KR101876826B1 - Cathode composite and all solid lithium secondary battery comprising the same - Google Patents

Abstract

The present invention relates to NMC; A positive electrode active material having a potential of less than 2.5 to 3.5 V and a positive electrode active material having a potential of 3.5 to 4.5 V; LLZO; Conductive material; And a binder. The entire solid lithium secondary battery of the present invention is excellent in cycle characteristics due to the use of the positive electrode composite material. Therefore, even if charge and discharge are repeated, voltage drop and capacity decrease Is small.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positive electrode composite material, and a full solid lithium secondary battery including the same. BACKGROUND OF THE INVENTION 1. Field of the Invention [0001]

The present invention relates to a positive electrode composite material and a pre-solid lithium rechargeable battery including the same, and more particularly, to a positive electrode composite material using a positive electrode active material having a different potential as an anode, and a pre-solid lithium rechargeable battery including the same.

2. Description of the Related Art With the rapid development of the electronics, communication, and computer industries, the demand for lithium secondary batteries has been increasing as a power source for driving these portable electronic communication devices as camcorders, mobile phones, notebook PCs, and the like have been remarkably developed. In particular, research and development are being actively carried out in Japan, Europe, and the United States, as well as domestic applications for applications such as electric vehicles, uninterruptible power supplies, power tools and satellites as eco-friendly power sources. Furthermore, recent commercialization of lithium secondary batteries has led to a problem of increasing the capacity and safety of lithium secondary batteries.

Meanwhile, lithium cobalt oxide (LiCoO ₂ ) has been mainly used as a positive electrode material of a lithium secondary battery. Currently, lithium nickel oxide (Li (Ni-Co-Al) O ₂ ) (Li (Ni-Co-Mn) O ₂ ) are also used. In addition, spinel-type lithium manganese oxide (LiMn ₂ O ₄ ) and olivine-type lithium iron phosphate compound (LiFePO ₄ ) of low cost and high stability are also attracting attention.

However, lithium secondary batteries using lithium cobalt oxide, lithium nickel oxide, lithium composite metal oxide or the like are excellent in basic battery characteristics, but safety, particularly, thermal stability, overcharging characteristics and the like are not sufficient. In order to solve this problem, various safety mechanisms such as a shut-down function of a separator, an additive for an electrolyte, a safety circuit such as a protection circuit and a PTC have been introduced. However, It was designed under circumstances. As a result, when the filling property of the anode material is increased in order to satisfy the demand for higher capacity, the operation of various safety mechanisms tends to be insufficient and the safety is lowered.

In this way, various battery solutions are being developed to innovate the anxiety about safety, limit of increase of energy density, and high cost burden which are pointed out as limitations of lithium secondary battery in the current market. All solid lithium secondary batteries Next-generation sodium-based batteries suitable for storing large amounts of energy, and magnesium batteries utilizing abundant magnesium resources are currently attracting attention as representative next-generation batteries.

In the case of all solid lithium secondary batteries, solid electrolytes are used instead of liquid electrolytes used in conventional lithium ion batteries, which is the most important advantage in ensuring perfect safety. The solid electrolyte is a key material for overcoming limitations of use of existing liquid electrolyte due to high capacity and high voltage of lithium ion battery electrode and assuring the safety of high performance lithium ion battery.

A solid-state lithium secondary battery is a cell that applies pressure to ceramic-based solid electrolyte (all-solid-state electrolyte) particles that do not contain any organic solvent. The solid electrolyte is applied to the positive and negative electrodes located on both sides of the electrolyte layer The pore existing in a conventional lithium ion battery electrode has an electrode structure in which an ion conductor solid electrolyte and an electron conductor are uniformly compounded in place of a liquid electrolyte and poses many problems in physical contact with the electrode.

Further, methods of coating a reaction inhibiting layer for suppressing side reactions due to problems such as deterioration of cycle characteristics due to side reactions with electrolytes on the surface of the positive electrode active material have been proposed.

SUMMARY OF THE INVENTION An object of the present invention is to provide a new anode composite material capable of improving degradation of cycle characteristics due to deterioration of a cathode material.

Another object of the present invention is to provide a pre-solid lithium secondary battery excellent in cycle characteristics to which the above-described anode composite material is applied.

According to an aspect of the present invention,

NMC represented by the formula (1); A positive electrode active material having a potential of less than 2.5 to 3.5 V and a positive electrode active material having a potential of 3.5 to 4.5 V; LLZO represented by formula (2); Conductive material; And a binder; and a positive electrode composite material for a pre-solid lithium rechargeable battery.

[Chemical Formula 1]

LiNi _p Co _q Mn _r M _s O ₂

In the formula 1, 0 <p <0.95, 0 <q <0.5, 0 <r <0.5, 0? S? 0.3, p + q + r + s = 1, and M is independently selected from Al, Mg, Fe, Wherein at least one element selected from the group consisting of Cu, Zn, Cr, Ag, Ca, Na, K, In, Ga, Ge, V, Mo, Nb, Si, Ti,

(2)

Li _p Al _q La _y Zr _z O

In Formula 2, 5? P <9, 0? Q? 1, 2? Y? 4, 1? Z?

The cathode active material having a potential of less than 2.5 to 3.5 V is preferably LiFePO ₄ , Li _x M ₂ (PO ₄ ) ₃ (M = Fe, Ti, 0 < _x ? 3), Li _{4 + x} Mn ₅ O ₁₂ < x &lt; 3), and Li ₂ Mn ₂ O ₄ .

The cathode active material having a potential of 3.5 to 4.5 V is preferably LiMn ₂ O ₄ , LiMnPO ₄ , LiFe _1-x Mn _x PO ₄ (0 < _x ≦ 0.8), LiVOPO ₄ , Li ₃ V ₂ (PO ₄ ) ₃ , LiNi _{0 . 5} Mn _{0 . 5} O ₂ .

The conductive material may be at least one selected from carbon black, acetylene black, ketjen black, carbon fiber, carbon nanotube, and graphene.

The binder may be selected from the group consisting of polyvinylidene fluoride (PVDF), hexafluoro propylene (HFP), polyvinylidene fluoride-hexafluoro propylene, poly But are not limited to, polyvinylidene fluoride-cotrichloroethylene, polybutyl acrylate, polymethyl methacrylate, polyacrylonitrile, polyvinylpyrrolidone ), Polyvinylacetate, polyethylene-co-vinyl acetate, polyethylene oxide, polypropylene oxide, polyarylate, cellulose acetate ), Cellulose acetate butyrate, Cellulose acetate propionate, cyanoethylpullulan, cyanoethylpolyvinylalcohol, cyanoethylcellulose, cyanoethylsucrose, pullulan (which may be referred to as &quot; pullulan, carboxyl methyl cellulose, styrene-butadiene rubber, acrylonitrile-styrenebutadiene copolymer, and polyimide. The term &quot; .

The binder may be polyethylene oxide.

Wherein the positive electrode composite material for the all-solid-state secondary battery comprises 100 parts by weight of the sum of the NMC and the cathode active material; 5 to 50 parts by weight of LLZO; 5 to 50 parts by weight of the conductive material; And 5 to 50 parts by weight of the binder.

The weight ratio of the NMC and the cathode active material may be 50: 50 to 95: 5.

The weight ratio of the NMC and the cathode active material may be 70:30 to 90:10.

The weight ratio of the NMC and the cathode active material may be 80:20.

According to another aspect of the present invention,

A positive electrode comprising a positive electrode composite material; A solid electrolyte layer comprising a solid electrolyte; A lithium secondary battery comprising:

Wherein the positive electrode composite material comprises NMC represented by Chemical Formula 1, a cathode active material having a potential of 2.5 to 3.5 V or less and a cathode active material having a potential of 3.5 to 4.5 V, and a cathode active material selected from the group consisting of LLZO , A conductive material, and a binder.

[Chemical Formula 1]

LiNi _p Co _q Mn _r M _s O ₂

In the formula 1, 0 <p <0.95, 0 <q <0.5, 0 <r <0.5, 0? S? 0.3, p + q + r + s = 1, and M is independently selected from Al, Mg, Fe, Wherein at least one element selected from the group consisting of Cu, Zn, Cr, Ag, Ca, Na, K, In, Ga, Ge, V, Mo, Nb, Si, Ti,

 (2)

Li _p Al _q La _y Zr _z O

In Formula 2, 5? P <9, 0? Q? 1, 2? Y? 4, 1? Z?

In addition, the negative electrode may be made of any one of soft carbon, hard carbon, artificial graphite, natural graphite, expanded graphite, carbon fiber, hard graphitizable carbon, carbon black, carbon nanotube, acetylene black, Ketjenblack, graphene, fullerene, Any carbon selected from beads; (Me) selected from among Si, Sn, Li, Al, Ag, Bi, In, Ge, Pb, Pt, Ti, Zn, Mg, Cd, Ce, Cu, Co, Ni and Fe; An alloy including at least two of the metals (Me); And at least one oxide (MeOx) of the metal (Me); And the like. Specific examples of the oxide (MeO x) include TiO ₂ and Li ₄ Ti ₅ O ₁₂ .

Further, the cathode may include lithium.

In addition, the solid electrolyte layer is _{LiCl, LiBr, LiI, LiClO 4} , LiBF 4, LiB 10 Cl 10, LiPF 6, LiCF 3 SO 3, LiCF 3 CO 2, LiAsF 6, LiSbF 6, LiAlCl 4, CH 3 SO 3 Li , CF ₃ SO ₃ Li, (CF ₃ SO ₂ ) ₂ NLi, chloroborane lithium, lithium lower aliphatic carboxylate, and lithium tetraphenylborate.

The cathode active material having a potential of less than 2.5 to 3.5 V is preferably LiFePO ₄ , Li _x M ₂ (PO ₄ ) ₃ (M = Fe, Ti, 0 < _x ? 3), Li _{4 + x} Mn ₅ O ₁₂ < x &lt; 3), and Li ₂ Mn ₂ O ₄ .

The cathode active material having a potential of 3.5 to 4.5 V is preferably LiMn ₂ O ₄ , LiMnPO ₄ , LiFe _1-x Mn _x PO ₄ (0 < _x ≦ 0.8), LiVOPO ₄ , Li ₃ V ₂ (PO ₄ ) ₃ , LiNi _{0 . 5} Mn _{0 . 5} O ₂ .

The positive electrode composite material of the present invention can improve degradation of cycle characteristics due to deterioration of the anode material.

The pre-solid lithium secondary battery of the present invention exhibits excellent cycle characteristics due to the use of the positive electrode composite material, so that the voltage drop and the capacity decrease are small even if the charge and discharge are repeated.

Fig. 1 is a graph showing charge-discharge characteristic curves of Examples 2-1 and 2-2 and Comparative Example 2. Fig.
Fig. 2 is a graph showing charge-discharge cycle characteristics of Examples 2-1 and 2-2 and Comparative Example 2. Fig.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention.

However, the following description does not limit the present invention to specific embodiments. In the following description of the present invention, detailed description of related arts will be omitted if it is determined that the gist of the present invention may be blurred .

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms " comprises ", or " having ", and the like, specify that the presence of stated features, integers, steps, operations, elements, or combinations thereof, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, or combinations thereof.

Hereinafter, the positive electrode composite material of the present invention will be described.

The positive electrode composite material of the present invention comprises NMC represented by formula (1); A positive electrode active material having a potential of less than 2.5 to 3.5 V and a positive electrode active material having a potential of 3.5 to 4.5 V; LLZO represented by formula (2); Conductive material; And a binder, and can be used for an anode for a pre-solid lithium secondary battery

[Chemical Formula 1]

LiNi _p Co _q Mn _r M _s O ₂

In the formula 1, 0 <p <0.95, 0 <q <0.5, 0 <r <0.5, 0? S? 0.3, p + q + r + s = 1, and M is independently selected from Al, Mg, Fe, Wherein at least one element selected from the group consisting of Cu, Zn, Cr, Ag, Ca, Na, K, In, Ga, Ge, V, Mo, Nb, Si, Ti,

(2)

Li _p Al _q La _y Zr _z O

In Formula 2, 5? P <9, 0? Q? 1, 2? Y? 4, 1? Z?

The cathode active material having a potential of less than 2.5 to 3.5 V is preferably LiFePO ₄ , Li _x M ₂ (PO ₄ ) ₃ (M = Fe, Ti, 0 < _x ? 3), Li _{4 + x} Mn ₅ O ₁₂ < x &lt; 3), and Li ₂ Mn ₂ O ₄ .

The cathode active material having a potential of 3.5 to 4.5 V is preferably LiMn ₂ O ₄ , LiMnPO ₄ , LiFe _1-x Mn _x PO ₄ (0 < _x ≦ 0.8), LiVOPO ₄ , Li ₃ V ₂ (PO ₄ ) ₃ , LiNi _{0 . 5} Mn _{0 . 5} O ₂ .

The conductive material may be at least one selected from carbon black, acetylene black, ketjen black, carbon fiber, carbon nanotube, and graphene.

The binder may be selected from the group consisting of polyvinylidene fluoride (PVDF), hexafluoro propylene (HFP), polyvinylidene fluoride-hexafluoro propylene, poly But are not limited to, polyvinylidene fluoride-cotrichloroethylene, polybutyl acrylate, polymethyl methacrylate, polyacrylonitrile, polyvinylpyrrolidone ), Polyvinylacetate, polyethylene-co-vinyl acetate, polyethylene oxide, polypropylene oxide, polyarylate, cellulose acetate ), Cellulose acetate butyrate, Cellulose acetate propionate, cyanoethylpullulan, cyanoethylpolyvinylalcohol, cyanoethylcellulose, cyanoethylsucrose, pullulan (which may be referred to as &quot; pullulan, carboxyl methyl cellulose, styrene-butadiene rubber, acrylonitrile-styrenebutadiene copolymer, and polyimide. The term &quot; .

The binder may be polyethylene oxide.

Wherein the positive electrode composite material for the all-solid-state secondary battery comprises 100 parts by weight of the sum of the NMC and the cathode active material; 5 to 50 parts by weight of LLZO; 5 to 50 parts by weight of the conductive material; And 5 to 50 parts by weight of the binder.

The weight ratio of the NMC and the cathode active material may be 50: 50 to 95: 5.

The weight ratio of the NMC and the cathode active material may be 70:30 to 90:10.

The weight ratio of the NMC and the cathode active material may be 80:20.

According to another aspect of the present invention,

A positive electrode comprising a positive electrode composite material; A solid electrolyte layer comprising a solid electrolyte; A lithium secondary battery comprising:

Wherein the positive electrode composite material comprises NMC represented by Chemical Formula 1, a cathode active material having a potential of 2.5 to 3.5 V or less and a cathode active material having a potential of 3.5 to 4.5 V, and a cathode active material selected from the group consisting of LLZO , A conductive material, and a binder.

[Chemical Formula 1]

LiNi _p Co _q Mn _r M _s O ₂

In the formula 1, 0 <p <0.95, 0 <q <0.5, 0 <r <0.5, 0? S? 0.3, p + q + r + M is independently selected from the group consisting of Al, Mg, Fe, Cu, Zn, Cr, Ag, Ca, Na, K, In, Ga, Ge, V, Mo, Nb, Si, Ti and Zr ,

 (2)

Li _p Al _q La _y Zr _z O

In Formula 2, 5? P <9, 0? Q? 1, 2? Y? 4, 1? Z?

In addition, the negative electrode may be made of any one of soft carbon, hard carbon, artificial graphite, natural graphite, expanded graphite, carbon fiber, hard graphitizable carbon, carbon black, carbon nanotube, acetylene black, Ketjenblack, graphene, fullerene, Any carbon selected from beads; (Me) selected from among Si, Sn, Li, Al, Ag, Bi, In, Ge, Pb, Pt, Ti, Zn, Mg, Cd, Ce, Cu, Co, Ni and Fe; An alloy including at least two of the metals (Me); And at least one oxide (MeOx) of the metal (Me); And the like. Specific examples of the oxide (MeO x) include TiO ₂ and Li ₄ Ti ₅ O ₁₂ . Further, the cathode may include lithium.

In addition, the solid electrolyte layer is _{LiCl, LiBr, LiI, LiClO 4} , LiBF 4, LiB 10 Cl 10, LiPF 6, LiCF 3 SO 3, LiCF 3 CO 2, LiAsF 6, LiSbF 6, LiAlCl 4, CH 3 SO 3 Li , CF ₃ SO ₃ Li, (CF ₃ SO ₂ ) ₂ NLi, chloroborane lithium, lithium lower aliphatic carboxylate, and lithium tetraphenylborate.

The cathode active material having a potential of less than 2.5 to 3.5 V is preferably LiFePO ₄ , Li _x M ₂ (PO ₄ ) ₃ (M = Fe, Ti, 0 < _x ? 3), Li _{4 + x} Mn ₅ O ₁₂ < x &lt; 3), and Li ₂ Mn ₂ O ₄ .

The cathode active material having a potential of 3.5 to 4.5 V is preferably LiMn ₂ O ₄ , LiMnPO ₄ , LiFe _1-x Mn _x PO ₄ (0 < _x ≦ 0.8), LiVOPO ₄ , Li ₃ V ₂ (PO ₄ ) ₃ , LiNi _{0 . 5} Mn _{0 . 5} O ₂ .

[Example]

Hereinafter, preferred embodiments of the present invention will be described. However, this is for illustrative purposes only, and thus the scope of the present invention is not limited thereto.

Example  1: Preparation of positive electrode

Example  1-1: anode composite material ( NMC / LFP ) &Lt; / RTI &gt;

Nickel sulphate (Sigma Aldrich), cobalt sulfate (SAMCHUN) and manganese sulfate (KANTO Chemical) were dissolved in distilled water such that the molar ratio of Ni: Co: Mn as the starting material for the cathode active material precursor was 0.7: 0.15: 0.15. / RTI &gt; was prepared. The starting material aqueous solution, the complexing agent (NH ₄ OH) and the pH adjusting solution (NaOH) of the reactor were charged into a coprecipitation reactor and co-precipitated at pH 11 to prepare a precipitate. The precipitate was washed, dried and pulverized to prepare a cathode active material precursor powder (NMC). 4 g of the cathode active material precursor powder and 1.815 g of LiOH were mixed and heat-treated at 850 ° C for 10 hours in an air atmosphere to prepare a positive electrode composite material.

NMC and LFP (LiFePO ₄ , Daejeong EM) synthesized by coprecipitation with Ni 70% were prepared by using a Thinky mixer mixer at a weight ratio of NMC: LFP of 8: 2. 10 wt% of Super P as a conductive material, 10 wt% of PEO (Sigma Aldrich, molecular weight: 200,000, LiClO ₄ salt added) as a binder was dissolved in a solvent (Acetonitrile ), And slurry was prepared by wet mixing using a Thinky mixer. The slurry was coated on an aluminum substrate and dried to prepare a cathode electrode.

Example  1-2: anode composite ( NMC / LMO ) &Lt; / RTI &gt;

A positive electrode composite electrode was prepared in the same manner as in Example 1-1, except that LMO (Daejeong EM Co.) was used instead of LFP.

Example  2: Manufacture of half-cell

Example  2-1: Half cell ( NMC / LFP )

Lithium foil was used for the positive electrode composite material electrode and the negative electrode prepared in Example 1-1, and 30 wt% of PEO (polyethylene oxide) containing 70 wt% of LLZO and LiClO ₄ salt was mixed with acetonitrile Acetonitrile) was used as a separator and an electrolyte. A 2032 type coin cell was used to fabricate a half cell and electrochemical evaluation was performed in a 70 ° C chamber.

Example  2-2: Half cell ( NMC / LMO )

A positive electrode composite material was prepared in the same manner as in Example 2-1, except that the positive electrode composite material of Example 1-2 was used instead of the positive electrode composite material of Example 1-1.

Comparative Example  1: anode material ( NMC )

Nickel sulphate (Sigma Aldrich), cobalt sulfate (SAMCHUN) and manganese sulfate (KANTO Chemical) were dissolved in distilled water such that the molar ratio of Ni: Co: Mn as the starting material for the cathode active material precursor was 0.7: 0.15: 0.15. / RTI &gt; was prepared. The starting material aqueous solution, the complexing agent (NH ₄ OH) and the pH adjusting solution (NaOH) of the reactor were charged into a coprecipitation reactor and co-precipitated at pH 11 to prepare a precipitate. The precipitate was washed, dried and pulverized to prepare a cathode active material precursor powder (NMC). 4 g of the cathode active material precursor powder and 1.815 g of LiOH were mixed and heat-treated at 850 ° C for 10 hours in an air atmosphere to prepare a positive electrode composite material.

Comparative Example  2: Half cell ( NMC )

A positive electrode composite material was prepared in the same manner as in Example 2-1, except that the positive electrode composite material of Comparative Example 1 was used instead of the positive electrode composite material of Example 1-1.

[Test Example]

Test Example  1: Evaluation of capacity and cycle characteristics

FIGS. 1 and 2 show the capacity and cycle characteristics of all solid lithium secondary batteries produced in accordance with Examples 2-1 and 2-2 and Comparative Example 2. FIG. The measurement conditions were a voltage range of 3.0 to 4.2 V, a current condition of 0.1 C, and a temperature of 70 캜 in a CC mode.

Referring to FIG. 1, there is shown a graph showing initial charge / discharge capacities for Comparative Examples and Examples. Compared with the NMC, the initial discharge capacity was increased and the oxidation and reduction potentials of the blended materials were clearly observed. More specifically, in the case of LFP, the plateau appears at around 3.4 V during the initial charge / discharge and it is hard to distinguish the LMO, but a slight flat slope can be observed at around 4.0 V. The oxidation and reduction potentials of the blending materials show increased plateau in proportion to the mixing ratio. However, the higher the mixing ratio, the lower the theoretical capacity and the lower the energy density due to the operating voltage drop.

Referring to FIG. 2, it is a graph showing the cycle characteristics of Comparative Examples and Examples. Initially, the capacity of the comparative example NMC seems to be excellent because of a slight increase in the capacity, but after 10 cycles, the capacity is rapidly decreased. On the other hand, the Blending composite material showed a small but steady capacity reduction at the beginning and a cycle characteristic superior to the comparative example NMC after 15 cycles. This is a result of demonstrating that battery cell degradation due to deterioration of NMC high capacity anode material in all solid state cells can be improved by blending with composite materials which complement each other.

Claims (16)

NMC represented by the formula (1);
A positive electrode active material having a potential of less than 2.5 to 3.5 V and a positive electrode active material having a potential of 3.5 to 4.5 V;
LLZO represented by formula (2);
Conductive material; And
And a binder,
Wherein the cathode active material having a potential of less than 2.5 to 3.5 V is LiFePO ₄ , Li _x M ₂ (PO ₄ ) ₃ (M = Fe, Ti, 0 < _x ? 3), Li _{4 + x} Mn ₅ O ₁₂ x? 3), and LiMn ₂ O ₄ ,
The positive electrode active material having a potential of the 3.5 to _{4.5 V LiMn 2 O 4, LiMnPO} 4, LiFe 1-x Mn x PO 4 (0 <x≤0.8), LiVOPO 4, Li 3 V 2 (PO 4) 3, LiNi _0.5 Mn _0.5 O ₂ ,
Wherein the binder is polyethylene oxide,
Wherein the weight ratio of the NMC and the cathode active material is from 70:30 to 90:10. A positive electrode composite material for a pre-solid lithium rechargeable battery,
[Chemical Formula 1]
LiNi _p Co _q Mn _r M _s O ₂
In the formula 1, 0 <p <0.95, 0 <q <0.5, 0 <r <0.5, 0? S? 0.3, p + q + r + s = 1, and M is independently selected from Al, Mg, Fe, Wherein at least one element selected from the group consisting of Cu, Zn, Cr, Ag, Ca, Na, K, In, Ga, Ge, V, Mo, Nb, Si, Ti,
(2)
Li _p Al _q La _y Zr _z O
In Formula 2, 5? P <9, 0? Q? 1, 2? Y? 4, 1? Z? delete delete The method according to claim 1,
Wherein the conductive material is at least one selected from the group consisting of carbon black, acetylene black, ketjen black, carbon fiber, carbon nanotube, and graphene. delete delete The method according to claim 1,
The positive electrode composite material for a full solid secondary battery according to claim 1,
100 parts by weight of the sum of the NMC and the cathode active material;
5 to 50 parts by weight of LLZO;
5 to 50 parts by weight of the conductive material; And
5 to 50 parts by weight of the binder;
Wherein the positive electrode composite material is a positive electrode composite material for an all solid secondary battery. delete delete 8. The method of claim 7,
Wherein the weight ratio of the NMC and the cathode active material is 80:20. A positive electrode comprising a positive electrode composite material;
A solid electrolyte layer comprising a solid electrolyte;
A lithium secondary battery comprising:
The positive electrode composite material
NMC represented by the general formula (1)
A positive electrode active material having a potential of 2.5 to 3.5 V or less and a positive electrode active material having a potential of 3.5 to 4.5 V,
LLZO represented by the general formula (2)
Conductive material,
Comprising a binder,
Wherein the cathode active material having a potential of less than 2.5 to 3.5 V is LiFePO ₄ , Li _x M ₂ (PO ₄ ) ₃ (M = Fe, Ti, 0 < _x ? 3), Li _{4 + x} Mn ₅ O ₁₂ x? 3), and LiMn ₂ O ₄ ,
The positive electrode active material having a potential of the 3.5 to _{4.5 V LiMn 2 O 4, LiMnPO} 4, LiFe 1-x Mn x PO 4 (0 <x≤0.8), LiVOPO 4, Li 3 V 2 (PO 4) 3, LiNi _0.5 Mn _0.5 O ₂ ,
Wherein the binder is polyethylene oxide,
Wherein the weight ratio of the NMC and the cathode active material is 70:30 to 90:10.
[Chemical Formula 1]
LiNi _p Co _q Mn _r M _s O ₂
In the formula 1, 0 <p <0.95, 0 <q <0.5, 0 <r <0.5, 0? S? 0.3, p + q + r + s = 1, and M is independently selected from Al, Mg, Fe, Wherein at least one element selected from the group consisting of Cu, Zn, Cr, Ag, Ca, Na, K, In, Ga, Ge, V, Mo, Nb, Si, Ti,
(2)
Li _p Al _q La _y Zr _z O
In Formula 2, 5? P <9, 0? Q? 1, 2? Y? 4, 1? Z? 12. The method of claim 11,
Wherein the negative electrode is at least one selected from the group consisting of soft carbon, hard carbon, artificial graphite, natural graphite, expanded graphite, carbon fiber, hard graphitizable carbon, carbon black, carbon nanotube, acetylene black, Ketjenblack, graphene, fullerene, Carbon; (Me) selected from among Si, Sn, Li, Al, Ag, Bi, In, Ge, Pb, Pt, Ti, Zn, Mg, Cd, Ce, Cu, Co, Ni and Fe; An alloy including at least two of the metals (Me); And at least one oxide (MeOx) of the metal (Me); Wherein the total amount of the at least one selected from the group consisting of lithium, 13. The method of claim 12,
Wherein the cathode comprises lithium. &Lt; RTI ID = 0.0 &gt; 11. &lt; / RTI &gt; 13. The method according to claim 11 or 12,
The solid electrolyte layer is _{LiCl, LiBr, LiI, LiClO 4} , LiBF 4, LiB 10 Cl 10, LiPF 6, LiCF 3 SO 3, LiCF 3 CO 2, LiAsF 6, LiSbF 6, LiAlCl 4, CH 3 SO 3 Li, CF ₃ SO ₃ Li, (CF ₃ SO ₂ ) ₂ NLi, chloroborane lithium, lithium lower aliphatic carboxylate, and lithium tetraphenylborate. delete delete

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