KR20050048453A - Cathod material for lithium second battery of which surface is processed and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a cathode active material for a lithium ion secondary battery and a manufacturing method thereof, and more particularly, to an amphoteric or basic compound capable of neutralizing an acid generated near a cathode active material, a metal oxyhydroxide having excellent electron conductivity, or ITO. The present invention relates to a structurally stable cathode active material for lithium ion secondary batteries having improved surface charging and discharging characteristics, lifetime characteristics, high rate characteristics, and thermal stability.

Description

Cathode material for Lithium second battery of which surface is processed and manufacturing method

Li-ion secondary batteries have been widely used as power sources for portable devices since they emerged in 1991 as small, light and large capacity batteries. Recently, with the rapid development of electronics, telecommunications, and computer industry, camcorders, mobile phones, notebook PCs, etc. have emerged, and they are developing remarkably, and the demand for lithium ion secondary battery as a power source to drive these portable electronic information communication devices is increasing day by day. It is increasing. In particular, research on power sources for electric vehicles by hybridizing an internal combustion engine and a lithium ion secondary battery has been actively conducted in the United States, Japan, and Europe.

Commercially available small lithium ion _secondary batteries use LiCoO ₂ for the positive electrode and carbon for the negative electrode. Japan's Molly Energy Corporation uses LiMn ₂ O ₄ as its anode, but its use is minimal. LiNiO ₂ , LiCo _x Ni _1-x O ₂ , and LiMn ₂ O ₄ may be cited as positive electrode materials currently being actively researched and developed.

LiCoO ₂ is an excellent material having stable charging and discharging characteristics, excellent electronic conductivity, high thermal stability, and flat discharge voltage characteristics. However, CoCo has low reserves, is expensive, and toxic to humans.

In addition, LiNiO ₂ is not commercialized because of difficulty in material synthesis and thermal stability, and part of LiMn ₂ O ₄ is commercialized in low-cost products. However, LiMn ₂ O ₄ having a spinel structure has a theoretical capacity of 148 mAh / g, which is smaller than that of other materials, and has a three-dimensional tunnel structure. It is lower than LiCoO ₂ and LiNiO ₂ and has poor cycle characteristics due to the Jahn-Teller effect.

In particular, the high temperature property at 55 ° C or higher is inferior to LiCoO ₂ and is not widely used in actual batteries. Therefore, much research has been conducted on materials having a layered crystal structure as a material capable of overcoming the above problems. Among these, Li [Ni _1/2 Mn _1/2 ] O ₂ and Li [Ni _{1/3 in} which nickel-manganese and nickel-cobalt-manganese are mixed 1: 1 in each of the most popular layered crystal structures. Co _1/3 Mn _1/3 ] O _2, etc. may be mentioned. These materials exhibit lower cost, higher capacity and better thermal stability than LiCoO ₂ .

However, these materials are poor in high rate and low temperature characteristics due to lower electronic conductivity than LiCoO ₂ , and the energy density of the battery is not improved despite the high capacity due to the low tap density. In particular, in the case of Li [Ni _1/2 Mn _1/2 ] O ₂ , the electron conductivity is very low, which makes it difficult to be practically used (J. of Power Sources, 112 (2002) 41-48). In particular, the high power characteristics of these materials are poor compared to LiCoO ₂ or LiMn ₂ O ₄ for use as hybrid power sources for electric vehicles. In order to solve this problem, Japanese Patent Laid-Open No. 2003-59491 proposes a method of treating conductive carbon black on a surface, but many improvements have not been reported.

Lithium ion secondary batteries have a problem in that their lifespan drops rapidly as they are repeatedly charged and discharged. In particular, this problem is more serious at high temperatures. This is due to the phenomenon that the electrolyte is decomposed or the active material is deteriorated due to moisture or other influences inside the battery, and the internal resistance of the battery is increased. Many efforts have been made to solve this problem. Korean Patent Publication No. 10-277796 discloses a technique for coating a metal oxide such as Mg, Al, Co, K, Na, Ca on the surface of the cathode active material through heat treatment. Electrochemical and Solid-State Letters, 4 (6), and A65-A67 (2001) disclose techniques for improving energy density and high rate properties by adding TiO ₂ to LiCoO ₂ active materials. . Electrochemical and Solid-State Letters, 4 (8) A109-A112 (2001), disclose a technique for improving the lifespan by surface treatment of natural graphite with aluminum.

However, the problem of deterioration of life and the generation of gas due to decomposition of electrolyte and the like during charging and discharging have not been completely solved. In addition, the Journal of Electrochemical Society, 143 (1996), p. 2204 discloses a phenomenon in which an active material is dissolved by an acid produced by oxidation of an electrolyte during charging due to a decrease in battery capacity. . Recently, Korean Patent Publication No. 2003-0032363 discloses Mg, Al, Co, K, Na, Ca, Si, Ti, Sn, V, Ge, Ga, B, As, Zr hydroxide and oxyhydride on the surface of the cathode active material. Techniques for coating the hydroxides, oxycarbonates, hydroxycarbonate salts are known.

Li [Ni _1/3 Co _1/3 Mn _1/3 ] O ₂ and Li [Ni _1/2 Mn _1/2 ] O ₂ are charged from Ni ²⁺ to Ni ³⁺ or Ni ⁴⁺ depending on the depth of charge. Change. Unlike the stable Ni ²⁺ , Ni ³⁺ or Ni ⁴⁺ (particularly Ni ⁴⁺ ) loses lattice oxygen due to instability and is reduced to Ni ²⁺ , which reacts with the electrolyte to alter or change the surface properties of the electrode. The charge transfer impedance of the capacitor is increased to decrease the capacity or the high rate characteristic.

In order to solve the problem of deterioration of the battery performance as described above, an object of the present invention is to prevent a phenomenon that the performance of the battery is reduced by adding a material that can neutralize the acid generated near the positive electrode active material.

More specifically, the cathode active material is provided with a cathode active material surface-treated with an amphoteric element, a basic element, or a complex oxide, hydroxide, or oxyhydroxide of an amphoteric element and a basic element.

In addition, the surface treatment with a material having a high electron conductivity to improve the electronic conductivity of the positive electrode active material to provide a positive electrode active material for lithium secondary battery excellent in high rate characteristics and life characteristics.

Another object of the present invention is to provide a cathode active material for a lithium secondary battery having excellent thermal stability.

Another object of the present invention is to provide a method for producing a cathode active material for a lithium secondary battery having the above characteristics.

In order to achieve the above object, the present invention provides a lithium secondary battery positive electrode active material, oxides, hydroxides, and oxyhydroxide of a material having high electron conductivity; Hydroxides, oxides, and oxyhydroxides of amphoteric elements; And it provides a surface-treated lithium secondary battery cathode active material, characterized in that the coating with at least one compound selected from the group consisting of hydroxides, oxides, and oxyhydroxides of basic elements.

In one embodiment of the present invention, the material having high electron conductivity is Co _1-x M _x (M = Al, Zn, Mg, In, Sb, Bi, Mn, 0≤x≤1.0), In _1-x Sn _x (0≤x≤1.0), Al _1-x N _x (N = Zn, Mg, In, Sb, Bi, Mn, 0≤x≤1.0), or Li (Co _1-x Al _x ) It provides a surface-treated lithium secondary battery cathode active material.

According to an embodiment of the present invention, the amphoteric element is antimony (Sb), zinc (Zn), indium (In), tin (Sn), lead (Pb), boron (B), or aluminum (Al). It provides a surface-treated lithium secondary battery cathode active material.

In one embodiment, the basic element is cobalt (Co), magnesium (Mg), silicon (Si), zirconium (Zr), manganese (Mn), bismuth (Bi) or cerium (Ce), characterized in that It provides a surface-treated lithium secondary battery cathode active material.

In one embodiment, the lithium secondary battery cathode active material provides a surface-treated lithium secondary battery cathode active material, characterized in that selected from the following compounds (1) to (8).

Li [Li _a (Ni _x Co _1-2x Mn _x ) _1-a ] O _2-b F _b , Li [Li _a (Ni _x Co _1-2x Mn _x ) _1-a ] with hexagonal layered rock salt structure O ₂ Sb (0≤a≤0.2, 0≤x≤0.5, 0≤b≤0.1) (1)

Li [Li _a (Ni _x Co _1-2x Mn _{xy / 2} M _y ) _1-a ] O _2-b F _b (M = Mg, Ca, Cu, Zn, 0≤a≤) with hexagonal layered rock salt structure 0.2, 0≤x≤0.5, 0≤y≤0.1, 0≤b≤0.1) (2)

Li [Li _a (Ni _1/3 Co _{(1 / 3-2x)} Mn _{( 1/3 + x)} M _x ) _1-a ] O _2-b F _b (M = Mg,) with hexagonal layered rock salt structure Ca, Cu, Zn, 0≤a≤0.2, 0≤x≤0.5, 0≤y≤0.1, 0≤b≤0.1) (3)

Li [Li _a (Ni _x Co _1-2x-y Mn _x M _y ) _1-a ] O _2-b F _b (M = B, Al, Fe, Cr, 0≤a≤) with hexagonal layered rock salt structure 0.2, 0≤x≤0.5, 0≤y≤0.1, 0≤b≤0.1) (4)

Li [Li _a (Ni _x Co _1-2x-y Mn _{xz / 2} M _y N _z ) _1-a ] O _2-b F _b (M = B, Al, Fe, Cr, with hexagonal layered rock salt structure) N = Mg, Ca, 0≤a≤0.2, 0≤x≤0.5, 0≤y≤0.1, 0≤b≤0.1) (5)

LiM _x Fe _1-x PO ₄ with Olivine structure (M = Co, Ni, Mn, 0 ≦ _x ≦ ₁ ) (6)

Spinel Li [Mn _2-x M _x ] O ₄ with cubic structure (M = Co, Ni, Cr, Mg, Al, 0 ≦ _x ≦ 0.1) (7)

Spinel Li [Ni _0.5 Mn _1.5-x M _x ] O ₄ with cubic structure (M = Co, Ni, Cr, Mg, Al, 0 ≦ _x ≦ 0.1) (8)

The present invention provides a surface-treated lithium secondary battery cathode active material, characterized in that the surface-treated surface is amorphous, crystalline, or a mixture of crystalline and amorphous.

In another embodiment, a chelating agent is added to an aqueous solution of an elemental precursor and a lithium secondary battery cathode active material to prepare a mixed solution, and after dispersing the mixed solution, removing the solvent. It provides a method of manufacturing a surface-treated lithium secondary battery cathode active material.

In another embodiment, a method for preparing a surface-treated lithium secondary battery cathode active material, comprising ammonia buffer solution in an aqueous solution of an element precursor and a lithium secondary battery positive electrode active material, and then adding an alkaline aqueous solution to precipitate. .

The present invention provides a method for manufacturing a surface-treated lithium secondary battery cathode active material, which further comprises the step of oxidizing by adding an oxidant to the cathode active material precipitated from the addition of an alkaline aqueous solution.

In one embodiment, the element precursor is lithium (Li), antimony (Sb), zinc (Zn), indium (In), tin (Sn), lead (Pb), boron (B), aluminum (Al ), Cobalt (Co), magnesium (Mg), silicon (Si), zirconium (Zr), manganese (Mn), bismuth (Bi), or alkoxide salts of sulfate (Ce), sulfates, nitrates, acetates, chlorides, It provides a method for producing a surface-treated lithium secondary battery cathode active material, characterized in that at least one compound selected from the group consisting of phosphate.

As an embodiment, the amount of the element precursor provides a method for producing a surface-treated lithium secondary battery cathode active material, characterized in that 0.1 to 10% by weight of the lithium secondary battery cathode active material.

In one embodiment, the cathode active material for a lithium secondary battery provides a method for manufacturing a surface-treated lithium secondary battery cathode active material, characterized in that selected from the following compounds (1) to (8).

Li [Li _a (Ni _x Co _1-2x Mn _x ) _1-a ] O _2-b F _b , Li [Li _a (Ni _x Co _1-2x Mn _x ) _1-a ] with hexagonal layered rock salt structure O ₂ Sb (0≤a≤0.2, 0≤x≤0.5, 0≤b≤0.1) (1)

Li [Li _a (Ni _x Co _1-2x Mn _{xy / 2} M _y ) _1-a ] O _2-b F _b (M = Mg, Ca, Cu, Zn, 0≤a≤) with hexagonal layered rock salt structure 0.2, 0≤x≤0.5, 0≤y≤0.1, 0≤b≤0.1) (2)

Li [Li _a (Ni _1/3 Co _{(1 / 3-2x)} Mn _{( 1/3 + x)} M _x ) _1-a ] O _2-b F _b (M = Mg,) with hexagonal layered rock salt structure Ca, Cu, Zn, 0≤a≤0.2, 0≤x≤0.5, 0≤y≤0.1, 0≤b≤0.1) (3)

Li [Li _a (Ni _x Co _1-2x-y Mn _x M _y ) _1-a ] O _2-b F _b (M = B, Al, Fe, Cr, 0≤a≤) with hexagonal layered rock salt structure 0.2, 0≤x≤0.5, 0≤y≤0.1, 0≤b≤0.1) (4)

Li [Li _a (Ni _x Co _1-2x-y Mn _{xz / 2} M _y N _z ) _1-a ] O _2-b F _b (M = B, Al, Fe, Cr, with hexagonal layered rock salt structure) N = Mg, Ca, 0≤a≤0.2, 0≤x≤0.5, 0≤y≤0.1, 0≤b≤0.1) (5)

LiM _x Fe _1-x PO ₄ with Olivine structure (M = Co, Ni, Mn, 0 ≦ _x ≦ ₁ ) (6)

Spinel Li [Mn _2-x M _x ] O ₄ with cubic structure (M = Co, Ni, Cr, Mg, Al, 0 ≦ _x ≦ 0.1) (7)

Spinel Li [Ni _0.5 Mn _1.5-x M _x ] O ₄ with cubic structure (M = Co, Ni, Cr, Mg, Al, 0 ≦ _x ≦ 0.1) (8)

Li [Ni _1/3 Co _1/3 Mn _1/3 ] O ₂ and Li [Ni _1/2 Mn _1/2 ] O ₂ are charged from Ni ²⁺ to Ni ³⁺ or Ni ⁴⁺ depending on the depth of charge. Change. Unlike stable Ni ²⁺ , Ni ³⁺ or Ni ⁴⁺ (particularly Ni ⁴⁺ ) loses lattice oxygen due to instability and is reduced to Ni ²⁺ , which reacts with the electrolyte to change the surface properties of the electrode The charge transfer impedance of the surface is increased to decrease capacity, high rate characteristics, and the like.

In order to solve the above problems, Li [Ni _1/3 Co _1/3 Mn _1/3 ] O with Co _1-x Al _x (x = 0-1) oxide or Li (Co _1-x Al _x ) oxide The surface of ₂ and Li [Ni _1/2 Mn _1/2 ] O ₂ is coated to prevent contact between the positive electrode active material and the electrolyte, thereby improving high rate and life characteristics.

In _{addition, Li (Co 1-x Al} x) surface treatment of the O ₂ is _{Li (Co 1-x Al x} ) as well as to prevent contact with the electrolyte O ₂ reduction per unit dose weight because it is used as a cathode active material itself, There is no.

Surface treatment with Li (Co _1-x Al _x ) O ₂ dissolves nitrates, acetates or sulfates of lithium, cobalt, and aluminum in distilled water in a composition ratio, and then a certain amount of chelating agent citric or glycolic acid and lithium complex oxide or phosphate The compound is mixed into the solution and dispersed in the mixer. The temperature of the mixing reactor is maintained at 50 ° C to 100 ° C, bubbling with nitrogen or argon as an inert gas, and the distilled water is removed while gradually stirring. Instead of bubbling gas, distilled water may be removed by maintaining the interior of the mixing reactor in a vacuum. The cathode active material from which distilled water has been removed may be used as it is, or may be used after adding a heat treatment process at 100 ° C. to 500 ° C. for 1 to 10 hours in an oxidizing atmosphere.

Another way to improve the electrochemical properties, such as the high rate and life characteristics of the positive electrode active material is to treat the surface with a high electron conductivity compound. Representative of such compounds is cobalt hydroxide (Co (OH) ₂ ) with divalent oxidation number.

At this time, in order to further improve the electron conductivity, it is necessary to form a cobalt layer having a mixed valence. At this time, the cobalt is preferably an oxide of 2.7 to 3.7.

When the cobalt hydroxide layer of the surface-treated positive electrode active material is further oxidized to oxyhydroxide (CoOOH), it is possible to provide a positive electrode active material having better electron conductivity.

To this end, the lithium complex oxide or phosphate compound is dispersed in pure distilled water. The lithium composite oxide or phosphate compound concentration in the slurry is preferably in the range of 100 g / L to 300 g / L, most preferably 200 g / L. Ammonia buffer is added to the mixed solution to stabilize the pH in the range of 9 to 11. The ammonia buffer used at this time is ammonia water, ammonium sulfate, or ammonium chloride. Nitrogen bubbling is carried out at a flow rate of 1 L / hr while slowly stirring the mixed solution to make the reactor in an inert atmosphere. While continuously bubbling nitrogen, a cobalt sulfate aqueous solution and an aqueous alkali solution (preferably NaOH aqueous solution) were continuously injected into the reactor to maintain the reaction solution at a pH of 9 to 11 and a reaction temperature of 40 ° C to 60 ° C. While stirring for 1 to 3 hours, the weight of the surface-treated cobalt is 0.1 to 10% by weight of the positive electrode active material weight ratio. If the cobalt weight is less than 0.1 wt%, there is no conductive effect. If the cobalt weight is more than 10 wt%, the conductivity of the positive electrode active material is improved, but the charge / discharge capacity is decreased because the amount of the active material is lowered. Then, the powder of Li [Ni _1/3 Co _1/3 Mn _1/3 ] O ₂ and Li [Ni _1/2 Mn _1/2 ] O ₂ cathode active material surface treated with cobalt hydroxide through a filter and drying process You can get it.

However, in order to oxidize the cobalt hydroxide layer to obtain a cathode active material treated with oxyhydroxide, the aqueous solution of sodium hydroxide and NaClO, Na ₂ S ₂ O ₈ , K ₂ S ₂ O ₈ , while maintaining the mixed solution at 50 ℃ to 70 ℃ Slowly inject oxidants such as NaClO ₂ and (NH ₄ ) ₂ S ₂ O ₈ . At this time, nitrogen was continuously bubbled into the reactor to maintain an inert atmosphere, and the amount of oxidant was adjusted so that divalent cobalt hydroxide was oxidized to trivalent cobalt oxyhydroxide. After reacting for 1 to 3 hours, the resultant was washed with pure distilled water and dried to obtain a cathode active material treated with cobalt oxyhydroxide.

The present invention also provides a method for synthesizing a cathode active material having excellent electron conductivity by treating the surface of the cathode active material with ITO (Indiun-Tin Oxide) having high electron conductivity.

Surface treatment using ITO dissolves indium, tin salt and chelating agent glucolic acid in distilled water or ethanol and mixes the positive electrode active material. Indium and tin salts used here include nitrates, chlorides, sulfates, oxides, or alkoxide salts. The solvents used are alcohols such as methanol, ethanol, or isopropanol, hexane, acetone, tetrahydrofuran, or ether. . The amount of the indium and tin as the surface treatment elements is suitably 0.1 to 10% by weight relative to the positive electrode active material. The solvent is evaporated while the mixed solution is bubbled with nitrogen at 70 ° C to 80 ° C. The solvent may be used as a cathode active material by vacuum drying at 120 ° C. for 5 to 20 hours or by heat treatment at 150 ° C. to 900 ° C. for 1 to 20 hours in an oxidizing atmosphere, inert atmosphere or vacuum state. have.

Another method to improve the electrochemical properties of the positive electrode active material is the amphoteric or basic compounds such as antimony (Sb), zinc (Zn), tin (Sn), indium (In), lead (Pb), boron (B), Surface treatment with oxides, hydroxides, or oxyhydroxides of aluminum (Al), cobalt (Co), magnesium (Mg), silicon (Si), zirconium (Zr), copper (Cu), bismuth (Bi) and cerium (Ce) Neutralize the acid generated near the positive electrode active material or suppress the reactivity between the positive electrode active material and the electrolyte solution to improve the phenomenon that the capacity of the battery is sharply reduced, and the positive electrode active material with excellent charge / discharge characteristics, life characteristics and thermal stability To provide.

Specifically, first, the metal salt of the amphoteric element or the basic element is dissolved in an alcohol solution such as methanol, ethanol, and isopropanol, and then a small amount of water is added to generate a hydroxyl group. The amount of distilled water used at this time is preferably 1 to 20 mol per 1 mol of the surface treatment element. As the metal salt, an alkoxide salt such as methoxide, ethoxide, isopropoxide, and butoxide, or sulfate, nitrate, acetate, chloride, or oxide salt may be used. In addition, the amount of the surface treatment element is 0.1 to 10% by weight relative to the positive electrode active material. If the amount of the surface treatment element is 0.1% by weight or less, no surface treatment effect is exhibited. If it is 10% by weight or more, the capacity or energy density decreases due to its own weight.

The solvent is evaporated while the mixed solution is nitrogen bubbled at 70 ° C to 80 ° C. Then, it can be used as a cathode active material by vacuum drying at 120 ℃ for 5 to 20 hours, or heat treatment in an oxidizing atmosphere, inert atmosphere or vacuum for 1 to 20 hours at 150 ℃ to 900 ℃.

Furthermore, when surface treatment is performed with a mixed compound of an amphoteric compound and a basic compound, the electrochemical characteristics of the battery can be improved, rather than surface treatment using an amphoteric compound and a basic compound alone. This is confirmed by a comparative experiment of the battery of Example 3 and Example 8 which will be described later.

The surface-treated surface of the lithium secondary battery cathode active material of the present invention is amorphous, crystalline, or a mixture of crystalline and amorphous.

The electrolyte that can be used in the lithium secondary battery according to the present invention is an ester, for example, ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (butylene carbonate) Cyclic carbonates such as (BC) and vinylene carbonate (VC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate Aliphatic carbonates such as (EMC) and zipurofilcarbonone (DPC), aliphatic such as methyl formate, methyl acetate (MA), methyl propionate (MP) and ethyl propionate (MA) And cyclic carboxylic acid esters such as carboxylic acid esters and butyl lactones (GBL). As cyclic carbonate, EC, PC, and VC are preferable. Moreover, it is also preferable to contain in the range of 20 volume% or less of aliphatic carboxylic acid ester (ester) as needed.

Lithium salts dissolved in these solvents include LiClO₄, LiBF₄, LiPF ₆ , LiAlCl ₄ , LiSbF ₆ , LiSCN, LiCF ₃ SO₃, LiCF ₃ CO₂, Li (CF3SO₂) ₂, LiAsF ₆ , LiN (CF ₃ SO₂) ₂, LiB ₁₀ Cl ₁₀ , lower aliphatic lithium carbonate, chloro borane Lithium, lithium tetraphenyl borate, or LiN (CF ₃ SO ₂ ) (C ₂ F ₅ SO ₂ ), LiN (CF ₃ SO ₂ And imides such as) 2, LiN (C ₂ F ₅ SO ₂ ) ₂ , and LiN (CF ₃ SO ₂ ) (C ₄ F ₉ SO ₂ ). These may each be used alone or in any combination in a range which does not impair the effects of the present invention. It is particularly preferable to include LiPF ₆ .

In addition, carbon tetrachloride, ethylene trifluoride chloride, or phosphate salt may be included in the electrolyte to render the electrolyte nonflammable.

On the other hand, a solid electrolyte can also be used. Inorganic solid electrolytes include Li ₄ SiO ₄ , Li ₄ SiO ₄ -LiI-LiOH, xLi ₃ PO _{4- (1-x)} Li ₄ SiO ₄ , Li ₂ SiS ₃ , Li ₃ PO ₄ -Li ₂ S-SiS ₂ , Phosphorus sulfide compounds and the like can be used. The organic solid electrolyte may be a polyethylene oxide, polypropylene oxide, polyvinyl alcohol, polyvinylidene, or polyexi fluoro propylene, or a derivative, mixture, or polymer of such a compound. Is preferred.

The separator mainly uses a polyethylene-based or polypropylene-based polymer such as porous polyethylene.

As the negative electrode material used in the present invention, lithium ions such as lithium, lithium alloy, alloy, intermetallic compound, carbon, organic compound, inorganic compound, metal complex and organic polymer compound can be occluded and released. It may be a compound. These may be used alone or in any combination within a range that does not impair the effects of the present invention.

Examples of lithium alloys include Li-Al alloys, Li-Al-Mn alloys, Li-Al-Mg alloys, Li-Al-Sn alloys, Li-Al-In alloys, and Li-Al- alloys. Cd alloy, Li-Al-Te alloy, Li-Ga alloy, Li-Cd alloy, Li-In alloy, Li-Pb alloy, Li-Bi alloy and Li-Mg alloy have.

As an alloy and an intermetallic compound, the compound of a transition metal and silicon, the compound of a transition metal, and tin, etc. are mentioned, Especially a compound of nickel and silicon is preferable.

Examples of carbonaceous materials include coke, pyrolytic carbon, natural graphite, artificial graphite, meso carbon micro beads, graphitized meso phase small spheres, vapor grown carbon, glassy carbon, carbon Fiber (poly acrylonitrile type, pitch type, cellulose type, gaseous growth carbon type), amorphous carbon, and carbon from which organic materials are fired. You may use these individually or in combination arbitrarily in the range which does not impair the effect of this invention, respectively.

On the other hand, the packaging material mainly uses a metal can or a packaging material composed of aluminum and several layers of polymers.

Hereinafter, although an Example is given and this invention is demonstrated concretely, this invention is not limited to these Examples.

Example 1 (Surface Treatment with Sb (OH) ₃ )

(1) Synthesis of Cathode Active Material

The reactor was 4L in size, and the rotor blades of the reactor were designed with two reverse blades for uniform mixing up and down, and the output of the rotor motor was more than 2.4kW. The rotation speed was 1000 rpm.

The total molar concentration of nickel sulfate, manganese, and cobalt was 1 M, sodium hydroxide solution was 4M, and ammonia water was used at a concentration of 3M. The feed rate of each reaction solution was adjusted to 0.5 L / hr of metal solution and 0.35 L / hr of ammonia water. The average residence time of the solution was adjusted to a flow rate of about 6 hours.

The pH of the solution was adjusted to 11.0 to 12.0 and the temperature was maintained at 50 ° C to 55 ° C. This increase in average temperature is because cobalt hydroxide is precipitated in the form of a complex salt at a low temperature, and therefore it is difficult to obtain a high density precipitate.

The obtained hydroxide was dried at 110 ℃ for 15 hours and naturally oxidized.

Next, 43.2 g of lithium monohydrate and 4.75 g of citric acid were dissolved in distilled water, followed by mixing 95 g of the complex hydroxide of nickel, manganese, and cobalt, followed by nitrogen purge, and distilled water was removed while maintaining the temperature at 80 ° C. The resulting mixture was heated at a temperature of 1 to 2 ° C./min, and then calcined at 950 ° C. for 20 hours and 1000 ° C. for 10 hours to 20 hours. The obtained LiNi _1/3 Co _1/3 Mn _1/3 O ₂ powder had a uniform particle size distribution with a size of about 10 μm.

(2) surface treatment

10 g (0.0389 mol) of antimony ethoxide (Sb (C ₂ H ₅ O) ₃ ) was added to isopropyl alcohol (C ₃ H ₇ OH) and mixed, and the mixture was continuously mixed at 30 ° C. for 0.5 hours or more to prepare a solution. It was. 0.11679 mole of distilled water was added to the solution to prepare a suspension solution in which Sb (OH) ₃ was dissolved in a colloidal form through a hydrolysis process and a condensation reaction. 200 g of LiNi _1/3 Co _1/3 Mn _1/3 O ₂ having an average particle diameter of 10 μm was prepared in the suspension solution thus prepared, followed by reaction at 50 ° C. for at least 5 hours, followed by reaction at 80 ° C. The reaction was continued for at least 3 hours to treat the surface of the positive electrode active material. In this process, LiNi _1/3 Co _1/3 Mn _1/3 O ₂ and the suspension solution are brought into contact with the surface of LiNi _1/3 Co _1/3 Mn _1/3 O ₂ by chemical substitution. , 80 ℃ and the solvent is evaporated Sb (OH) ₃ is LiNi _1/3 attached to the well surface Co _1/3 Mn _1/3 O ₂ was obtained. The obtained LiNi _1/3 Co _1/3 Mn _1/3 O ₂ was dried at 110 ° C. for at least 10 hours, and then used as a cathode active material. A schematic manufacturing process is shown in FIG.

(3) production of batteries

Acetylene black containing the surface-treated positive electrode active material and the conductive material, polyvinylidene fluoride (PVdF) as a binder was mixed in a weight ratio of 80:10:10 to prepare a slurry. The slurry was uniformly applied to a 20 μm thick aluminum foil, and vacuum dried at 120 ° C. to prepare a positive electrode.

The prepared anode and lithium foil were used as counter electrodes, and a porous polyethylene membrane (manufactured by Celgard ELC, Celgard 2300, thickness: 25 µm) was used as a separator, and ethylene carbonate and diethyl carbonate were mixed at a volume ratio of 1: 1. A coin battery was prepared according to a commonly known manufacturing process using a liquid electrolyte in which LiPF ₆ was dissolved at a molar concentration in a solvent.

The manufactured coin cell was evaluated at 30 ° C. and 55 ° C. in the 4.4 to 2.8 volt region using an electrochemical analyzer (Toyo System, Toscat 3100U).

Example 2 (Surface Treatment with Al (OH) ₃ )

10 g of aluminum isopropoxide (Al (C ₃ H ₇ O) instead of 10 g (0.0389 mol) of antimony ethoxide (Sb (C ₂ H ₅ O) ₃ ) in the surface treatment of Example 1 ) ₃₎ was obtained in isopropyl alcohol ((CH _3), and is surface-treated positive electrode active material in the same manner as example 1, except that dissolved in ₂ CHOH) was evaluated for battery characteristics by producing a coin cell in the same manner .

Example 3 (Surface Treatment with Al (OH) ₃ )

In the surface treatment process of Example 1, 10 g of aluminum isopropoxide (Al (C ₃ H ₇ O) ₃ ) was added to isopropyl alcohol ((CH ₃ ) ₂ CHOH) and mixed for 0.5 hours at 30 ° C. Continuous mixing was continued to prepare a solution. 0.1469 mole of distilled water was added to the solution to prepare a suspension solution in which Al (OH) ₃ was dissolved in a colloidal form through a hydrolysis process and a condensation reaction.

200 g of LiNi _1/3 Co _1/3 Mn _1/3 O ₂ with an average particle diameter of 10 μm was added to the suspension solution, and the mixture was reacted at 50 ° C. for at least 5 hours, followed by reaction at 80 ° C. for at least 3 hours. The active material surface was treated. In this process, LiNi _1/3 Co _1/3 Mn _1/3 O ₂ and the suspension solution are brought into contact with the surface of LiNi _1/3 Co _1/3 Mn _1/3 O ₂ by chemical substitution. At 80 ° C., the solvent was evaporated to obtain surface-treated LiNi _1/3 Co _1/3 Mn _1/3 O _{2 in} which Al (OH) ₃ adhered well to the surface. The obtained LiNi _1/3 Co _1/3 Mn _1/3 O ₂ was dried at 110 ° C. for 10 hours or more and heat-treated at 400 ° C. for 5 hours to prepare a cathode active material containing Al ₂ O ₃ .

Then, a coin battery was manufactured in the same manner as in Example 1 (3), and a battery characteristic evaluation experiment was performed.

Example 4 (Surface Treatment with Al (OH) ₃ )

A coin-type half cell was prepared in the same manner as in Example 3 except that aluminum sulfate 16hydrate (Al ₂ (SO ₄ ) ₃ .16H ₂ O) instead of aluminum isopropoxide and distilled water were used instead of isopropyl alcohol. Battery characteristic evaluation experiment was performed.

Example 5 (Surface Treatment with Co (OH) ₂ )

Cobalt sulphate chihydrate (Co (SO ₄ ) .7H ₂ O) was dissolved in distilled water to make 50 ml of a solution of 0.02 M concentration, and the average particle diameter prepared in Example 1 (1) was 10 μm of LiNi _1/3 Co _{1 2} g of ₃ Mn _1/3 O ₂ was added and mixed at 30 ° C. for 1 hour (preparation of Solution A). Ammonium hydroxide (NaOH) is dissolved in distilled water to make a solution of 0.024M concentration, mixed and precipitated at 50 ° C while slowly entering the solution A prepared previously. In this process, Co (OH) ₂ x H ₂ O is precipitated on the surface of LiNi _1/3 Co _1/3 Mn _1/3 O ₂ . Next, while drying at 130 ℃ vacuum dried for more than 10 hours to obtain a surface-treated positive electrode active material. A coin battery was prepared in the same manner as in Example 1 (3) using the obtained cathode active material.

Battery characteristic evaluation was carried out in the same manner as in Example 1.

Example 6 (Surface Treatment with Al (OH) ₃ )

Dissolve aluminum sulfate 16hydrate (Al ₂ (SO ₄ ) ₃ ㆍ 16H ₂ O) in distilled water to make 50 ml of a 0.004M solution, and add LiNi _1/3 Co _1/3 Mn _1/3 O ₂ to the resulting solution. It mixed at 30 degreeC for 1 hour (made solution A). Ammonium hydroxide (NaOH) was dissolved in tertiary distilled water to make a solution of 0.024M concentration, and mixed and precipitated at 50 ° C while slowly entering the solution A prepared above. In this process, Al (OH) ₃ xH ₂ O precipitates on the surface of LiNi _1/3 Co _1/3 Mn _1/3 O ₂ . The mixture was further mixed for 10 hours while drying at 130 ° C. A coin-type half cell was manufactured by the same method as Example 1 with the surface-treated LiNi _1/3 Co _1/3 Mn _1/3 O ₂ , and the battery characteristics evaluation experiment was performed.

Example 7 (Surface Treatment of Cathode Active Material LiNi _1/2 Mn _1/2 O ₂ with Al (OH) ₃ )

A positive electrode active material LiNi _1/2 Mn _1/2 O ₂ having an average particle diameter of 5 μm was obtained in the same manner as in Example 1 (1), except that nickel sulfate and manganese were used instead of nickel sulfate, manganese, and cobalt.

Then, coin type halves in the same manner as in Example 3, except that LiNi _1/2 Mn _1/2 O ₂ having an average particle diameter of 5 μm was used instead of LiNi _1/3 Co _1/3 Mn _1/3 O _2. The battery was manufactured and the battery characteristic evaluation experiment was carried out.

Example 8 (Surface Treatment with Al-Zn Composite Oxide)

As in Example 3, a cathode active material surface-treated with Al ₂ O ₃ was prepared. Next, 1.5 g of zinc acetate dihydrate (Zn (CH ₃ COO) 2 .2H ₂ O) was dissolved in distilled water, and then the positive electrode active material prepared in Example 3 was added thereto, stirred at 50 ° C. for at least 5 hours, and dried at 130 ° C. Mix for another 10 hours while stirring. The powder thus obtained was dried at 110 ° C. for at least 10 hours, and then heat-treated at 400 ° C. for 5 hours to prepare a cathode active material in which Al-Zn formed a complex oxide.

Coin preparation and battery characteristics were evaluated in the same manner as in Example 1.

Example 9 (Surface Treatment with Li-Co-Al Composite Oxide)

Lithium nitrate, cobalt nitrate, and aluminum nitrate were dissolved in distilled water at a molar ratio of 1: 0.5: 0.5, respectively, and then 1 mole citric acid was added to prepare 50 ml of a coating solution having a molar ratio of 1: 0.5: 0.5 of lithium, cobalt, and aluminum. . 5 g of LiNi _1/3 Co _1/3 Mn _1/3 O ₂ having an average particle diameter of 10 μm prepared in Example 1 (1) was stirred at 50 ° C. for at least 5 hours, and then dried at 130 ° C. for 10 hours. Mix more. The powder thus obtained was dried at 110 ° C. for at least 10 hours, and then heat-treated at 400 ° C. for 5 hours to prepare a cathode active material coated with Li-Co-Al as a composite oxide.

Coin preparation and battery characteristics were evaluated in the same manner as in Example 1.

Example 10 (Surface Treatment with ITO)

0.1 mol (95: 5 mole ratio) of indium acetate and tin acetate were dissolved in distilled water, and then 0.1 mol of citric acid, a chelating agent, was dissolved. 2 mol of LiNi _1/3 Co _1/3 Mn _1/3 O ₂ was added to the mixed aqueous solution, followed by mixing for 1 hour. At this time, the indium and tin was ultrasonicated for 20 minutes to adhere well to the surface of the positive electrode active material. Distilled water was removed while bubbling this mixed solution with nitrogen at 70 degreeC. This cathode active material was vacuum dried at 120 deg. C for 15 hours.

Coin preparation and battery characteristics were evaluated in the same manner as in Example 1.

Example 11 (Surface Treatment with ITO—Heat Treatment)

LiNi _1/3 Co _1/3 Mn _1/3 O ₂ surface-treated with indium and tin was carried out in the same manner as in Example 10 except that heat treatment was performed at 350 ° C. for 5 hours in air.

Example 12 (Surface Treatment with ITO)

95: 5 molar ratio of indium isopropoxide (In (C ₂ H ₅ O) ₃ ) and tin butoxide (Sn (C) instead of 10 g of antimony ethoxide (Sb (C ₂ H ₅ O) ₃ ) ₄ H ₉ O) ₃ ) 10g was dissolved in isopropyl alcohol ((CH ₃ ) ₂ CHOH), except that the positive electrode active material was obtained in the same manner as in Example 1, and the coin cell was prepared in the same manner to characterize the battery Was evaluated.

Example 13 (Surface Treatment with Bi (OH) ₃ )

Bismuth nitrate was dissolved in distilled water to make 50 ml of a 0.4 mol solution, and 8 mol of LiNi _1/3 Co _1/3 Mn _1/3 O ₂ was added to the resulting solution, followed by mixing at 30 ° C. for 1 hour. Ammonium hydroxide (NaOH) is dissolved in tertiary distilled water to form a solution of 0.024 molar concentration, and mixed and precipitated at 50 ° C while slowly entering the solution A prepared above. In this process, Bi (OH) ₃ xH ₂ O precipitates on the surface of LiNi _1/3 Co _1/3 Mn _1/3 O ₂ . Mix further for 10 hours while drying at 130 ° C. A coin-type half cell was manufactured in the same manner as in Example 1, except that surface treated LiNi _1/3 Co _1/3 Mn _1/3 O ₂ was obtained.

Comparative Example 1 ( Preparation of Cathode Active Material LiNi _1/3 Co _1/3 Mn _1/3 O ₂ )

(2) Except for the surface treatment, positive electrode active material, coin preparation, and electrode characteristics evaluation experiment were carried out in the same manner as in Example 1.

Comparative Example 2 ( Preparation of Cathode Active Material LiNi _1/2 Mn _1/2 O ₂ )

Except for using nickel sulfate and manganese instead of nickel sulfate, manganese, and cobalt was tested in the same manner as in Comparative Example 1.

In Figure 2 (a) is Comparative Example 1 (b) is a field mission scanning electron microscopy (FE-SEM) photograph of the positive electrode active material prepared by the method of Example 2 particles of Comparative Example 1 has a large particle size itself , Example 2 can be confirmed that the fine particles are agglomerated.

Figure 3 is a photograph of the element analysis results of the EDS (Energy Dispersive Spectroscopy) element of the positive electrode active material can be seen that it contains the aluminum element as a coating material.

4 to 10 are discharge curves of the batteries prepared by Examples 1, 2, 3, 5, 8, 9, and 12 and Comparative Example 1 with varying charge / discharge rates in the range of 2.8V to 4.4V and 55 ° C. And lifetime characteristic graphs.

4 (a), 5 (a), 6 (a), 7 (a), 8 (a), 9 (a), and 10 (a), the characteristics of the two batteries are almost the same at low rate discharge (0.11C). Similar, however, the battery of Examples 1, 2, 3, 5, 8, 9, and 12 was found to have a much smaller decrease in discharge capacity as compared to the Comparative Example 1 battery.

4 (b), 5 (b), 6 (b), 7 (b), 8 (b), 9 (b), and 10 (b), Examples 1, 2, 3, The batteries of 5, 8, 9, and 12 were much smaller than the cells of Comparative Example 1, and it can be seen that the surface treatment of the positive electrode active material improves the cycle life of the battery. In particular, it can be seen that the surface coating of the positive electrode active material also improves the high temperature characteristics of the battery from the charge / discharge test results made at 55 ° C.

That is, it can be seen that the electrochemical properties of the battery is improved when coated with Sb (OH) ₃ , Al (OH) ₃ , Co (OH) ₂ , Al-Zn, Li-Co-Al, ITO.

11 (a) and 11 (b) illustrate a discharge curve and a lifetime characteristic graph of a battery prepared in Example 7 and Comparative Example 2, varying the charge / discharge rate in the range of 2.8V to 4.4V and 55 ° C. will be.

Similarly, the battery of Example 7 has a much smaller reduction rate than the battery of Comparative Example 2 in decreasing the discharge capacity as the high rate discharge in FIG. 11 (a) increases, and the cycle life of FIG. It can be seen that excellent.

12 is a comparison of the electrochemical characteristics of the battery of Example 3 and Example 8, Al- in the form of a mixture of a basic compound and an amphoteric compound than coating the positive electrode active material with Al (OH) ₃ as the amphoteric compound It can be seen that the coating treatment with Zn composite oxide is excellent in high rate characteristics and life characteristics.

The surface-treated cathode active material for lithium secondary battery of the present invention reduces the reactivity with electrolyte and acid concentration, stabilizes the structure of the cathode active material, and improves the electronic conductivity of the cathode active material, thereby improving the high rate characteristics, life characteristics, and thermal properties of the battery. Improved stability

In addition, by coating the positive electrode active material in the form of a mixture of a basic compound and an amphoteric compound, the electrochemical characteristics of the battery than the coating treatment of any one of them improved.

In particular, the surface treatment to the _{Li (Co 1-x Al x} ) O 2 is not the _{Li (Co 1-x Al x} ) O 2 itself a reduced capacity per unit weight because it is used as a cathode active material.

1 is a view briefly showing a process for producing a cathode active material according to Example 1

Figure 2 is a (FE) SEM (Field mission Scanning Electron Microscopy) photograph of the positive electrode active material of Comparative Example 1 and (b) Example 2

Figure 3 is a photograph of the results of element analysis of EDS (Energy Dispersive Spectroscopy) of the positive electrode active material of Example 2

4A and 4B are graphs of discharge curves and lifetime characteristics according to C-Rate of batteries prepared by Example 1 and Comparative Example 1

5A and 5B are graphs of discharge curves and lifetime characteristics according to C-Rate of batteries prepared by Example 2 and Comparative Example 1

6A and 6B are graphs of discharge curves and lifespan characteristics according to C-Rate of batteries manufactured by Example 3 and Comparative Example 1;

7A and 7B are graphs of discharge curves and lifespan characteristics according to C-Rate of batteries prepared in Example 5 and Comparative Example 1

8A and 8B are graphs of discharge curves and lifespan characteristics according to C-Rate of batteries manufactured by Example 8 and Comparative Example 2;

9A and 9B are graphs of discharge curves and lifespan characteristics according to C-Rate of batteries prepared according to Example 9 and Comparative Example 1;

10A and 10B are graphs of discharge curves and lifespan characteristics according to C-Rate of batteries manufactured by Example 12 and Comparative Example 1;

11A and 11B are graphs of discharge curves and lifespan characteristics according to C-Rate of batteries prepared by Example 7 and Comparative Example 2;

12 is a graph of life characteristics of a battery manufactured by the method of Example 3 and Example 8.

Claims (12)

In the lithium secondary battery cathode active material, Oxides, hydroxides, and oxyhydroxides of materials with high electron conductivity; Hydroxides, oxides, and oxyhydroxides of amphoteric elements; And Surface-treated lithium secondary battery cathode active material, characterized in that the coating is coated with at least one compound selected from the group consisting of hydroxides, oxides, and oxyhydroxides of basic elements, except indium tin oxide (ITO) . The material of claim ₁ , wherein the material having high electron conductivity is Co _1-x M _x (M = Al, Zn, Mg, In, Sb, Bi, Mn, 0 ≦ _x ≦ 1.0), Al _1-x N _x (N = Zn, Mg, In, Sb, Bi, Mn, 0≤x≤1.0), or Li (Co _1-x Al _x ) A surface-treated lithium secondary battery cathode active material, characterized in that. The surface of claim 1, wherein the amphoteric element is antimony (Sb), zinc (Zn), indium (In), tin (Sn), lead (Pb), boron (B), or aluminum (Al). Treated lithium secondary battery cathode active material. The method of claim 1, wherein the basic element is cobalt (Co), magnesium (Mg), silicon (Si), zirconium (Zr), manganese (Mn), bismuth (Bi) or cerium (Ce) Lithium secondary battery cathode active material. The cathode active material of claim 1, wherein the lithium secondary battery positive electrode active material is selected from the following compounds (1) to (8). Li [Li _a (Ni _x Co _1-2x Mn _x ) _1-a ] O _2-b F _b , Li [Li _a (Ni _x Co _1-2x Mn _x ) _1-a ] with hexagonal layered rock salt structure O ₂ Sb (0≤a≤0.2, 0≤x≤0.5, 0≤b≤0.1) (1) Li [Li _a (Ni _x Co _1-2x Mn _{xy / 2} M _y ) _1-a ] O _2-b F _b (M = Mg, Ca, Cu, Zn, 0≤a≤) with hexagonal layered rock salt structure 0.2, 0≤x≤0.5, 0≤y≤0.1, 0≤b≤0.1) (2) Li [Li _a (Ni _1/3 Co _{(1 / 3-2x)} Mn _{( 1/3 + x)} M _x ) _1-a ] O _2-b F _b (M = Mg,) with hexagonal layered rock salt structure Ca, Cu, Zn, 0≤a≤0.2, 0≤x≤0.5, 0≤y≤0.1, 0≤b≤0.1) (3) Li [Li _a (Ni _x Co _1-2x-y Mn _x M _y ) _1-a ] O _2-b F _b (M = B, Al, Fe, Cr, 0≤a≤) with hexagonal layered rock salt structure 0.2, 0≤x≤0.5, 0≤y≤0.1, 0≤b≤0.1) (4) Li [Li _a (Ni _x Co _1-2x-y Mn _{xz / 2} M _y N _z ) _1-a ] O _2-b F _b (M = B, Al, Fe, Cr, with hexagonal layered rock salt structure) N = Mg, Ca, 0≤a≤0.2, 0≤x≤0.5, 0≤y≤0.1, 0≤b≤0.1) (5) LiM _x Fe _1-x PO ₄ with Olivine structure (M = Co, Ni, Mn, 0 ≦ _x ≦ ₁ ) (6) Spinel Li [Mn _2-x M _x ] O ₄ with cubic structure (M = Co, Ni, Cr, Mg, Al, 0 ≦ _x ≦ 0.1) (7) Spinel Li [Ni _0.5 Mn _1.5-x M _x ] O ₄ with cubic structure (M = Co, Ni, Cr, Mg, Al, 0 ≦ _x ≦ 0.1) (8) The surface-treated lithium secondary battery cathode active material according to claim 1, wherein the surface-treated surface is amorphous, crystalline, or a mixture of crystalline and amorphous. A surface-treated lithium secondary battery positive electrode comprising the step of preparing a mixed solution by adding a chelating agent to an aqueous solution of an element precursor and a lithium secondary battery positive electrode active material, dispersing the mixed solution, and then removing the solvent Method for producing an active material (except for lithium secondary battery cathode active material surface-treated with Indium Tin Oxide (ITO)). Ammonia buffer solution is added to an aqueous solution of an element precursor and a lithium secondary battery positive electrode active material, and an alkaline aqueous solution is added to precipitate the surface-treated lithium secondary battery positive electrode active material [with indium tin oxide (ITO)]. Surface-treated lithium secondary battery positive electrode active material]. The method of claim 8, further comprising the step of oxidizing by adding an oxidant to the positive electrode active material precipitated from the addition of the alkaline aqueous solution. The method of claim 7 or 8, wherein the element precursor is lithium (Li), antimony (Sb), zinc (Zn), indium (In), tin (Sn), lead (Pb), boron (B), aluminum ( Al), cobalt (Co), magnesium (Mg), silicon (Si), zirconium (Zr), manganese (Mn), bismuth (Bi), or alkoxide salts of sulfate (Ce), sulfates, nitrates, acetates, chlorides , At least one compound selected from the group consisting of phosphates. The method of claim 7 or 8, wherein the amount of the element precursor is 0.1 to 10% by weight of the lithium secondary battery cathode active material. 9. The method of claim 7, wherein the cathode active material for a lithium secondary battery is selected from the following compounds (1) to (8). Li [Li _a (Ni _x Co _1-2x Mn _x ) _1-a ] O _2-b F _b , Li [Li _a (Ni _x Co _1-2x Mn _x ) _1-a ] with hexagonal layered rock salt structure O ₂ Sb (0≤a≤0.2, 0≤x≤0.5, 0≤b≤0.1) (1) Li [Li _a (Ni _x Co _1-2x Mn _{xy / 2} M _y ) _1-a ] O _2-b F _b (M = Mg, Ca, Cu, Zn, 0≤a≤) with hexagonal layered rock salt structure 0.2, 0≤x≤0.5, 0≤y≤0.1, 0≤b≤0.1) (2) Li [Li _a (Ni _1/3 Co _{(1 / 3-2x)} Mn _{( 1/3 + x)} M _x ) _1-a ] O _2-b F _b (M = Mg,) with hexagonal layered rock salt structure Ca, Cu, Zn, 0≤a≤0.2, 0≤x≤0.5, 0≤y≤0.1, 0≤b≤0.1) (3) Li [Li _a (Ni _x Co _1-2x-y Mn _x M _y ) _1-a ] O _2-b F _b (M = B, Al, Fe, Cr, 0≤a≤) with hexagonal layered rock salt structure 0.2, 0≤x≤0.5, 0≤y≤0.1, 0≤b≤0.1) (4) Li [Li _a (Ni _x Co _1-2x-y Mn _{xz / 2} M _y N _z ) _1-a ] O _2-b F _b (M = B, Al, Fe, Cr, with hexagonal layered rock salt structure) N = Mg, Ca, 0≤a≤0.2, 0≤x≤0.5, 0≤y≤0.1, 0≤b≤0.1) (5) LiM _x Fe _1-x PO ₄ with Olivine structure (M = Co, Ni, Mn, 0 ≦ _x ≦ ₁ ) (6) Spinel Li [Mn _2-x M _x ] O ₄ with cubic structure (M = Co, Ni, Cr, Mg, Al, 0 ≦ _x ≦ 0.1) (7) Spinel Li [Ni _0.5 Mn _1.5-x M _x ] O ₄ with cubic structure (M = Co, Ni, Cr, Mg, Al, 0 ≦ _x ≦ 0.1) (8)