KR20120113008A - Cathode active material for series-type phev (plug-in hybrid electric vehicle) and lithium secondary battery comprising thereof - Google Patents

Abstract

PURPOSE: A positive electrode material for a lithium secondary battery is provided to improve a safety of a cell, to widen an variable SOC region through a power maintenance in a low SOC region and to obtain constant power over a PHEV required power by mixing metal oxide of an olivine structure into ternary lithium-containing metal oxide. CONSTITUTION: A positive electrode material of a lithium secondary battery comprises ternary lithium-containing metal oxide of a layered structure represented by chemical formula 1: Li_(1+a)Ni_xCo_yMn_(1-x-y)O_2, and a mixed positive electrode active material comprising metal oxide of an olivine structure represented by chemical formula 2: A_xM_yM'_zXO_4, and is used in a direct type PHEV. In the chemical formulas, 0<=a<0.5, 0<x<1, 0<y<0.5, A is one or more kinds selected from alkali metals, M and M' is one or more kinds selected from transition metals, X is one or selected from P, Si, S, As, Sb and combinations thereof, and x+y+z=2. [Reference numerals] (AA) Embodiment; (BB) Comparative embodiment

Description

Lithium secondary battery positive electrode material for series PH, and lithium secondary battery comprising same

The present invention relates to a lithium secondary battery positive electrode material for a series PHEV and a lithium secondary battery comprising the same. More specifically, the three-component lithium-containing metal oxide having a layered structure represented by the following [Formula 1] (hereinafter referred to as 'three component system') Lithium secondary battery cathode material comprising a mixed oxide material of the olivine structure (hereinafter abbreviated as 'olivin') represented by [abbreviated name) and [Formula 2], and applied to a series PHEV, and It relates to a lithium secondary battery containing.

[Formula 1] Li _{1 + a} Ni _x Co _y Mn _{1 -x- y} O ₂ , 0≤a <0.5, 0 <x <1, 0 <y <0.5

[Formula 2] A _x M _y M ' _z XO ₄

(A is at least one selected from alkali metals, M, M 'is at least one selected from transition metal elements, X is any one selected from the group consisting of P, Si, S, As, Sb, and combinations thereof, x + y + z = 2.)

Recently, lithium secondary batteries have been used in various fields including portable electronic devices such as mobile phones, PDAs, and laptop computers. In particular, as interest in environmental issues grows, lithium secondary batteries having high energy density and discharge voltage as driving sources of electric vehicles that can replace fossil fuels such as gasoline and diesel vehicles, which are one of the main causes of air pollution, are developed. Research on batteries is actively underway and some commercialization stages are in progress. Meanwhile, in order to use a lithium secondary battery as a driving source of such an electric vehicle, it must be able to maintain a stable output in a SOC section with high output.

Electric vehicles are typical electric vehicles (EVs), battery electric vehicles (BEVs), hybrid electric vehicles (HEVs), and plug-in hybrids depending on the type of driving source. Electric Vehicle, PHEV).

Among them, a HEV (Hybrid Electric Vehicle) is a vehicle that obtains driving power from a combination of a conventional internal combustion engine (engine) and an electric battery. The driving is mainly performed through an engine, and requires more power than usual, such as driving uphill. Only when the battery supports the engine's lack of power, it regains the SOC by charging the battery when the car is stopped. In other words, the main driving source in the HEV is the engine, and the battery is used only intermittently as the auxiliary driving source.

The Plug-in Hybrid Electric Vehicle (PHEV) is a vehicle that is connected to an engine and an external power source and obtains driving power from a combination of a rechargeable battery. The PHEV is divided into a parallel type PHEV and a series type PHEV.

Among these, the parallel type PHEV has an equal relationship between the engine and the battery as the driving source, and the engine or the battery alternately serves as the main driving source depending on the situation. In other words, when the engine is the main driving source, the battery compensates for the insufficient power of the engine, and when the battery is the main driving source, the engine operates in parallel to each other in a manner that compensates for the insufficient output of the battery.

However, the tandem PHEV is basically a battery-powered car, and the engine only charges the battery. Therefore, unlike the above-described HEV or parallel PHEV, the driving of the vehicle is entirely dependent on the battery rather than the engine. Therefore, the stable output maintenance according to the characteristics of the battery in the SOC section used for driving stability is relatively higher than that of other types of electric vehicles. This is a very important factor.

Meanwhile, as a cathode material of a high capacity lithium secondary battery, LiCoO ₂ , which is a typical cathode material, has reached an increase in energy density and a practical limit of output characteristics, and especially when used in high energy density applications, due to its structural instability. In high temperature state of charge, oxygen is released in the structure along with structural modification, causing exothermic reaction with electrolyte in the battery, which is the main cause of battery explosion. In order to improve the safety problem of LiCoO ₂ , lithium-containing manganese oxides such as LiMnO _{2 having} a layered crystal structure and LiMn ₂ O _{4 having a} spinel crystal structure, and lithium-containing nickel oxide (LiNiO ₂ ) have been considered. A lot of research is being conducted on using a three-component metal oxide having a layered structure of, Co, and Mn.

The layered three-component metal oxide (for example, Li _{1 + a} Ni _x Co _y Mn _{1 -x- y} O ₂ ) has a high output in the high SOC section, but has a low SOC section (for example, SOC 30% or less) has a disadvantage in that the output is suddenly lowered (resistance rises sharply in the lower region of the three component system) and the SOC section that can be used is greatly limited. This is also the case when blending the three-component system with lithium manganese spinel for the safety of the cell, because the lithium manganese spinel has a higher operating voltage than the three-component system because only the three-component system operates alone in the low SOC period. This problem is inevitably a big obstacle in applying the three-component system to the field where the output characteristics are particularly important.

In particular, unlike the HEV, which is the main driving source of the engine, or the parallel type PHEV, in which the engine and the battery act as the equal driving source, the series type PHEV, which is completely dependent on the battery, is used only in the SOC section where the required output is maintained. When the three-component material is used alone as the cathode active material, the output of the low SOC section is reduced, so that the available SOC section is greatly narrowed.

Therefore, in applying a three-component metal oxide with a layered structure of Ni, Co, and Mn to a series PHEV in an electric vehicle, the available SOC section is widened by maintaining the output in a low SOC section, and a certain level of output above the required PHEV output is provided. The development of cathode materials characterized by collateral-type PHEV is urgently needed.

The present invention has been made to solve the above-mentioned demands and conventional problems, the inventors of the present application after a series of in-depth studies and various experiments, a lithium secondary battery mixed cathode material for a series PHEV as described later Developed.

In contrast to HEVs, where the engine is the main driving source, and parallel PHEVs, where the engine and the battery act as the equivalent driving source, the series PHEV has a characteristic of being completely dependent on the battery in driving the vehicle, and as a result, the required output is maintained. Only available in SOC section. When the three-component system is used alone as the cathode active material in the series PHEV, the resistance increases significantly in the low SOC section, and the available SOC section in which the output above the required output can be greatly narrowed due to the characteristic of the three-component system in which the output drops sharply. This phenomenon is the same in the case of a mixed anode of a three-component system and a lithium manganese spinel having a higher operating voltage range.

Accordingly, the present invention blends an olivine with an operating voltage slightly lower than this to the three component system, thereby improving safety and at the same time, the olivine compensates for the low output of the three component system in the low SOC section, thereby outputting more than the required output of the PHEV. By maintaining the present invention, it is intended to provide a lithium secondary battery mixed cathode material for a series type PHEV that can widen the available SOC section. In particular, by controlling the content of olivine, it is possible to maximize the effect of high energy density and output maintenance, and to control the particle size and morphology of the three component system and olivine, or to consider the difference in particle shape. By applying this, the output characteristics of the battery can be further improved by increasing the overall conductivity of the mixed cathode material.

In addition, unlike the HEV or parallel PHEV, the mixed cathode material is particularly limited to the series PHEV, which depends solely on the battery for driving the vehicle, and shows a large output at high SOC and a low SOC section. It was confirmed that the level of output can be maintained higher than the required value, so that the available SOC section can be widened.

The present invention is to solve the above problems,

It includes a mixed cathode material in which the three-component lithium-containing metal oxide of the layered structure represented by the following [Formula 1] and the metal oxide of the olivine structure represented by the following [Formula 2], it is used in a series PHEV It relates to a lithium secondary battery cathode material.

[Formula 1] Li _{1 + a} Ni _x Co _y Mn _{1 -x- y} O ₂ , 0≤a <0.5, 0 <x <1, 0 <y <0.5

[Formula 2] A _x M _y M ' _z XO ₄

(A is at least one selected from alkali metals, M, M 'is at least one selected from transition metal elements, X is any one selected from the group consisting of P, Si, S, As, Sb, and combinations thereof, x + y + z = 2.)

Preferably, the three-component lithium-containing metal oxide of the layered structure represented by [Formula 1] is Li _{1 + a} Ni _x Co _y Mn _{1 -x- y} O ₂ , 0≤a <0.2, 0 <x <0.8 , may be 0 <y <0.5, x = y = 1/3 of _{Li 1 + a Ni 1/3} Co 1/3 Mn 1/3 O 2 (0≤a <0.2) are more preferred.

In addition, the metal oxide of the olivine structure represented by the above [Formula 2] is preferably LiMPO 4 (M is at least one selected from the group consisting of Fe, Co, Ni, Mn), more preferably LiFePO 4 day Can be.

In the mixed cathode material, the olivine of [Formula 2] may be included in an amount of 5 to 50 parts by weight, preferably 10 to 40 parts by weight, based on 100 parts by weight of the mixed cathode material. When the olivine is contained in less than 5 parts by weight, it is difficult to compensate for the output degradation of the three-component system in the low-voltage section, and when included in the mixed cathode material in excess of 50 parts by weight, the amount of the three-component system is relatively reduced, so that the secondary battery of high capacity It is difficult to express.

On the other hand, the three-component system of the layered structure represented by the above [Formula 1] and the metal oxide of the olivine structure of [Formula 2], may be appropriate pretreatment so that the particle size or particle shape of both materials can be similar, Preferably, the particles may be sintered to have a size similar to that of the particle size of the olivine and the three-component system.

This prevents the output from dropping in the operating voltage range of the three-component system due to the difference in particle size or specific surface area between the two materials to be mixed, so that the conductive material is mainly dispersed around the relatively small particle size of the olivine. For sake.

In addition, the mixed cathode material may include two or more conductive materials having different particle sizes in addition to the three-component system and olivine.

In addition, the conductive material may be made of graphite and conductive carbon.

Here, the conductive material is preferably 0.5 to 15 parts by weight based on 100 parts by weight of the mixed cathode material. Specifically, the graphite is not limited to natural graphite or artificial graphite, the conductive carbon is carbon black or crystalline structure consisting of carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, summer black One or more selected from the group consisting of materials containing graphene or graphite may be mixed materials.

The mixed cathode material may further include one or more lithium-containing metal oxides selected from the group consisting of lithium manganese spinels and oxides in which ellipsoid (s) are substituted or doped thereto.

Here, the ellipsoid (s) consists of Al, Mg, Ni, Co, Fe, Cr, V, Ti, Cu, B, Ca, Zn, Zr, Nb, Mo, Sr, Sb, W, Ti, and Bi It may be one or more selected from the group.

Specifically, the lithium-containing metal oxide may be included within 50 parts by weight based on 100 parts by weight of the mixed cathode material.

On the other hand, the present invention relates to a lithium secondary battery positive electrode characterized in that the mixed positive electrode material is applied on the current collector and a lithium secondary battery comprising such a positive electrode.

In addition, the lithium secondary battery may have an output in the SOC 10 to SOC 40 section 40% or more, preferably 50% or more compared to the output in the SOC 50.

According to the present invention, in a lithium secondary battery cathode material for a series PHEV, by mixing a three-component lithium-containing metal oxide having a layered structure with an olivine-structured metal oxide having a lower operating voltage, the safety of the cell is improved and a low Olivin compensates for the decrease in output caused by the rapid increase in resistance of the three-component system in the SOC section, and maintains the output beyond the required output, it can be used in a wider SOC section than the conventional three-component alone and three-component / lithium manganese spinel mixed anodes.

1 is a graph showing an output change according to SOC of a lithium secondary battery according to an embodiment and a comparative example of the present invention. (Vmax = 4.2V, Vmin = 2.5V)

Hereinafter, the present invention will be described in detail.

The present invention is to solve the above problems,

It includes a mixed cathode material in which the three-component lithium-containing metal oxide of the layered structure represented by the following [Formula 1] and the metal oxide of the olivine structure represented by the following [Formula 2] is used, characterized in that it is used in series PHEV It relates to a lithium secondary battery cathode material.

[Formula 1] Li _{1 + a} Ni _x Co _y Mn _{1 -x- y} O ₂ , 0≤a <0.5, 0 <x <1, 0 <y <0.5

[Formula 2] A _x M _y M ' _z XO ₄

(A is at least one selected from alkali metals, M, M 'is at least one selected from transition metal elements, X is any one selected from the group consisting of P, Si, S, As, Sb, and combinations thereof, x + y + z = 2.)

The three-component lithium-containing metal oxide of the layered structure represented by the above [Formula 1] has a high output in the high SOC section, but in the low SOC section, the output is drastically lowered as resistance increases, so that the available SOC section is greatly limited. Has

This is also the case when blending the three-component system with lithium manganese spinel for the safety of the cell, because the spinel has a higher operating voltage than the three-component system because only the three-component system operates alone in the low SOC period.

Accordingly, the present invention is to form a mixed cathode material by mixing olivine, which is a material having a lower operating voltage than the three component system, rather than a material having a higher operating voltage than the three component system, such as spinel.

As a result, in addition to the three-component system in the low SOC section, olivine is involved in the insertion and desorption process of Li, thereby compensating for the low output of the three-component system, thereby greatly widening the available SOC section. That is, in the case of mixing olivine in the three component system, the output in the high SOC section may be slightly lower than in the case of using the three component system alone due to the proportion of the three component system reduced by the fraction of the olivine included. Olivin compensates for the low output caused by the rapid increase in the resistance of the component system is maintained above the required output, so that the available SOC interval is widened and at the same time the safety of the cell is improved due to the presence of the excellent safety olivine.

The compound of the olivine structure for improving the instability of the three-component system may be represented by the following formula (2).

[Formula 2] A _x M _y M ' _z XO ₄

(A is at least one selected from alkali metals, M, M 'is at least one selected from transition metal elements, X is any one selected from the group consisting of P, Si, S, As, Sb, and combinations thereof, x + y + z = 2.)

The olivine may be preferably represented by LiMPO ₄ (1 or more selected from the group consisting of M = Fe, Mn, Co, Ni), more preferably in order to secure a discharge output in the 3V region. It may be LiFePO ₄ having a low charging potential, a stable crystal structure, and low cost.

The metal oxide of the olivine structure has an average theoretical capacity of 170 mAh / g and a standard reduction potential of 3.4 V. At this voltage, no side reactions such as electrolyte decomposition are induced, and energy density can be maintained stably.

Preferably, the three-component system of the present invention may be represented by the formula (1) as described above,

[Formula 1] Li _{1 + a} Ni _x Co _y Mn _{1 -x- y} O ₂ , 0≤a <0.5, 0 <x <1, 0 <y <0.5

Preferably, 0 ≦ a <0.2.

And more preferably it may use a _{Ni, Co, Li 1 + a} Ni 1/3 Co 1/3 Mn 1/3 O 2 by the content of Mn equal.

In the present invention, the method of forming the mixed cathode material by mixing the three component system and the olivine is not particularly limited, and various methods known in the art may be adopted.

On the other hand, the mixed cathode material of the present invention is applied in series PHEV.

As described above, the series PHEV is an electric vehicle driven only by a battery, unlike an HEV in which an engine is a main driving source or a parallel PHEV in which an engine and a battery operate in an equal relationship as a driving source. It can be used only in SOC section where abnormality is maintained.

In addition, the olivine represented by [Formula 2] may be included in 5 to 50 parts by weight, preferably 10 to 40 parts by weight based on 100 parts by weight of the mixed cathode material.

When the content of the olivine exceeds 50 parts by weight, it may be difficult to high energy of the cell due to the low energy density of the olivine, and when the content of the olivine is less than 5 parts by weight, the output in the low SOC section pursued by the present invention is too small. It may be difficult to achieve the goal of improving assistance and safety.

On the other hand, when the mixed cathode material of the three-component system and the olivine is formed, it is necessary to consider the problems that may occur depending on the particle size and the (non) surface area difference of the two materials.

Specifically, it is preferable to limit the difference between the particle size and the (non) surface area of the three-component system and the olivine used in the present invention to within a predetermined range or to apply an appropriate conductive system.

Thus, the present invention is a three-component lithium-containing metal oxide of the layered structure represented by the above [Formula 1] and the metal oxide of the olivine structure represented by the [Formula 2] is appropriately treated so that the particle size of both materials can be similar In one preferred embodiment, by sintering the olivine may be a secondary particle by agglomeration to a size similar to the particle size of the three-component lithium-containing metal oxide represented by the [Formula 1]. . As such, the method of sintering LiFePO ₄ having an olivine structure to form secondary particles is not particularly limited and may be prepared using methods known in the art.

The reason why the three-component system and the olivine particle size or shape are appropriately treated in a similar range is that when the difference in particle size and (specific) surface area between the materials to be mixed is large, the conductive material to be coated has a large (specific) surface area. This is because the other material, which is biased to one material and has relatively less distribution of the conductive material, may have a higher resistance than the single material, resulting in lower overall conductivity.

Specifically, when the three-component system and the olivine are mixed, the particle size of the olivine is much smaller than that of the three-component system, so that the olivine has a surface area of about 0.5 m 2 / g or less, whereas the olivine is about 10 to g / g. It has a surface area of 40 m 2 because the conductive material is biased toward the olivine and thus the conductivity of the entire cathode active material can be reduced by increasing the relative resistance of the three-component system.

Accordingly, in order to reduce the difference between the particle size and the specific surface area of the three-component system and the olivine, a method of forming the particle size of the olivine into secondary particles as described above, a method of forming a small particle size of the three-component system, or two Can be applied simultaneously.

Next, the mixed cathode material may include two or more conductive materials having different particle sizes in consideration of the properties of the three component system and the olivine having different particle sizes or specific surface areas. The method of including the conductive material is not particularly limited, and conventional methods known in the art, such as coating on the positive electrode active material, may be adopted.

As described above, in order to prevent the reduction of the conductivity of the entire cathode active material due to the bias of the conductive material to the olivine having a much larger surface area than the three-component system, graphite and conductive as a conductive material are preferred embodiments of the present invention. Carbon can also be used simultaneously. That is, by coating and applying graphite and conductive carbon having different particle sizes and shapes as conductive materials to the mixed cathode material of the three component system and the olivine simultaneously, the above-mentioned whole due to the difference in particle size or surface area of the three component system and the olivine is applied. It is possible to provide a cathode material for a high capacity series PHEV having a wide available SOC section while improving conductivity reduction and low output problem of the cathode active material.

The graphite and the conductive carbon are not particularly limited as long as they have excellent electrical conductivity and have conductivity without causing side reactions in the internal environment of the lithium secondary battery or causing chemical changes in the battery.

Specifically, the graphite is not limited to natural graphite or artificial graphite, and the conductive carbon is preferably a highly conductive carbon-based material, specifically, carbon black, acetylene black, Ketjen black, channel black, furnace black, Carbon black, such as lamp black, summer black, or a mixture of one or more selected from the group consisting of a material having a crystal structure including graphene or graphite may be used. In some cases, a conductive polymer having high conductivity is also possible.

Here, the conductive material made of graphite and conductive carbon is preferably contained in 0.5 to 15 parts by weight based on 100 parts by weight of the mixed cathode material. If the content of the conductive material is too small, less than 0.5 parts by weight, it is difficult to expect the effects as described above. If the content of the conductive material is more than 15 parts by weight, the amount of the positive electrode active material is relatively small, which makes it difficult to increase the capacity or the high energy density. Can be.

In this case, the content of the conductive carbon may be included in an amount of 1 to 13 parts by weight, preferably 3 to 10 parts by weight, based on 100 parts by weight of the cathode material.

The mixed cathode material related to the present invention may further include at least one lithium-containing metal oxide selected from the group consisting of lithium manganese spinels and oxides substituted or doped with ellipso (s).

Here, the ellipsoid (s) consists of Al, Mg, Ni, Co, Fe, Cr, V, Ti, Cu, B, Ca, Zn, Zr, Nb, Mo, Sr, Sb, W, Ti, and Bi It may be one or more selected from the group.

Specifically, the lithium-containing metal oxide may be included within 50 parts by weight based on 100 parts by weight of the mixed cathode material.

On the other hand, the present invention relates to a lithium secondary battery positive electrode characterized in that the mixed positive electrode material is applied on the current collector and a lithium secondary battery comprising such a positive electrode.

In general, a lithium secondary battery includes a positive electrode composed of a positive electrode material and a current collector, a negative electrode composed of a negative electrode material and a current collector, and a separator capable of blocking electron conduction and conducting lithium ions between the positive electrode and the negative electrode. The void of the membrane material contains an electrolyte for conducting lithium ions.

The positive electrode and the negative electrode are usually prepared by applying a mixture of an electrode active material, a conductive agent and a binder on a current collector and then drying, and a filler may be further added to the mixture as necessary.

The lithium secondary battery of the present invention can be manufactured according to a conventional method in the art. Specifically, it can be prepared by putting a porous separator between the positive electrode and the negative electrode, the non-aqueous electrolyte.

Preferably, in order to maintain stable output in the low SOC section and improve safety, a power variation in a specific SOC section may be limited to a certain range.

In a preferred embodiment of the present invention, the lithium secondary battery may have an output in the SOC 10 to SOC 40 section is more than 40% of the output in the SOC50. More preferably, the output in the SOC 10 to SOC 40 section may be more than 50% of the output in the SOC50.

The mixed cathode material, the positive electrode, and the lithium secondary battery according to the present invention are limited to the series PHEV, and are maintained at or above the required output by olivin supplementing the low output caused by the rapid decrease of the three component system in the low SOC section. The interval can be widened and the safety of the cell can be improved.

Hereinafter, the content of the present invention through the specific examples will be described in more detail.

Example

Manufacture of anode

As a cathode active material _{LiNi 1/3 Co 1/3} Mn 1/3 O 2 (70 wt%) and LiFePO mixture consisting of ₄ (30%) 90% by weight, the conductive recognition dengka Black 6% by weight, the binder is PVDF 4 wt. The slurry was added by adding to NMP with%. This was coated on aluminum (Al) foil, which is a positive electrode current collector, and rolled and dried to prepare a positive electrode for a lithium secondary battery.

Of lithium secondary battery  Produce

A polymer electrolyte was manufactured by injecting a lithium electrolyte solution through a separator of porous polyethylene between the positive electrode and the graphite negative electrode prepared as described above.

The polymer-type lithium secondary battery was formed at 4.2V, and then output was measured according to SOC while charging and discharging between 4.2V and 2.5V. (C-rate = 1C).

Comparative example  One

As a cathode active material _{LiNi 1/3 Co 1/3} Mn 1/3 O 2 It is the same as that of an Example except only using.

Experimental Example

The output change according to SOC in the voltage range of 4.2V to 2.5V for the full cell lithium secondary batteries manufactured by the above Examples and Comparative Examples was measured and shown in FIG. 1.

Referring to FIG. 1, in the embodiment, the output in the high SOC section is somewhat lower than the comparative example, but in the low SOC section (approximately SOC 50 to 10% region on the drawing), the output remains stable with little decrease and is available. It can be seen that the SOC interval is quite wide. On the other hand, in the comparative example, the output in the high SOC section is somewhat higher than in the example, but in the low SOC section (approximately SOC 50 to 10% region on the drawing) it can be seen that the available SOC section becomes narrow. (The data shown in FIG. 1 is just an example, and the detailed power values according to SOC will vary depending on the specification of the cell. Therefore, the trend of the graph is more important than the detailed values.)

As a result, the lithium secondary battery according to the present invention mixes LiFePO ₄ having an olivine structure having a lower operating voltage than the three-component lithium-containing metal oxide, thereby supplementing the low output caused by the rapid decrease of the three-component system in the low SOC section. By maintaining above the required output, it can be used in a wider SOC section than the conventional three-component alone and three-component / lithium manganese spinel composite anode, it was confirmed that the cell safety is also improved.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and changes without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but are intended to be described. The protection scope of the present invention should be interpreted by the following claims, and all technical spirits within the equivalent range are It should be interpreted as being included in the scope of the present invention.

Claims (20)

Lithium comprising a mixed positive electrode material mixed with a three-component lithium-containing metal oxide represented by the following [Formula 1] and the metal oxide of the olivine structure represented by the following [Formula 2], characterized in that used in series PHEV Secondary battery cathode material.
[Formula 1] Li _{1 + a} Ni _x Co _y Mn _{1 -x- y} O ₂ , 0≤a <0.5, 0 <x <1, 0 <y <0.5
[Formula 2] A _x M _y M ' _z XO ₄
(A is at least one selected from alkali metals, M, M 'is at least one selected from transition metal elements, X is any one selected from the group consisting of P, Si, S, As, Sb, and combinations thereof, x + y + z = 2.)
The method of claim 1, wherein the three-component lithium-containing metal oxide represented by Li _{1 + a} Ni _x Co _y Mn _{1- x- y} O ₂ is 0 ≦ a <0.2, 0 <x <0.8, 0 Lithium secondary battery positive electrode material, characterized in that <y <0.5.
2. The method of claim 1, wherein in Formula 1 wherein the 3-component system lithium-containing metal oxide is _{Li 1 + a Ni 1/3} Co 1/3 Mn 1/3 O 2 (0≤a <0.2) represented by the Lithium secondary battery cathode material. According to claim 1, wherein the metal oxide of the olivine structure represented by [Formula 2] is LiMPO 4 (M is at least one selected from the group consisting of Fe, Co, Ni, Mn) Lithium secondary battery positive electrode ashes.
The cathode material of claim 1, wherein the metal oxide having an olivine structure represented by [Formula 2] is LiFePO ₄ .
The cathode material of claim 1, wherein the metal oxide of the olivine structure represented by [Formula 2] is contained in an amount of 5 to 50 parts by weight based on 100 parts by weight of the mixed cathode material.
The cathode material of claim 1, wherein the metal oxide of the olivine structure represented by [Formula 2] is contained in an amount of 10 to 40 parts by weight based on 100 parts by weight of the mixed cathode material.
According to claim 1, wherein the three-component lithium-containing metal oxide represented by the [Formula 1] and the metal oxide of the olivine structure represented by the [Formula 2] is pre-treated to reduce the difference in particle size or particle form Lithium secondary battery cathode material characterized in that.
The method of claim 8, wherein the pretreatment is sintered metal oxide of the olivine structure represented by the formula [2] to secondary particle to be similar to the particle size of the three-component lithium-containing metal oxide represented by the [Formula 1] Lithium secondary battery cathode material characterized in that.
The method of claim 1, wherein the mixed cathode material further comprises two or more conductive materials having different particle sizes in addition to the tricomponent lithium-containing metal oxide represented by the above [Formula 1] and the metal oxide of the olivine structure represented by the [Formula 2]. Lithium secondary battery cathode material characterized in that.
The method of claim 10, wherein the conductive material is a lithium secondary battery cathode material, characterized in that consisting of graphite and conductive carbon.
The method of claim 10, wherein the conductive material is a lithium secondary battery cathode material, characterized in that contained in 0.5 to 15 parts by weight based on 100 parts by weight of the mixed cathode material.
The method of claim 10, wherein the conductive carbon is carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, summer black carbon black or a group consisting of a material containing graphene or graphite crystal structure One or more selected from the lithium secondary battery cathode material characterized in that the mixed material.
2. The lithium secondary of claim 1, wherein the mixed cathode material further includes at least one lithium-containing metal oxide selected from the group consisting of lithium manganese spinels and oxides substituted or doped with ellipsoid (s). Battery cathode material.
15. The method of claim 14, wherein the ellipsoid (s) is Al, Mg, Ni, Co, Fe, Cr, V, Ti, Cu, B, Ca, Zn, Zr, Nb, Mo, Sr, Sb, W, Ti And at least one member selected from the group consisting of Bi and a lithium secondary battery cathode material.
The cathode material of claim 14, wherein the lithium-containing metal oxide is included within 50 parts by weight based on 100 parts by weight of the mixed cathode material.
A lithium secondary battery positive electrode comprising the lithium secondary battery positive electrode material according to any one of claims 1 to 16.
A lithium secondary battery comprising the positive electrode according to claim 17.
19. The lithium secondary battery of claim 18, wherein the output of the lithium secondary battery is at least 40% of the output at the SOC 10 to the SOC 50 section.
The lithium secondary battery of claim 18, wherein the output of the lithium secondary battery is greater than or equal to 50% of the output of the SOC 50 to the SOC 50.

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