cobalt contents.Opposite with above-mentioned EP1556915 A1, there is not stoichiometric radial variations among the present invention.It is equivalent to have LiMO ₂The multicenter gradient on island, this LiMO ₂The island is positioned at the surface and as the gradient center.In addition, the LiCoO that is only partly covered by the island ₂It is very important difference.

Another importance of the present invention is that described island does not cover LiCoO fully ₂Particle.Can be by mixed hydroxides be deposited to LiCoO ₂Realize on the surface covering fully-in other words-LiCoO ₂Nuclear-LiM ' O ₂Shell morphology.This method has been disclosed among above-mentioned patent application EP1556915A1 and the EP1716609 A1 (people such as Paulsen).MOOH shell-LiCoO ₂The situation of nuclear precursor has two major defects, as described in following document: nucleocapsid cathode material with the composition that depends on size, Jens M.Paulsen, Jong-Seok Jeong, and Ki-Young Lee, Electrochem.Solid-State Lett., volume 10, the 4th phase, A101-A105 page or leaf (2007).(1) this technology is more expensive, and more cobalts enter shell from atomic scatterring during (2) sintering.Therefore shell expands, and nuclear shrinks simultaneously.This causes shell to separate from the nuclear part usually, produces big cavity.These big cavitys are very undesirable because: (i) their increase electrode hole-so the decrease of power density and (ii) the overslaugh lithium pass cavity and directly diffuse into or leave LiCoO ₂Particulate nuclear zone-so cause losing speed ability.

This situation is different from cathode material of the present invention.Contain the manganese island and only covered LiCoO ₂The sub-fraction of particle surface.Therefore cobalt spreads island swelling and the LiCoO that causes ₂Nuclear shrinks and does not produce big cavity.The result can obtain high volume density and high speed performance.

The present invention also comprises a kind of electrochemical cell that comprises negative electrode, and described powder lithium transition-metal oxide was as active substance before described negative electrode comprised.

A kind of be used to prepare before the method for described powder lithium transition-metal oxide, comprise step:

-LiCoO is provided ₂Powder or cobalt contents at least 90mol% the mixture that contains cobalt precursors compound and Li-Ni-Mn-Co oxide compound or Ni-Mn-Co precursor powder and optional Li precursor compound (preferred Quilonum Retard) and

-at least 900 ℃, preferred at least 950 ℃ the described mixtures of temperature T sintering, sintering time t is 1 to 48 hour, to obtain to have in its surface the LiCoO that contains Mn and Ni on Mn and Ni enrichment island ₂Particle.

Thereby, by at high temperature surpassing 900 ℃ of sintering LiCoO ₂Based powders and Li-Ni-Mn-Co-oxide compound or contain the Ni-Mn-Co powder and lithium source such as Li ₂CO ₃Mixture and prepare cathode material.This temperature must surpass 900 ℃, for example 910 ℃ or 920 ℃.During the sintering, LiCoO ₂The partial cation exchange appears in particle and containing between the Ni-Mn particle.If sintering temperature is low, then do not have enough cationic exchange, and negative electrode does not show high speed performance.If the sintering temperature height, then particle becomes too fine and close, and metal ingredient is too average, i.e. LiCoO ₂And the too much cationic exchange of appearance between the Mn-Ni-Co.In the case, will there be Mn and Ni enrichment island on the first phase particle.

Alternatively, can mix and contain cobalt precursors powder (as cobalt oxide, cobaltous hydroxide or cobaltous carbonate) and contain Ni-Mn-Co powder and lithium source, subsequently by at high temperature, preferably surpass 950 ℃ of following sintering.

A kind ofly be used to prepare the method that has biphase powder lithium transition-metal oxide as mentioned above, comprise step:

-LiCoO is provided ₂Powder or cobalt contents at least 90mol% the mixture that contains cobalt precursors compound and Li-Ni-Mn-Co-oxide compound or Ni-Mn-Co precursor powder and optional Li precursor compound (preferred Quilonum Retard) and

-at least 900 ℃, preferred at least 950 ℃ the described mixtures of temperature T sintering, sintering time t is 1 to 48 hour,

To obtain the LiCoO of described Mn of containing and Ni ₂Particle mutually with described no island with lattice parameter a ' and c ' mutually, it has following relationship, wherein the reference lithium transition-metal (M that obtains at the described Ni-Mn-Co precursor powder of uniform temp T sintering and described Li precursor compound uniform temp T and identical time t _Ref) the described relation of lattice parameter a " and c " of oxide compound or described Li-Ni-Mn-Co-oxide compound is

0.980＜a '/a "＜0.998 and 0.9860＜c '/c "＜0.9985,

Preferred 0.990＜a '/a "＜0.997 and 0.9920＜c '/c "＜0.9980.

In these methods, the Ni-Mn-Co precursor powder is transition metal hydroxide, hydrogen oxide oxide compound, carbonate, oxycarbonate, or lithium transition metal compound, wherein transiting metal component M " being M "=Ni _oMn _pCo _1-o-p, wherein o+p＞0.5, and o＞p.In addition, the Ni-Mn-Co precursor powder preferably includes the levels of transition metals of 5 to 70mol% described powder lithium transition-metal oxides.

In the embodiment, the LiCoO of use ₂Powder has the tap density of at least 2 gram/cubic centimetres, and is made of the monoblock particle of d50 at least 10 μ m, preferably these d50 at least 15 μ m, most preferably at least 20 μ m.

On the other hand, contain the cobalt precursors compound and be preferably oxyhydroxide, oxyhydroxide or the carbonate that one or more plant cobalt.

In another embodiment, described LiCoO ₂Or contain the transition metal that cobalt precursors comprises at least 80% described powder lithium transition-metal oxide, containing the Ni-Mn-Co precursor powder is the granulometric composition of 1 to 3 μ m size distribution by d50.

In another embodiment, described LiCoO ₂Or contain cobalt precursors and comprise the transition metal that is lower than 80% described powder lithium transition-metal oxide, contain the Conglobation type granulometric composition of Ni-Mn-Co precursor by d50 size distribution with 4 to 10 μ m.

In these two embodiments, contain the Ni-Mn-Co precursor and can further comprise Ti, be preferably the TiO that d50 is lower than 100 nanometers ₂Particle form.

Below details of the present invention further is discussed.

Cathode material of the present invention is a powder, wherein comprises modification LiCoO ₂Still be not only second transition metal mutually with major part.Two are the lithium transition-metal oxide phase with layering crystalline structure mutually: orderly rock salt crystalline structure-spacer r-3m.Negative electrode can be stoichiometry Li ₁M ₁O ₂, wherein M is cobalt, manganese and/or nickel, or slightly poor lithium (Li _1-xM _1+xO ₂) or rich lithium Li _1+xM _1-xO ₂, x＜0.3 wherein.Usually suspect and have non-stoichiometric oxygen.Therefore oxygen stoichiometry is approximately 2.0, but can not get rid of negative electrode for omiting oxygen deprivation or oxygen coalescence.Therefore all consist of Li _xM _yO _{2 ± δ}, 0.97＜x＜1.03,0.97＜y＜1.03 wherein, x+y=2, δ＜0.05.M is manganese, cobalt and nickel, M=Co _1-f-gNi _fMn _g, condition is 0.05＜f+g＜0.5, and f 〉=g.

First is obtained from LiCoO mutually ₂Precursor, and be modification LiCoO ₂This composition can be defined as LiCo _1-a-bNi _aMn _bO ₂, a 〉=b wherein, 0.03＜a+b＜0.5, preferred 0.1＜a+b＜0.5.This general formula is Utopian, does not consider little possibility deviation such as lithium is excessive or lack oxygen nonstoichiometry or aforesaid doping.Preferred LiCoO ₂The base particle is a monoblock.The particle of monoblock does not show internal void, and is not made up of littler primary granule coacervate.One aspect of the invention is for forming incomplete same LiCoO ₂The variable grain of phase.The actual composition of particulate depends on that how much nickel and manganese diffuse into LiCoO during the sintering ₂Particle.Ni and Mn are obtained from second mutually the precursor, it typically is mixed hydroxides.Except many other factorses such as temperature Li: M ratio etc. diffuse into LiCoO during the sintering ₂The Mn of base phase and Ni amount depend on the arrangement of adjacent Ni-Mn base particulate, contact area and contact pressure to a great extent.As a result, different LiCoO ₂Particle has different compositions.

Secondly, the very important aspect of the present invention is single LiCoO ₂It is not uniform that base particulate metal is formed.Typical case's particle has the island configuration of surface, and this island is obtained from the intensive LiCoO of sintering to ₂The less Ni-Mn base particle or the crystal grain of particle surface.This island has the manganese concentration that is higher than away from zone, island or granule interior zone.Having the island form is the inherent feature of cathode material of the present invention.Higher manganese content center, these islands-have-can't with particle separation.They are intensive and be connected to LiCoO continuously ₂The particle main body.Therefore manganese metering-along with the island apart from increasing-may reduce, in granule interior or be far apart between the island on the surface near zero with the gradual change similar fashion.The inventor notices that the island form relates to the observed speed ability of open cathode material.If the author thinks island-be free of attachment to LiCoO ₂Particle-will have different lattice parameters.Yet, the intensive LiCoO that is connected in island ₂, at LiCoO ₂The zone that has manganese metering gradual change between particle and the island.Therefore island and particle will suffer strong lattice strain.Strain reason-author does not know accurate mechanism-make lithium can obviously diffuse into particle quickly.

Second is LiM ' O mutually ₂, M '=Ni wherein _mMn _nCo _1-m-n, m 〉=n, this general formula of 0.1＜m+n＜0.9 is Utopian, does not consider little possibility deviation such as lithium is excessive or lack, oxygen nonstoichiometry or mix as mentioned above.Second preferably is obtained from mutually and contains Ni-Mn-Co precursor such as mixed hydroxides, mixed oxidization oxyhydroxide, mixed oxide, hybrid metal lithium oxide compound or mixed carbonate.The metal of second phase is formed change during the sintering.Cobalt is from LiCoO ₂Particle diffuses into LiM ' O ₂Particle.LiM ' O is left in some Ni and Mn diffusion ₂Particle enters LiCoO ₂Particle.As a result, the cobalt stoichiometry of second phase is higher than the cobalt stoichiometry that contains the Ni-Mn-Co precursor.Changing the cobalt stoichiometry is importance of the present invention.Only during sintering, significantly increase the cobalt stoichiometry, produce enough cationic exchange, and only fully improve the speed ability of the negative electrode that obtains in this case.

The inventor has two more surprising observations, and this is considered to another basic sides of the present invention:

First observation: the second part increase mutually during the sintering.Obviously, compare and diffuse into LiCoO ₂The nickel of phase and manganese, more cobalt diffuses into the second phase (LiMO ₂).The inventor thinks that the difference in this diffusion has strengthened observed island form.Relevant with this observation is the clear variation of voltage curve.LiCoO ₂And LiM ' O ₂Mixture have character voltage curve at the 3.88V platform.Along with cationic exchange increases, the author observes the 3.88V abolition of plateau, and the sparking voltage tail end reduces.In addition, cobalt not only diffuses into LiM ' O ₂Particle, and diffuse into upward manganiferous zone, surface; During this technology, the effect of Co source is played in the zone between the island.Island itself is the cobalt absorption agent simultaneously.In the sketch-contain the manganese island with the cobalt swelling, just as sponge water absorption and swelling around it.How this process explanation produces the island form.

Second observes: first has mutually and obviously is different from pure LiCoO ₂Composition.The first phase particulate major part comprises at least 3%, more preferably 10% manganese and nickel.This stoichiometry changes the considerable change that is accompanied by lattice parameter usually.Yet X-ray diffraction analysis shows that surprisingly the lattice parameter (deriving from two-phase Rietveld purifies) of first phase is basically less than variation-they keep and LiCoO ₂Identical.The inventor believes that this is the very important aspect of the present invention, and the improvement that shows the first phase velocity performance is not because at LiCoO ₂And LiM ' O ₂Between form sosoloid and produce.(sosoloid shows that the gradual change of lattice parameter depends on its composition.)

Another aspect of the present invention is LiM ' O ₂Particle (second phase) has crystal grain, and the size of described crystal grain is relevant with cobalt contents.Obviously, during the sintering, along with LiM ' O is left in more Ni (and Mn) diffusion ₂, enter LiCoO ₂Particle, and along with more Co diffuse into LiM ' O ₂Particle causes crystal grain accelerated growth.As a result, has the stoichiometric LiM ' O of higher cobalt ₂Particle (second phase) has bigger elementary crystal grain.This is very useful technology, because obtain to optimize form in the self-organization mode.This is because the cobalt contents increase causes the faster diffusion of lithium, and this allows big crystal grain and does not lose speed ability.Yet the relation between high cobalt content and the large-size only is meant the size of crystal grain, is not meant particle diameter.Larger particles on average has and is lower than short grained cobalt stoichiometry probably, the longer path of diffusion because more cobalts are had to.

The inventor understands this reaction and produces island as described below form: during the sintering, and less and reunion LiM ' O ₂The most of contact of particulate LiCoO ₂Particle.This point of contact is the cobalt pond, and at LiCoO ₂Form inner the embedding on the particle surface and contain the manganese island.Simultaneously, nickel (with some manganese) diffuses into LiCoO ₂, and cobalt diffuses into LiM ' O ₂Particle.During the sintering, since cobalt picked-up and thermal sintering, reunion LiM ' O ₂Particulate density increases.During the densification, swelling island and LiM ' O ₂Contact loss between the particle, and obtain by two final negative electrodes of homophase granulometric composition not.

If LiM ' is O ₂Particle is a coacervate, LiM ' O ₂And LiCoO ₂Between contact lose easily.In this case, only consume partial L iM ' O ₂Particle, and form the island seed.Alternatively, if the Ni-Mn-Co precursor has the very little particle that d50 is lower than the 1-2 micron, require not have contact loss.In this case, consume most of and even whole Ni-Mn-Co particle, form the island seed.Therefore, different embodiment of the present invention is feasible.

First exemplary embodiment: preferred especially Ni-Mn-Co precursor is made up of reunion crystal grain.A preferred embodiment is a mixed hydroxides, and wherein secondary granule is made up of not too fine and close primary granule coacervate.Very fine and close and bigger Ni-Mn-Co precursor is not too suitable.Preferable particle size distributes and has the d50 of 4-8 micron.LiM ' O in this case ₂Particle is enough little, and consequently (a) supports very high speed and (b) their embed big LiCoO just ₂The particulate space, this allows low porosity electrode and high volume energy density.

Preferably, the first phase (LiCoO ₂) precursor be the monoblock densification, and have much larger than second phase (LiM ' O ₂) size of precursor, and this second phase (LiM ' O ₂) be reunion, not too fine and close, and have reduced size.The preferred precursor of first phase is to have the fine and close monoblock particulate of 10-20 micron LiCoO at least ₂Many commercial LiCoO ₂Material has this required form.Alternatively, if having larger particles (10-20 micron at least) and high-density, cobaltous hydroxide, cobalt oxidation oxyhydroxide, cobalt oxide or cobaltous carbonate are suitable precursor.For example suitable precursor is cobaltous hydroxide or hydrogen oxide oxide compound, and it is rough spheroidal particle, and vibration density is higher than 2.0 gram/cubic centimetres, and the d50 of size distribution is greater than the 15-20 micron.

If the Ni-Mn-Co precursor is a coacervate, and have the size distribution that d50 is the 4-10 micron, at least 20% transition metal of then preferred final negative electrode is obtained from the Ni-Mn-Co precursor, and is lower than 80% transition metal and is obtained from LiCoO ₂Precursor.

Second exemplary embodiment: also preferred Ni-Mn-Co precursor is by very little granulometric composition.An example has the typical particle that is lower than the 0.5-1.5 micron for spraying the mixed hydroxides of milling.In this case, preferably be lower than 20 or even 15% final negative electrode transition metal be obtained from the Ni-Mn-Co precursor, yet at least 80, preferred 85% is obtained from cobalt precursors.Preferred cobalt precursors is made up of larger particles (d50＞10-20 micron), and this particle is densification and monoblock.Suitable cobalt precursors is commodity LiCoO ₂, or high-density (vibration density＞2 gram/cubic centimetres) cobaltous hydroxide, hydrogen oxide oxide compound or carbonate.For example, suitable precursor is shaped as spherical or irregular potato shape particle.

Two kinds of exemplary embodiment are not considered as replacement scheme, but are equivalent to two extreme example.For example, the feasible Ni-Mn-Co precursor that comprises little (being lower than the 0.5-1.5 micron) particle and big (4-8 micron) agglomerating particles, has bimodal grain size distribution that is to use, wherein most of small-particle is consumed and forms the island, and the wherein major part of larger particles separation during the sintering.Feasible in addition less cobalt granule and the submicron MOOH of being to use can expect the hypervelocity performance in this case.

Contain the formation reaction on manganese island in two embodiments, be attended by the cationic exchange between cobalt and the nickel.The inventor thinks that the basic sides that forms the island form is that the movability of (4 valency) manganese is lower than LiCoO ₂In 3 valency nickel and LiM ' O ₂In 3 valency cobalts.In addition, during the cell charging, (4 valency) manganese does not participate in electrochemistry insertion/extraction lithium, and some manganese can be replaced by other positively charged ion.Suitable in addition positively charged ion is a titanium.Be similar to manganese, it is the electrochemistry inert, has than Hypomobility, and can mix and enter the Ni-Mn-Co precursor.For example, be similar to manganese, titanium can mix and enter LiNiO ₂

Even another importance of the present invention is a cathode material is lithium substoichiometric a little, also can obtain high speed performance.We notice if total lithium content of every transition metal is approximately 0.98 and promptly are lower than one, obtain the top speed performance.This is very surprising, because M comprises the lithium transition-metal oxide Li of nickel therein _1+zM _1-ZO ₂Situation under, what accept extensively is that lithium lacks and to cause positively charged ion to mix (being that the nickle atom misplace is on crystallization lithium site), and the positively charged ion that increases mixes and causes speed ability relatively poor.

Illustrate that Summary of drawings of the present invention is as follows:

Fig. 1: the SEM microgram of sample REF1 and REF2.

Fig. 2: the scanning electron microscopy of sample CX2 and CX3.

Fig. 3: the scanning electron microscopy of sample EX1 and EX3.

Fig. 4: sample EX2-is 1 and 2 scanning electron microscopy mutually.

Fig. 5: be used for the EX1 particulate scan electron micrograph that EDS analyzes.

The phase 1 particulate EDS drawing of Fig. 6: EX1.

Fig. 7: be used for the EX1 particulate scan electron micrograph that EDS analyzes.

Fig. 8: be used for the EX1 phase 2 particulate scanning electron microscopies that EDS analyzes.

Fig. 9: commodity LiCoO ₂(REF1) and the cycle performance of sample EX4

Figure 10: the scanning electron microscopy of sample EX5E and CX6.

Figure 11: the crystallization figure of REF 1-2, CX2-3 and EX 1-3.

Figure 12: the crystallization figure of REF 1-2, CX5 and EX4-5.

Figure 13: CX2, CX4 ﹠amp; The X-ray diffractogram of CX5 and EX1.

The X-ray diffractogram of Figure 14: CX6 and EX9E.

Figure 15: CX2, CX3 and the EX1-EX3 voltage curve of slow interdischarge interval.

Figure 16: the cycle performance of sample EX1 and speed ability.

Figure 17: the speed ability of comparative sample CX6 and EX5E.

The following example further specifies some aspect of the present invention.Following tabulation provides test conditions and result's general introduction.

Table 1 general introduction sample and preparation condition

Table 2 general introduction X ray and BET surface data.

Table 3 general introduction derives from the electrochemical results of button cell

Reference example

Use following reference sample:

-REF1-LiCoO ₂Be commodity LiCoO ₂, and have the d50 of ≈ 20 μ m, and by monoblock, fine and close granulometric composition.

-from mixed hydroxides MOOH and Li ₂CO ₃, in air, prepare REF2-LiM ' O with 950 ℃ ₂Li: the M ratio is Li: M '=1.01: 1, M '=Ni _0.53Mn _0.27Co _0.2REF2 has agglomerate morphology.

Before button cell assembly and BET measure, in 8 hours, with 850 ℃ of reheat sample REF1 and REF2.The measured X x ray diffration pattern x, and carry out Rietveld and purify.Fig. 1 has showed the scanning electron microscopy of sample REF1 and REF2.Left hand view has been showed REF1 with the 1000x magnification.Particle is erose.There is not the island form.Right part of flg has been showed REF2 with the 2500x magnification.Particle is a coacervate, is made up of the elementary crystal grain that sinters bigger erose secondary granule into.

Calculate embodiment

For imaginary calculation sample CC1, by calculating the weight in average of REF1 and REF2 analog value, estimate expected value, capacity and the speed ability of BET surface-area, wherein sample CC1 is 60%REF1-LiCoO ₂And 40%REF2-LiM ' O ₂Mixture.

The comparative example

Embodiment C X2: by mixing 60%REF1-LiCoO ₂With 40%REF2-LiM ' O ₂The preparation cathode powder.Before the mixing, in air in 5 hours, with 850 ℃ of thermal treatment REF1-LiCoO ₂And REF2-LiM ' O ₂Whole LiM ' O that consist of of final CX2 negative electrode ₂, M '=Co wherein _0.68Ni _0.21Mn _0.11Fig. 2 a has showed the scanning electron microscopy (5000x magnification) of biased sample CX2.Measure the BET surface-area of mixed powder CX2.Can observe and not have the island form.The preparation button cell, measuring capacity, irreversible capacity, cyclical stability and speed ability.The measured X x ray diffration pattern x, and carry out Rietveld and purify.Take scanning electron microscopy.

Table 2 and 3 has showed that sample CX2 has the character that is similar to precursor weight in average among the imaginary sample CC1 substantially.This mixing does not have obvious benefit to speed ability or cyclical stability.Scanning electron microscopy confirms LiCoO ₂Particle does not have the island form.Rietveld purifies and confirms from the lattice parameter of mixture X ray diagram acquisition and from LiCoO ₂And LiM ' O ₂The lattice parameter that obtains respectively of X ray picture identical.

Embodiment C X3: by mixing 60%REF1-LiCoO ₂With 40%REF2-LiM ' O ₂The preparation cathode powder.In air, in 5 hours,, produce sample CX3 with 850 ℃ of these mixtures of thermal treatment.Whole LiM ' O that consist of of negative electrode ₂, M '=Co wherein _0.68Ni _0.21Mn _0.11, identical with CX2.Fig. 2 b has showed the scanning electron microscopy of sample CX3.Magnification is 2500x.There is not the island form.

Obviously, compare with CX2 (being the mixture of heat treated sample), the character of sample CX3 (being thermally treated mixture) such as cyclical stability and speed ability are improved a little.Rietveld purifies and confirms to constitute compound L iM ' O ₂And LiCoO ₂Lattice parameter during heating treatment do not have considerable change.

The constant of REF1 is identical with phase 1 among CX2 and the CX3, and the lattice parameter of REF2 is identical with phase 2 among CX2 and the CX3.

Embodiment C X4: according to comparative example CX3 in the cathode powder that identical method is prepared as thermally treated mixture is described, replaced in 5 hours producing sample CX4 except being used in 900 ℃ of heating 850 ℃ of heating 5 hours.The preparation button cell.The measured X x ray diffration pattern x, and carry out Rietveld and purify.Take scanning electron microscopy.

Table 2 and 3 has showed that sample CX4 has the character that is similar to substantially at the CX3 of low temperature preparation.Scanning electron microscopy shows does not have the island form basically.X-ray diffraction shows the phase mixture of two phases, and first has REF1-LiCoO ₂Lattice parameter, second has the sample of being similar to REF2-LiM ' O ₂Lattice parameter.Obviously, Co does not appear from phase 1 LiCoO ₂Obviously diffuse into the second phase LiM ' O ₂Speed ability is similar to sample CX3.This comparative example shows that thermal treatment temp is increased to 900 ℃ from 850 ℃ and does not obviously improve the button cell performance.

The embodiment of the invention

Embodiment 1 (EX1): by mixing 60% commercially available LiCoO ₂(sample REF1) and 40%MOOH hybrid transition metal oxyhydroxide and Li ₂CO ₃, the preparation cathode powder.Li ₂CO ₃: MOOH ratio and mixed hydroxides and be used to prepare REF2-LiM ' O ₂Identical.Total composition of cathode powder is LiM ' O ₂, M '=Co wherein _0.68Ni _0.21Mn _0.11, identical with total composition of CX2 and CX3.This mixture of heating is 8 hours in 970 ℃ of air, produces sample EX1.

The preparation button cell.The measured X x ray diffration pattern x, and carry out Rietveld and purify.Take scanning electron microscopy.Fig. 3 a has showed the scanning electron microscopy of sample EX1.Magnification is 5000x.There is two types particle: (a) phase 1: fine and close erose LiCoO ₂The base particle has specific island form and (b) mutually 2: Conglobation type LiM ' O ₂Particle: elementary grain-size has the distribution of widening.Illustrate phase 1 among Fig. 3 c.EDS analyzes (seeing below) and emphasizes at modification LiCoO ₂There is Mn in the island on the particle surface.

Character such as cyclical stability and speed ability are more much better than imaginary sample CC1, if compare obvious improvement with CX3 with sample CX2.Scanning electron microscopy alleged occurrence LiCoO ₂Particulate island form.Rietveld purifies and confirms 1 (LiCoO mutually ₂) lattice parameter during heating treatment do not change, but mutually 2 (LiM ' O ₂) lattice parameter considerable change.LiM ' O ₂Lattice parameter change proof and between 1 and mutually 2 obvious cationic exchange taking place mutually.

Embodiment E X2 and EX3: be similar to EX1 preparation and the research cathode powder of embodiment 1, except sintering temperature is respectively 960 and 950 ℃ (sintering times: 8 hours).Fig. 3 b has showed the scanning electron microscopy of sample EX3.Fig. 4 has showed the scanning electron microscopy of two phases of sample EX2: left figure has showed main phase 2 particles, and right figure mainly is phase 1 particle, and wherein smaller phase 2 coacervates of 1 particle are much bigger mutually as can be seen in addition.

In addition, character such as cyclical stability and speed ability are more much better than imaginary sample CC1, if compare obvious improvement with CX3 with sample CX2.

Scanning electron microscopy confirms LiCoO ₂There is the island form in particle.Rierveld purifies and confirms LiCoO ₂Lattice parameter during heating treatment do not change, but LiM ' O ₂The lattice parameter of phase changes obviously.EX1,2 and 3 relatively can sum up in this variation of comparatively high temps more obviously, shows that (a) diffuses into LiM ' O ₂Co amount along with temperature increases, but (b) character of improving depends on LiM ' O insensitively simultaneously ₂Co amount mutually.

The EDS of sample analyzes

Use energy dispersal x-ray spectrometry (EDS), can study sample CX2 and the LiCoO of CX3 (comparative example) and embodiment E X1 ₂(phase 1) and LiM ' O ₂The composition of (phase 2).

It is the effective tool that research is formed near surface particles that EDS analyzes.EDS helps monitoring to change and trend especially, but it is bad to obtain quantitative result accurately.Table 4 has been listed the EDS analytical results of reference sample REF1 and REF2, the reference point that this analyzes as the EDS of more complex sample CX2, CX3 and EX1.

With EDS spectral investigation sample REF1 (LiCoO ₂).Collection is from the spectrum of many particle sizings.Magnification is 1000x, has showed the zone of scanning among Fig. 1.Collected the similar EDS spectrum of sample REF2 with the 1000x magnification.

The levels of transition metals of table 4:ICP and EDS measure R EF1 and 2

Sample	Form (by ICP)	Levels of transition metals (by the mol% of EDS)	Impurity (by the mol% of EDS)
Sample	Form (by ICP)	Levels of transition metals (by the mol% of EDS)	Impurity (by the mol% of EDS)	??REF1	??Li _1.02Co	??Mn：0.00??Co：99.56??Ni：0.00	??SO ₄：0.44
??REF2	??Li∶M’＝0.97??M’＝??Co _0.21Mn _0.264Ni _0.526??SO ₄∶M＝0.009	??Mn：27.34??Co：20.72??Ni：50.39	??SO ₄：1.55	??REF1	??Li _1.02Co	??Mn：0.00??Co：99.56??Ni：0.00	??SO ₄：0.44

Relatively analyze the result who obtains, EDS is described from ICP chemical analysis and EDS

(1) measuring the transition metal ratio is in the main true

(2) exaggerative sulphur content (sulphur impurity may be positioned at the surface)

Analyze research cathode sample EX1 by individual particle being carried out EDS.Obtain 6 not homophase 1 particulate EDS spectrum.All particle has been showed the island form.Fig. 5 has showed this 6 particulate scanning electron microscopies.

EDS analyzes the clear 1 (LiCoO mutually that shows ₂) particle comprises (＞15%) nickel and manganese in a large number, (referring to following table 5).This is very surprising, shows mutually to have and LiCoO for 1 (comprising Ni and Mn) because the Rietveld of X-ray diffractogram purifies ₂Identical lattice parameter.In addition, in 6 particles 5 have and be higher than 3.0 Ni: the Mn ratio.This shows than the more nickel of manganese and diffuses into first phase.During the sintering, cationic exchange takes place, wherein most of nickel and manganese are from LiM ' O ₂Particle enters LiCoO ₂Particle.EDS analyzes and confirms the first phase (LiCoO in addition ₂) particle have the composition that form to change along with transition metal and distribute.

Table 5:EDS measures EX1 particulate levels of transition metals

Sample EX1	??Ni??(mol％)	??Mn??(mol％)	??Co??(mol％)	Ni: Mm mol ratio	(Ni+Mn)/M mol ratio (%)
Sample EX1	??Ni??(mol％)	??Mn??(mol％)	??Co??(mol％)	Ni: Mm mol ratio	(Ni+Mn)/M mol ratio (%)	Particle #1	??14.01	??3.22	??82.77	??4.35	??17
Particle #2	??13.74	??3.47	??82.78	??3.96	??17	Particle #1	??14.01	??3.22	??82.77	??4.35	??17
Particle #2	??13.74	??3.47	??82.78	??3.96	??17	Particle #3	??18.67	??5.42	??75.9	??3.44	??24
Particle #4	??10.62	??5.54	??83.46	??1.92	??16	Particle #3	??18.67	??5.42	??75.9	??3.44	??24
Particle #4	??10.62	??5.54	??83.46	??1.92	??16	Particle #5	??17.46	??4.77	??77.57	??3.66	??22
Particle #6	??18.49	??6.07	??75.25	??3.05	??25	Particle #5	??17.46	??4.77	??77.57	??3.66	??22

With 2 particles (particle #1 and particle #2) in 6 particles in the EDS figure research table 5.The EDS figure of particle #1 shows that " island " has higher manganese content among Fig. 6, yet regional between the island, and " ocean " (or main body) has low manganese content.Analyze further research particle #4 and #6 (referring to table 6) with an EDS.Fig. 7 has showed the position of these points.Bleeding point spectrum.

Table 6:EDS measures the levels of transition metals of EX1 particle different zones

Sample EX1	The ocean, island	??Ni??(mol％)	??Mn??(mol％)	??Co??(mol％)	Ni: Mm mol ratio	(Ni+Mn)/M mol ratio (%)
Sample EX1	The ocean, island	??Ni??(mol％)	??Mn??(mol％)	??Co??(mol％)	Ni: Mm mol ratio	(Ni+Mn)/M mol ratio (%)	Particle #4 point X2	??I	??5.91	??8.27	??85.75	??0.71	??14
Point X4	??I	??7.39	??7.66	??84.92	??0.96	??15	Particle #4 point X2	??I	??5.91	??8.27	??85.75	??0.71	??14
Point X4	??I	??7.39	??7.66	??84.92	??0.96	??15	Point X5	??O	??2.97	??1.98	??95.05	??1.50	??5
							Point X5	??O	??2.97	??1.98	??95.05	??1.50	??5
							Particle #6 point X6	??I	??21.75	??8.62	??69.63	??2.52	??30
Point X7	??I	??20.80	??12.88	??66.27	??1.61	??34	Particle #6 point X6	??I	??21.75	??8.62	??69.63	??2.52	??30
Point X7	??I	??20.80	??12.88	??66.27	??1.61	??34	Point X8	??O	??11.43	??1.55	??87.02	??7.37	??13
Point X9	??O	??14.48	??1.92	??83.34	??7.54	??16	Point X8	??O	??11.43	??1.55	??87.02	??7.37	??13

All " island " point (X2, X4, X6, X7) has and is starkly lower than whole particulate Ni: Mn ratio (table 5).All " ocean " point (X5, X8, X9) has the manganese content more much lower than whole particles.This embodiment confirms that the particle with island form has high Mn content in most of island, have low manganese content between the island.Obviously have the manganese gradual change, the island is the gradual change center.

Collection sample EX1 second phase (LiM ' O ₂) the EDS spectrum of 3 individual particles.These particles are obtained from MOOH, and it has the metal identical with sample REF2 forms, and Ni: the Mn ratio is near 2.0, and cobalt contents is near 20%.Fig. 8 has showed scanning electron microscopy.These three particles obviously have different size crystal grain.Particle 1 (left side) has the crystal grain near 0.5-1.5 μ m; Particle 2 (centre) has the crystal grain near 1-2 μ m, and particle 3 (the right) has the crystal grain near 1.5-3 μ m.Similarly, collect the single LiM ' O of sample CX2 and CX3 ₂The EDS spectrum of particle (phase 2).All the results are shown in table 7.

Table 7: second phase (LiM ' O ₂) the EDS of levels of transition metals measure

Sample	??Ni??(mol％)	??Mn??(mol％)	??Co??(mol％)	Ni: Mn mol ratio	(Ni+Mn)/M mol ratio (%)
Sample	??Ni??(mol％)	??Mn??(mol％)	??Co??(mol％)	Ni: Mn mol ratio	(Ni+Mn)/M mol ratio (%)	The many particles of REF2	??50.39	??27.34	??20.72	??1.84	??79
CX2 particle 1	??49.34	??26.09	??24.19	??1.89	??76	The many particles of REF2	??50.39	??27.34	??20.72	??1.84	??79
CX2 particle 1	??49.34	??26.09	??24.19	??1.89	??76	Particle 2	??49.34	??25.40	??23.39	??1.94	??76
CX3 particle 1	??49.14	??26.58	??23.03	??1.85	??77	Particle 2	??49.34	??25.40	??23.39	??1.94	??76
CX3 particle 1	??49.14	??26.58	??23.03	??1.85	??77	Particle 2	??47.34	??25.86	??26.22	??1.83	??74
EX1 particle 1	??41.18	??22.32	??36.13	??1.84	??64	Particle 2	??47.34	??25.86	??26.22	??1.83	??74
EX1 particle 1	??41.18	??22.32	??36.13	??1.84	??64	Particle 2	??39.49	??21.80	??38.18	??1.81	??62
Particle 3	??37.38	??20.08	??42.19	??1.86	??58	Particle 2	??39.49	??21.80	??38.18	??1.81	??62

The sample EX1 second phase LiM ' O ₂The particulate cobalt contents obviously increases during sintering.This is the LiM ' O with sample CX2 and CX3 ₂Particle result's stark contrast, the EDS spectrum of itself and sample REF2 is roughly the same.Cationic exchange takes place during showing the EX1 sintering in this observation, and wherein cobalt is from LiCoO ₂(phase 1) enters LiM ' O ₂(phase 2) particle.In addition, in the comparison diagram 8 in scanning electron microscopy and the table data show sample EX1 mutually the elementary grain-size of 2 particulate be relevant with cobalt contents.Obviously, along with cobalt diffuses into LiM ' O ₂, LiM ' O ₂Sinterability strengthen, cause crystal grain to increase quickly.

Embodiment 4: spray the precursor of milling

By the injection mixed hydroxides MOOH that mills, preparation submicron-scale mixed hydroxides.This MOOH be used to prepare REF2-LiM ' O ₂Identical.Utilize the laser diffraction measurement size distribution.After 3 injections were milled, 80% volume was by the granulometric composition that is lower than 1 micron-scale.

The commercially available LiCoO that mixes 90 weight % ₂(sample REF1 has 20 micron particle), spray mill MOOH and Li for 10%3 times ₂CO ₃For 1 mole of injection MOOH that mills, add 0.5mol Li ₂CO ₃(this Li: the M ratio be used to prepare REF2-LiM ' O ₂Identical.) after the mixing, 970 ℃ of sintered samples 8 hours.

With the final sample EX4 of SEM, BET surface analysis and X-ray diffraction studies.Make button cell.Measuring speed performance and cyclical stability.Fig. 9 has compared on the left (A) commodity LiCoO ₂(REF1) speed ability (cell voltage V is to capacity mAh/g), and the speed ability of (B) sample EX4 on the right.This figure has showed the curve of sparking voltage during C/10, C/5, C/2,1C, 1.5C, 2C, 3C, 5C and the 10C speed, and wherein 1C (corresponding to discharge in a hour) is defined as 160mA/g.Temperature is held constant at 24 ℃, and voltage range is 4.3-3.0V.Obviously, speed ability significantly increases.There is the island form in scanning electron microscopy (not show) clear displaying.

Research co-sintering condition

With sample EX1, EX2, the identical perparation of specimen CX5 of EX3, except the sintering temperature that is lower than 900 ℃ (sintering times: 8 hours).This sample obviously is different from EX1, EX2, EX3.The BET surface-area is very big: 0.35 meters squared per gram.X-ray diffraction has been showed the biphase phase mixture, and first has REF1-LiCoO ₂Lattice parameter, second has the sample of being similar to REF2-LiM ' O ₂Lattice parameter.Obviously, Co does not appear from phase 1 LiCoO ₂Obviously diffuse into the second phase LiM ' O ₂Similarly, the volume fraction of second phase is obviously littler, this diffuse into mutually 2 with Co still less (LiM ' O ₂) be consistent.

Electrochemical properties relatively poor (table 3).Observe cyclical stability relatively poor (than the about soon 2-3 of sample EX1-EX3 doubly) at the 4.5V decline rate.Speed ability reduces obviously that (in 3C speed is 87.5%, compares with the 90-91% of sample EX1, EX2, EX3.Speed ability is similar to sample CX3.Scanning electron microscopy (not show) has been showed and has been connected big LiCoO ₂Lip-deep some little LiM ' O ₂Particle, but the island form do not had basically.

Identical with embodiment 4 cathode powder, make and analyze cathode powder CX6.Yet, use and the second LiM ' O mutually ₂Different precursors.Mix 90%REF1 LiCoO among this embodiment ₂With 10% jet grinding precursor and 0.05mol%Li ₂CO ₃Precursor is the Li that lithium lacks _1-xM _1+xO ₂Be similar to REF2-LiM ' O ₂Make this precursor, except Li: the M ratio is 0.9, and temperature is outside 900 ℃.After the preparation, jet grinding precursor twice produces the submicron particles product.In water, utilize the laser diffraction measurement size distribution.This size distribution is a bimodal, and about 50% volume has the size of 0.05-1 μ m (maximum near 0.3 μ m), and all the other 50% volumes have the size of 1-6 μ m (maximum near 2 μ m).Heated mixt is 8 hours in 970 ℃ of air.The measured X x ray diffration pattern x, and carry out Rietveld and purify.Take scanning electron microscopy.Make button cell.

This ray diffraction pattern has showed that single-phase basically lattice parameter is similar to LiCoO ₂Can not obviously distinguish the 2nd LiM ' O ₂(this is different from the sample of embodiment 4, and it obviously shows existence second phase).Figure 10 b has showed scanning electron microscopy.LiM ' the O that has the type of seldom reuniting ₂Particle (=phase 2).Nearly all particle is LiCoO ₂Base (=phase 1).These particles have very slick surface usually.Obviously, there is not the island form.Consistent with this observation is to observe the only low-down BET surface-area of 0.14 meters squared per gram.

Obviously, than sample EX4 sintered sample CX6 more effectively.Cobalt is from phase 1 LiCoO too much ₂Diffuse into 2 LiM ' O mutually ₂Simultaneously, little LiM ' O ₂Particle is by bigger LiCoO ₂Particle consumes, and LiCoO ₂Middle manganese positively charged ion may be diluted, and the result does not have the island form.Mutually 2 with 1 composition is effectively approaching mutually mutually.Second phase, even comprise more most negative electrode under the sintered sample situation than still less be very similar to mutually 1 now, and this phase for example can not be distinguished clearly with X ray.

Electrochemical test shows:

(a) slope of voltage curve disappearance when discharge finishes-this is consistent with phase 2

Basically there is not LiM ' O ₂,

(b) speed ability is starkly lower than sample EX4,

(c) cyclical stability is relatively poor

Can draw, island form and existence second are necessary with respect to obtaining high speed performance.In addition, there is the quite narrow window that obtains the high speed negative electrode.If sintering is strong (sample CX6) too, the island disappearance owing to high transition metal diffusing is not if sintering deficiency (sample CX3 and CX4) then because the transition metal diffusion is not enough, forms the island.Table 2 and 3 has been summarized the data that obtain.For correct execution technology of the present invention, need set up temperature to the sintering time matrix, the scanning electron microscopy of the product that wherein obtains has clearly demonstrated the island structure of EX 1-4.If co-sintering does not take place, clearly difference phase 2 and pure LiCoO ₂, do not observe island structure.If too strong co-sintering, 2 near disappearing mutually, and the Li-Co-Ni-Mn oxide compound that obtains has the smooth surface of circular edge.

If there are two phase LiCoO ₂And LiM ' O ₂, the lattice parameter of the sample that can measure in addition, and with reference sample relatively, wherein reference sample is that the sintered compound that only obtains with the phase 2 required precursors that obtain (does not have LiCoO ₂Or corresponding cobalt precursors).Relation between the lattice parameter that obtains should be in restriction before.

The substoichiometric influence

The following example (EX5A to F) shows if sample has slight substoichiometric lithium, can further improve chemical property.Identical preparation sample with sample EX4 is except adding still less Li ₂CO ₃, sometimes sintering temperature raises a little.

Under any circumstance mix 90%20 μ m LiCoO ₂(=REF1) and 10% jet grinding MOOH and Li ₂CO ₃Provide Li (Li in the following table 8 ₂CO ₃In) with the molar ratio of MOOH.Table 8 is listed the result that sintering temperature and BET surface-area measure in addition.Li: the M hurdle provides the lithium that the chemical analysis final sample obtains and the result of transition metal ratio.Chemical analysis results is very similar to expected value, has the Li near 1.02: Co if remember sample REF1, and depends on temperature, lithium in small amounts evaporation all the time during the specimen preparation.Obviously the lithium substoichiometric of sample EX5D, EX5E and EX5F increases.Carry out scanning electron microscopy analysis, confirm that whole 6 samples show island structure.The scanning electron microscopy that has represented sample EX5E among Figure 10 a.Under any circumstance X-ray analysis shows two-phase mixture (as follows).

Table 8: analyze substoichiometric sample (sintering time: 8 hours)

	??Li∶M	??T	??BET??m ²/g	Li: M chemical analysis
	??Li∶M	??T	??BET??m ²/g	Li: M chemical analysis	??EX5A	??0.98	??970℃	??0.19
??EX5B	??0.96	??970℃	??0.21		??EX5A	??0.98	??970℃	??0.19
??EX5B	??0.96	??970℃	??0.21		??EX5C	??0.85	??970℃	??0.22	??1.0
??EX5D	??0.7	??970℃	??0.23	??0.991	??EX5C	??0.85	??970℃	??0.22	??1.0
??EX5D	??0.7	??970℃	??0.23	??0.991	??EX5E	??0.7	??985℃	??0.20	??0.986
??EX5F	??0.65	??985℃	??0.21	??0.972	??EX5E	??0.7	??985℃	??0.20	??0.986

With to described similar condition preparation before and test button cell.The result is summarized in following table 9.

Obtain electrochemical data from two groups of two button cells.Utilize two batteries of cyclical stability program test first series.Utilize another series of speed ability program test.The cyclical stability program provides following numerical value: Qrev, Qirr, the rate of decay (C/10) and the rate of decay (C1), lists in table 3 and 9.Described electrochemical data is the mean value of two batteries of each series.Qrev and Qirr be the first round-robin reversibility (mAh/g) of C/10 velocity survey and irreversible performance (%, Qirr[QCh-QDC]/QCh).By relatively obtaining rate of decay numerical value, by the 1C rate of decay that relatively obtains at faster (1C) the 4th and the 42nd round-robin discharge capacity at C/10 at slow (C/10) the 3rd and the 41st round-robin discharge capacity.From circulating 5 to 40, charge and C/2 discharge rate cycle battery with C/5 at 4.5-3.0V.The rate of decay is extrapolated to 100 circulations.

The speed ability program provides the numerical value of the speed ability of numerical value 1C/0.1C, 2C/0.1C and 3C/0.1C, lists in table 3 and 9.Described program is as described below.1 slowly after the circulation (C/10), at the C/5 speed described battery that charges, and in (C/5, C/2,1C, 1.5C, 2C, 3C, 5C and the 10C) discharge down that gathers way.Voltage range is 4.3-3.0V.

For with high reliability measuring capacity and speed ability, electrode load (gram/square centimeter) difference of battery.The battery that is used for stable program test has the electrode load near 12 milligrams/square centimeter.Battery with the speed program test has the load of approaching 5-6 milligram/square centimeter.

Table 9: the electrochemical data of substoichiometric sample

	??Q _rev??4.3-3V??C/10	??Q _irr??(％)	??1C/0.1C??(％)	??2C/0.1C??(％)	??3C/0.1C??(％)	Fading rate C/10 %/100	Fading rate C/1 %/100
	??Q _rev??4.3-3V??C/10	??Q _irr??(％)	??1C/0.1C??(％)	??2C/0.1C??(％)	??3C/0.1C??(％)	Fading rate C/10 %/100	Fading rate C/1 %/100	??EX5A	??156.9	??3.92	??95.39	??93.74	??92.49	??8.84	??15.19
??EX5B	??157.1	??3.79	??95.98	??94.25	??92.84	??8.34	??13.80	??EX5A	??156.9	??3.92	??95.39	??93.74	??92.49	??8.84	??15.19
??EX5B	??157.1	??3.79	??95.98	??94.25	??92.84	??8.34	??13.80	??EX5C	??157.3	??4.32	??95.76	??93.66	??91.49	??11.06	??24.66
??EX5D	??156.5	??4.89	??96.56	??94.98	??93.62	??6.76	??12.47	??EX5C	??157.3	??4.32	??95.76	??93.66	??91.49	??11.06	??24.66
??EX5D	??156.5	??4.89	??96.56	??94.98	??93.62	??6.76	??12.47	??EX5E	??156.5	??4.71	??96.67	??95.21	??94.16	??5.19	??7.03
??EX5F	??153.7	??5.84	??95.57	??91.86	??88.42	??6.69	??15.01	??EX5E	??156.5	??4.71	??96.67	??95.21	??94.16	??5.19	??7.03

Data show if Li in the table: the M ratio reduces, and speed ability increases.Obtain top speed near the substoichiometric sample of 1.5% lithium.Simultaneously, the substoichiometric sample EX5E of 1.5% lithium is further illustrated in the highest cyclical stability of 4.5V.Yet, if the lithium substoichiometric is too big, degradation.Therefore relatively poor near the capacity of the substoichiometric sample EX5F of 3% lithium, and the non-constant of speed ability.

Table 1: sample general introduction (title, composition and preparation)

	The sample name	Form (always) sintering T	Precursor	Remarks
	The sample name	Form (always) sintering T	Precursor	Remarks		??REF1	??LiCoO ₂，??≈1000℃		??D50≈20μm
	??REF2	??LiNi _0.53Mn _0.27Co _0.2O ₂，??950℃	??MOOH，Li ₂CO ₃，			??REF1	??LiCoO ₂，??≈1000℃		??D50≈20μm
	??REF2	??LiNi _0.53Mn _0.27Co _0.2O ₂，??950℃	??MOOH，Li ₂CO ₃，		Calculate embodiment 1	??CC1	??LiCo _0.68Ni _0.21Mn _0.11O ₂，??n/a	??-	60%REF1, the weight in average of 40%REF2
Comparative Examples 2	??CX2	??LiCo _0.68Ni _0.21Mn _0.11O ₂，??n/a	??LiCoO ₂，??LiNi _0.53Mn _0.27Co _0.2，	Preheating LiCoO ₂And LiM ' O ₂Mixture	Calculate embodiment 1	??CC1	??LiCo _0.68Ni _0.21Mn _0.11O ₂，??n/a	??-	60%REF1, the weight in average of 40%REF2
Comparative Examples 2	??CX2	??LiCo _0.68Ni _0.21Mn _0.11O ₂，??n/a	??LiCoO ₂，??LiNi _0.53Mn _0.27Co _0.2，	Preheating LiCoO ₂And LiM ' O ₂Mixture	Comparative Examples 3	??CX3	??LiCo _0.68Ni _0.21Mn _0.11O ₂，??850℃	??LiCoO ₂，??LiNi _0.53Mn _0.27Co _0.2，	??LiCoO ₂And LiM ' O ₂Heated mixt
Comparative Examples 4	??CX4	??LiCo _0.68Ni _0.21Mn _0.11O ₂，??900℃	??LiCoO ₂，??LiNi _0.53Mn _0.27Co _0.2，	??LiCoO ₂And LiM ' O ₂Heated mixt	Comparative Examples 3	??CX3	??LiCo _0.68Ni _0.21Mn _0.11O ₂，??850℃	??LiCoO ₂，??LiNi _0.53Mn _0.27Co _0.2，	??LiCoO ₂And LiM ' O ₂Heated mixt
Comparative Examples 4	??CX4	??LiCo _0.68Ni _0.21Mn _0.11O ₂，??900℃	??LiCoO ₂，??LiNi _0.53Mn _0.27Co _0.2，	??LiCoO ₂And LiM ' O ₂Heated mixt	Comparative Examples 5	??CX5	??LiCo _0.68Ni _0.21Mn _0.11O ₂，??900℃	??LiCoO ₂，MOOH??Li ₂CO ₃	??LiCoO ₂, MOOH and Li ₂CO ₃Heated mixt
Comparative Examples 6	??CX6	??LiCo _0.91Ni _0.06Mn _0.03O ₂，??970℃	??LiCoO ₂，Li ₂CO ₃??Li _0.9Ni _0.53Mn _0.27Co ₀?? _.2O ₂，	??LiCoO ₂, T LiM ' O is hanged down in jet grinding ₂And Li ₂CO ₃Heated mixt	Comparative Examples 5	??CX5	??LiCo _0.68Ni _0.21Mn _0.11O ₂，??900℃	??LiCoO ₂，MOOH??Li ₂CO ₃	??LiCoO ₂, MOOH and Li ₂CO ₃Heated mixt
Comparative Examples 6	??CX6	??LiCo _0.91Ni _0.06Mn _0.03O ₂，??970℃	??LiCoO ₂，Li ₂CO ₃??Li _0.9Ni _0.53Mn _0.27Co ₀?? _.2O ₂，		Embodiment
1	??EX1	??LiCo _0.68Ni _0.21Mn _0.11O ₂，??970℃	??LiCoO ₂，MOOH??Li ₂CO ₃	??LiCoO ₂, MOOH and Li ₂CO ₃Heated mixt	Embodiment
1	??EX1	??LiCo _0.68Ni _0.21Mn _0.11O ₂，??970℃	??LiCoO ₂，MOOH??Li ₂CO ₃	??LiCoO ₂, MOOH and Li ₂CO ₃Heated mixt	Embodiment
2	??EX2	??LiCo _0.68Ni _0.21Mn _0.11O ₂，??960℃	??LiCoO ₂，MOOH??Li ₂CO ₃	??LiCoO ₂, MOOH and Li ₂CO ₃Heated mixt	Embodiment
2	??EX2	??LiCo _0.68Ni _0.21Mn _0.11O ₂，??960℃	??LiCoO ₂，MOOH??Li ₂CO ₃	??LiCoO ₂, MOOH and Li ₂CO ₃Heated mixt	Embodiment
3	??EX3	??LiCo _0.68Ni _0.21Mn _0.11O ₂，??950℃	??LiCoO ₂，MOOH??Li ₂CO ₃	??LiCoO ₂, MOOH and Li ₂CO ₃Heated mixt	Embodiment
3	??EX3	??LiCo _0.68Ni _0.21Mn _0.11O ₂，??950℃	??LiCoO ₂，MOOH??Li ₂CO ₃	??LiCoO ₂, MOOH and Li ₂CO ₃Heated mixt	Embodiment 4	??EX4	??LiCo _0.91Ni _0.06Mn _0.03O ₂，??970℃	??LiCoO ₂，MOOH??Li ₂CO ₃	??LiCoO ₂, jet grinding MOOH and Li ₂CO ₃Heated mixt
Embodiment					Embodiment 4	??EX4	??LiCo _0.91Ni _0.06Mn _0.03O ₂，??970℃	??LiCoO ₂，MOOH??Li ₂CO ₃	??LiCoO ₂, jet grinding MOOH and Li ₂CO ₃Heated mixt
Embodiment	5	??EX5A-??EX5F	??Li _xCo _0.91Ni _0.06Mn _0.03O ₂??，970-985℃	??LiCoO ₂，MOOH??Li ₂CO ₃	??LiCoO ₂, jet grinding MOOH and Li ₂CO ₃Heated mixt

Crystallization figure

Obtain reference sample REF1, REF2, the X-ray diffractogram of comparative sample CX2-CX3 and sample EX1-3.Sample CX2, CX3, EX1-EX3 are by two phase composites, and first based on LiCoO ₂, second based on LiM ' O ₂Purify to obtain the lattice parameter of these phases by two-phase Rietveld, and can with the sample REF1 (LiCoO that obtains by single-phase purification ₂) and REF2 (LiM ' O ₂) lattice parameter relatively.

Table 2 is enumerated described result.Figure 11 has showed the result with suitable method, and the author is called crystallization figure, and mapping sexangle c axle is to sexangle a-axle.This figure provides the crystallization figure of sample REF1, REF2, CX2, CX3, EX1, EX2 and EX3.Inlet has been showed the zonule drawing with rectangle marked, amplification.Table 2 and Figure 11 most clearly illustrated sample EX1, EX2 and EX3 mutually 2 (LiM ' O ₂) lattice parameter distance R EF2 value have obvious variation, and mutually 2 lattice parameter is identical with REF2 among CX2, the CX3.This variation is more obvious with the sintering temperature increase.Increasing sintering temperature causes the figure position to shift to LiCoO ₂, leave the REF2 position of expectation.Change in location is for LiCoO on this figure ₂And LiM ' O ₂Between sosoloid be typical.Obviously cobalt is from phase 1 (LiCoO ₂) diffuse into mutually 2 (LiM ' O ₂) particle.

Surprisingly, during the sintering, phase 1 (LiCoO ₂) lattice parameter do not change.All sample CX2, CX3 have the lattice parameter identical with REF1 with EX1, EX2 and EX3.

Also generation part of Rietveld purification phase 2 (LiM ' O ₂), list in table 2.Phase 2 marks increased during these data showed sintering.LiM ' the O of sample CX2 ₂Mark should be 40%.Obviously Rietveld is for LiM ' O ₂Produce bigger value mutually.This mistake may be due to during the X ray specimen preparation, small-particle (phase 2, LiM ' O ₂) with macrobead (mutually 1, LiCoO ₂) permutatation, it can cause mutually 1 in the near surface enrichment.1 particulate preferred orientation can strengthen this effect mutually.Yet, ignoring this mistake, we observe trend clearly.LiM ' O ₂Mark increase with sintering temperature.It shows during the sintering that more Co are from phase 1 (LiCoO ₂) diffuse into mutually 2, with respect to Ni (with Mn) from 2 diffusing into phase 1 mutually.

Figure 12 has showed to have sample EX4, EX5A-EX5F and CX5, and the crystallization figure of sample REF1, REF2 data point.Utilize two-phase Rietveld to purify and obtain data point.This figure clearly illustrate that EX4, EX5A-EX5F phase 2 (LiM ' O ₂) lattice parameter at LiCoO ₂-REF1 and REF2-LiM ' O ₂Between.This diffuses into second mutually identical with the Co that discusses.1 lattice parameter does not change at all mutually simultaneously, and and REF1-LiCoO ₂Identical.

Figure 12 has compared sample CX5 and sample EX4, EX5A-F also according to position on the crystallization figure.The lattice parameter that can sum up CX5 phase 2 is identical with REF2.This meets the phase 1 of reduction sintering temperature generation and the cationic exchange deficiency between the phase 2.

X-ray diffractogram

Sample REF 1 and REF2 have high-crystallinity, so their X-ray diffractogram has sharp-pointed diffraction peak.Figure 13 has showed the X-ray diffractogram (matrix: scattering angle (degree)) of CX2, CX4, CX5 and EX1.All these samples have identical total composition.The inlet of Figure 13 has been showed with the magnification region of rectangle marked and has been mapped again.As expected, the sample CX2 for (heat treated) REF1 and REF2 mixture shows the X-ray diffractogram that is higher than REF 1 and REF2 figure position.Even at 900 ℃ of thermal treatment mixtures (sample CX4) or LiCoO ₂Mixture, mixed hydroxides and Li ₂CO ₃(CX5), X-ray diffractogram keeps basic identical.This tells us the first phase LiCoO ₂With the second LiM ' O mutually ₂Do not change.

Yet this situation is obviously different with typical sample of the present invention.Figure 13 has showed the peak of sample EX1 and peak value alteration of form.Phase 1 (LiCoO ₂Base) peak value keeps quite sharp-pointed sample, and the position is identical, however phase 2 (LiM ' O ₂Base) peak value obviously broadens, and obviously move its position.This major cause that broadens is the stoichiometric distribution of Co and Ni.During the sintering, second phase is left in the Ni diffusion, and cobalt diffuses into second phase.As a result, variable grain and/or crystal grain have the different chemical metering, and each stoichiometry has the peak of oneself, thereby observes wideer diffraction peak.During Rietveld purifies, the distribution that is difficult to simulate lattice parameter.Yet quite fortunately, small crystalline size produces similar spectrum peak broadening to a certain extent.Negative electrode typical R ietveld therefore of the present invention purifies and shows the first phase (LiCoO ₂Base) be big grain-size, and second phase (LiM ' O ₂) grain-size is much smaller.Simultaneously, the peak of the second phase diffraction peak is towards a LiCoO ₂Obviously move the position of phase.

Figure 14 has showed the X-ray diffractogram of sample CX6 and EX9E.All these samples have identical total composition.Sample CX6 is different from sample as mentioned above.The sample sintering is too strong.Therefore diffusion is carried out excessively.Second become mutually and be similar to first phase as a result, and can not be with their X ray picture difference.The whole of maintenance are that the small shoulder in phase 1 peak is towards low angle.In contrast, but sample EX9E has showed little clearly peak value at low angle.Use some such peaks of arrow mark among Figure 14.

In contrast, but sample EX9E has showed little clearly peak at low angle.Enter second phase if we understand Co, it measures increase, and its lattice parameter is towards LiCoO ₂Lattice parameter (referring to top) move, so the X ray peak moves more approachingly, overlapping and last coincidence.Therefore excessively the middle mutually phase 2 of sintering may not disappear, but becomes too similar, with LiCoO ₂Different.

Can sum up negative electrode of the present invention shows near the LiCoO with high-crystallinity ₂The X ray picture of figure, and LiM ' O with low-crystallinity ₂Figure.Degree of crystallinity still quite is suitable for two phases.Some commercial cathode materials are than 2 still less crystallizations mutually.In addition, the lattice parameter of second phase is lower than desired value (this peak is more near LiCoO ₂The peak); Desired value is the LiM ' O from identical MOOH precursor preparation ₂The representative value of phase.

Table 2 has been summarized the result that Rietveld purifies.

Table 2:BET surface-area and crystallization data

Voltage curve

Prepare button cell from whole reference sample REF1, REF2, whole comparative sample CX2, CX3 and EX1, EX2 and EX3.Showed slow interdischarge interval among Figure 15, the voltage curve of CX2, CX3 and EX1-EX3.Sample CX2 and CX3 have showed platform clearly at 3.88V.This platform is for LiCoO ₂Be typical.The existence of this platform shows that phase 1 is pure LiCoO ₂Yet for sample EX1, EX2 and EX3, along with sintering temperature increases, this platform fades away.Obviously, phase 1 does not have LiCoO ₂This coincide with the fact that 1 particle mutually comprises Ni and Mn, analyzes as EDS clearly to show.Yet very surprisingly, 1 has LiCoO mutually ₂Definite X-ray diffractogram, its lattice parameter obviously is different from Li doped CoO ₂The Ni-Mn desired value.

Speed ability and cyclical stability

Table 3 has been enumerated with reference to the button cell of REF1 and REF2 and sample CX2, CX3, EX1, EX2 and EX3 and has been tested the result who obtains, and the calculated value of assumes samples CC1.All sample has identical total composition.This table provides the average data of 2 button cells of each sample.

We notice sample CX2 (heating LiCoO ₂And LiM ' O ₂Mixture) have a performance of the assumes samples of being very similar to.Significantly-mixing LiCoO ₂And LiM ' O ₂Do not produce any benefit.Sample CX3 and CX4 (heating LiCoO ₂And LiM ' O ₂Mixture) cyclical stability that has a little better speed ability and improve a little, but performance obviously different with sample CX2 or CC1 usually.

Yet sample EX1, EX2 and EX3 show the speed ability of obvious improvement.At 1C, 2C, 3C, compare with 83-86% with 91-93, the 86-88 of assumes samples CC1 or mixture CX2, or compare with 89% with 94,91 of sample CX3, obtain capacity near 95,93 and 91%.

We notice that improving speed ability does not relate to different forms.All sample CX2, CX3, EX1-3 have BET surface-area much at one, among the common figure all samples are mixtures of the erose particle (mutually 1) of big densification and reunion than small-particle (mutually 2).In addition, size distribution is identical substantially.Acquisition speed increases, and not increasing the BET specific surface area is the very important aspect of the present invention.Basically can reduce the BET surface-area satisfying security and density requirements, and still obtain enough speed abilities.

Significantly improved simultaneously the cyclical stability of EX1, EX2 and EX3.Figure 16 has showed the data that sample EX1 obtains.Figure 16 a has showed that the calculated value (capacity is to cycling numerical value #) of per 100 loop attenuation speed is 6.4%.Point is represented charging capacity, a little bigger expression discharge.Figure 16 b has showed the cyclical stability of EX1.Figure 16 c has showed the speed ability of EX1.

Among Figure 17, the comparative sample CX6 (left side: A) with EX5E (the right: cycle performance B).

Table 3: the electrochemical test result is the mean value of two button cells.

The sample name	??Q _rev??4.3-3V??C/10	??Q _irr??(％)	??1C/0.1C??(％)	??2C/0.1C??(％)	??3C/0.1C??(％)	Fading rate C/10 %/100	Fading rate C/1 %/100
The sample name	??Q _rev??4.3-3V??C/10	??Q _irr??(％)	??1C/0.1C??(％)	??2C/0.1C??(％)	??3C/0.1C??(％)	Fading rate C/10 %/100	Fading rate C/1 %/100	The REF1 of heating	??153.8	??5.3	??90.9	??85.3	??81.6	??76	??171
??REF2	??158.2	??3.1	??95.6	??93.1	??91.0	??40	??110	The REF1 of heating	??153.8	??5.3	??90.9	??85.3	??81.6	??76	??171
??REF2	??158.2	??3.1	??95.6	??93.1	??91.0	??40	??110	The REF2 of heating	??169.2	??13.5	??91.4	??88.7	??86.0	??0.4	??2.8
??CC1	??159.4	??8.9	??90.9	??86.0	??82.9	??47	??107	The REF2 of heating	??169.2	??13.5	??91.4	??88.7	??86.0	??0.4	??2.8
??CC1	??159.4	??8.9	??90.9	??86.0	??82.9	??47	??107	??CX2	??159.9	??7.9	??92.2	??88.1	??85.3	??55.6	??128
??CX3	??161.7	??7.7	??93.8	??90.7	??88.5	??31.5	??79.3	??CX2	??159.9	??7.9	??92.2	??88.1	??85.3	??55.6	??128
??CX3	??161.7	??7.7	??93.8	??90.7	??88.5	??31.5	??79.3	??CX4	??161.0	??7.7	??93.8	??90.8	??88.2	??22.3	??59.0
??CX5	??157.7	??9.5	??92.9	??89.8	??87.5	??6.6	??18.9	??CX4	??161.0	??7.7	??93.8	??90.8	??88.2	??22.3	??59.0
??CX5	??157.7	??9.5	??92.9	??89.8	??87.5	??6.6	??18.9	??CX6	??156.8	??4.0	??91.6	??89.8	??89.6	??32.3	??68.0
??EX1	??159.6	??6.4	??95.0	??92.7	??91.1	??5.6	??9.5	??CX6	??156.8	??4.0	??91.6	??89.8	??89.6	??32.3	??68.0
??EX1	??159.6	??6.4	??95.0	??92.7	??91.1	??5.6	??9.5	??EX2	??160.2	??6.5	??94.5	??92.0	??90.4	??5.7	??10.1

??EX3	??159.5	??7.4	??94.4	??92.0	??90.7	??3.4	??6.5
??EX3	??159.5	??7.4	??94.4	??92.0	??90.7	??3.4	??6.5	??EX4	??156.5	??4.2	??95.5	??93.6	??91.9	??10.5	??27.4
??EX5A	??156.9	??3.9	??95.4	??93.7	??92.5	??8.8	??15.2	??EX4	??156.5	??4.2	??95.5	??93.6	??91.9	??10.5	??27.4
??EX5A	??156.9	??3.9	??95.4	??93.7	??92.5	??8.8	??15.2	??EX5B	??157.1	??3.8	??96.0	??94.3	??92.8	??8.3	??13.8
??EX5C	??157.3	??4.3	??95.8	??93.7	??91.5	??11.1	??24.7	??EX5B	??157.1	??3.8	??96.0	??94.3	??92.8	??8.3	??13.8
??EX5C	??157.3	??4.3	??95.8	??93.7	??91.5	??11.1	??24.7	??EX5D	??156.5	??4.9	??96.6	??95.0	??93.6	??6.8	??12.5
??EX5E	??156.5	??4.7	??96.7	??95.2	??94.2	??5.2	??7.0	??EX5D	??156.5	??4.9	??96.6	??95.0	??93.6	??6.8	??12.5
??EX5E	??156.5	??4.7	??96.7	??95.2	??94.2	??5.2	??7.0	??EX5F	??153.7	??5.8	??95.6	??91.9	??88.4	??6.7	??15.0

Claims

1. one kind comprises the LiCoO that contains Mn and Ni ₂Particulate powder lithium transition-metal oxide, described particle has the island of enrichment Mn and Ni in its surface, and described island comprises 5mol% at least, the preferred Mn of 10mol% at least.

2. according to the described powder lithium transition-metal oxide of claim 1, it is characterized in that described Mn and Ni enrichment island have the thickness of 100nm at least, and cover, preferably less than 50% the described LiCoO that contains Mn and Ni less than 70% ₂The particulate surface.

3. according to claim 1 or 2 described powder lithium transition-metal oxides, the described LiCoO that contains Mn and Ni of the Mn concentration ratio in the wherein said island ₂The high at least 4mol% of Mn concentration in the particle body, preferably high at least 7mol%.

4. according to any one described powder lithium transition-metal oxide of claim 1 to 3, the described LiCoO that contains Mn and Ni of Ni concentration ratio in wherein said Mn and the Ni enrichment island ₂The high at least 2mol% of Ni concentration in the particle body, and preferably high at least 6mol%.

5. according to any one described powder lithium transition-metal oxide of claim 1 to 4, has the LiCoO that contains Mn and Ni ₂Particle wherein comprises Ni and the Mn of 3mol% at least, preferably 10mol% at least.

6. according to any one described powder lithium transition-metal oxide of claim 1 to 5, it is characterized in that the LiCoO of described Mn of containing and Ni ₂Particulate lattice parameter a and c are respectively 2.815+/-0.002 and 14.05+/-0.01.

7. according to any one described powder lithium transition-metal oxide of claim 1 to 6, it is characterized in that containing the LiCoO of Mn and Ni ₂Particle is a monoblock, and does not have internal void.

8. according to any one described powder lithium transition-metal oxide of claim 1 to 7, it is characterized in that the LiCoO of described Mn of containing and Ni ₂The d50 that the particulate distribution of sizes has is preferably greater than 15 μ m greater than 10 μ m, most preferably greater than 20 μ m.

9. according to any one described powder lithium transition-metal oxide of claim 1 to 8, comprise the described Mn of containing of 30wt% to 95wt% and the LiCoO of Ni ₂Particle.

10. according to any one described powder lithium transition-metal oxide of claim 1 to 9, comprise LiCoO by described Mn of containing and Ni ₂First phase that particle constitutes, and

Further comprise and have general formula Li _1+aM ' _1-aO _{2 ± b}The second no island phase,

Wherein-and 0.03＜a＜0.05, b＜0.02, M '=Ni _mMn _nCo _1-m-n, wherein m 〉=n, and 0.1＜m+n＜0.9.

11., have composition Li according to the described powder lithium transition-metal oxide of claim 10 _xM _yO _{2 ± δ}, wherein:

0.97＜x＜1.03,0.97＜y＜1.03, x+y=2, and preferred 0.98＜x/y＜1.00; And δ＜0.05;

And M=Co _1-f-gNi _fMn _g, wherein 0.05＜f+g＜0.5, and f 〉=g.

12. according to claim 10 or 11 described powder lithium transition-metal oxides, it is characterized in that described oxide compound constitutes mutually by two, first is the LiCoO of described Mn of containing and Ni ₂Particle, second is described no island phase.

13. according to the described powder lithium transition-metal oxide of claim 12, it is characterized in that the lattice parameter a ' of described no island phase and c ' with reference to lithium transition-metal (M _Ref) the lattice parameter a " and c " of corresponding no island phase of oxide compound has following relationship, has identical composition Li _xM _yO _{2 ± δ}, and by pure LiCoO ₂Particle constitutes mutually with described corresponding no island:

0.980＜a '/a "＜0.998 and 0.9860＜c '/c "＜0.9985,

With preferred 0.990＜a '/a "＜0.997,0.9920＜c '/c "＜0.9980.

14. according to any one described powder lithium transition-metal oxide of claim 10 to 13, it is characterized in that described no island has secondary granule mutually, its size distribution that has has 2 to 10 microns d50, described secondary granule is made of the elementary grain colony aggressiveness of agglomerating, and wherein the size distribution that has of coacervate has the d50 of 0.5 to 2 μ m.

15., it is characterized in that described Mn further comprises Ti with Ni enrichment island mutually with described no island, thereby Ti content is less than oxide compound Li according to any one described powder lithium transition-metal oxide of claim 10 to 14 _xM _yO _{2 ± δ}The 10mol% of middle M.

16. according to any one described powder lithium transition-metal oxide of claim 10 to 15, oxide compound Li _xM _yO _{2 ± δ}In, further comprise less than one or more of the M of 5mol% and be selected from the hotchpotch of Al and Mg, and one or more are selected from the hotchpotch of Be, B, Ca, Zr, S, F and P less than the M of 1mol%.

17. an electrochemical cell that comprises negative electrode, wherein negative electrode comprises any one described powder lithium transition-metal oxide of claim 1 to 16 as active substance.

18. a method for preparing any one described powder lithium transition-metal oxide of claim 1 to 16 comprises step:

-LiCoO is provided ₂Powder or cobalt contents at least 90mol% contain cobalt precursors compound and Li-Ni-Mn-Co oxide compound or Ni-Mn-Co precursor powder and optional Li precursor compound, the mixture of preferred Quilonum Retard and

To obtain to have in its surface the LiCoO that contains Mn and Ni on Mn and Ni enrichment island ₂Particle.

19. a method for preparing any one described powder lithium transition-metal oxide of claim 12 to 16 comprises step:

-LiCoO is provided ₂Powder or cobalt contents at least 90mol% contain cobalt precursors compound and Li-Ni-Mn-Co-oxide compound or Ni-Mn-Co precursor powder and optional Li precursor compound, the mixture of preferred Quilonum Retard and

To obtain the LiCoO of described Mn of containing and Ni ₂Particle mutually with the described no island with lattice parameter a ' and c ' mutually, its with wherein by the described Li-Ni-Mn-Co oxide compound that obtains at the identical time t of the described Ni-Mn-Co precursor powder of uniform temp T sintering or with reference to lithium transition-metal (M with described Li precursor compound _Ref) the lattice parameter a " and c " of oxide compound has following relationship, described relation is

0.980＜a '/a "＜0.998 and 0.9860＜c '/c "＜0.9985,

With preferred 0.990＜a '/a "＜0.997,0.9920＜c '/c "＜0.9980.

20. according to claim 18 or 19 described methods, wherein the Ni-Mn-Co precursor powder is transition metal hydroxide, oxyhydroxide, carbonate, oxycarbonate or lithium transition metal compound, wherein transition metal is formed M " being M "=Ni _oMn _pCo _1-o-p, wherein o+p＞0.5, and o＞p.

21. according to any one described method of claim 18 to 20, wherein the Ni-Mn-Co precursor powder comprises the levels of transition metals of 5 to 70mol% described powder lithium transition-metal oxides.

22. according to claim 18 to 21 any one described method, wherein LiCoO ₂Powder has the tap density of at least 2 gram/cubic centimetres, and is made of the monoblock particle of d50 at least 10 μ m, preferably at least 15 μ m, most preferably at least 20 μ m.

23. according to any one described method of claim 18 to 21, wherein containing the cobalt precursors compound is one or more oxyhydroxide, oxyhydroxide or carbonate of planting cobalt.

24. according to any one described method of claim 18 to 23, wherein said LiCoO ₂Or contain the transition metal that cobalt precursors comprises at least 80% described powder lithium transition-metal oxide, and the precursor powder that contains Ni-Mn-Co is made of the particle of the size distribution with the d50 between 1 to the 3 μ m.

25. according to any one described method of claim 18 to 23, wherein said LiCoO ₂Or contain cobalt precursors and comprise transition metal less than 80% described powder lithium transition-metal oxide, and contain the Ni-Mn-Co precursor and constitute by the Conglobation type particle, wherein the Conglobation type particle has the size distribution of the d50 between 4 to the 10 μ m.

26. according to any one described method of claim 18 to 25, the precursor that wherein contains Ni-Mn-Co further comprises Ti, is preferably the TiO of d50 less than 100 nanometers ₂Particle form.