Olivine-type composite positive electrode material, preparation method and application thereof, and lithium ion battery

Abstract

The application relates to the new energy and lithium ion battery technical field, and discloses an olivine-type composite positive electrode material, a preparation method and application thereof, and a lithium ion battery. The composite positive electrode material comprises a matrix and a composite phase; the matrix has a composition shown in formula I: Li x M 1 y Mn z Fe 1‑z‑u M 2 u (PO4) w (RO a ) b Cv formula I; the composite phase has a composition shown in formula II: T m G n Formula II. The composite phase is introduced into the positive electrode material in an in-situ mode, is uniformly compounded on the grain boundary and the surface of the positive electrode material matrix, and is closely fused with the positive electrode material matrix, the electronic conductivity and the surface structure stability of the positive electrode material in a working process are improved, the composite phase has a metalloid electronic structure, shows the characteristics of low resistivity, strong chemical adsorption capacity, stable chemical performance and the like, the composite positive electrode material has high conductivity and excellent chemical stability, and is suitable for fields of supercapacitors, lithium ion batteries and lithium-sulfur batteries and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of new energy and lithium ion battery, and particularly relates to an olivine-type composite cathode material, a preparation method and application thereof, and a lithium ion battery. BACKGROUND

[0002] The rapid development of new energy automobile power battery and energy storage battery market has prompted people to put forward higher requirements for the fast charging performance and safety performance of lithium ion batteries. The cathode material of lithium ion battery is one of the key materials with the highest cost and quality proportion in lithium ion battery, and its performance determines the energy density, fast charging performance and safety performance of lithium ion battery to a great extent. The olivine structure cathode material represented by lithium iron phosphate has become one of the mainstream cathode material systems in the current power and energy storage battery field market due to its high energy density, excellent cycle performance and safety performance, low cost and sales price.

[0003] However, the lithium iron phosphate LiFePO4 cathode material has a maximum discharge specific capacity of only 170 mAh / g due to its special chemical composition and structure, and the discharge voltage platform is usually lower than 3.4 V. The low electronic conductivity of the lithium iron phosphate LiFePO4 cathode material causes poor low-temperature performance and rate performance. The lithium manganese iron phosphate LiMn x Fe 1-x PO4 cathode material can further improve the discharge voltage platform by substituting Mn for Fe based on LiFePO4, thereby improving the energy density of the battery. However, the electronic conductivity of LiMn x Fe 1-x PO4 is even worse, and there is serious Mn dissolution, which adversely affects the low-temperature performance, rate performance, cycle performance and safety performance of the battery, so it has not been truly industrialized and applied. SUMMARY

[0004] The present application relates to the technical field of new energy and lithium ion battery, and particularly relates to an olivine-type composite cathode material, a preparation method and application thereof, and a lithium ion battery, the olivine-type composite cathode material contains 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, which can make the composite phase uniformly composite and tightly fuse with the matrix of the cathode material at the grain boundaries and surface of the cathode material matrix, thereby improving the electronic conductivity and surface structure stability of the cathode material during the working process, and the composite phase T m G nThe electronic structure with metalloid generally exhibits low resistivity (<10 Ω·cm), strong chemical adsorption capacity, stable chemical properties and the like, so that the composite positive electrode material containing the composite phase has high conductivity and excellent chemical stability, and can be applied to the fields of supercapacitors, lithium ion batteries and lithium-sulfur batteries, and the like. In particular, the lithium ion battery containing the composite positive electrode material has significantly improved rate performance and cycle life.

[0005] To achieve the above-mentioned purpose, the first aspect of the present application provides an olivine-type composite positive electrode material, characterized in that the composite positive electrode material comprises a matrix and a composite phase.

[0006] The matrix has a composition shown in Formula I:

[0007] Li x M 1 y Mn z Fe 1-z-u M 2 u (PO4) w (RO a ) b Cv Formula I;

[0008] 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 selected from at least one element of Mg, Na and K; M 2 is selected from at least one element of Ga, Sn, V, Y, Mo, Al, Mg, Ce, Ti, Zr, Nb, Si, W and In; R is selected from at least one element of Si, Cl, Br, S, Sb and Sn;

[0009] The composite phase has a composition shown in Formula II:

[0010] T m G n Formula II;

[0011] Wherein, 0.1≤m≤5, 0.1≤n≤5, T is selected from at least one element of Ti, Mo, Co, W, Zn, Cu, B, V, Nb, Ta, Pd, Cr, Ag, Al, Mn, Sn, Mg, Sc, Zr and Hf, and G is selected from N and / or C.

[0012] The second aspect of the present application provides a preparation method of an olivine-type composite positive electrode material, characterized in that the method comprises the following steps:

[0013] (1) mixing a compound containing T element with a compound containing 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;

[0014] (2) mixing a lithium source, a carbon source, a phosphorus source, optionally a ferrous source, a manganese source, optionally an R source, optionally an M 1 source, optionally an M 2 source, and a solvent to obtain a second mixture, and grinding the second mixture to obtain a slurry;

[0015] (3) mixing the compound containing T and G with the slurry, drying to obtain a powder;

[0016] (4) performing a second heat treatment on the powder in the presence of a non-oxidizing atmosphere, and crushing to obtain the olivine-type composite cathode material.

[0017] The third aspect of the present application provides an olivine-type composite cathode material prepared by the above preparation method. The fourth aspect of the present application provides 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.

[0018] The fifth aspect of the present application provides a lithium ion battery, characterized in that the lithium ion battery comprises the above olivine-type composite cathode material.

[0019] Through the above technical solutions, the olivine-type composite cathode material, the preparation method and the application thereof, and the lithium ion battery provided by the present application have the following beneficial effects:

[0020] (1) The olivine-type composite cathode material provided by the present application comprises 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, which can make the composite phase uniformly composite at the grain boundaries and the surface of the cathode material matrix and tightly fuse with the cathode material matrix, thereby improving the electronic conductivity and the surface structure stability of the cathode material during the working process, making the composite cathode material exhibit the characteristics of low resistivity (<10 Ω·cm), strong chemical adsorption capacity, stable chemical performance, etc., and being applicable to the fields of supercapacitors, lithium ion batteries and lithium-sulfur batteries, etc. In particular, the lithium ion battery comprising the composite cathode material has significantly improved rate performance and cycle life.

[0021] (2) The preparation method of the olivine-type composite positive electrode material provided by the application can make the composite phase formed by the T and G containing compound uniformly composite at the grain boundary and surface of the positive electrode material matrix and tightly fuse with the positive electrode material matrix, thereby improving the electronic conductivity and surface structure stability of the positive electrode material during the working process, and the raw material source is abundant, the preparation cost is low, and the overall process is easy to industrialize.

[0022] (3) The preparation method of the olivine-type composite positive electrode material provided by the application can complete the material matrix synthesis, carbon coating, and T and G containing compound and matrix material compounding through only one sintering, thereby shortening the sample preparation time, effectively saving energy, and reducing carbon emissions. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 T distribution diagram of sintered material for Example 3;

[0024] Figure 2 T distribution diagram of sintered material for Comparative Example 3;

[0025] Figure 3 0.1C rate charge-discharge curve and 2C rate charge-discharge curve of the liquid ion battery assembled by the positive electrode material of Comparative Example 3 and Example 3;

[0026] Figure 4 1C cycle performance diagram of the liquid ion battery assembled by the positive electrode material of Comparative Example 3 and Example 3. DETAILED DESCRIPTION

[0027] The endpoints of the ranges and any values disclosed herein are not limited to the precise values recited as the exact dimensions are not critical to the application. Any numerical values need not be a precision as the same is understood in the art. For values whose endpoints contain the integer, we consider the integer as an explicit disclosable endpoint. For values whose endpoints do not contain the integer, we do not consider the integer as an explicit disclosable endpoint. The disclosure of a range should be considered as a disclosure of any value and subset of the range. For numerical values that include only whole numbers, any number in the range should be considered a separate and independent disclosure.

[0028] The first aspect of the application provides an olivine-type composite positive electrode material, characterized in that the composite positive electrode material comprises a matrix and a composite phase.

[0029] The matrix has a composition shown in formula I:

[0030] Li x M 1 y Mn z Fe 1-z-u M 2u (PO4) w (RO a ) b Cv formula I;

[0031] wherein, 0.5≤x<1.3, 0≤y≤0.5, 0 1 at least one element selected from Mg, Na and K; M 2 at least one element selected from Ga, Sn, V, Y, Mo, Al, Mg, Ce, Ti, Zr, Nb, Si, W and In; R is at least one element selected from Si, Cl, Br, S, Sb and Sn;

[0032] The composite phase has a composition shown in formula II:

[0033] T m G n formula II;

[0034] 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, Nb, Ta, Pd, Cr, Ag, Al, Mn, Sn, Mg, Sc, Zr and Hf, and G is selected from N and / or C.

[0035] In the present application, the olivine-type composite cathode material comprises a matrix and a composite phase T m G n , and the composite phase is introduced into the cathode material in situ, which can make the composite phase uniformly composite and closely fuse with the matrix of the cathode material at the grain boundaries and surface of the cathode material matrix, thereby improving the electronic conductivity and surface structure stability of the cathode material during the working process.

[0036] Further, the composite phase T m G n , such as TiN, MoN, Co3N, W2N, VN and the like has a metalloid electronic structure, and usually exhibits low resistivity (<10 Ω·cm), strong chemical adsorption capacity, stable chemical properties and the like, thereby making the composite cathode material containing the composite phase have high conductivity and excellent chemical stability, which can be applied in the fields of supercapacitors, lithium ion batteries and lithium-sulfur batteries and the like, in particular, the lithium ion battery containing the composite cathode material has significantly improved rate performance and cycle life.

[0037] Further, in formula I, 0.9≤x<1.1, 0 0.5≤z≤1, 0

[0038] Further, in formula II, 0.5≤m≤3, 1≤n≤5, T is selected from at least one element of Ti, Mo, Co, W, Zn, Cu, B, V, Nb, Ta, Cr, Ag, Al, Mn, Sn, Mg, Sc and Zr.

[0039] According to the present application, the content of the composite phase is 0.01-10wt% based on the total weight of the composite cathode material.

[0040] In the present application, the content of the composite phase in the composite cathode material is measured by ICP method.

[0041] In the present application, when the content of the composite phase in the composite cathode material meets the above range, the interface electron conductivity and the structural stability of the matrix can be improved, so that the composite cathode material has low powder resistivity and excellent surface stability, and when the composite cathode material is used in lithium ion battery, the rate performance and cycle performance of the lithium ion battery can be significantly improved, and the manganese dissolution amount is reduced.

[0042] Further, the content of the composite phase is 0.01-1wt% based on the total weight of the composite cathode material.

[0043] According to the present application, the compaction density of the composite cathode material is 1.5-3g / cm 3 .

[0044] In the present application, the composite cathode material has high compaction density, and when the composite cathode material is used in lithium ion battery, more cathode material can be carried in the same volume, thereby improving the battery capacity and energy density.

[0045] Further, the compaction density of the composite cathode material is 2-3g / cm 3 .

[0046] According to the present application, the resistivity of the composite cathode material is ≤2500Ω / cm.

[0047] In the present application, the composite cathode material has low resistivity, which indicates that the composite cathode material has high conductivity, so that when the composite cathode material is used in lithium ion battery, the rate performance and cycle life of the lithium ion battery can be improved.

[0048] Further, the resistivity of the composite cathode material is ≤1000Ω / cm.

[0049] According to the present application, in the composite cathode material, 0.5≤m / n≤7.

[0050] In the present application, when m / n satisfies the above range, it indicates that the composite phase of the composite cathode material is a pure phase, and the advantages of high electrical conductivity and structural stability of the composite phase can be fully utilized, so that the lithium ion battery containing the composite cathode material has excellent rate performance and cycle performance.

[0051] In the present application, the content m of the T element in the composite cathode material is measured by EDS surface scanning; and the content n of the G element is measured by EDS surface scanning.

[0052] Further, in the composite cathode material, 1≤m / n≤5.

[0053] According to the present application, the average particle size D of the composite cathode material is 0.5-20 μm, preferably 1-15 μm. 50

[0054] According to the present application, in the EDS element analysis of the composite cathode material, the standard deviation of m / n at any position is ≤1%.

[0055] In the present application, in the EDS element analysis of the composite cathode material, at any position, the composite phase T m G n , the standard deviation of the molar ratio m / n of the T element and the G element satisfies the above range, which indicates that the composite phase T m G n is uniformly compounded in the cathode material, and exists in the form of T m G n pure phase, thereby ensuring the characteristics of low electrical resistivity and structural stability of the composite phase, and further maintaining the electrical resistivity of the composite cathode material at a low level, ensuring the smoothness of the electron transmission channel during the charging and discharging process, and ensuring the stability of the surface structure and the low metal dissolution rate. 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.

[0056] Further, the standard deviation of m / n is ≤0.8%.

[0057] The second aspect of the present application provides a preparation method of an olivine-type composite cathode material, characterized in that the method comprises the following steps:

[0058] (1) mixing a compound containing a T element with 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;

[0059] (2) mixing 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 The source is mixed with a solvent to obtain a second mixture, and the second mixture is ground to obtain a slurry;

[0060] (3) The T and G containing compound is third mixed with the slurry, and after drying, a powder is obtained;

[0061] (4) The powder is subjected to a second heat treatment in the presence of a non-oxidizing atmosphere, and after crushing, the olivine type composite positive electrode material is obtained.

[0062] In the present application, by heat treating the mixture of the T element containing compound and the G element containing compound in a protective atmosphere, introducing the heat treated T and G containing compound into the composite olivine type positive electrode material, the composite phase formed by the T and G containing compound is uniformly compounded at the grain boundary and surface of the positive electrode material matrix and tightly fused with the positive electrode material matrix, thereby improving the electronic conductivity and surface structure stability of the positive electrode material during operation, and the raw material source is abundant, the preparation cost is low, and the overall process is easy to industrialize.

[0063] Further, the preparation method provided by the present application can complete the material matrix synthesis, carbon coating, and T and G containing compound and matrix material compounding by only one sintering, thereby shortening the sample preparation time, effectively saving energy, and reducing carbon emissions.

[0064] According to the present application, in step (1), the T element containing compound is selected from at least one of the elemental T, the oxide of T, the nitrate of T, and the hydroxide of T.

[0065] In the present application, the morphology of the oxide of T is not particularly limited, for example, the oxide of T can be selected from at least one of nanoparticles, nanosheets, and nanowires.

[0066] In the present application, the average particle size D 50 of the oxide of T is 0.001-1 μm.

[0067] According to the present application, the G element containing compound is selected from at least one of nitrogen, ammonia, melamine, polydopamine, urea, glucose, starch, sucrose, and graphite.

[0068] Further, the G element containing compound is selected from at least one of nitrogen, ammonia, urea, and glucose.

[0069] According to the present application, the conditions of the first heat treatment include that the heat treatment temperature is 400-1000℃, and the heat treatment time is 2-8h.

[0070] In the present application, the first mixture is subjected to heat treatment under the above conditions, so that the compound containing the element T and the compound containing the element G can be completely converted into a pure-phase compound containing the elements T and G (nitride and / or carbide), and the composite phase in the composite positive electrode material prepared by compounding the compound containing the elements T and G with the slurry can be ensured to be a pure phase, thereby making the prepared composite positive electrode material have high electrical conductivity and good structural stability, and when the composite positive electrode material is used in a lithium ion battery, the rate performance and cycle performance of the lithium ion battery can be significantly improved.

[0071] Further, the conditions of the first heat treatment include that the heat treatment temperature is 500-800 DEG C, and the heat treatment time is 4-10 h.

[0072] According to the present application, the molar ratio of the compound containing the element T to the compound containing the element G is 0.5-7:1.

[0073] In the present application, when the molar ratio of the compound containing the element T to the compound containing the element G satisfies the above range, the composite phase in the composite positive electrode material prepared by compounding the compound containing the elements T and G with the slurry can be ensured to be a pure phase, thereby making the prepared composite positive electrode material have high electrical conductivity and good structural stability, and when the composite positive electrode material is used in a lithium ion battery, the rate performance and cycle performance of the lithium ion battery can be significantly improved.

[0074] In the present application, the conditions of the first mixing are not particularly limited, as long as the compound containing the element T and the compound containing the element G can be sufficiently mixed and uniform. Preferably, the conditions of the first mixing include that the mixing rotation speed is 100-1000 rpm, and the mixing time is 1-10 h.

[0075] In the present application, the method of the first mixing is not particularly limited, and the first mixing can be realized by the method in the art, specifically, the method of the first mixing is selected from at least one of mechanical planetary mixing, mechanical high-speed mixing, ball milling and sand milling.

[0076] In the present application, the type of the protective atmosphere is not particularly limited, and a conventional protective atmosphere in the art can be selected, for example, nitrogen and / or argon.

[0077] According to the present application, in step (2), the lithium source is selected from at least one of lithium carbonate, lithium hydroxide, lithium oxide and lithium nitrate.

[0078] According to the present application, the phosphorus source is selected from at least one of phosphoric acid, metaphosphoric acid, pyrophosphoric acid, ammonium dihydrogen phosphate, diammonium hydrogen phosphate and phosphorus oxide.

[0079] According to the present application, the carbon source is selected from at least one of glucose, sucrose, starch, graphene and carbon nanotube.

[0080] According to the present application, the iron source is selected from at least one of ferric phosphate, ferrous oxalate, ferric acetate, ferroferric oxide and hydroxy ferric oxide.

[0081] According to the present application, the manganese source is selected from at least one of manganese oxide, manganese carbonate and manganese nitrate.

[0082] According to the present application, the R source is selected from a compound containing at least one element of Si, Cl, Br, S, Sb and Sn. Specifically, the R source is selected from at least one of an acid containing R element, an oxide containing R element and a hydroxide containing R element.

[0083] According to the present application, the M 1 source is selected from a compound containing at least one element of Mg, Na and K. Specifically, the M 1 source is selected from at least one of an oxide containing M 1 element, a hydroxide containing M 1 element and a carbonate containing M 1 element.

[0084] According to the present application, the M 2 source is selected from a compound 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 selected from at least one of an oxide containing M 2 element, a hydroxide containing M 2 element and a carbonate containing M 2 element.

[0085] According to the present application, the solvent is selected from at least one of water, ethanol, methanol, NMP and isopropanol.

[0086] According to the present application, the molar ratio of the lithium source calculated as Li, the phosphorus source calculated as P, the carbon source calculated as C, the iron source calculated as Fe, the manganese source calculated as Mn, the R source calculated as R, the M 1 source calculated as M 1 source calculated as M 2 source calculated as M 2 is (0.5-1.3):(0-1):(0-0.05):(0-1):(0-1):(0-1):(0-0.5):(0-0.01), wherein the amount of the phosphorus source, the manganese source and the carbon source is not 0.

[0087] In the present application, when the lithium source, the phosphorus source, the carbon source, the iron source, the manganese source, the R source, the M 1 source, the M 2 source meet the above range, the prepared composite positive electrode material has high ionic conductivity and excellent structural stability, and when it is used in a lithium ion battery, the charge-discharge capacity, rate performance and cycle performance of the lithium ion battery can be significantly improved.

[0088] Further, the molar ratio of the lithium source calculated by Li, the phosphorus source calculated by P, the carbon source calculated by C, the iron source calculated by Fe, the manganese source calculated by Mn, the R source calculated by R, the M 1 source calculated by M 1 , the M 2 source calculated by M 2 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), wherein the content of the M 1 source, the iron source, the R source and the M 2 source is not zero.

[0089] According to the present application, the solid content of the slurry is 10-60wt%.

[0090] Further, the solid content of the slurry is 20-50wt%.

[0091] In the present application, the amount of solvent is not particularly required, as long as the solid content of the slurry meets the above range.

[0092] According to the present application, the average particle size D 50 of the slurry is 0.1-1μm.

[0093] In the present application, when the average particle size D 50 of the slurry meets the above range, it is beneficial to improve the loose bulk density of the powder after the slurry and the compound containing T and G are dried, to improve the loading amount and sintering capacity. Further, controlling the average particle size of the slurry to meet the above range is more suitable for spray drying.

[0094] Further, the average particle size D 50 of the slurry is 0.1-0.8μm.

[0095] In the present application, the conditions of the second mixing are not particularly limited, as long as the lithium source, the phosphorus source, the carbon source, the iron source, the manganese source, the R source, the M 1 source, the M 2 source and the solvent can be fully mixed and uniform.

[0096] In the present application, the grinding conditions are not particularly limited, as long as the average particle size D 50 The grinding conditions include a grinding rotation speed of 500-2000 rpm and a grinding time of 1-10 h.

[0097] In the present application, the grinding method is not particularly limited, and the grinding can be achieved by any method known in the art. Specifically, the grinding method is selected from at least one of stirring grinding, ball grinding, and sand grinding.

[0098] In the present application, the grinding includes grinding the second mixture to obtain the slurry. The grinding equipment includes one or more of stirring grinding, ball grinding, and sand grinding.

[0099] According to the present application, in step (3), the solid-liquid ratio of the T and G containing compound to the slurry is 0.000001-10 g / mL.

[0100] In the present application, when the solid-liquid ratio of the T and G containing compound to the slurry satisfies the above range, the T and G containing compound has good dispersibility in the slurry, and the composite phase and the matrix in the positive electrode material prepared therefrom can be uniformly compounded without aggregation, so that the lithium ion battery containing the composite positive electrode material has more stable electrochemical performance.

[0101] Further, the solid-liquid ratio of the T and G containing compound to the slurry is 0.00001-1 g / mL.

[0102] In the present application, the third mixing conditions are not particularly limited, as long as the T and G containing compound and the slurry can be sufficiently mixed and uniformly dispersed.

[0103] In the present application, the drying conditions and the drying equipment are not particularly limited, as long as the mixture of the T and G containing compound and the slurry can be sufficiently dried. The drying equipment can be selected from at least one of a spray dryer, a blast oven, a vacuum oven, a freeze dryer, and a flash evaporator.

[0104] According to the present application, in step (4), the second heat treatment conditions include a heat treatment temperature of 400-1000℃ and a heat treatment time of 4-12 h.

[0105] In the present application, the second heat treatment of the powder under the above conditions can in-situ compound T m G n in the matrix material during phase formation, and make the composite phase T m G nThe prepared composite positive electrode material has high conductivity and excellent cycle performance, and when the positive electrode material is used in a lithium ion battery, the rate performance and cycle performance of the lithium ion battery can be significantly improved.

[0106] Further, the second heat treatment has a temperature of 500-900 DEG C and a time of 6-10 hours.

[0107] In the present application, the non-oxidizing atmosphere is not particularly limited, and conventional non-oxidizing atmospheres such as nitrogen and / or argon can be used.

[0108] In the present application, the device used for crushing is not particularly limited, and conventional devices such as at least one of a mechanical mill, a colloid mill and an air jet mill can be used.

[0109] The third aspect of the present application provides an olivine-type composite positive electrode material prepared by the above preparation method.

[0110] The fourth aspect of the present application provides a use of the above olivine-type composite positive electrode material in at least one of a supercapacitor, a lithium ion battery and a lithium-sulfur battery.

[0111] The fifth aspect of the present application provides a lithium ion battery, characterized in that the lithium ion battery comprises the above olivine-type composite positive electrode material.

[0112] In the present application, when the olivine-type composite positive electrode material is a Mn-containing positive electrode material, i.e. z is not 0, the lithium ion battery using the olivine-type composite positive electrode material is a liquid lithium ion battery, and after 1000 cycles at 45 DEG C, the manganese dissolution amount of the negative electrode of the liquid lithium ion battery is ≤3000 ppm, preferably 500-2000 ppm.

[0113] The present application will be described in detail below by way of examples. In the following examples,

[0114] The composition of the composite positive electrode material is measured by an ICP method;

[0115] The content of the composite phase in the composite positive electrode material is measured by an ICP method;

[0116] The compaction density of the composite positive electrode material is measured by a powder compaction density instrument method;

[0117] The resistivity of the composite positive electrode material is measured by a resistivity instrument method;

[0118] The content of element G in the composite cathode material is measured by EDS area scanning; the content and distribution of element T are measured by EDS area scanning.

[0119] The raw materials used in the examples and comparative examples are commercially available.

[0120] Example 1

[0121] (1) 10 g of TiO2nanoparticles with an average particle size of 0.05 μm and 80 g of urea were mixed in a ball mill tank at 600 rpm for 5 h, and the mixture was placed in a tube furnace for heat treatment at 550 °C under a nitrogen atmosphere for 10 h to obtain TiN nanoparticles. The molar ratio of the T-containing compound to the G-containing compound was 1:1 in terms of T and G, respectively.

[0122] (2) 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) were mixed in 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 a particle size of 0.62 μm. The molar ratio of the lithium source to the phosphorus source to the carbon source to the iron source to the manganese source was 1:1:0.1:0.4:0.6 in terms of Li, P, C, Fe, and Mn, respectively. The solid content of the slurry was 45 wt%. 50

[0123] (3) The slurry obtained in step (2) was mechanically stirred with 0.3 g of TiN nanoparticles for 30 min to obtain a uniformly dispersed mixed slurry, and the mixed slurry was dried in a spray dryer to obtain a powder. The solid-liquid ratio of the TiN nanoparticles to the slurry was 0.0001 g / mL.

[0124] (4) The powder obtained in step (3) was treated at 750 °C under a nitrogen atmosphere in a tube furnace for 8 h to obtain a sintered material, which was crushed by a jet mill to obtain the olivine-type composite cathode material A1. The amounts of the materials used in the preparation process and the process conditions are shown in Table 1.

[0125] A portion of the sintered material was subjected to plasma beam cutting to obtain a material section, and the uniformity of the distribution of Ti element in the material was tested by EDS area scanning. The results are shown in Table 2.

[0126] The composition, the content of the composite phase, the particle size, the compacted density, the resistivity, and T / G of the olivine-type composite cathode material A1 were tested, and the results are shown in Table 2.

[0127] Example 2

[0128] ​(1) Weigh 10g of Co3O4 nanosheets with an average particle size of 0.09μm and mix them with 80g of melamine in a ball mill jar at 600rpm for 5h. Place the mixture in a tube furnace and heat-treat it at 600℃ for 10h under a nitrogen atmosphere to obtain Co3N nanoparticles. The molar ratio of the compound containing element T to the compound containing element G is 3:1.

[0129] (2) Weigh out 24.04g of lithium carbonate (lithium source), 95.93g of iron phosphate (iron source, phosphorus source), 44.16g of manganese carbonate (manganese source), and 0.04g of titanium dioxide (M). 2 14.34 g of glucose (carbon source) was mixed with 200 g of pure water. The mixture was then ball-milled in a planetary ball mill at 500 rpm for 6 hours to obtain D. 50 The slurry has a particle size of 0.48 μm. The composition is as follows: (calculated as Li), (calculated as P), (calculated as C), (calculated as Fe), (calculated as Mn), and (calculated as Mn). 2 The M 2 The molar ratio of the sources is 1:1:0.1:0.4:0.599:0.001. The solid content of the slurry is 45 wt%.

[0130] (3) The slurry obtained in step (2) is mechanically stirred with 0.2g of Co3N nanoparticles for 30min to obtain a uniformly dispersed mixed slurry. The mixed slurry is then dried in a spray dryer to obtain powder. The solid-liquid ratio of the Co3N nanoparticles to the slurry is 0.001g / mL.

[0131] (4) The powder obtained in step (3) is treated at 800°C for 8 hours in a tube furnace under a nitrogen atmosphere to obtain sintered material, which is then pulverized by an air jet mill to obtain the olivine-type composite cathode material A2.

[0132] A portion of the sintered material was subjected to plasma beam cutting to obtain a material profile. The uniformity of Co element distribution in the material was tested by EDS surface scanning, and the results are shown in Table 1.

[0133] The composition, composite phase content, particle size, compaction density, resistivity, and T / G of the olivine-type composite cathode material A2 were tested, and the results are shown in Table 1.

[0134] Example 3

[0135] (1) 10g of MoO3 nanowires with an average particle size of 0.07μm were weighed and heat-treated in a tube furnace at 700℃ for 10h under an ammonia atmosphere to obtain MoN nanoparticles. The molar ratio of the compound containing element T to the compound containing element G is 1:1.

[0136] (2) Weigh out 24.28g lithium carbonate (lithium source), 99.96g ferric nitrate (iron source), 132.83g manganese nitrate (manganese source), 73.52g phosphoric acid (phosphorus source), and 0.17g niobium oxide (M 2 62.52g of glucose (carbon source) was mixed with 200g of pure water. The mixture was stirred at 300rpm for 6 hours in a mechanical mixer to obtain a slurry. The lithium source was calculated as Li, the phosphorus source as C, the carbon source as Fe, the iron source as Mn, and the manganese source as Mn. 2 The M 2 The molar ratio of the sources is 1:1:0.1:0.398:0.6:0.002. The solid content of the slurry is 45 wt%.

[0137] (3) The slurry obtained in step (2) is mechanically stirred with 0.5g of MoN nanoparticles for 30min to obtain a uniformly dispersed mixed slurry. The mixed slurry is then dried in a vacuum oven to obtain a dry gel powder. The solid-liquid ratio of the MoN nanoparticles to the slurry is 0.0001g / mL.

[0138] (4) The powder obtained in step (3) is treated at 760°C for 8 hours in a tube furnace under a nitrogen atmosphere to obtain sintered material, which is then pulverized by an air jet mill to obtain the olivine-type composite cathode material A3.

[0139] A portion of the sintered material was subjected to plasma beam cutting to obtain a material profile. The uniformity of the distribution of Mo elements in the material was tested by EDS surface scanning, and the results are shown in Table 1.

[0140] The composition, composite phase content, particle size, compaction density, resistivity, and T / G of the olivine-type composite cathode material A3 were tested, and the results are shown in Table 1.

[0141] Example 4

[0142] (1) Weigh 10g of V2O5 nanoparticles with an average particle size of 0.05μm and mix them with 20g of urea in a ball mill jar at 600rpm for 5h. Place the mixture in a tube furnace and heat-treat it at 550℃ for 10h under an ammonia atmosphere to obtain VN nanoparticles. The molar ratio of the compound containing element T to the compound containing element G is 1:1.

[0143] (2) Weigh out 24.04g of lithium carbonate (lithium source), 95.58g of ferric ammonium manganese phosphate (phosphorus source, iron source, manganese source), 14.34g of glucose (carbon source), and 0.06g of magnesium carbonate (M). 1 Source), 0.17g niobium oxide (M) 2The mixture is ball milled in a planetary ball mill at a speed of 500 rpm for 6 h to obtain D 50 The slurry has a solid content of 45 wt%. The molar ratio of the lithium source, the phosphorus source, the carbon source, the iron source, the manganese source, the M 1 source, the M 1 source, the M 2 source, the M 2 source is 1:1:0.1:0.398:0.6:0.001:0.002.

[0144] (3) The slurry obtained in step (2) is mechanically stirred with 0.3 g of VN nanoparticles for 30 min to obtain a uniformly dispersed mixed slurry, and the mixed slurry is dried in a spray dryer to obtain a powder. The solid-liquid ratio of the VN nanoparticles to the slurry is 0.0001 g / mL.

[0145] (4) The powder obtained in step (3) is treated at 750°C for 8 h under a nitrogen atmosphere in a tube furnace to obtain a sintered material, and the sintered material is pulverized by a jet mill to obtain the olivine-type composite positive electrode material A4.

[0146] A portion of the sintered material is subjected to plasma beam cutting to obtain a material section, and the uniformity of the V element in the material is tested by EDS area scanning. The results are shown in Table 1.

[0147] The composition, the content of the composite phase, the particle size, the compacted density, the resistivity, and the T / G of the olivine-type composite positive electrode material A4 are tested, and the results are shown in Table 1.

[0148] Example 5

[0149] (1) B2O3 nanosheets with an average particle size of 0.09 μm and glucose are mixed in a ball mill tank at 600 rpm for 5 h, and the mixture is placed in a tube furnace and heat treated at 1800°C for 5 h under a nitrogen atmosphere to obtain B4C nanoparticles. The molar ratio of the T-containing compound to the G-containing compound is 4:1.

[0150] (2) 24.04 g of lithium carbonate (lithium source), 111.92 g of iron phosphate (phosphorus source and iron source), 33.12 g of manganese carbonate (manganese source), 0.04 g of titanium oxide (M 2 source), and 14.34 g of glucose (carbon source) are mixed in 200 g of pure water, and the mixture is ball milled in a planetary ball mill at a speed of 500 rpm for 6 h to obtain D 50The slurry has a solid content of 45 wt%. The molar ratio of the lithium source, the phosphorus source, the carbon source, the iron source, the manganese source, and the M source, calculated based on Li, P, C, Fe, Mn, and M, respectively, is 1:1:0.1:0.3:0.699:0.001. 2 2 The slurry has a solid content of 45 wt%. The molar ratio of the lithium source, the phosphorus source, the carbon source, the iron source, the manganese source, and the M source, calculated based on Li, P, C, Fe, Mn, and M, respectively, is 1:1:0.1:0.3:0.699:0.001.

[0151] (3) The slurry obtained in step (2) is mechanically stirred with 0.2 g of B4C nanoparticles for 30 min to obtain a uniformly dispersed mixed slurry, and the mixed slurry is subjected to drying treatment in a spray dryer to obtain a powder. The solid-liquid ratio of the B4C nanoparticles to the slurry is 0.00015 g / mL.

[0152] (4) The powder obtained in step (3) is subjected to treatment at 800°C for 8 h under a nitrogen atmosphere in a tube furnace to obtain a sintered material, and the sintered material is subjected to pulverization by a jet mill to obtain the olivine-type composite cathode material A5.

[0153] A portion of the sintered material is subjected to plasma beam cutting to obtain a material section, and the uniformity of the distribution of B elements in the material is tested by EDS area scanning. The results are shown in Table 1.

[0154] The composition, the content of the composite phase, the particle size, the tap density, the resistivity, and the T / G of the olivine-type composite cathode material A5 are tested, and the results are shown in Table 1.

[0155] Example 6

[0156] (1) 10 g of TiO2nanoparticles with an average particle size of 0.05 μm and 80 g of urea are mixed in a ball mill jar at 600 rpm for 5 h, and the mixed material is placed in a tube furnace and subjected to heat treatment at 550°C under a nitrogen atmosphere for 10 h to obtain TiN nanoparticles. The molar ratio of the T-containing compound to the G-containing compound, calculated based on T and G, respectively, is 1:1.

[0157] (2) 10 g of TiO2nanoparticles with an average particle size of 0.05 μm and 100 g of glucose are mixed in a ball mill jar at 600 rpm for 5 h, and the mixed material is placed in a tube furnace and subjected to heat treatment at 550°C under a nitrogen atmosphere for 10 h to obtain TiC nanoparticles. The molar ratio of the T-containing compound to the G-containing compound, calculated based on T and G, respectively, is 1:1.

[0158] ​(3) Take 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) in 200 g of pure water, and mix them. Mill the mixture in a planetary ball mill at a speed of 500 rpm for 6 h to obtain a slurry D. 50 The slurry has a solid content of 45 wt%. The molar ratio of the lithium source (calculated as Li), the phosphorus source (calculated as P), the carbon source (calculated as C), the iron source (calculated as Fe), the manganese source (calculated as Mn), and the R source (calculated as R) is 1:1:0.1:0.4:0.6:0.01.

[0159] (4) Mechanically stir the slurry obtained in step (2) with 0.15 g of TiN and 0.15 g of TiC nanoparticles for 30 min to obtain a uniformly dispersed mixed slurry, and dry the mixed slurry in a spray dryer to obtain a powder. The solid-liquid ratio of the TiN / TiC nanoparticles to the slurry is 0.0001 g / mL.

[0160] (5) The same as step (1) in Example 1, to obtain the olivine-type composite cathode material A6.

[0161] Take part of the sintered material to obtain a material section by plasma beam cutting, and test the uniformity of the Ti element in the material by EDS area scanning. The results are shown in Table 1.

[0162] Test the composition, content of composite phase, particle size, tap density, resistivity, and T / G of the olivine-type composite cathode material A6. The results are shown in Table 1.

[0163] Comparative Example 1

[0164] Prepare the cathode material according to the method of Example 1, except that:

[0165] Step (1) is not performed;

[0166] No TiN nanoparticles are added in step (3).

[0167] Obtain an olivine-type cathode material D1. Test the composition, content of composite phase, particle size, tap density, and resistivity of the olivine-type composite cathode material D1. The results are shown in Table 1.

[0168] Comparative Example 2

[0169] Prepare the cathode material according to the method of Example 1, except that:

[0170] Step (1) is not performed;

[0171] In step (2), 24.04 g of lithium carbonate (lithium source), 95.93 g of iron phosphate (iron source and 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 weighed and mixed in 200 g of pure water. The mixture was ball milled in a planetary ball mill at a speed of 500 rpm for 6 h to obtain a slurry. The molar ratio of the lithium source calculated based on Li, the phosphorus source calculated based on P, the carbon source calculated based on C, the iron source calculated based on Fe, the manganese source calculated based on Mn, and the calcium oxide calculated based on Ca was 1:1:0.1:0.4:0.6:0.0001. The solid content of the slurry was 30 wt%. 50 The average particle size D 50 of the sintered material was 1.5 μm, and the chemical formula of the broken material was LiMn 0.6 Fe 0.398 Ba 0.002 PO4 C 0.1 .

[0172] In step (3), no TiN nanoparticles were added.

[0173] The olivine-type positive electrode material D2 was prepared.

[0174] The composition, content of the composite phase, particle size, tap density, and resistivity of the olivine-type composite positive electrode material D2 were tested, and the results are shown in Table 1.

[0175] Comparative Example 3

[0176] The positive electrode material was prepared according to the method of Example 1.

[0177] Step (1) was the same as step (1) in Example 1.

[0178] In step (2), 24.04 g of lithium carbonate (lithium source), 95.93 g of iron phosphate (iron source and 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 weighed and mixed in 200 g of pure water. The mixture was ball milled in a planetary ball mill at a speed of 500 rpm for 6 h to obtain a slurry. The molar ratio of the lithium source calculated based on Li, the phosphorus source calculated based on P, the carbon source calculated based on C, the iron source calculated based on Fe, the manganese source calculated based on Mn, and the calcium oxide calculated based on Ca was 1:1:0.1:0.4:0.6:0.0001. The solid content of the slurry was 30 wt%.

[0179] Step (3) in Example 1 was not performed.

[0180] In step (4), the second heat treatment was performed at 750°C for 8 h to obtain a sintered material, which was crushed by a jet mill to obtain a broken material with an average particle size D 50 of 1.5 μm and a chemical formula of LiMn 0.6 Fe 0.398 Ba 0.002 PO4 C 0.1 .

[0181] Step (5): The LiMn 0.6 Fe 0.398 Ba 0.002 PO4C 0.1 The crushed material and the TiN nanoparticles obtained in step (1) are mixed in a ball mill tank at a rotation speed of 850 rpm for 4 h to obtain a mixture, and the mixture is heat treated at 600°C for 4 h under a nitrogen atmosphere to finally obtain a sintered material of the chemical formula LiMn 0.6 Fe 0.398 Ba 0.002 PO4C 0.1 @TiN olivine-type positive electrode material D3. Among them, the amount of TiN nanoparticles is 15wt% relative to LiMn 0.6 Fe 0.398 Ba 0.002 PO4C 0.1 The crushed material, and the amount of TiN nanoparticles is 15wt%.

[0182] Part of the material is taken for EDS surface scanning test to test the uniformity of Ti element in the material, and the results are shown in Table 1.

[0183] The composition, the content of the composite phase, the particle size, the compactness density, the resistivity and the T / G of the olivine-type composite positive electrode material D3 are tested, and the results are shown in Table 1.

[0184] Table 1

[0185]

[0186]

[0187] Table 1 (continued)

[0188]

[0189] As can be seen from Table 1, compared with Comparative Examples 1-3, the positive electrode materials prepared in Examples 1-6 have high compactness density and low resistivity, specifically, the compactness density is generally higher than 2 g / cm 3 , and the resistivity is lower than 500Ω·cm, at the same time, the T element in the positive electrode materials prepared in Examples 1-6 is uniformly distributed, so the electrical performance of the lithium ion battery assembled from the above positive electrode materials, especially the high rate performance, is excellent, while the resistivity of the positive electrode materials prepared in Comparative Examples 1-3 is higher than 2500Ω·cm, and the T element is not uniformly distributed, the electrical performance of the lithium ion battery assembled from the positive electrode materials is poor, and the rate performance is seriously deteriorated.

[0190] Figure 1 is the T distribution diagram of the sintered material of Example 3, Figure 2 is the T distribution diagram of the sintered material of Comparative Example 3. FromFigure 1 and Figure 2 It can be seen that, Figure 1 In the N element distribution of the sample prepared in the application, Figure 2 In the N element distribution of the sample prepared in the application,

[0191] Test Example 1

[0192] Preparation method of the liquid lithium ion battery: the olivine positive electrode material, acetylene black and polyvinylidene fluoride (PVDF) of the examples and the comparative examples were mixed in a mass ratio of 90:5:5, coated on an aluminum foil and dried, and then punched into a positive electrode sheet with a diameter of 12 mm and a thickness of 120 μm under a pressure of 100 MPa, and then the positive electrode sheet was placed in a vacuum drying oven at 120°C for 12 h. The negative electrode used a Li metal sheet with a diameter of 17 mm and a thickness of 1 mm; the separator used a Celgard 2400 porous membrane with a thickness of 25 μm; the electrolyte used an equal amount of 1 mol / L LiPF6, ethylene carbonate (EC) and diethyl carbonate (DEC) mixed solution. The positive electrode sheet, the separator, the negative electrode sheet and the electrolyte were assembled into a 2025 type button cell in an Ar glove box with water content and oxygen content less than 5 ppm. The assembled button cell was tested at 25°C for capacity under 0.1C and 2C rates and cycled at 1C rate for 100 cycles, and the results are shown in Table 2.

[0193] Table 2

[0194]

[0195] Figure 3 The 0.1C rate charge-discharge curve and the 2C rate charge-discharge curve of the liquid lithium ion battery assembled by the positive electrode material of the comparative example 3 and the example 1. Figure 4 The 1C cycle performance diagram of the liquid lithium ion battery assembled by the positive electrode material of the comparative example 3 and the example 1. From Table 2, Figure 3 and Figure 4 It can be seen that the discharge capacity, high rate and cycle retention rate of the liquid lithium ion battery assembled by the positive electrode material prepared by the example of the application are significantly better than those of the liquid lithium ion battery assembled by the positive electrode material prepared by the comparative example.

[0196] Test Example 2

[0197] Preparation method of all-solid-state lithium battery: the olivine positive electrode material, conductive carbon black and polyvinylidene fluoride (PVDF) of the examples and the comparative examples were mixed in a mass ratio of 90:5:5, an appropriate amount of NMP was added, and after stirring uniformly, it was coated on an aluminum foil and dried in a 120℃ air oven for 1h, and then punched into a positive electrode sheet with a diameter of 11mm; the prepared positive electrode sheet, the composite electrolyte film and the negative electrode were assembled into a 2025 type button cell in an Ar glove box with water content and oxygen content less than 5ppm, with lithium metal as the negative electrode and PEO-based solid electrolyte film as the electrolyte. The assembled button cell was tested for capacity at 2C rate and cycled at 1C rate for 100 cycles at 25℃, and the results are shown in Table 3.

[0198] Table 3

[0199]

[0200] As can be seen from Table 3, the high rate and cycle retention rate of the solid-state lithium ion battery assembled by the positive electrode material prepared by the examples of the present application are significantly better than those of the solid-state lithium ion battery assembled by the positive electrode material prepared by the comparative examples.

[0201] Test example 3

[0202] Preparation method of liquid lithium ion battery: the positive electrode material, acetylene black and polyvinylidene fluoride (PVDF) were mixed in a mass ratio of 90:5:5, coated on an aluminum foil and dried, and then pressed into a positive electrode sheet with a diameter of 12mm and a thickness of 120μm under a pressure of 100MPa, and then the positive electrode sheet was placed in a vacuum drying oven and dried at 120℃ for 12h. The negative electrode used a conventional graphite negative electrode; the separator used a Celgard 2400 porous membrane with a thickness of 25μm; the electrolyte used an equal amount of mixture of 1mol / L LiPF6, ethylene carbonate (EC) and diethyl carbonate (DEC). The positive electrode sheet, the separator, the negative electrode sheet and the electrolyte were assembled into a 2025 type button cell in an Ar glove box with water content and oxygen content less than 5ppm. The assembled button cell was cycled at 1C for 1000 cycles at 45℃, and the negative electrode was obtained after the battery was disassembled after cycling, and the manganese content in the negative electrode was tested by ICP, and the results are shown in Table 4.

[0203] Table 4

[0204] Item Negative Mn elution content after 1000 cycles at 45°C, 1C ppm Example 1 1820 Example 2 1840 Example 3 1850 Example 4 1800 Example 5 1950 Example 6 1800 Comparative Example 1 8450 Comparative Example 2 8430 Comparative Example 3 5960

[0205] As can be seen from Table 4, the amount of Mn dissolved after long cycle of the liquid lithium ion battery assembled by the positive electrode material prepared by the examples of the present application is significantly lower than that of the liquid lithium ion battery assembled by the positive electrode material prepared by the comparative examples.

[0206] The preferred embodiments of the present application are described in detail above, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including that each technical feature is combined in any other suitable manner. These simple modifications and combinations should also be considered as disclosed by the present application and fall within the protection scope of the present application.

Claims

1. An olivine-type composite cathode material, characterized in that, The composite positive electrode material comprises a matrix and a composite phase; The matrix has a composition shown in Formula I: Li x M 1 y Mn z Fe 1-z-u M 2 u (PO4) w (RO a ) b C v Formula I; wherein 0.5≤ x <1.3, 0≤ y ≤0.5, 0< x < 1 z ≤1, 0≤ u ≤0.01, 0< x < 1 w ≤1; 0< x < 1 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 the group consisting of Mg, Na, and K; M 2 is at least one element selected from the group consisting of Ga, Sn, V, Y, Mo, Al, Mg, Ce, Ti, Zr, Nb, Si, W, and In; R is at least one element selected from the group consisting of Si, Cl, Br, S, Sb, and Sn. The composite phase has a composition shown in Formula II: T m G n Formula II; 0.1≤m≤5, 0.1≤n≤5, T is selected from at least one element of Ti, Mo, Co, W, Zn, Cu, B, V, Nb, Ta, Pd, Cr, Ag, Al, Mn, Sn, Mg, Sc, Zr and Hf, and G is selected from N. In the EDS element analysis of the composite positive electrode material, the standard deviation of m / n at any position is ≤1%.

2. The olivine-type composite cathode material of claim 1, wherein, 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.

3. The olivine-type composite cathode material according to claim 1 or 2, wherein, In Formula II, 0.5≤m≤3, 1≤n≤5, T is selected from at least one element of Ti, Mo, Co, W, Zn, Cu, B, V, Nb, Ta, Cr, Ag, Al, Mn, Sn, Mg, Sc and Zr.

4. The olivine-type composite cathode material according to claim 1 or 2, wherein, The content of the composite phase is 0.01-10wt% based on the total weight of the composite positive electrode material.

5. The olivine-type composite cathode material according to claim 1 or 2, wherein, The compacted density of the composite cathode material is 1.5-3 g / cm 3 .

6. The olivine-type composite cathode material of claim 1 or 2, wherein, The resistivity of the composite positive electrode material is ≤2500Ω / cm.

7. The olivine-type composite cathode material of claim 1 or 2, wherein, In the composite positive electrode material, 0.5≤m / n≤7.

8. The olivine-type composite cathode material of claim 1 or 2, wherein, The average particle size D of the composite cathode material is 0.5-20 μm. 50 is 0.5-20 μm.

9. A method of producing the olivine-type composite cathode material according to any one of claims 1 to 8, characterized by, The method comprises the following steps: (1) mixing a T-containing compound with a G-containing compound to obtain a first mixture, and performing first heat treatment on the first mixture in the presence of a protective atmosphere to obtain a T-and-G-containing compound; (2) mixing a lithium source, a carbon source, a phosphorus source, an iron source, a manganese source, an R source, an M 1 source, an M 2 source, and a solvent to obtain a second mixture, and grinding the second mixture to obtain a slurry; (3) mixing the T-and-G-containing compound with the slurry, drying to obtain a powder; (4) performing second heat treatment on the powder in the presence of a non-oxidizing atmosphere, and crushing to obtain the olivine-type composite positive electrode material; In step (1), the T-containing compound is selected from at least one of the following: elemental T, oxide of T, nitrate of T and hydroxide of T; The G-containing compound is selected from at least one of the following: nitrogen, ammonia, melamine, polydopamine and urea; The first heat treatment has a temperature of 400-1000°C and a time of 2-8h. wherein, in step (2), the molar ratio of the lithium source calculated as Li, the phosphorus source calculated as P, the carbon source calculated as C, the iron source calculated as Fe, the manganese source calculated as Mn, the R source calculated as R, the M 1 source calculated as M 1 , the M 2 source calculated as M 2 is (0.5-1.3):(0-1):(0-0.05):(0-1):(0-1):(0-1):(0-0.5):(0-0.01), wherein the amount of the phosphorus source, the manganese source, and the carbon source is not 0.

10. The production method according to claim 9, wherein The molar ratio of the T-containing compound (calculated based on T) to the G-containing compound (calculated based on G) is 0.5-7:

1.

11. The production method according to claim 9 or 10, wherein In step (2), the R source is selected from a compound containing at least one of Si, Cl, Br, S, Sb and Sn.

12. The production method according to claim 9 or 10, wherein In step (2), the M 1 is selected from a compound containing at least one element of Mg, Na and K.

13. The production method according to claim 9 or 10, wherein In step (2), the M 2 The source is selected from a compound of at least one element from the group consisting of Ga, Sn, V, Y, Mo, Al, Mg, Ce, Ti, Zr, Nb, Si, W and In.

14. The production method according to claim 9 or 10, wherein In step (2), the solvent is selected from at least one of the following: water, ethanol, methanol, NMP and isopropanol.

15. The production method according to claim 9 or 10, wherein In step (2), the solid content of the slurry is 10-60wt%.

16. The production method according to claim 9 or 10, wherein In step (2), the average particle size D 50 of the slurry is 0.1-1 μm.

17. The method of making according to claim 9 or 10, wherein, In step (3), the solid-liquid ratio of the T-and-G-containing compound to the slurry is 0.000001-10g / mL.

18. The method of making according to claim 9 or 10, wherein, In step (4), the second heat treatment has a temperature of 400-1000°C and a time of 4-12h.

19. An olivine-type composite positive electrode material prepared by the preparation method of any one of claims 9-18.

20. Use of the olivine-type composite positive electrode material of any one of claims 1-8 and 19 in at least one of the following: supercapacitors, lithium ion batteries and lithium-sulfur batteries.

21. A lithium-ion battery, characterized by, The lithium ion battery comprises the olivine-type composite positive electrode material of any one of claims 1-8 and 19.

22. The lithium-ion battery of claim 21, wherein, The lithium ion battery is a liquid lithium ion battery, and the manganese dissolution amount of the negative electrode of the liquid lithium ion battery is less than or equal to 3000 ppm after 1000 cycles at 45 DEG C.

23. The lithium-ion battery of claim 21 or 22, wherein, The lithium ion battery is a liquid lithium ion battery, and the manganese dissolution amount of the negative electrode of the liquid lithium ion battery is 500-2000 ppm after 1000 cycles at 45 DEG C.

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