Olivine-type composite cathode material, method for producing the same, application thereof, and lithium-ion battery

Abstract

The present invention relates to the technical fields of new energy and lithium ion batteries, and in particular to an olivine-type composite positive electrode material and its manufacturing method and application, and a lithium ion battery. The composite positive electrode material includes a substrate and a composite phase, and the substrate is Li x M 1 y Mn z Fe 1-z-u M 2 u (PO4) w (RO a ) b The composite phase has a composition represented by formula I, represented by T m G n The composite phase has a composition represented by formula II. The composite phase is introduced into the positive electrode material in situ, so that the composite phase is uniformly composited with the crystal boundary and surface of the substrate of the positive electrode material, and is closely fused with the substrate of the positive electrode material. This improves the electronic conductivity and stability of the surface structure during the use of the positive electrode material, and the composite phase has a metal-like electronic structure and exhibits properties such as low electrical resistivity, strong chemical adsorption ability, and chemical stability, so that the composite positive electrode material has high electrical conductivity and excellent chemical stability, and is suitable for the fields of supercapacitors, lithium ion batteries, lithium sulfur batteries, etc.

Description

Technical Field

[0001] The present disclosure relates to the technical field of new energy and lithium-ion batteries, and in particular, to an olivine-type composite cathode material, a manufacturing method and applications thereof, and a lithium-ion battery.

Background Art

[0002] The rapid development of the power battery and energy storage battery markets for new energy vehicles has prompted people to have higher requirements for the fast charging performance and safety performance of lithium-ion batteries. The cathode material of a lithium-ion battery is one of the most important materials with the highest cost-quality ratio in a lithium-ion battery, and its performance greatly affects the energy density, fast charging performance, and safety performance of the lithium-ion battery. Among them, the cathode material with an olivine structure represented by lithium iron phosphate has become one of the mainstream cathode material systems in the current power and energy storage battery markets due to its high energy density, excellent cycle performance and safety performance, and low cost and price.

[0003] However, due to the particularity of its chemical composition and structure, the cathode material of lithium iron phosphate LiFePO4 can only reach a maximum discharge specific capacity of 170 mAh / g, the discharge voltage platform is usually less than 3.4 V, and the electron conductivity is low, so the low-temperature performance and rate performance are poor. Lithium manganese iron phosphate LiMn x Fe 1-x PO4 cathode material can further improve the discharge voltage platform by substituting Fe with Mn based on LiFePO4, thereby increasing the energy density of the battery. However, LiMn x Fe 1-x PO4 has worse electron conductivity, and the dissolution of Mn is serious, which has an adverse impact on the low-temperature performance, rate performance, cycle performance, and safety performance of the battery, so it has not yet reached actual industrialization.

Summary of the Invention

Problems to be Solved by the Invention

[0004] The object of the present invention is to provide an olivine-type composite cathode material, a manufacturing method and application thereof, and a lithium-ion battery in order to overcome the above-mentioned problems in the existing technology. Regarding the lithium-ion battery, the olivine-type composite cathode material includes a matrix and a composite phase T m G n and the composite phase is introduced into the cathode material in an in-situ manner, so that the composite phase is uniformly compounded on the grain boundaries and the surface of the matrix of the cathode material and is closely fused with the matrix of the cathode material. Thereby, the electronic conductivity and the stability of the surface structure during the use process of the cathode material are improved. The composite phase T m G n has an electron structure similar to that of a metal and usually exhibits characteristics such as a low electrical resistivity (<10 Ω·cm), a strong chemisorption ability, and chemical stability. Thereby, the composite cathode material containing the composite phase has high conductivity and excellent chemical stability and can be suitable for fields such as supercapacitors, lithium-ion batteries, and lithium-sulfur batteries. In particular, the lithium-ion battery containing the composite cathode material has significantly improved rate performance and cycle life.

Means for Solving the Problems

[0005] In order to achieve the above object, in a first aspect of the present invention, there is provided an olivine-type composite cathode material, the composite cathode material includes a matrix and a composite phase, the matrix has a composition represented by Formula I, Li x M 1 y Mn z Fe 1-z-u M 2 u (PO4) w (RO a ) b Cv (Formula I) wherein 0.5 ≦ x < 1.3, 0 ≦ y ≦ 0.5, 0 < z ≦ 1, 0 ≦ u ≦ 0.01, 0 < w ≦ 1, 0 < v ≦ 0.05, 0 ≦ a ≦ 8, 0 ≦ b ≦ 1, M 1 is at least one element selected from Mg, Na, and K, and M 2is at least one element selected from Ga, Sn, V, Y, Mo, Al, Mg, Ce, Ti, Zr, Nb, Si, W, and In, and R is at least one element selected from Si, Cl, Br, S, Sb, and Sn. The composite phase has a composition represented by Formula II. T m G n (Formula II) Among them, 0.1 ≦ m ≦ 5, 0.1 ≦ n ≦ 5, T is at least one element selected from Ti, Mo, Co, W, Zn, Cu, B, V, Nb, Ta, Pd, Cr, Ag, Al, Mn, Sn, Mg, Sc, Zr, and Hf, and G is an element selected from N and / or C. An olivine-type composite cathode material is provided.

[0006] In a second aspect of the present invention, there is provided a method for manufacturing an olivine-type composite cathode material, comprising: Performing a first mixing on a compound containing the T element and a compound containing the G element to obtain a first mixture, and performing a first heat treatment on the first mixture in the presence of a protective atmosphere to obtain a compound containing T and G (Step 1); Performing a second mixing on a lithium source, a carbon source, a phosphorus source, optionally an iron source, a manganese source, optionally an R source, optionally an M 1 source, and optionally an M2 source and a solvent to obtain a second mixture, and polishing the second mixture to obtain a slurry (Step 2); Performing a third mixing and drying on the compound containing T and G and the slurry to obtain a powder (Step 3); Performing a second heat treatment on the powder in the presence of an atmosphere of a non-oxidizing gas to crush and obtain the olivine-type composite cathode material (Step 4).

[0007] In a third aspect of the present invention, there is provided an olivine-type composite cathode material manufactured by the above manufacturing method.

[0008] In a fourth aspect of the present invention, there is provided an application of the above olivine-type composite cathode material in at least one of a supercapacitor, a lithium-ion battery, and a lithium-sulfur battery.

[0009] In a fifth aspect of the present invention, there is provided a lithium-ion battery including the above olivine-type composite cathode material.

Advantages of the Invention

[0010] According to the above technical solution, the olivine-type composite cathode material, its manufacturing method and application, and the lithium-ion battery according to the present invention have the following beneficial effects.

[0011] (1) In the olivine-type composite cathode material according to the present invention, it includes a matrix and a composite phase T m G n and the composite phase is introduced into the cathode material in an in-situ manner, so that the composite phase is uniformly compounded on the grain boundaries and the surface of the matrix of the cathode material and is closely fused with the matrix of the cathode material. Thereby, the electron conductivity and the stability of the surface structure during the use process of the cathode material are improved, and the composite phase exhibits characteristics such as a low electrical resistivity (<10 Ω·cm), a strong chemisorption ability, and chemical stability. Thereby, it can be suitable for fields such as supercapacitors, lithium-ion batteries, and lithium-sulfur batteries. In particular, the lithium-ion battery including the composite cathode material has significantly improved rate performance and cycle life.

[0012] (2) In the manufacturing method of the olivine-type composite cathode material according to the present invention, in a protective atmosphere, heat treatment is performed on a mixture of a compound containing element T and a compound containing element G, and the compound containing T and G obtained by the heat treatment is introduced into the composite olivine-type cathode material. Thereby, the composite phase formed from the compound containing T and G can be uniformly compounded on the grain boundaries and the surface of the matrix of the cathode material and is closely fused with the matrix of the cathode material. Thereby, the electron conductivity and the stability of the surface structure during the use process of the cathode material are improved, and the raw material supply source is rich, the manufacturing cost is low, and the overall process is easy to industrialize.

[0013] (3) In the method for manufacturing the olivine-type composite cathode material according to the present invention, the synthesis of the material substrate, carbon coating, and the composite of the compound containing T and G with the substrate material are completed by only one sintering, shortening the manufacturing time of the sample, effectively saving energy, and reducing carbon emissions.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0015] Regarding the endpoints and any values within the ranges disclosed in the present text, they are not limited to their exact ranges or values, and these ranges or values should be understood to include values approximated thereto. In a numerical range, the endpoints of each range, the values of the endpoints and individual points, and the values of individual points can be combined to form one or more new numerical ranges. These numerical ranges should be regarded as specifically disclosed in the present application.

[0016] In the first aspect of the present disclosure, an olivine-type composite cathode material, The composite cathode material includes a substrate and a composite phase, The substrate has a composition represented by Formula I, Li x M 1 y Mn z Fe 1-z-u M 2 u (PO4) w (RO a )b Cv (Formula I) Among them, 0.5 ≦ x < 1.3, 0 ≦ y ≦ 0.5, 0 < z ≦ 1, 0 ≦ u ≦ 0.01, 0 < w ≦ 1, 0 < v ≦ 0.05, 0 ≦ a ≦ 8, 0 ≦ b ≦ 1, M 1 is at least one element selected from Mg, Na, and K, and M 2 is at least one element selected from Ga, Sn, V, Y, Mo, Al, Mg, Ce, Ti, Zr, Nb, Si, W, and In, and R is at least one element selected from Si, Cl, Br, S, Sb, and Sn, the composite phase has a composition represented by Formula II, T m G n (Formula II) Among them, 0.1 ≦ m ≦ 5, 0.1 ≦ n ≦ 5, T is at least one element selected from Ti, Mo, Co, W, Zn, Cu, B, V, Nb, Ta, Pd, Cr, Ag, Al, Mn, Sn, Mg, Sc, Zr, and Hf, and G is an element selected from N and / or C. An olivine-type composite cathode material is provided.

[0017] In the present invention, the olivine-type composite cathode material includes a substrate and a composite phase T m G n By introducing the composite phase into the cathode material in an in-situ manner, the composite phase is uniformly compounded at the grain boundaries and surfaces of the substrate of the cathode material and is closely fused with the substrate of the cathode material. Thereby, the electron conductivity and the stability of the surface structure during the use of the cathode material are improved.

[0018] Furthermore, the composite phase T m G n (such as TiN, MoN, Co3N, W2N, VN, etc.) has an electron structure similar to that of a metal and usually exhibits characteristics such as a low electrical resistivity (<10 Ω·cm), a strong chemisorption ability, and chemical stability. Thereby, the composite cathode material containing the composite phase has high conductivity and excellent chemical stability and can be suitable for fields such as supercapacitors, lithium-ion batteries, and lithium-sulfur batteries. In particular, the lithium-ion battery containing the composite cathode material has significantly improved rate performance and cycle life.

[0019] Furthermore, in Formula I, 0.9 ≦ x < 1.1, 0 < y ≦ 0.01, 0.5 ≦ z ≦ 1, 0 < u ≦ 0.005, 0.5 ≦ w < 1, 0.001 < v ≦ 0.03, 0 ≦ a ≦ 4, 0 < b ≦ 0.1.

[0020] Furthermore, in Formula II, 0.5 ≦ m ≦ 3, 1 ≦ n ≦ 5, and T is at least one element selected from Ti, Mo, Co, W, Zn, Cu, B, V, Nb, Ta, Cr, Ag, Al, Mn, Sn, Mg, Sc, and Zr.

[0021] According to the present invention, based on the total weight of the composite cathode material, the content of the composite phase is 0.01 to 10 wt%.

[0022] In the present invention, the content of the composite phase in the composite cathode material is measured using the ICP method.

[0023] In the present invention, when the content of the composite phase in the composite cathode material satisfies the above range, the electron conductivity and the structural stability of the matrix interface can be improved. As a result, the composite cathode material has a low powder resistivity and excellent surface stability. When the composite cathode material is used in a lithium-ion battery, the rate performance and the cycle performance of the lithium-ion battery are significantly improved, and the manganese elution amount is also reduced.

[0024] Furthermore, based on the total weight of the composite cathode material, the content of the composite phase is 0.01 to 1 wt%.

[0025] According to the present invention, the compression density of the composite cathode material is 1.5 to 3 g / cm 3 is.

[0026] In the present invention, the composite cathode material has a high compression density. When the composite cathode material is used in a lithium-ion battery, more cathode material can be loaded in the same volume, thereby improving the capacity and the energy density of the battery.

[0027] Furthermore, the compression density of the composite cathode material is 2 to 3 g / cm3 is as follows.

[0028] According to the present invention, the electrical resistivity of the composite cathode material is ≤ 2500 Ω / cm.

[0029] In the present invention, the composite cathode material has a low electrical resistivity, which indicates that the composite cathode material has high electrical conductivity. Therefore, when used in a lithium-ion battery including the composite cathode material, the rate performance and cycle life of the lithium-ion battery can be improved.

[0030] Furthermore, the electrical resistivity of the composite cathode material is ≤ 1000 Ω / cm.

[0031] According to the present invention, in the composite cathode material, 0.5 ≤ m / n ≤ 7.

[0032] In the present invention, when m / n in the composite cathode material satisfies the above range, it indicates that the composite phase of the composite cathode material is a pure phase. As a result, the advantages such as high electron conductivity and structural stability of the composite phase can be fully exerted. Consequently, the lithium-ion battery including the composite cathode material can have excellent rate performance and cycle performance.

[0033] In the present invention, the content m of element T in the composite cathode material is measured by EDS surface scanning, and the content n of element G is also measured by EDS surface scanning.

[0034] Furthermore, in the composite cathode material, 1 ≤ m / n ≤ 5.

[0035] According to the present invention, the average particle size D of the composite cathode material 50 is 0.5 to 20 μm, preferably 1 to 15 μm.

[0036] According to the present invention, for the composite cathode material, in the EDS elemental analysis, the standard dispersion of m / n at any position is ≤ 1%.

[0037] In the present invention, when performing EDS elemental analysis of the composite cathode material, at any position, the standard dispersion of the molar ratio m / n of the T element and the G element in the composite phase T m G n G satisfies the above range, the composite phase T m G n is uniformly composite in the cathode material, and all the existing forms are T m G n pure phase, indicating this. Thereby, the low resistivity and the structural stability of the composite phase part are ensured, and as a result, the electrical resistivity of the entire composite cathode material is maintained at a low level. A smooth flow of the electron transmission channel is ensured during the charge and discharge process, and at the same time, the stability of the surface structure is ensured, the elution rate of the metal is reduced, and when this composite cathode material is used in a lithium-ion battery, the rate performance and the cycle performance of the lithium-ion battery are significantly improved.

[0038] Furthermore, the standard dispersion of m / n is ≦0.8%.

[0039] In the second aspect of the present invention, there is provided a method for manufacturing an olivine-type composite cathode material, comprising: performing a first mixing on a compound containing the T element and a compound containing the G element to obtain a first mixture, and performing a first heat treatment on the first mixture in the presence of a protective atmosphere to obtain a compound containing T and G (step (1)); performing a second mixing on a lithium source, a carbon source, a phosphorus source, optionally an iron source, a manganese source, optionally an R source, optionally an M 1 source, and optionally an M2 source and a solvent to obtain a second mixture, and polishing the second mixture to obtain a slurry (step (2)); performing a third mixing and drying on the compound containing T and G and the slurry to obtain a powder (step (3)); performing a second heat treatment on the powder in the presence of an atmosphere of a non-oxidizing gas to crush and obtain the olivine-type composite cathode material (step (4)).

[0040] In the present invention, in a protective atmosphere, a mixture of a compound containing a T element and a compound containing a G element is heat-treated, and the compound containing T and G obtained by the heat treatment is introduced into a composite olivine-type cathode material. Thereby, a composite phase formed from the compound containing T and G can be uniformly compounded at the grain boundaries and the surface of the matrix of the cathode material and closely fused to the matrix of the cathode material. Thereby, the electron conductivity and the stability of the surface structure during the use process of the cathode material are improved, the raw material supply source is abundant, the manufacturing cost is low, and the overall process is easy to industrialize.

[0041] Furthermore, in the manufacturing method according to the present invention, the synthesis of the material matrix, carbon coating, and the compounding of the compound containing T and G with the matrix material are completed by only one sintering, shortening the manufacturing time of the sample, effectively saving energy, and reducing carbon emissions.

[0042] According to the present invention, in step (1), the compound containing the T element is at least one selected from the group consisting of a simple substance of T, an oxide of T, a nitrate of T, and a hydroxide of T.

[0043] In the present invention, there is no special limitation on the shape of the oxide of T. For example, the oxide of T may be selected from at least one of nanoparticles, nanosheets, and nanowires.

[0044] In the present invention, the average particle size D of the oxide of T 50 is 0.001 to 1 μm.

[0045] According to the present invention, the compound containing the G element is at least one selected from the group consisting of nitrogen gas, ammonia gas, melamine, polydopamine, urea, glucose, starch, sucrose, and graphite.

[0046] Furthermore, the compound containing the G element is at least one selected from the group consisting of nitrogen gas, ammonia gas, urea, and glucose.

[0047] According to the present invention, the conditions of the first heat treatment include that the heat treatment temperature is 400 to 1000 °C and the heat treatment time is 2 to 8 h.

[0048] In the present invention, by performing heat treatment on the first mixture under the above conditions, the compound containing element T and the compound containing element G can be completely converted into a pure-phase compound (nitride and / or carbide) containing T and G. Thereby, by being manufactured by compounding the compound containing T and G with the slurry, it can be ensured that the composite phase in the obtained composite cathode material is a pure phase. As a result, the manufactured composite cathode material has high electronic conductivity and good structural stability. When the composite cathode material is used in a lithium-ion battery, the rate performance and cycle performance of the lithium-ion battery can be significantly improved.

[0049] Furthermore, the conditions of the first heat treatment include that the heat treatment temperature is 500 to 800 °C and the heat treatment time is 4 to 10 h.

[0050] According to the present invention, the molar ratio of the compound containing element T as T to the compound containing element G as G is 0.5 to 7:1.

[0051] In the present invention, when the molar ratio of the compound containing element T and the compound containing element G satisfies the above range, by being manufactured by compounding the compound containing T and G with the slurry, it can be ensured that the composite phase in the obtained composite cathode material is a pure phase. As a result, the manufactured composite cathode material has high electronic conductivity and good structural stability. When the composite cathode material is used in a lithium-ion battery, the rate performance and cycle performance of the lithium-ion battery can be significantly improved.

[0052] In the present invention, there is no special limitation on the conditions of the first mixing, as long as the compound containing element T and the compound containing element G can be mixed sufficiently uniformly. Preferably, the conditions of the first mixing include that the mixing rotation speed is 100 to 1000 rpm and the mixing time is 1 to 10 h.

[0053] In the present invention, there is no special limitation on the method of the first mixing, and the first mixing can be realized by the methods in this field. Specifically, the method of the first mixing is at least one selected from a mechanical planetary mixer, a mechanical high-speed mixer, ball polishing, and sand polishing.

[0054] In the present invention, there is no special limitation on the type of the protective atmosphere, and a protective atmosphere generally used in this field, such as nitrogen and / or argon, can be selected.

[0055] According to the present invention, in step (2), the lithium source is at least one selected from lithium carbonate, lithium hydroxide, lithium oxide, and lithium nitrate.

[0056] According to the present invention, the phosphorus source is at least one selected from phosphoric acid, metaphosphoric acid, pyrophosphoric acid, ammonium dihydrogen phosphate, diamine hydrogen phosphate, and phosphorus oxide.

[0057] According to the present invention, the carbon source is at least one selected from glucose, sucrose, starch, graphene, and carbon nanotubes.

[0058] According to the present invention, the iron source is at least one selected from iron phosphate, iron oxalate, iron acetate, iron oxide, and iron oxyhydroxide.

[0059] According to the present invention, the manganese source is at least one selected from manganese oxide, manganese carbonate, and manganese nitrate.

[0060] According to the present invention, the R source is selected from compounds containing at least one element of Si, Cl, Br, S, Sb, and Sn. Specifically, the R source is at least one selected from an acid containing the R element, an oxide containing the R element, and a hydroxide containing the R element.

[0061] According to the present invention, the M 1The source is selected from compounds containing at least one element of Mg, Na, and K. Specifically, the M 1 source is 1 an oxide containing the M 1 element, a hydroxide containing the M 1 element, and at least one selected from carbonates containing the M

[0062] According to the present invention, the M 2 source is selected from compounds containing at least one element of Ga, Sn, V, Y, Mo, Al, Mg, Ce, Ti, Zr, Nb, Si, W, and In. Specifically, the M 2 source is 2 an oxide containing the M 2 element, a hydroxide containing the M 2 element, and at least one selected from carbonates containing the M

[0063] According to the present invention, the solvent is at least one selected from water, ethanol, methanol, NMP, and isopropanol.

[0064] According to the present invention, the molar ratio of the lithium source as Li, the phosphorus source as P, the carbon source as C, the iron source as Fe, the manganese source as Mn, the R source as R, the M 1 source as M 1 , and the M 2 source as M 2 is (0.5 to 1.3):(0 to 1):(0 to 0.05):(0 to 1):(0 to 1):(0 to 1):(0 to 0.5):(0 to 0.01), where the dosages of the phosphorus source, the manganese source, and the carbon source are not zero.

[0065] In the present invention, the lithium source, the phosphorus source, the carbon source, the iron source, the manganese source, the R source, the M 1 source, the M 2When the source meets the above range, the resulting composite cathode material has high ionic conductivity and excellent structural stability. When this is used in a lithium-ion battery, the charge-discharge capacity, rate performance, and cycle performance of the lithium-ion battery are significantly improved.

[0066] Furthermore, the mole of Li of the lithium source, the mole of P of the phosphorus source, the mole of C of the carbon source, the mole of Fe of the iron source, the mole of Mn of the manganese source, the mole of R of the R source, the M 1 source of M 1 as a mole, and the M 2 source of M 2 as a mole ratio of moles is (0.9~1.1):(0.5~1):(0.001~0.03):(0~0.495):(0.5~1):(0~0.1):(0~0.01):(0~0.005), where the M 1 source, the iron source, the R source, and the M 2 source contents are all not zero.

[0067] According to the present invention, the solid content of the slurry is 10~60 wt%.

[0068] Furthermore, the solid content of the slurry is 2~50 wt%.

[0069] In the present invention, there is no special requirement for the dosage of the solvent, as long as the solid content of the slurry meets the above range.

[0070] According to the present invention, the average particle size D of the slurry 50 is 0.1~1 μm.

[0071] In the present invention, when the average particle size D of the corresponding slurry 50 meets the above range, it is advantageous for the slurry to increase the tap density of the powder after drying together with the compound containing T and G, and to improve the filling amount and sintering ability. Furthermore, controlling the average particle size of the slurry to meet the above range is particularly suitable for spray drying.

[0072] Furthermore, the average particle size D of the slurry 50 is 0.1 to 0.8 μm.

[0073] In the present invention, there is no special limitation on the conditions of the second mixing. However, as long as the lithium source, phosphorus source, carbon source, iron source, manganese source, R source, M 1 source, M 2 source can be sufficiently and uniformly mixed with the solvent.

[0074] In the present invention, there is no special limitation on the polishing conditions. However, as long as the average particle size D of the slurry 50 can satisfy the above range. Preferably, the polishing conditions include a polishing rotation speed of 500 to 2000 rpm and a polishing time of 1 to 10 h.

[0075] In the present invention, there is no special limitation on the polishing method, and the polishing can be realized by adopting a method in this field. Specifically, the polishing method is at least one selected from stirrer polishing, ball polishing, and sand polishing.

[0076] In the present invention, the polishing includes polishing the second mixture to obtain a slurry, and the polishing equipment includes one or more of a stirrer mill, a ball mill, and a sand mill.

[0077] According to the present invention, in step (3), the solid-liquid ratio of the compound containing T and G and the slurry is 0.000001 to 10 g / mL.

[0078] In the present invention, when the solid-liquid ratio of the compound containing T and G and the slurry satisfies the above range, the compound containing T and G will have good dispersibility in the slurry. As a result, in the positive electrode material produced thereby, the composite phase and the matrix are uniformly composite, aggregation does not occur, and the lithium ion battery including the composite positive electrode material has more stable electrochemical performance.

[0079] Furthermore, the solid-liquid ratio of the compound containing T and G and the slurry is 0.00001 to 1 g / mL.

[0080] In the present invention, there is no special limitation on the third mixing condition, as long as the compound containing T and G and the slurry can be sufficiently and uniformly mixed.

[0081] In the present invention, there is no special limitation on the drying conditions or drying equipment, as long as the mixture of the compound containing T and G and the slurry can be sufficiently dried. The drying equipment may be at least one selected from a spray dryer, a forced air drying furnace, a vacuum drying furnace, a freeze dryer, a flash dryer, etc.

[0082] According to the present invention, in step (4), the conditions of the second heat treatment include that the heat treatment temperature is 400 to 1000 °C and the heat treatment time is 4 to 12 h.

[0083] In the present invention, by performing the second heat treatment on the powder under the above conditions, T m G n is composited in an in-situ manner, and the composite phase T m G n is closely bonded to the substrate. At the same time, a carbon coating layer can be uniformly formed on the surfaces of the composite phase and the substrate. The composite cathode material produced in this way has high conductivity and excellent cycle performance. When this cathode material is used in a lithium-ion battery, the rate performance and cycle performance of the lithium-ion battery are significantly improved.

[0084] Furthermore, the conditions of the second heat treatment include that the heat treatment temperature is 500 to 900 °C and the heat treatment time is 6 to 10 h.

[0085] In the present invention, there is no special limitation on the type of the non-oxidizing gas atmosphere, and the non-oxidizing gas atmosphere commonly used in this field, such as nitrogen or argon, may be used.

[0086] In the present invention, there is no special limitation on the equipment for crushing. At least one of the equipment commonly used in this field, such as a mechanical mill, a colloid mill, and an air jet mill, may be used.

[0087] In the third aspect of the present invention, an olivine-type composite cathode material manufactured by the above manufacturing method is provided.

[0088] In the fourth aspect of the present invention, an application of the above olivine-type composite cathode material in at least one of a supercapacitor, a lithium-ion battery, and a lithium-sulfur battery is provided.

[0089] In the fifth aspect of the present invention, a lithium-ion battery including the above olivine-type composite cathode material is provided.

[0090] In the present invention, when the olivine-type composite cathode material is a cathode material containing Mn, that is, when z is not 0, when the olivine-type composite cathode material is used in a lithium-ion battery, the lithium-ion battery becomes a liquid lithium-ion battery. After 1000 cycles at 45 °C, the amount of manganese elution from the negative electrode of the liquid lithium-ion battery is ≤ 3000 ppm, preferably 500 - 2000 ppm.

[0091] Hereinafter, the present invention will be described in detail through examples. In the following examples, The composition of the composite cathode material is measured by the ICP method. The content of the composite phase in the composite cathode material is also measured by the ICP method. The compression density of the composite cathode material is measured by the method of a powder compression density meter. The electrical resistivity of the composite cathode material is measured by the method of an electrical resistivity meter. The content of element G in the composite cathode material is measured by EDS surface scanning, and the content and distribution of element T are also measured by EDS surface scanning. The raw materials used in the examples and comparative examples are commercially available products.

[0092] Example 1

[0093] (1) Mix 10 g of TiO₂ nanoparticles with an average particle size of 0.05 μm and 80 g of urea in a ball milling jar at 600 rpm for 5 h, and heat-treat the mixture in a tube furnace at 550 °C for 10 h under a nitrogen gas atmosphere to obtain TiN nanoparticles. Here, the molar ratio of the mole of T in the compound containing the T element to the mole of G in the compound containing the G element is 1:1.

[0094] (2) Mix 24.04 g of lithium carbonate (lithium source), 19.89 g of iron oxide (iron source), 44.12 g of manganese carbonate (manganese source), 73.24 g of ammonium dihydrogen phosphate (phosphorus source), and 14.34 g of glucose (carbon source) in 200 g of pure water, and ball mill the mixture at a rotational speed of 500 rpm for 6 h in a planetary ball mill to obtain a slurry with D 50 of 0.62 μm. Here, the mole of Li in the lithium source, the mole of P in the phosphorus source, the mole of C in the carbon source, the mole of Fe in the iron source, the mole of Mn in the manganese source, M 2 source of M 2 The molar ratio of the moles is 1:1:0.1:0.4:0.599:0.001. The solid content of the slurry is 45 wt%.

[0095] (3) Mechanically stir 0.3 g of TiN nanoparticles into the slurry obtained in step (2) for 30 min to obtain a uniformly dispersed mixed slurry, and dry-treat the mixed slurry with a spray dryer to obtain a powder. Here, the solid-liquid ratio of the TiN nanoparticles to the slurry is 0.0001 g / mL.

[0096] (4) Treat the powder obtained in step (3) in a tube furnace at 750 °C for 8 h under a nitrogen gas atmosphere to obtain a sintered product, and then pulverize it with an air jet mill to obtain olivine-type composite cathode material A1. The dosages of each material and the process conditions in the manufacturing process are shown in Table 1.

[0097] Cut a part of the sintered product with a plasma beam to obtain a material cross-section, perform a surface scan on the material cross-section with EDS, and test the distribution uniformity of Ti elements. The results are shown in Table 2.

[0098] The composition, content of the composite phase, particle size, tap density, electrical resistivity, and T / G of the olivine-type composite cathode material A1 were tested, and the results are shown in Table 2.

[0099] Example 2

[0100] (1) 10 g of Co3O4 nanosheets with an average particle size of 0.09 μm and 80 g of melamine were mixed in a ball milling can at 600 rpm for 5 h, and the mixture was heat-treated in a tube furnace at 600 °C for 10 h in a nitrogen gas atmosphere to obtain Co3N nanoparticles. Here, the molar ratio of the mole of T as the compound containing element T to the mole of G as the compound containing element G is 3:1.

[0101] (2) 24.04 g of lithium carbonate (lithium source), 95.93 g of iron phosphate (iron source, phosphorus source), 44.16 g of manganese carbonate (manganese source), 0.04 g of titanium oxide (M 2 source), and 14.34 g of glucose (carbon source) were mixed with 200 g of pure water, and the mixture was ball-milled in a planetary ball mill at a rotation speed of 500 rpm for 6 h to obtain a slurry with D 50 of 0.48 μm. Here, the molar ratio of the mole of Li as the lithium source, the mole of P as the phosphorus source, the mole of C as the carbon source, the mole of Fe as the iron source, the mole of Mn as the manganese source, and the mole of M 2 as the M 2 source is 1:1:0.1:0.4:0.599:0.001, and the solid content of the slurry is 45 wt%.

[0102] (3) 0.2 g of Co3N nanoparticles were mechanically stirred in the slurry obtained in step (2) for 30 min to obtain a uniformly dispersed mixed slurry, and the mixed slurry was dried by a spray dryer to obtain a powder. Here, the solid-liquid ratio of the Co3N nanoparticles to the slurry is 0.001 g / mL.

[0103] (4) The powder obtained in step (3) is treated in a tube furnace at 800 °C for 8 h in a nitrogen gas atmosphere to obtain a sintered product, which is then pulverized by an air jet mill to obtain olivine-type composite cathode material A2.

[0104] A part of the sintered product is cut by a plasma beam to obtain a material cross-section, and the material cross-section is surface scanned by EDS to test the distribution uniformity of Co element, and the results are shown in Table 1.

[0105] The composition, content of composite phase, particle size, tap density, electrical resistivity and T / G of olivine-type composite cathode material A2 are tested, and the results are shown in Table 1.

[0106] Example 3

[0107] (1) 10 g of MoO3 nanowires with an average particle size of 0.07 μm are heat-treated in a tube furnace at 700 °C for 10 h in an ammonia gas atmosphere to obtain MoN nanoparticles. Here, the molar ratio of the mole of T as the T of the compound containing the T element to the mole of G as the G of the compound containing the G element is 1:1.

[0108] (2) 24.28 g of lithium carbonate (lithium source), 99.96 g of iron nitrate (iron source), 132.83 g of manganese nitrate (manganese source), 73.52 g of phosphoric acid (phosphorus source), 0.17 g of niobium oxide (M 2 source), and 62.52 g of glucose (carbon source) are mixed with 200 g of pure water, and the mixture is stirred by a mechanical mixer at a rotation speed of 300 rpm for 6 h to obtain a slurry. Here, the mole of Li as the lithium source, the mole of P as the phosphorus source, the mole of C as the carbon source, the mole of Fe as the iron source, the mole of Mn as the manganese source, M 2 source of M 2 The molar ratio of the mole of M as M is 1:1:0.1:0.398:0.6:0.002, and the solid content of the slurry is 45 wt%.

[0109] (3) Mechanically stir 0.5 g of MoN nanoparticles in the slurry obtained in step (2) for 30 min to obtain a uniformly dispersed mixed slurry, and dry-treat the mixed slurry in a vacuum drying furnace to obtain a dried gel powder. Here, the solid-liquid ratio of the MoN nanoparticles to the slurry is 0.0001 g / mL.

[0110] (4) Treat the powder obtained in step (3) in a tube furnace at 760 °C for 8 h in a nitrogen gas atmosphere to obtain a sintered product, and then grind it with an air jet mill to obtain the olivine-type composite cathode material A3.

[0111] Cut a part of the sintered product with a plasma beam to obtain a material cross-section, perform a surface scan with EDS to test the distribution uniformity of the Mo element, and the results are shown in Table 1.

[0112] Test the composition, composite phase content, particle size, compression density, electrical resistivity, and T / G of the olivine-type composite cathode material A3, and the results are shown in Table 1.

[0113] Example 4

[0114] (1) Mix 10 g of V2O5 nanoparticles with an average particle size of 0.05 μm and 20 g of urea in a ball milling can at 600 rpm for 5 h, and heat-treat the mixture in a tube furnace at 550 °C for 10 h in an ammonia gas atmosphere to obtain VN nanoparticles. Here, the molar ratio of the molar of T of the compound containing the T element to the molar of G of the compound containing the G element is 1:1.

[0115] (2) 24.04 g of lithium carbonate (lithium source), 95.58 g of ammonium manganese iron phosphate (phosphorus source, iron source, manganese source), 14.34 g of glucose (carbon source), 0.06 g of magnesium carbonate (M 1 source), 0.17 g of niobium oxide (M 2 source) are mixed with 200 g of pure water, and the mixture is ball-milled with a planetary ball mill at a rotation speed of 500 rpm for 6 h, D 50A slurry with a particle size of 0.62 μm is obtained. Here, the molar ratio of Li as the lithium source, P as the phosphorus source, C as the carbon source, Fe as the iron source, Mn as the manganese source, M 1 source of M 1 as the molar ratio, M 2 source of M 2 as the molar ratio is 1:1:0.1:0.398:0.6:0.001:0.002, and the solid content of the slurry is 45 wt%.

[0116] (3) 0.3 g of VN nanoparticles are mechanically stirred in the slurry obtained in step (2) for 30 min to obtain a uniformly dispersed mixed slurry, and the mixed slurry is dried by a spray dryer to obtain a powder. Here, the solid-liquid ratio of VN nanoparticles to the slurry is 0.0001 g / mL.

[0117] (4) The powder obtained in step (3) is treated in a tube furnace at 750 °C for 8 h in a nitrogen gas atmosphere to obtain a sintered product, which is then ground by an air jet mill to obtain the olivine-type composite cathode material A4.

[0118] A part of the sintered product is cut by a plasma beam to obtain a material cross-section, and the surface is scanned by EDS to test the distribution uniformity of V element, and the results are shown in Table 1.

[0119] The composition, composite phase content, particle size, tap density, electrical resistivity and T / G of the olivine-type composite cathode material A4 are tested, and the results are shown in Table 1.

[0120] Example 5

[0121] (1) B2O3 nanosheets with an average particle size of 0.09 μm and glucose are mixed in a ball milling can at 600 rpm for 5 h, and the mixture is heat-treated in a tube furnace at 1800 °C for 5 h in a nitrogen gas atmosphere to obtain B4C nanoparticles. Here, the molar ratio of T as the molar of the compound containing T element and G as the molar of the compound containing G element is 4:1.

[0122] (2) 24.04 g of lithium carbonate (lithium source), 111.92 g of iron phosphate (phosphorus source, iron source), 33.12 g of manganese carbonate (manganese source), 0.04 g of titanium oxide (M 2 source), 14.34 g of glucose (carbon source) are mixed with 200 g of pure water, and the mixture is ball-milled in a planetary ball mill at a rotation speed of 500 rpm for 6 h to obtain a slurry with D 50 of 0.48 μm. Here, the mole of Li as the lithium source, the mole of P as the phosphorus source, the mole of C as the carbon source, the mole of Fe as the iron source, the mole of Mn as the manganese source, M 2 source of M 2 and the molar ratio of the moles is 1:1:0.1:0.3:0.699:0.001, and the solid content of the slurry is 45 wt%.

[0123] (3) 0.2 g of B4C nanoparticles are mechanically stirred in the slurry obtained in step (2) for 30 min to obtain a uniformly dispersed mixed slurry, and the mixed slurry is dried by a spray dryer to obtain a powder. Here, the solid-liquid ratio of the B4C nanoparticles to the slurry is 0.00015 g / mL.

[0124] (4) The powder obtained in step (3) is treated in a tube furnace at 800 °C for 8 h in an atmosphere of nitrogen gas to obtain a sintered product, and then it is pulverized by an air jet mill to obtain the olivine-type composite cathode material A5.

[0125] A part of the sintered product is cut by a plasma beam to obtain a material cross-section, and the surface is scanned by EDS to test the distribution uniformity of the B element, and the results are shown in Table 1.

[0126] The composition, content of the composite phase, particle size, compression density, electrical resistivity, and T / G of the olivine-type composite cathode material A5 are tested, and the results are shown in Table 1.

[0127] Example 6

[0128] (1) 10 g of TiO₂ nanoparticles with an average particle size of 0.05 μm and 80 g of urea are mixed in a ball milling jar at 600 rpm for 5 h, and the mixture is heat-treated in a tube furnace at 550 °C for 10 h in a nitrogen gas atmosphere to obtain TiN nanoparticles. Here, the molar ratio of the mole of T in the compound containing the T element to the mole of G in the compound containing the G element is 1:1.

[0129] (2) 10 g of TiO₂ nanoparticles with an average particle size of 0.05 μm and 100 g of glucose are mixed in a ball milling jar at 600 rpm for 5 h, and the mixture is heat-treated in a tube furnace at 550 °C for 10 h in a nitrogen gas atmosphere to obtain TiC nanoparticles. Here, the molar ratio of the mole of T in the compound containing the T element to the mole of G in the compound containing the G element is 1:1.

[0130] (3) 24.04 g of lithium carbonate (lithium source), 19.89 g of iron oxide (iron source), 44.12 g of manganese carbonate (manganese source), 72.5 g of ammonium dihydrogen phosphate (phosphorus source), 0.6 g of silicon dioxide (R source), and 14.34 g of glucose (carbon source) are mixed with 200 g of pure water, and the mixture is ball milled in a planetary ball mill at a rotation speed of 500 rpm for 6 h to obtain a slurry with D 50 of 0.62 μm. Here, the molar ratio of the mole of Li in the lithium source, the mole of P in the phosphorus source, the mole of C in the carbon source, the mole of Fe in the iron source, the mole of Mn in the manganese source, and the mole of R in the R source is 1:1:0.1:0.4:0.6:0.01, and the solid content of the slurry is 45 wt%.

[0131] (4) 0.15 g of TiN nanoparticles and 0.15 g of TiC nanoparticles are mechanically stirred in the slurry obtained in step (2) for 30 min to obtain a uniformly dispersed mixed slurry, and the mixed slurry is dried by a spray dryer to obtain a powder. Here, the solid-liquid ratio of the TiN / TiC nanoparticles to the slurry is 0.0001 g / mL.

[0132] (5) Olivine-type composite cathode material A6 is obtained in the same manner as in step (1) of Example 1.

[0133] A part of the sintered body was cut with a plasma beam to obtain a material cross-section, and the surface was scanned by EDS to test the distribution uniformity of Ti element, and the results are shown in Table 1.

[0134] The composition, content of composite phase, particle size, compression density, electrical resistivity and T / G of the olivine-type composite cathode material A6 were tested, and the results are shown in Table 1.

[0135] Comparative Example 1

[0136] The cathode material was manufactured according to the method of Example 1, but the differences are that

[0137] step (1) was not carried out, and TiN nanoparticles were not added in step (3).

[0138] After manufacturing the olivine-type cathode material D1, the composition, content of composite phase, particle size, compression density, and electrical resistivity of the olivine-type composite cathode material D1 were tested, and the results are shown in Table 1.

[0139] Comparative Example 2

[0140] The cathode material was prepared according to the method of Example 1, but the differences are that step (1) was not carried out, and in step (2), 24.04 g of lithium carbonate (lithium source), 95.93 g of iron phosphate (iron source, phosphorus source), 44.08 g of manganese carbonate (manganese source), 0.05 g of calcium oxide (Ca), and 14.34 g of glucose (carbon source) were mixed with 200 g of pure water, and the mixture was ball-milled in a planetary ball mill at a rotation speed of 500 rpm for 6 h to obtain a slurry with D 50 of 0.62 μm. Here, the molar ratio of Li as the lithium source, P as the phosphorus source, C as the carbon source, Fe as the iron source, Mn as the manganese source, and Ca as calcium oxide is 1:1:0.1:0.4:0.6:0.0001, and the solid content of the slurry is 30 wt%, and Not adding TiN nanoparticles in step (3).

[0141] After manufacturing the olivine-type cathode material D2, test the composition, content of the composite phase, particle size, compression density, and electrical resistivity of the olivine-type composite cathode material D2, and the results are shown in Table 1.

[0142] Comparative Example 3

[0143] Manufacture the cathode material according to the method of Example 1.

[0144] Step (1) is the same as step (1) of Example 1.

[0145] In step (2), 24.28 g of lithium carbonate (lithium source), 99.96 g of iron nitrate (iron source), 132.83 g of manganese nitrate (manganese source), 73.52 g of phosphoric acid (phosphorus source), 0.33 g of barium nitrate (Ba), and 62.52 g of glucose (carbon source) are mixed with 200 g of pure water, and the mixture is stirred with a mechanical mixer at 300 rpm for 6 h to obtain a slurry. Here, the molar ratio of Li as the lithium source, P as the phosphorus source, C as the carbon source, Fe as the iron source, Mn as the manganese source, and Ba as the barium nitrate is 1:1:0.1:0.4:0.6:0.0008, and the solid content of the slurry is 45 wt%.

[0146] Do not perform step (3) of Example 1.

[0147] In step (4), regarding the conditions of the second heat treatment, the slurry is treated at 750 °C for 8 h to obtain a sintered product, which is pulverized with an air jet mill and the average particle size D 50 is 1.5 μm and the chemical formula is LiMn 0.6 Fe 0.398 Ba 0.002 PO4C 0.1 of the crushed material is obtained.

[0148] In step (5), LiMn obtained in step (4) 0.6 Fe 0.398Ba 0.002 PO4C 0.1 The crushed material of PO4C and the TiN nanoparticles obtained in step (1) were mixed in a ball milling jar at a rotation speed of 850 rpm for 4 h to obtain a mixture, and the mixture was heat-treated at 600 °C for 4 h in an atmosphere of nitrogen gas, and finally the chemical formula LiMn 0.6 Fe 0.398 Ba 0.002 PO4C 0.1 @TiN olivine-type cathode material D3 was obtained. Here, the dosage of TiN nanoparticles is 15 wt% with respect to the crushed material of LiMn0.6Fe0.398Ba0.002PO4C0.1.

[0149] Some of the materials were taken and subjected to EDS surface scanning to test the distribution uniformity of Ti elements in the materials, and the results are shown in Table 1.

[0150] The composition, composite phase content, particle size, compression density, electrical resistivity and T / G of the olivine-type composite cathode material D3 were tested, and the results are also shown in Table 1.

[0151]

Table 1

[0152]

Table 2

[0153] As can be seen from Table 1, compared with Comparative Examples 1 to 3, the cathode materials manufactured in Examples 1 to 6 have a high compression density and a low electrical resistivity. Specifically, the compression density is generally more than 2 g / cm 3 sup, and the electrical resistivity is all less than 500 Ω·cm. At the same time, since the distribution of T elements in the cathode materials manufactured in Examples 1 to 6 is uniform, the electrical performance of the lithium-ion batteries assembled from the above-mentioned cathode materials, especially the high-rate performance, is excellent. On the other hand, the cathode materials manufactured in Comparative Examples 1 to 3 all have an electrical resistivity exceeding 2500 Ω·cm, and since the distribution of T elements is non-uniform, the electrical performance of the lithium-ion batteries assembled from the cathode materials is inferior, and the deterioration of the rate performance is remarkable.

[0154] Figure 1 is the distribution diagram of T of the sintered product of Example 3, and Figure 2 is the distribution diagram of T of the sintered product of Comparative Example 3. As can be seen from Figures 1 and 2, in Figure 1, the distribution of N element is relatively uniform, and in Figure 2, the distribution of N element is non-uniform and there are many aggregates. This indicates that the composite phase of the sample manufactured according to the present invention is uniformly distributed within the matrix, and can better play the role of improving the electron transmission on the surface and enhancing the stability of the surface structure.

[0155] Test Example 1

[0156] Regarding the manufacturing method of a liquid lithium-ion battery, an olivine-type cathode material, acetylene black, and polyvinylidene fluoride (PVDF) of Examples and Comparative Examples are mixed at a mass ratio of 90:5:5, applied to an aluminum foil, and then dried. Next, it is punched and formed into a cathode sheet with a diameter of 12 mm and a thickness of 120 μm at a pressure of 100 MPa. Then, the cathode sheet is dried in a vacuum drying furnace at 120 °C for 12 h. As the anode, a Li metal sheet with a diameter of 17 mm and a thickness of 1 mm is used. As the separator, a 25-μm-thick Celgard 2400 porous membrane is used, and as the electrolyte, an equal-volume mixture of 1 mol / L LiPF6, ethylene carbonate (EC), and diethyl carbonate (DEC) is used. The cathode sheet, separator, anode sheet, and electrolyte are assembled in an Ar gas glove box with the content of moisture and oxygen both less than 5 ppm to create a 2025-type coin cell. The assembled coin cell is tested for capacity at 0.1C and 2C rates in an environment of 25 °C, and cycled 100 times at 1C rate, and the results are shown in Table 2.

[0157]

Table 3

[0158] Figure 3 shows the charge-discharge curves at a rate of 0.1C and the charge-discharge curves at a rate of 2C of the liquid lithium-ion battery assembled with the positive electrode materials of Comparative Example 3 and Example 1. Figure 4 is a diagram showing the cycle performance at 1C of the liquid lithium-ion battery assembled with the positive electrode materials of Comparative Example 3 and Example 1. As can be seen from Table 2, Figure 3 and Figure 4, the liquid lithium-ion battery assembled with the manufactured positive electrode material according to the example of the present invention is significantly superior in discharge capacity, high-rate performance and cycle retention rate to the liquid lithium-ion battery assembled with the manufactured positive electrode material according to the comparative example.

[0159] Test Example 2

[0160] Regarding the manufacturing method of the all-solid-state lithium battery, the olivine-type positive electrode material, conductive carbon black, and polyvinylidene fluoride (PVDF) of the example and the comparative example were mixed at a mass ratio of 90:5:5, an appropriate amount of NMP was added and stirred uniformly, and then coated on an aluminum foil by the doctor blade method, dried in a forced air drying oven at 120 °C for 1 h, and punched into a positive electrode sheet with a diameter of 11 mm. As the negative electrode, using metallic lithium, with a PEO-based solid electrolyte membrane as the electrolyte, in an Ar gas glove box with the water content and oxygen content both less than 5 ppm, the manufactured positive electrode sheet, composite electrolyte membrane, and negative electrode were assembled to create a 2025-type coin cell. The assembled coin cell was tested for its capacity at a rate of 2C in an environment of 25 °C and cycled 100 times at a rate of 1C, and the results are shown in Table 3.

[0161]

Table 4

[0162] As can be seen from Table 3, the all-solid-state lithium-ion battery assembled with the manufactured positive electrode material according to the example of the present invention is significantly superior in high-rate performance and cycle retention rate to the all-solid-state lithium-ion battery assembled with the manufactured positive electrode material according to the comparative example.

[0163] Test Example 3

[0164] Regarding the maintenance method of a liquid lithium-ion battery, a positive electrode material, acetylene black, and polyvinylidene fluoride (PVDF) are mixed at a mass ratio of 90:5:5. After coating on an aluminum foil, a drying process is performed. Next, it is punched and formed into a positive electrode sheet with a diameter of 12 mm and a thickness of 120 μm under a pressure of 100 MPa. Then, the positive electrode sheet is dried in a vacuum drying oven at 120 °C for 12 h. As the negative electrode, a standard graphite negative electrode is used. As the separator, a 25-μm-thick Celgard 2400 porous membrane is used. As the electrolyte, an equal-volume mixture of 1 mol / L LiPF6, ethylene carbonate (EC), and diethyl carbonate (DEC) is used. The positive electrode sheet, separator, negative electrode sheet, and electrolyte are assembled in an Ar gas glove box with the water content and oxygen content both less than 5 ppm to create a 2025-type coin cell. The assembled coin cell is cycled at 1C for 1000 cycles in an environment of 45 °C. After cycling, the battery is dissected to obtain the negative electrode, and the manganese content in the negative electrode is tested by ICP. The results are shown in Table 4.

[0165]

Table 5

[0166] As can be seen from Table 4, the liquid lithium-ion batteries assembled with the positive electrode materials manufactured according to the embodiments of the present invention have significantly lower manganese elution amounts after long-term cycling than the liquid lithium-ion batteries assembled with the positive electrode materials manufactured according to the comparative examples.

[0167] As described above, the preferred embodiments of the present invention have been described in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the present invention, many simple modifications can be made to the technical content of the present invention, including combining each technical feature in some other appropriate way. These simple modifications and combinations are also considered as the content disclosed by the present invention and belong to the protection scope of the present invention. The present disclosure includes the following embodiments. <1> An olivine-type composite cathode material, wherein the composite cathode material includes a matrix and a composite phase, the matrix has a composition represented by Formula I, Li x M 1 y Mn z Fe 1-z-u M 2 u (PO 4 ) w (RO a ) b Cv (Formula I) wherein 0.5 ≦ x < 1.3, 0 ≦ y ≦ 0.5, 0 < z ≦ 1, 0 ≦ u ≦ 0.01, 0 < w ≦ 1, 0 < v ≦ 0.05, 0 ≦ a ≦ 8, 0 ≦ b ≦ 1, M 1 is at least one element selected from Mg, Na, and K, and M 2 is at least one element selected from Ga, Sn, V, Y, Mo, Al, Mg, Ce, Ti, Zr, Nb, Si, W, and In, and R is at least one element selected from Si, Cl, Br, S, Sb, and Sn, the composite phase has a composition represented by Formula II, T m G n (Formula II) wherein 0.1 ≦ m ≦ 5, 0.1 ≦ n ≦ 5, T is at least one element selected from Ti, Mo, Co, W, Zn, Cu, B, V, Nb, Ta, Pd, Cr, Ag, Al, Mn, Sn, Mg, Sc, Zr, and Hf, and G is an element selected from N and / or C, an olivine-type composite cathode material. <2> In Formula I, 0.9 ≦ x < 1.1, 0 < y ≦ 0.01, 0.5 ≦ z ≦ 1, 0 < u ≦ 0.005, 0.5 ≦ w < 1, 0.001 < v ≦ 0.03, 0 ≦ a ≦ 4, 0 < b ≦ 0.1, preferably, in Formula II, 0.5 ≦ m ≦ 3, 1 ≦ n ≦ 5, T is at least one element selected from Ti, Mo, Co, W, Zn, Cu, B, V, Nb, Ta, Cr, Ag, Al, Mn, Sn, Mg, Sc, and Zr, the olivine-type composite cathode material according to <1> above. <3> Based on the total weight of the composite cathode material, the content of the composite phase is 0.01 to 10 wt%, preferably 0.01 to 1 wt%, the olivine-type composite cathode material according to <1> or <2> above. <4> The compression density of the composite cathode material is 1.5 to 3 g / cm 3 preferably 2 to 3 g / cm 3 and preferably, the resistivity of the composite cathode material is ≦ 2500 Ω / cm, preferably ≦ 1000 Ω / cm, preferably, in the composite cathode material, 0.5 ≦ m / n ≦ 7, preferably 1 ≦ m / n ≦ 5, preferably, the average particle size D 50 of the composite cathode material is 0.5 to 20 μm, preferably 1 to 15 μm, Preferably, the composite cathode material is the olivine-type composite cathode material according to any one of <1> to <3>, wherein in EDS elemental analysis, the standard dispersion of m / n is ≦1% at any position. <5> A method for manufacturing an olivine-type composite cathode material, comprising: Step (1) of performing a first mixing on a compound containing a T element and a compound containing a G element to obtain a first mixture, and performing a first heat treatment on the first mixture in the presence of a protective atmosphere to obtain a compound containing T and G; A lithium source, a carbon source, a phosphorus source, optionally an iron source, a manganese source, optionally an R source, optionally an M 1 source, and optionally an M 2 source and a solvent are subjected to a second mixing to obtain a second mixture, and the second mixture is polished to obtain a slurry; Step (3) of obtaining a powder after performing a third mixing and drying on the compound containing T and G and the slurry; Step (4) of performing a second heat treatment on the powder in the presence of an atmosphere of a non-oxidizing gas, crushing the powder to obtain the olivine-type composite cathode material. A method for manufacturing an olivine-type composite cathode material, comprising: <6> In step (1), the compound containing the T element is at least one selected from the group consisting of a simple substance of T, an oxide of T, a nitrate of T, and a hydroxide of T; Preferably, the compound containing the G element is at least one selected from the group consisting of nitrogen gas, ammonia gas, melamine, polydopamine, urea, glucose, starch, sucrose, and graphite; Preferably, the conditions of the first heat treatment include a heat treatment temperature of 400 to 1000 °C and a heat treatment time of 2 to 8 h; Preferably, the molar ratio of the mole of T in the compound containing the T element to the mole of G in the compound containing the G element is 0.5 to 7:1, according to the manufacturing method described in <5>. <7> In step (2), the lithium source is at least one selected from the group consisting of lithium carbonate, lithium hydroxide, lithium oxide, and lithium nitrate; Preferably, the phosphorus source is at least one selected from the group consisting of phosphoric acid, metaphosphoric acid, pyrophosphoric acid, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, and phosphorus oxide; Preferably, the carbon source is at least one selected from the group consisting of glucose, sucrose, starch, graphene, and carbon nanotubes; Preferably, the iron source is at least one selected from the group consisting of iron phosphate, iron oxalate, iron acetate, iron oxide, and iron oxyhydroxide; Preferably, the manganese source is at least one selected from manganese oxide, manganese carbonate, and manganese nitrate, Preferably, the R source is selected from compounds containing at least one element among Si, Cl, Br, S, Sb, and Sn, Preferably, the M 1 source is selected from compounds containing at least one element among Mg, Na, and K, Preferably, the M 2 source is selected from compounds containing at least one element among Ga, Sn, V, Y, Mo, Al, Mg, Ce, Ti, Zr, Nb, Si, W, and In, Preferably, the solvent is at least one selected from water, ethanol, methanol, NMP, and isopropanol, Preferably, the molar ratio of Li of the lithium source, P of the phosphorus source, C of the carbon source, Fe of the iron source, Mn of the manganese source, R of the R source, M 1 of the M 1 source, and M 2 of the M 2 source is (0.5 to 1.3):(0 to 1):(0 to 0.05):(0 to 1):(0 to 1):(0 to 1):(0 to 0.5):(0 to 0.01), Preferably, the solid content of the slurry is 10 to 60 wt%, Preferably, the average particle size D 50 of the slurry is 0.1 to 1 μm, and the manufacturing method according to <5> or <6>. <8> In step (3), the solid-liquid ratio of the compound containing T and G and the slurry is 0.000001 to 10 g / mL, Preferably, in step (4), the conditions of the second heat treatment include a heat treatment temperature of 400 to 1000 °C and a heat treatment time of 4 to 12 h, and the manufacturing method according to any one of <5> to <7>. <9> An olivine-type composite cathode material manufactured by the manufacturing method according to any one of <5> to <8>. <10> Application of the olivine-type composite cathode material according to any one of <1> to <4> and 9 in at least one of a supercapacitor, a lithium-ion battery, and a lithium-sulfur battery. <11> A lithium-ion battery including the olivine-type composite cathode material according to any one of <1> to <4> and 9. <12> The lithium ion battery is a liquid lithium ion battery, and after 1000 cycles at 45 °C, the amount of manganese eluted from the negative electrode of the liquid lithium ion battery is ≦ 3000 ppm, preferably 500 to 2000 ppm, the lithium ion battery according to <11>.

Claims

1. An olivine-type composite cathode material, wherein the composite cathode material includes a matrix and a composite phase, the matrix has a composition represented by Formula I, Li ｘ M １ ｙ Mn ｚ Fe １－ｚ－ｕ M ２ ｕ (PO ４ ) ｗ (RO ａ ) ｂ Cv (Formula I) Among them, 0.5 ≤ x < 1.3, 0 ≤ y ≤ 0.5, 0 < z ≤ 1, 0 ≤ u ≤ 0.01, 0 < w ≤ 1, 0 < v ≤ 0.05, 0 ≤ a ≤ 8, 0 ≤ b ≤ 1, 0.3 ≤ 1 - z - u ≤ 0.4, M １ is at least one element selected from Mg, Na, and K, and M ２ is at least one element selected from Ga, Sn, V, Y, Mo, Al, Mg, Ce, Ti, Zr, Nb, Si, W, and In, and R is at least one element selected from Si, Cl, Br, S, Sb, and Sn the composite phase has a composition represented by Formula II, T ｍ G ｎ (Formula II) wherein 0.1 ≦ m ≦ 5, 0.1 ≦ n ≦ 5, T is at least one element selected from Ti, Mo, Co, W, Zn, Cu, B, V, Nb, Ta, Pd, Cr, Ag, Al, Mn, Sn, Mg, Sc, Zr, and Hf, and G is N, or an element selected from N and C, an olivine-type composite cathode material.

2. In Formula I, 0.9 ≦ x < 1.1, 0 < y ≦ 0.01, 0.5 ≦ z ≦ 1, 0 < u ≦ 0.005, 0.5 ≦ w < 1, 0.001 < v ≦ 0.03, 0 ≦ a ≦ 4, 0 < b ≦ 0.1, In Formula II, 0.5 ≦ m ≦ 3, 1 ≦ n ≦ 5, T is at least one element selected from Ti, Mo, Co, W, Zn, Cu, B, V, Nb, Ta, Cr, Ag, Al, Mn, Sn, Mg, Sc, and Zr, the olivine-type composite cathode material according to Claim 1.

3. Based on the total weight of the composite cathode material, the content of the composite phase is 0.01 to 10 wt%, the olivine-type composite cathode material according to Claim 1 or 2.

4. The compression density of the composite cathode material is 1.5 to 3 g / cm3, the olivine-type composite cathode material according to Claim 1 or 2.

5. The resistivity of the composite cathode material is ≦ 2500 Ω / cm, the olivine-type composite cathode material according to Claim 1 or 2.

6. In the composite cathode material, 0.5 ≦ m / n ≦ 7, the olivine-type composite cathode material according to Claim 1 or 2.

7. The average particle size D50 of the composite cathode material is 0.5 to 20 μm, the olivine-type composite cathode material according to Claim 1 or 2.

8. In the composite cathode material, in EDS elemental analysis, the standard dispersion of m / n at any position is ≦ 1%, the olivine-type composite cathode material according to Claim 1 or 2.

9. A method for manufacturing an olivine-type composite cathode material, performing a first mixing on a compound containing element T and a compound containing element G to obtain a first mixture, and performing a first heat treatment on the first mixture in the presence of a protective atmosphere to obtain a compound containing T and G in step (1); A lithium source, a carbon source, a phosphorus source, optionally an iron source, a manganese source, optionally an R source, optionally an M １ source, and optionally an M ２ performing a second mixing on the source and the solvent to obtain a second mixture, and polishing the second mixture to obtain a slurry (step 2); performing a third mixing and drying on the compound containing T and G and the slurry, and then obtaining a powder in step (3); Step (4) of performing a second heat treatment on the powder in the presence of an atmosphere of non-acid gas to crush the powder to obtain the olivine-type composite cathode material, In step (1), the compound containing the T element is at least one selected from the group consisting of a simple substance of T, an oxide of T, a nitrate of T, and a hydroxide of T, The compound containing the G element is at least one selected from nitrogen gas, ammonia gas, melamine, polydopamine, and urea, or a method for producing an olivine-type composite cathode material containing at least one selected from nitrogen gas, ammonia gas, melamine, polydopamine, and urea and at least one selected from glucose, starch, sucrose, and graphite.

10. In step (1), the conditions of the first heat treatment include that the heat treatment temperature is 400 to 1000 ° C and the heat treatment time is 2 to 8 h, The production method according to claim 9, wherein the molar ratio of the mole of T of the compound containing the T element to the mole of G of the compound containing the G element is 0.5 to 7:

1.

11. In step (2), the lithium source is at least one selected from lithium carbonate, lithium hydroxide, lithium oxide, and lithium nitrate, The phosphorus source is at least one selected from phosphoric acid, metaphosphoric acid, pyrophosphoric acid, ammonium dihydrogen phosphate, diamine hydrogen phosphate, and phosphorus oxide, The carbon source is at least one selected from glucose, sucrose, starch, graphene, and carbon nanotubes, The iron source is at least one selected from iron phosphate, iron oxalate, iron acetate, iron oxide, and iron oxyhydroxide, The manganese source is at least one selected from manganese oxide, manganese carbonate, and manganese nitrate, The R source is selected from compounds containing at least one element of Si, Cl, Br, S, Sb, and Sn, The foregoing M １ source is selected from compounds containing at least one element of Mg, Na, and K, The foregoing M ２ source is selected from compounds containing at least one element among Ga, Sn, V, Y, Mo, Al, Mg, Ce, Ti, Zr, Nb, Si, W, and In, The solvent is at least one selected from water, ethanol, methanol, NMP, and isopropanol, The mole of Li of the lithium source, the mole of P of the phosphorus source, the mole of C of the carbon source, the mole of Fe of the iron source, the mole of Mn of the manganese source, the mole of R of the R source, the M １ source of M １ as a mole, and the M ２ source of M ２ The molar ratio of the moles is (0.5 to 1.3):(0 to 1):(0 to 0.05):(0 to 1):(0 to 1):(0 to 1):(0 to 0.5):(0 to 0.01), and the production method according to claim 9 or 10.

12. In step (2), the solid content of the slurry is 10 to 60 wt%, and the average particle size D50 of the slurry is 0.1 to 1 μm. The production method according to claim 9 or 10.

13. In step (3), the solid-liquid ratio of the compound containing T and G to the slurry is 0.000001 to 10 g / mL, In step (4), the conditions of the second heat treatment include that the heat treatment temperature is 400 to 1000 ° C and the heat treatment time is 4 to 12 h. The manufacturing method according to claim 9 or 10.

14. Application of the olivine-type composite cathode material according to claim 1 or 2 in at least one of a supercapacitor, a lithium-ion battery, and a lithium-sulfur battery.

15. A lithium-ion battery comprising the olivine-type composite cathode material according to claim 1 or 2.

16. The lithium-ion battery according to claim 15, wherein the lithium-ion battery is a liquid lithium-ion battery, and after 1000 cycles at 45 ° C, the manganese elution amount from the negative electrode of the liquid lithium-ion battery is ≦ 3000 ppm.

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