CN111883829B - A kind of lithium-ion battery non-aqueous electrolyte and lithium-ion battery - Google Patents

Abstract

The invention provides a non-aqueous electrolyte solution for lithium ion batteries and a lithium ion battery. The nonaqueous electrolyte solution for lithium ion batteries includes a compound additive with the structure shown in formula I below. The additive can make the lithium ion battery cycle at 45°C for 200 The sub-capacity retention rate is above 73%, the high temperature storage at 60°C for 30 days, the capacity retention rate is above 71%, the capacity recovery rate is above 72%, and the thickness expansion rate is below 31%. The capacity decay of the cycle is too fast and the problem of severe gas expansion at high temperature.

Description

A kind of lithium-ion battery non-aqueous electrolyte and lithium-ion battery

technical field

The invention belongs to the field of lithium ion batteries, and relates to a lithium ion battery nonaqueous electrolyte and a lithium ion battery.

Background technique

With the development of new energy vehicles, power storage and high-performance digital products, people have higher requirements for the performance and scope of application of batteries, which requires the development of lithium-ion batteries that can meet the growing demand. It is especially important to improve the cycle life and temperature suitability of the battery.

Contents of the invention

Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a lithium-ion battery non-aqueous electrolyte and a lithium-ion battery. The non-aqueous electrolyte of the lithium-ion battery can solve the problems of rapid capacity attenuation and severe inflation at high temperature in the circulation of the non-aqueous electrolyte of the current lithium-ion battery.

For reaching this purpose, the present invention adopts following technical scheme:

On the one hand, the present invention provides a kind of non-aqueous electrolytic solution of lithium ion battery, comprises the compound additive that structure is shown in following formula I in the non-aqueous electrolytic solution of lithium ion battery:

Wherein R ₁ is selected from one of unsubstituted C1-C4 hydrocarbon groups, C1-C4 fluorohydrocarbon groups, C1-C4 silicon-containing hydrocarbon groups, and cyano-substituted C1-C4 hydrocarbon groups. _R2 is selected from one of hydrogen atom, fluorine atom, unsubstituted C1-C4 hydrocarbon group, C1-C4 fluorohydrocarbon group, C1-C4 oxygen-containing hydrocarbon group, C1-C4 silicon-containing hydrocarbon group, and cyano-substituted C1-C4 hydrocarbon group kind.

In the present invention, the restriction on carbon atoms in the group, such as C1-C4, means that the number of carbon atoms in the defined group can be 1, 2, 3 or 4.

In the present invention, the use of such special additives can improve the high-temperature stability of the electrolyte due to the existence of the phosphazene structure in the structure, thereby inhibiting the decomposition of the electrolyte under high-temperature conditions to a certain extent, so that the lithium ion can be effectively improved. Battery cycle performance and high temperature storage performance.

Preferably, the compound additive is selected from any one or a combination of at least two of the compounds shown in the following structures:

The synthetic route of the compound additive shown in formula I of the present invention is as follows:

Taking compound 1 as an example, the specific implementation method is as follows:

Compound 1 is obtained by combining hydroxymethanedioic acid and methyl dichlorophosphate at a molar ratio of 1:1 in a solvent of triethylamine at a temperature of 0-70°C and using a catalyst TBU or TBD.

Preferably, based on the total mass of the lithium-ion battery non-aqueous electrolyte as 100%, the mass percentage of the compound additive represented by formula I is 0.1-5%, such as 0.5%, 0.8%, 1%, 1.5% %, 1.8%, 2%, 2.5%, 2.8%, 3%, 3.5%, 3.8%, 4%, 4.5% or 5%, preferably 1-3%.

Preferably, the solvent in the non-aqueous electrolyte of the lithium ion battery is selected from ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), dimethyl carbonate (DMC), diethyl carbonate Any one or a combination of at least two of ester (DEC), ethyl methyl carbonate (EMC) or methyl propyl carbonate (MPC).

Preferably, the lithium-ion battery non-aqueous electrolyte also includes other additives other than the compound additive shown in formula I.

Preferably, the other additives include at least one of unsaturated cyclic carbonate compounds or sultone compounds.

Preferably, the unsaturated cyclic carbonate compound includes at least one of vinylene carbonate (abbreviated as VC) and vinylethylene carbonate (abbreviated as VEC).

Preferably, the sultone compound includes at least one of 1,3-propane sultone (PS) and 1,4-butane sultone.

Preferably, based on 100% of the total mass of the lithium-ion battery non-aqueous electrolyte, the mass percentage of the unsaturated cyclic carbonate compound is 0.1-5%, such as 0.5%, 0.8%, 1%. , 1.5%, 1.8%, 2%, 2.5%, 2.8%, 3%, 3.5%, 3.8%, 4%, 4.5%, or 5%.

Preferably, based on 100% of the total mass of the lithium-ion battery non-aqueous electrolyte, the mass percentage of the sultone compound is 0.1-5%, such as 0.5%, 0.8%, 1%, 1.5%, 1.8%, 2%, 2.5%, 2.8%, 3%, 3.5%, 3.8%, 4%, 4.5%, or 5%.

Preferably, the other additives also include lithium salt additives, and the lithium salt additives include LiBOB (bisoxalate borate), LiFSi (lithium difluorosulfonate imide), LiODFB (lithium difluorooxalate borate), Any one or a combination of at least two of LiBF ₄ (lithium tetrafluoroborate), LiPO ₂ F ₂ (lithium difluorophosphate) or LiDFOP (lithium difluorobisoxalate phosphate).

Preferably, based on 100% of the total mass of the lithium-ion battery non-aqueous electrolyte, the mass percentage of the lithium salt additive is 0.1-5%, such as 0.5%, 0.8%, 1%, 1.5% , 1.8%, 2%, 2.5%, 2.8%, 3%, 3.5%, 3.8%, 4%, 4.5%, or 5%.

Preferably, the electrolyte in the non-aqueous electrolyte of the lithium ion battery is a lithium salt, and the lithium salt is preferably LiPF ₆ .

Preferably, the mass percentage of the electrolyte lithium salt in the non-aqueous electrolyte of the lithium-ion battery is 0.1-20%, such as 0.5%, 0.8%, 1%, 1.5%, 2%, 3%, 4%, 5%. %, 6%, 7%, 8%, 9%, 10%, 12%, 14%, 16%, 18% or 20%.

In another aspect, the present invention provides a lithium-ion battery, the lithium-ion battery includes a positive electrode, a negative electrode, a separator disposed between the positive electrode and the negative electrode, and an electrolyte, the electrolyte is as described above Lithium-ion battery non-aqueous electrolyte.

Preferably, the positive electrode includes an active material, and the active material is _LiNix Co _y Mn _z L _(1-xyz) O ₂ , _LiCox L _(1-x') O ₂ , LiNi _x L _y Mn _{(2- x”-y’)} At least one of O ₄ Li _z’ MPO ₄ ; where L is at least one of Co, Al, Sr, Mg, Ti, Ca, Zr, Zn, Si, Fe; 0≤x ≤1, 0≤y≤1, 0≤z≤1, 0<x+y+z≤1, 0<x'≤1, 0.3<x"≤0.6, 0.01<y'≤0.2, 0.5≤z' ≤1, M is at least one of Fe, Mn and Co.

In the present invention, the positive electrode, negative electrode, and separator are not particularly limited, and conventional positive electrodes, negative electrodes, and separators in the art can be used.

The non-aqueous electrolyte of the lithium ion battery provided by the invention effectively improves the cycle and high-temperature storage performance of the battery, and the lithium-ion battery containing the non-aqueous electrolyte has both excellent cycle performance and high-temperature storage performance.

Compared with the prior art, the present invention has the following beneficial effects:

Due to the use of compound additives shown in formula I in the lithium ion battery non-aqueous electrolyte of the present invention, this type of special additive can be used. Due to the existence of the phosphazene structure in the structure, the high temperature stability of the electrolyte can be improved, thereby to a certain extent Inhibiting the decomposition of the electrolyte under high temperature conditions can effectively improve the cycle performance and high temperature storage performance of lithium-ion batteries. It can make the lithium-ion battery have a capacity retention rate of more than 73% after 200 cycles at 45°C, a capacity retention rate of more than 71%, a capacity recovery rate of more than 72%, and a thickness expansion rate of less than 31% when stored at a high temperature of 60°C for 30 days. Broad market application prospects.

Detailed ways

The technical solutions of the present invention will be further described below through specific embodiments. It should be clear to those skilled in the art that the examples are only for helping to understand the present invention, and should not be regarded as specific limitations on the present invention.

Example 1

A LiNi _0.5 Co _0.2 Mn _0.3 O ₂ /artificial graphite battery, including positive pole (NCM523 from Mengguli), negative pole (artificial graphite P15 from Shanshan), separator (PP/PE from Dinghao), and electrolyte, wherein The electrolyte is a non-aqueous electrolyte, and the total weight of the non-aqueous electrolyte is 100%, containing the components shown in Table 1, Example 1, and 12% LiPF ₆ salt by mass.

Example 2

A LiNi _0.5 Co _0.2 Mn _0.3 O ₂ /artificial graphite battery, including positive pole (NCM523 from Mengguli), negative pole (artificial graphite P15 from Shanshan), separator (PP/PE from Dinghao), and electrolyte, wherein The electrolyte is a non-aqueous electrolyte, and the total weight of the non-aqueous electrolyte is 100%, containing the components shown in Table 1, Example 2, and 12% LiPF ₆ salt by mass.

Example 3

A LiNi _0.5 Co _0.2 Mn _0.3 O ₂ /artificial graphite battery, including positive pole (NCM523 from Mengguli), negative pole (artificial graphite P15 from Shanshan), separator (PP/PE from Dinghao), and electrolyte, wherein The electrolyte is a non-aqueous electrolyte, and the total weight of the non-aqueous electrolyte is 100%, containing the components shown in Table 1, Example 3, and 12% LiPF ₆ salt by mass.

Example 4

A LiNi _0.5 Co _0.2 Mn _0.3 O ₂ /artificial graphite battery, including positive pole (NCM523 from Mengguli), negative pole (artificial graphite P15 from Shanshan), separator (PP/PE from Dinghao), and electrolyte, wherein The electrolyte is a non-aqueous electrolyte, and the total weight of the non-aqueous electrolyte is 100%, containing the components shown in Table 1, Example 4, and 12% LiPF ₆ salt by mass.

Example 5

A LiNi _0.5 Co _0.2 Mn _0.3 O ₂ /artificial graphite battery, including positive pole (NCM523 from Mengguli), negative pole (artificial graphite P15 from Shanshan), separator (PP/PE from Dinghao), and electrolyte, wherein The electrolyte is a non-aqueous electrolyte, and the total weight of the non-aqueous electrolyte is 100%, containing the components shown in Table 1, Example 5, and 12% LiPF ₆ salt by mass.

Example 6

A LiNi _0.5 Co _0.2 Mn _0.3 O ₂ /artificial graphite battery, including positive pole (NCM523 from Mengguli), negative pole (artificial graphite P15 from Shanshan), separator (PP/PE from Dinghao), and electrolyte, wherein The electrolyte is a non-aqueous electrolyte, and the total weight of the non-aqueous electrolyte is 100%, containing the components shown in Table 1, Example 6, and 12% LiPF ₆ salt by mass.

Example 7

A LiNi _0.5 Co _0.2 Mn _0.3 O ₂ /artificial graphite battery, including positive pole (NCM523 from Mengguli), negative pole (artificial graphite P15 from Shanshan), separator (PP/PE from Dinghao), and electrolyte, wherein The electrolyte is a non-aqueous electrolyte, and the total weight of the non-aqueous electrolyte is 100%, containing the components shown in Table 1, Example 7, and 12% LiPF ₆ salt by mass.

Example 8

A LiNi _0.5 Co _0.2 Mn _0.3 O ₂ /artificial graphite battery, including positive pole (NCM523 from Mengguli), negative pole (artificial graphite P15 from Shanshan), separator (PP/PE from Dinghao), and electrolyte, wherein The electrolyte is a non-aqueous electrolyte, and the total weight of the non-aqueous electrolyte is 100%, containing the components shown in Table 1, Example 8, and 12% LiPF ₆ salt by mass.

Example 9

A LiNi _0.5 Co _0.2 Mn _0.3 O ₂ /artificial graphite battery, including positive pole (NCM523 from Mengguli), negative pole (artificial graphite P15 from Shanshan), separator (PP/PE from Dinghao), and electrolyte, wherein The electrolyte is a non-aqueous electrolyte, and the total weight of the non-aqueous electrolyte is 100%, containing the components shown in Table 1, Example 9, and 12% LiPF ₆ salt by mass.

Example 10

A LiNi _0.5 Co _0.2 Mn _0.3 O ₂ /artificial graphite battery, including positive pole (NCM523 from Mengguli), negative pole (artificial graphite P15 from Shanshan), separator (PP/PE from Dinghao), and electrolyte, wherein The electrolyte is a non-aqueous electrolyte, and the total weight of the non-aqueous electrolyte is 100%, containing the components shown in Table 1, Example 10, and 12% LiPF ₆ salt by mass.

Example 11

A LiNi _0.5 Co _0.2 Mn _0.3 O ₂ /artificial graphite battery, including positive pole (NCM523 from Mengguli), negative pole (artificial graphite P15 from Shanshan), separator (PP/PE from Dinghao), and electrolyte, wherein The electrolyte is a non-aqueous electrolyte, and the total weight of the non-aqueous electrolyte is 100%, containing the components shown in Table 1, Example 11, and 12% LiPF ₆ salt by mass.

Example 12

A LiNi _0.5 Co _0.2 Mn _0.3 O ₂ /artificial graphite battery, including positive pole (NCM523 from Mengguli), negative pole (artificial graphite P15 from Shanshan), separator (PP/PE from Dinghao), and electrolyte, wherein The electrolyte is a non-aqueous electrolyte, and the total weight of the non-aqueous electrolyte is 100%, containing the components shown in Table 1, Example 12, and 12% LiPF ₆ salt by mass.

Example 13

A LiNi _0.5 Co _0.2 Mn _0.3 O ₂ /artificial graphite battery, including positive pole (NCM523 from Mengguli), negative pole (artificial graphite P15 from Shanshan), separator (PP/PE from Dinghao), and electrolyte, wherein The electrolyte is a non-aqueous electrolyte, and the total weight of the non-aqueous electrolyte is 100%, containing the components shown in Table 1, Example 13, and 12% LiPF ₆ salt by mass.

Example 14

A LiNi _0.5 Co _0.2 Mn _0.3 O ₂ /artificial graphite battery, including positive pole (NCM523 from Mengguli), negative pole (artificial graphite P15 from Shanshan), separator (PP/PE from Dinghao), and electrolyte, wherein The electrolyte is a non-aqueous electrolyte, and the total weight of the non-aqueous electrolyte is 100%, containing the components shown in Table 1, Example 14, and 12% LiPF ₆ salt by mass.

Comparative example 1

A LiNi _0.5 Co _0.2 Mn _0.3 O ₂ /artificial graphite battery, including positive pole (NCM523 from Mengguli), negative pole (artificial graphite P15 from Shanshan), separator (PP/PE from Dinghao), and electrolyte, wherein The electrolyte is a non-aqueous electrolyte, and the total weight of the non-aqueous electrolyte is 100%, containing the components shown in Table 1, Comparative Example 1, and 12% LiPF ₆ salt.

Comparative example 2

A LiNi _0.5 Co _0.2 Mn _0.3 O ₂ /artificial graphite battery, including positive pole (NCM523 from Mengguli), negative pole (artificial graphite P15 from Shanshan), separator (PP/PE from Dinghao), and electrolyte, wherein The electrolyte is a non-aqueous electrolyte, and the total weight of the non-aqueous electrolyte is 100%, containing the components shown in Table 1, Comparative Example 2, and 12% LiPF ₆ salt.

Comparative example 3

A LiNi _0.5 Co _0.2 Mn _0.3 O ₂ /artificial graphite battery, including positive pole (NCM523 from Mengguli), negative pole (artificial graphite P15 from Shanshan), separator (PP/PE from Dinghao), and electrolyte, wherein The electrolyte is a non-aqueous electrolyte, and the total weight of the non-aqueous electrolyte is 100%, containing the components shown in Table 1, Comparative Example 3, and 12% LiPF ₆ salt.

Comparative example 4

A LiNi _0.5 Co _0.2 Mn _0.3 O ₂ /artificial graphite battery, including positive pole (NCM523 from Mengguli), negative pole (artificial graphite P15 from Shanshan), separator (PP/PE from Dinghao), and electrolyte, wherein The electrolyte is a non-aqueous electrolyte, and the total weight of the non-aqueous electrolyte is 100%, containing the components shown in Table 1, Comparative Example 4, and 12% LiPF ₆ salt.

Carry out performance test with embodiment 1-14 of the present invention, comparative example 1-4, test index and test method are as follows:

(1) High-temperature cycle performance, which is reflected by testing the capacity retention rate of 1C cycles at 45°C for N times. The specific method is: at 45°C, charge the formed battery with 1C constant current and constant voltage to 4.35V (LiNi _0.5 Co _0.2 Mn _0.3 O ₂ /artificial graphite), the cut-off current is 0.02C, and then discharge to 3.0V with 1C constant current. After such a charge/discharge cycle, calculate the capacity retention rate after the 200th cycle to evaluate its high-temperature cycle performance.

The formula for calculating the capacity retention after 200 cycles at 45°C is as follows:

200th cycle capacity retention rate (%) = (200th cycle discharge capacity / 1st cycle discharge capacity) × 100%

(2) Test method of capacity retention rate, capacity recovery rate and thickness expansion rate after storage at 60°C for 30 days: charge the formed battery to 4.4V (LiNi _0.5 Co _0.2 Mn _0.3 O ₂ /artificial graphite), the cut-off current is 0.02C, then discharge to 3.0V with 1C constant current, measure the initial discharge capacity of the battery, and then charge to 4.4V with 1C constant current and constant voltage, the cut-off current is 0.01C, measure the battery The initial thickness of the battery, and then store the battery at 60 ° C for 30 days, measure the thickness of the battery, and then discharge to 3.0V with a constant current of 1C, measure the holding capacity of the battery, and then charge to 3.0V with a constant current and constant voltage of 1C, the cut-off battery is 0.02C, then discharge to 3.0V with 1C constant current, and measure the recovery capacity. The calculation formulas of capacity retention rate, capacity recovery rate and thickness expansion are as follows:

Battery capacity retention rate (%) = retention capacity/initial capacity × 100%

Battery capacity recovery rate (%) = recovery capacity / initial capacity × 100%

Battery thickness expansion rate (%) = (thickness after 30 days - initial thickness) / initial thickness × 100%

Table 1

The test results of Experimental Examples 1-14 and Comparative Examples 1-4 are shown in Table 2 below.

Table 2

According to the results in Table 2, it can be seen that the addition of the non-aqueous lithium-ion battery electrolyte additive according to the present invention can make the lithium-ion battery have a capacity retention rate of more than 73% after 200 cycles at 45°C, and store at a high temperature of 60°C for 30 days. The capacity retention rate is above 71%, the capacity recovery rate is above 72%, and the thickness expansion rate is below 31%. However, no such additive was added in the comparative example, so that the high temperature capacity retention rate, capacity recovery rate and cycle performance were significantly reduced, and the thickness expansion rate was significantly increased.

The applicant declares that the present invention illustrates the non-aqueous electrolyte solution for lithium-ion batteries of the present invention and the lithium-ion batteries containing it through the above-mentioned examples, but the present invention is not limited to the above-mentioned examples, that is, it does not mean that the present invention must rely on The above-mentioned embodiment just can implement. Those skilled in the art should understand that any improvement of the present invention, the equivalent replacement of each raw material of the product of the present invention, the addition of auxiliary components, the selection of specific methods, etc., all fall within the scope of protection and disclosure of the present invention.

Claims (18)

1. a non-aqueous electrolytic solution for lithium-ion batteries, characterized in that, the non-aqueous electrolytic solution for lithium-ion batteries comprises a compound additive shown in the following formula I of structure: Wherein R ₁ is selected from one of unsubstituted C1-C4 hydrocarbon groups, C1-C4 fluorohydrocarbon groups, C1-C4 silicon-containing hydrocarbon groups, and cyano-substituted C1-C4 hydrocarbon groups; R ₂ is selected from hydrogen atoms, fluorine atoms, One of unsubstituted C1-C4 hydrocarbon groups, C1-C4 fluorinated hydrocarbon groups, C1-C4 oxygen-containing hydrocarbon groups, C1-C4 silicon-containing hydrocarbon groups, and cyano-substituted C1-C4 hydrocarbon groups; or any of the following compound additives One or a combination of both: 2. lithium ion battery non-aqueous electrolyte according to claim 1, is characterized in that, described compound additive is selected from any one or the combination of at least two in the compound shown in following structure: 3. lithium-ion battery non-aqueous electrolyte according to claim 1, is characterized in that, with the gross mass of described lithium-ion battery non-aqueous electrolyte being 100%, the mass percentage of the compound additive shown in formula I The content is 0.1-5%. 4. lithium-ion battery non-aqueous electrolyte according to claim 3, is characterized in that, with the gross mass of described lithium-ion battery non-aqueous electrolyte being 100%, the mass percentage of the compound additive shown in formula I The content is 1-3%. 5. lithium ion battery non-aqueous electrolytic solution according to claim 1, is characterized in that, the solvent in described lithium ion battery non-aqueous electrolytic solution is selected from ethylene carbonate, propylene carbonate, butylene carbonate, dicarbonate Any one or a combination of at least two of methyl ester, diethyl carbonate, ethyl methyl carbonate or methyl propyl carbonate. 6. The nonaqueous electrolytic solution for lithium ion batteries according to claim 1, characterized in that, the nonaqueous electrolytic solution for lithium ion batteries also includes other additives except the compound additive shown in formula I. 7. The non-aqueous electrolyte solution for lithium ion batteries according to claim 6, wherein the other additives include at least one of unsaturated cyclic carbonate compounds or sultone compounds. 8. The nonaqueous electrolyte solution for lithium ion batteries according to claim 7, wherein the unsaturated cyclic carbonate compound comprises at least one of vinylene carbonate and vinylethylene carbonate. 9. The non-aqueous electrolyte solution for lithium-ion batteries according to claim 7, wherein the sultone compounds include 1,3-propane sultone, 1,4-butane sultone at least one of the 10. The nonaqueous electrolytic solution for lithium ion batteries according to claim 7, characterized in that, based on the total mass of the nonaqueous electrolytic solution for lithium ion batteries as 100%, the amount of the unsaturated cyclic carbonate compound The content is 0.1-5%. 11. The non-aqueous electrolyte solution for lithium ion batteries according to claim 7, wherein the total mass of the nonaqueous electrolyte solution for lithium ion batteries is 100%, and the mass of the sultone compound is 100%. Mineral content is 0.1 to 5%. 12. The non-aqueous electrolyte solution for lithium ion batteries according to claim 6, wherein the other additives also include lithium salt additives, and the lithium salt additives include LiBOB, LiFSi, LiODFB, LiBF ₄ , LiPO ₂ Any one or a combination of at least two of _F2 or LiDFOP. 13. The nonaqueous electrolytic solution for lithium ion batteries according to claim 12, characterized in that, based on the total mass of the nonaqueous electrolytic solution for lithium ion batteries as 100%, the mass percentage of the lithium salt additive 0.1 to 5%. 14. The nonaqueous electrolyte solution for lithium ion batteries according to claim 1, wherein the electrolyte in the nonaqueous electrolyte solution for lithium ion batteries is a lithium salt. 15 . The nonaqueous electrolyte solution for lithium ion batteries according to claim 14 , wherein the lithium salt is LiPF ₆ . 16 . The non-aqueous electrolyte solution for lithium ion batteries according to claim 14 , characterized in that the lithium salt of the electrolyte in the nonaqueous electrolyte solution for lithium ion batteries is 0.1-20% by mass. 17. A lithium-ion battery, characterized in that, the lithium-ion battery comprises a positive pole, a negative pole, a diaphragm arranged between the positive pole and the negative pole, and an electrolytic solution, and the electrolytic solution is as claimed in claim 1- The lithium ion battery non-aqueous electrolytic solution described in any one in 16. 18. The lithium ion battery according to claim 17, wherein the positive electrode comprises an active material, and the active material is LiNi _x Co _{y Mnz} L _(1-xyz) O ₂ , _LiCox L _(1- At least one of _x') O ₂ , LiNi _x L _y Mn _(2-x"-y') O ₄ Li _z' MPO ₄ ; wherein L is Co, Al, Sr, Mg, Ti, Ca, Zr, At least one of Zn, Si, Fe; 0≤x≤1, 0≤y≤1, 0≤z≤1, 0<x+y+z≤1, 0<x'≤1, 0.3<x" ≤0.6, 0.01<y'≤0.2, 0.5≤z'≤1, M is at least one of Fe, Mn and Co.