12275results about "Nickel compounds" patented technology

The embodiment of the invention relates to a lithium cobalt oxide positive electrode material with a composite phase as well as a preparation method and application of the lithium cobalt oxide positive electrode material. The chemical general formula of the lithium cobalt oxide positive electrode material with the composite phase is AXCo (1-y) M (1y) O2, wherein x is more than or equal to 0.5 and less than or equal to 1, y is more than or equal to 0 and less than or equal to 0.03, A is Li or Li and Na, and M1 is one or more of A1, Zr, Ni, Mn, Y, Nb, La, Fe, Cu, Cr, Ti, W, Mg, Mo or Yb; the composite phase of the lithium cobalt oxide positive electrode material comprises an O2 phase, a T2 phase and an O3 phase; wherein the sum of the molar ratios of the O2 phase and the T2 phase in the composite phase is greater than or equal to 90%, and the molar ratio of the O3 phase is less than or equal to 10%. By regulating and controlling the composite phase proportion of the lithium cobalt oxide positive electrode material, the rate capability, the structural stability under high voltage, the stability of a thermodynamic structure, the specific capacity, a discharge platform and other characteristics of the positive electrode material can be effectively improved, so that the lithium cobalt oxide positive electrode material with high energy density and high stability is realized.

The lithium nickel manganese oxide positive electrode material, the preparation method thereof and the electrochemical device are characterized in that the lithium nickel manganese oxide positive electrode material provided by the embodiment of the invention comprises a base material and a coating layer located on the surface of the base material, the general formula of the base material is Li (LiaNixMnyMbO4), the element M comprises at least one of Ti, Zr, Al, Nb and Mo, and a is more than or equal to 0.02 and less than or equal to 0.06; 0.45 < = x < = 0.55, 1.4 < = y < = 1.6; 0.05 < = b < = 0.55; a + x + y + b = 2, and the coating layer contains phosphate. According to the lithium nickel manganese oxide positive electrode material, through doping and coating technologies, under the condition that the capacity is not sacrificed, the gas production phenomenon is effectively reduced, the cycling stability of the lithium nickel manganese oxide positive electrode material is improved, and the service life of an electrochemical device applying the lithium nickel manganese oxide positive electrode material is prolonged.

The invention belongs to the technical field of sodium ion batteries, and particularly relates to a calcium ion doped modified sodium ion positive electrode material and a preparation method thereof, a positive electrode plate and a half battery. The calcium ion doped modified sodium ion positive electrode material comprises a sodium source, a doping source and a precursor, and is characterized in that the chemical general formula of the positive electrode material is Na < 1-x > M < x > Ni Fe Mn < c > O < 2 >, the value range of the doping sources M and x is x < = 0.05, a + b + c = 1, and all elements in the chemical formula meet charge balance. Sodium sites in a layered structure are replaced by calcium ion doping, so that interlayer spacing is enlarged, sodium ion transmission kinetics is enhanced, and adverse phase change is inhibited. The sodium ion positive electrode material shows high specific capacity and excellent cycle stability, the capacity retention ratio is 93.03% after 100 times of cycle charge and discharge at 1C, and the sodium ion positive electrode material has the characteristics of simple preparation, low cost, high specific capacity and excellent cycle performance.

The invention relates to a surface-modified lithium-rich manganese-based positive electrode material, a preparation method and a lithium ion battery, and the preparation method comprises the following steps: uniformly mixing a lithium-rich manganese-based precursor, a lithium source and a metal oxide required by garnet type solid electrolyte to obtain a mixture; and performing gradient temperature calcination on the mixture in an oxidizing atmosphere to obtain the surface-modified lithium-rich manganese-based positive electrode material, the surface-modified lithium-rich manganese-based positive electrode material comprises a lithium-rich manganese-based material, a disordered spinel self-protection layer coated on the surface of the lithium-rich manganese-based material, and a garnet type solid electrolyte coated on the surface of the disordered spinel self-protection layer, the gradient temperature calcination comprises the following steps: calcining at the nucleation temperature of the lithium-rich manganese-based material, and then heating to the nucleation temperature of the garnet type solid electrolyte for calcining. The lithium-rich manganese-based positive electrode material can solve the problems of low first coulombic efficiency and poor rate capability of the lithium-rich manganese-based positive electrode material in related technologies.

The invention discloses a method for activating and precipitating MHP through magnesium, and belongs to the technical field of hydrometallurgy. The method comprises the following steps: S1, mixing a magnesium-containing solution with a sodium hydroxide solution, and carrying out precipitation reaction for 3-5 minutes to obtain a precipitator; s2, immediately mixing a precipitator with the laterite-nickel ore iron and aluminum removed liquid, and then carrying out first-stage nickel and cobalt precipitation reaction to obtain first-stage nickel and cobalt precipitation slurry; s3, performing first thickening treatment on the first-section nickel and cobalt deposited slurry to obtain first dense underflow and first dense overflow; and S4, filtering the first dense underflow to obtain an MHP product. According to the method, after the magnesium-containing solution and the sodium hydroxide solution are mixed, the magnesium solution and the sodium hydroxide solution are controlled to be mixed and react for 3-5 min, then the nickel and cobalt precipitation reaction is immediately carried out, the MHP product with high purity and quality can be obtained, and the whole method is simple and convenient for large-scale industrial application.

The invention belongs to the technical field of SERS (Surface Enhanced Raman Scattering) detection, and particularly relates to a preparation method and application of an Ag-coated NiFe2O4 composite SERS substrate. The preparation method comprises the following steps: firstly, preparing Ag nanoparticles which are uniformly distributed and have the same size through a sodium citrate reduction method; secondly, a nanometer flower type NiFe2O4 material is prepared through a hydrothermal method and a calcination method; and finally, the novel SERS substrate Ag-coated NiFe2O4 is prepared through a physical stirring method. The novel SERS substrate made of the Ag nano particles and the nano-flower type NiFe2O4 material is constructed, and compared with a conventional SERS substrate made of independent Ag nano particles, the SERS substrate can detect stronger intrinsic Raman signals of probe molecules. As the SERS substrate needs to be compounded with a nano-flower type NiFe2O4 material during preparation, a charge transfer phenomenon can occur at an interface where the SERS substrate is in contact with probe molecules, so that intrinsic Raman signals of the probe molecules can be enhanced, and the SERS substrate can be better used for detecting and analyzing chemical substances.

The invention provides a sodium-ion battery positive electrode material and a preparation method thereof, a sodium-ion battery and electric equipment, and relates to the field of sodium-ion batteries. The positive electrode material of the sodium ion battery provided by the invention comprises an inner core and a shell, wherein the shell covers the inner core; the chemical formula of the inner core is NaaNixFeyMnzM1-x-y-zO2, wherein a is more than or equal to 0.9 and less than or equal to 1.05, x is more than 0 and less than 1.0, y is more than 0 and less than 1.0, z is more than 0 and less than 1.0, and 1-x-y-z is more than 0 and less than 1; the chemical formula of the shell is NaLarCa1-rO2, wherein r is more than 0 and less than 1; in the inner core, the element M comprises one or more of Al, Mg, Ti, Zr, Y, La, Ca, Zn, Cu, W, Li and B. The sodium-ion battery positive electrode material provided by the invention can reduce residual alkali on the surfaces of particles, can inhibit side reaction with an electrolyte, and improves the performance stability of the positive electrode material.

The invention relates to the technical field of sodium ion battery positive electrode materials, and provides a sodium ion battery layered high-entropy oxide positive electrode material, a preparation method thereof, a positive electrode plate and a sodium ion battery. The chemical general formula of the layered high-entropy oxide positive electrode material provided by the invention is NaxNiaMnbMcO2, wherein M is at least four of Li, Zn, Cu, Mg, Ca, Fe, Al, Co, Y, Ru, Ti, Ir, Sb, Te, Sn and Nb. The positive electrode material provided by the invention is good in structural stability, and can effectively inhibit phase change, so that the cycle stability is improved, and the electrochemical performance of sodium storage is enhanced. According to the invention, the precursor is obtained by adopting a sol-gel method, and then is sintered into a phase by adopting a solid-phase reaction method, so that the obtained positive electrode material is uniform in particle distribution and shows good structural stability, and the obtained positive electrode material is obviously superior to a material prepared by adopting a common high-temperature solid-phase method in the aspects of reversible capacity and electrochemical reversibility.

The invention belongs to but not limited to the technical field of electrode materials, and particularly relates to a high-tap-density lithium nickel manganese oxide positive electrode material, a preparation method and a lithium ion battery, the chemical general formula of the high-tap-density lithium nickel manganese oxide positive electrode material is LiNi < 0.5-x > Mn < 1.5-y > M < x > N < y > O < 4 >, 0.1, 0 < = y < lt >; 0.1, M and N are doping elements and comprise one or more of Mg, Co, Al, Zr, W, Sb, Ta and Ti; the material is micron-sized spherical secondary particles formed by stacking and aggregating nano-sized octahedral primary particles, and is uniformly dispersed without agglomeration; the spherical secondary particles are formed by mixing spherical secondary particles with large and small particle size distribution, and the average particle size range of the large particles is 3lt; d < 50lt >; the average particle size range of the small particles is 1lt; d < 50lt >; 2 [mu] m.

The invention provides a surface interface modified lithium-rich manganese-based positive electrode material and a lithium ion secondary battery. According to the invention, active oxygen substances such as O2, O2-, O-and oxygen polymer On-are absorbed and embedded into lattice gaps from the particle surface interface of the lithium-rich manganese-based positive electrode material under the driving of potential when the functional material is charged to a high voltage, and then the active oxygen is released when the functional material is discharged to a low potential, so that the active oxygen returns to the lithium-rich manganese-based positive electrode material again; and an active oxygen utilization reversible closed loop is formed. In the surface-interface modified lithium-rich manganese-based positive electrode material provided by the invention, the application of the surface functional material inhibits oxidation precipitation of lattice oxygen of the lithium-rich manganese-based positive electrode material in a high-voltage lithium removal state, and the positive electrode material can realize controllable oxygen reversible electrochemical deintercalation / intercalation at different potentials; and the cycling stability and the thermal stability of the material in a high-temperature and high-voltage environment are remarkably improved.

The invention discloses a uniformly radial positive electrode material precursor and a preparation method thereof. The cross section of the uniformly radial positive electrode material precursor is uniformly radial, and the shape of the uniformly radial positive electrode material precursor is divided into a core and an outer layer, the core is loose and porous, and the outer layer is in a regular radial shape; the method adopts a coprecipitation method to carry out two-stage reaction preparation, in the first reaction stage, an inner core layer is prepared; a second reaction stage: preparing a shell layer to reach a target particle size; the secondary particle D50 is 6.0-14.0 microns, the TD is greater than 1.90 g / cm, and the BET is less than or equal to 14m < 2 > / g; the precursor is small in structure core and compact in outer layer, particles grow in a radial mode from inside to outside, lithium ions can be separated and embedded out easily, the particle structure is more stable, and excellent rate performance and cycling stability are shown; a staged coprecipitation method is adopted, and controllable growth of a particle structure is realized by accurately controlling the ratio of oxygen to nitrogen and reaction conditions; according to the whole process design, the complex parameter adjusting range is reduced, and the production stability and repeatability are improved.

The invention provides a lithium-rich manganese-based positive electrode active material and a preparation method and application thereof. The lithium-rich manganese-based positive electrode active material comprises a lithium-rich manganese-based core, a first coating layer and a second coating layer, the chemical formula of the lithium-rich manganese-based core is Li < 1 + x > Ni Mn M < c > O < 2 + x >; 0.25 < = x < = 0.4, a + b + c = 1, 0.33 < = a < = 0.35, 0.63 < = b < = 0.65, and 0 < = c < = 0.02; m is selected from at least one of W, Ta, Nb, Ti, Sb, Al, Mg, Zr, Sr and Mo; the first coating layer is X-doped nano layered lithium cobalt oxide, and X is selected from at least two of Al, La, Nb, Sr, Ti, Mn, Mo, Ta, W, K, B and F; and the second coating layer comprises a fast ion conductor and / or a spinel-like phase cobalt lithium compound. The positive electrode active material provided by the invention has excellent storage capacity.

The invention provides an in-situ modified lithium-rich manganese-based precursor and a preparation method and application thereof.The preparation method comprises the following steps that a nickel-cobalt-manganese mixed metal salt solution, a precipitator solution and a complexing agent solution are introduced into a base solution for a first coprecipitation reaction, and after the first coprecipitation reaction is finished, feeding is stopped; and introducing a doped nickel-cobalt-manganese mixed metal salt solution, a precipitant solution, a complexing agent solution and a carbon source solution into a system after the first coprecipitation reaction is finished, and carrying out a second coprecipitation reaction to obtain the in-situ modified lithium-rich manganese-based precursor. According to the preparation method, doping elements and a carbon source are introduced when the lithium-rich manganese-based precursor is prepared through the coprecipitation reaction, in-situ uniform construction of oxygen vacancies and a carbon coating layer on the surface of the material is synchronously achieved, the in-situ modified lithium-rich manganese-based precursor is obtained, the treatment step of subsequent secondary coating can be reduced, the production cost can be reduced, and the method is suitable for industrial production. The technological process is shortened.

The invention discloses a molybdenum disulfide and lithium-lanthanum-niobium-oxygen co-coated lithium-rich manganese-based positive electrode material and a preparation method thereof, and realizes double uniform coating of molybdenum disulfide and lithium-lanthanum-niobium-oxygen on the surface of the lithium-rich manganese-based positive electrode material by combining freeze drying and calcining technologies. The double coating layer not only can be used as a stable protective layer to prevent the positive electrode material from being eroded, but also can form a stable coating structure by utilizing the physical and electrochemical compatibility between two adjacent elements of molybdenum and niobium in the same period, so that the electrochemical performance is optimized, the'deoxidation 'phenomenon is avoided, and the service life of the positive electrode material is prolonged. Under co-coating of the molybdenum disulfide and the lithium lanthanum niobium oxide, the lithium-rich manganese-based positive electrode material co-coated with the molybdenum disulfide and the lithium lanthanum niobium oxide is obtained, and the lithium-rich manganese-based positive electrode material co-coated with the molybdenum disulfide and the lithium lanthanum niobium oxide can guarantee the first effect and the specific capacity of the battery and can fully optimize the cycle performance of the battery.

The invention relates to a preparation method of a multi-coated lithium-rich manganese-based battery positive electrode material and the positive electrode material, and belongs to the technical field of battery positive electrode materials. The multi-coated lithium-rich manganese-based material is prepared by adopting a wet chemical method. The defects of an existing coated modified lithium-rich manganese-based positive electrode material in the aspects of relieving transition metal dissolution, inhibiting surface and interface side reactions and improving ion transmission performance synergism are overcome; the invention provides a multi-coated lithium-rich manganese-based material formed by an inert oxide, a fast ion conductor and high-stability phosphate and a preparation method of the multi-coated lithium-rich manganese-based material. According to the invention, the generation of side reactions on the surface and the interface is inhibited, the electrolyte decomposition is reduced, the cycling stability is enhanced, and the discontinuous island-shaped coating discontinuously forms a protective layer on the surface of the material, and a plurality of uncovered areas are left, so that the high lithium ion transmission efficiency can be maintained, and the charging and discharging performance of the battery is improved.

The invention relates to the technical field of battery materials, in particular to a ternary precursor, a preparation method thereof and a ternary positive electrode material. The preparation method of the ternary precursor comprises the following steps: preparing a mixed metal salt solution containing a nickel source, a cobalt source and a manganese source; the mixed metal salt solution, alkali liquor and a complexing agent are added into the base solution for a coprecipitation reaction, and the coprecipitation reaction comprises the steps that a nucleation reaction is conducted when the pH value of a reaction system ranges from 12 to 13, and then the pH value is gradually reduced to 11 or above along with the growth reaction till product particles reach the target particle size, in the process of gradually reducing the pH value to 11 or above, at least two times of pH value constant time exist, and the pH value constant time of one time is 40 hours or above; and carrying out solid-liquid separation on the product after the coprecipitation reaction is finished to obtain the ternary precursor. According to the preparation method, the ternary precursor material which is narrow in span distribution, small in particle and stable can be obtained.

The invention belongs to the technical field of energy storage materials, and particularly relates to a high-entropy oxide Fe0. 2Co0. 2Ni0. 2Cu0. 2Zn0. 2O and an ultrafast synthesis method and application thereof. According to the preparation method, ferroferric oxide, cobalt oxide, nickel oxide, copper oxide and zinc oxide with equal molar ratio are adopted as direct synthesis raw materials, toxic gases such as chlorine and nitrogen dioxide generated in the synthesis process of a metal salt precursor are avoided, and the uniformly distributed single-phase high-entropy oxide is synthesized in an ultrafast manner within 10 seconds by using a Joule heating technology; the synthesized high-entropy oxide is used as a lithium ion battery negative electrode material, and shows more excellent electrochemical performance and cycling stability compared with other high-entropy oxides prepared from transition metals with different proportions; in the preparation process, extra additives are not needed, operation is easy, the synthesis speed is high, the yield is high, element distribution is uniform, and the method has the advantages of being low in cost, high in efficiency and free of pollution and has the industrialization prospect.

The invention relates to the technical field of wave-absorbing materials. Specifically, the invention relates to a ferrite composite multi-walled carbon nanotube wave-absorbing material and a preparation method thereof. The invention also relates to electronic equipment containing the ferrite composite multi-walled carbon nanotube wave-absorbing material. The ferrite composite multi-walled carbon nanotube wave-absorbing material prepared by the invention comprises a ferrite magnetic material with magnetic loss and a multi-walled carbon nanotube material with electrical loss, and the composite material introduces multiple electromagnetic energy loss modes through unique structural design and component synergy, so that the wave-absorbing performance of the material is enhanced. In addition, the preparation method disclosed by the invention is simple in process, low in requirement on equipment, green and environment-friendly, and free from any toxic and harmful by-products.

The invention discloses a high-nickel ternary positive electrode material as well as a preparation method and application thereof. The chemical formula of the positive electrode material is LixNiyCozMaNbOc, M is at least one of Mn and Al, N is at least one of Ti, V, Nb, Zr, Ta, W or Mo, x is larger than or equal to 0.9 and smaller than 1.2, y is larger than or equal to 0.6 and smaller than or equal to 0.95, 0 lt, and z is larger than or equal to 0.5. Z < = 0.2, 0lt; a < = 0.2, 0 < b < = 0.02, and values of x, y, z, a, b and c accord with an electrically neutral principle; the positive electrode material has a single crystal morphology, the average size of primary particles is 0.20-1.50 microns, and the c / a ratio in lattice parameters is greater than 4.9360. The positive electrode material is applied to a positive electrode of a lithium ion battery, and shows good first coulombic efficiency and charge-discharge capacity.

The present disclosure relates to a recycled positive electrode active material, a method of producing the recycled positive electrode active material, and a secondary battery including the same. The recycled positive electrode active material, including: 60 mol % or more of Ni; and crystalline LiF, or 0.24% by weight or less of residual Li2CO3, where the recycled positive electrode active material is one or more selected from the group consisting of a lithium nickel oxide (LNO)-based positive electrode active material, a nickel·cobalt·manganese (NCM)-based positive electrode active material, a nickel·cobalt·aluminum (NCA)-based positive electrode active material, and a nickel·cobalt·manganese·aluminum (NCMA)-based positive electrode active material.

The invention belongs to the technical field of batteries, and particularly discloses a positive electrode material and a preparation method thereof, a lithium ion battery and a power utilization device, and the positive electrode material meets the following conditions: 1.5 < Kn90 = (Ln90-Ln10) / Ln50 < 4.5; ln10 is more than 0 and less than 2000; ln50 is more than Ln10 and less than 3000; and Ln90 is more than Ln50 and less than 15000. The positive electrode material has relatively high capacity, relatively good cycle retention rate and excellent low-temperature performance, the preparation method is simple to operate and relatively low in cost, and the comprehensive performance of the battery is favorably improved when the positive electrode material is applied to the battery.

The invention provides a nickel-metal hydride battery positive electrode material and a preparation method thereof, a nickel-metal hydride battery and electric equipment, the nickel-metal hydride battery positive electrode material is nickel-containing hydroxide doped with cobalt element and zinc element, the nickel-metal hydride battery positive electrode material comprises secondary particles composed of a plurality of primary particles, and the section porosity of the secondary particles is less than or equal to 3.0%. The nickel-metal hydride battery positive electrode material provided by the embodiment of the invention is doped with the cobalt element and the zinc element, attenuation of the capacity and the service life of the positive electrode material at high temperature can be slowed down through the doped elements, and the secondary particles are integrally of a compact structure, have few internal pores and are not easy to crack when bearing stress, so that the nickel-metal hydride battery positive electrode material is better in structural stability, and the service life is prolonged. And the cycle performance and the capacity retention ratio can be considered.

The invention belongs to the technical field of lithium batteries, and discloses a lithium nickel manganese oxide positive electrode material, a preparation method thereof and a lithium ion battery. Wherein the lithium nickel manganese oxide positive electrode material has a regular truncated octahedron single crystal structure, and the ratio K of a (111) crystal face orientation parameter to a (100) crystal face orientation parameter in an XRD (X-Ray Diffraction) spectrogram of the lithium nickel manganese oxide positive electrode material is 1-1.6. The lithium nickel manganese oxide positive electrode material provided by the invention has excellent rate capability and cycling stability, and can be well applied to production and manufacturing of lithium ion batteries.

The present invention relates to a positive electrode active material in a single particle form, the positive electrode active material including a lithium composite transition metal oxide in a single particle form, the lithium composite transition metal oxide including Al, Y, and Zr, a method for producing the positive electrode active material, and a positive electrode and a lithium secondary battery including the positive electrode active material.

The invention provides a ternary precursor and a preparation method thereof, a positive electrode material and a preparation process thereof, and a battery. The ternary precursor comprises an inner core, and a transition layer and a shell which are sequentially coated outside the inner core, the nickel content of the inner core is gt; the nickel content of the transition layer is gt; and the nickel content of the shell. The inner core in the ternary precursor has the highest nickel content, so that the capacity of the positive electrode material prepared from the ternary precursor is ensured; the nickel contents of the inner core, the transition layer and the shell are changed in a gradient manner, so that the thermal stability of the ternary precursor is improved; the shell reduces the interface side reaction between the positive electrode material prepared from the ternary precursor and an electrolyte; the transition layer can be used as a buffer layer between the inner core and the shell, so that the ternary precursor and the structural stability are improved. Therefore, the battery containing the positive electrode material prepared from the ternary precursor has excellent capacity and cycling stability at normal temperature and high temperature.

The invention relates to the field of batteries, and discloses a single crystal type lithium-rich manganese-based positive electrode material and a preparation method thereof, a lithium ion battery positive plate and a lithium ion battery, and the preparation method comprises the following steps: carrying out first sintering on a first part of lithium source and a nickel-manganese-containing multi-element precursor according to a molar ratio of 0.2-1: 1 to obtain an intermediate with a spinel structure; a first part of lithium source and the intermediate of the spinel structure are sintered for the first time according to the molar ratio of 0.5-1.4: 1, a second part of lithium source and the intermediate of the spinel structure are sintered for the second time according to the molar ratio of 0.5-1.4: 1, the single crystal type lithium-rich manganese-based positive electrode material is obtained, and the molar ratio of the total amount of the first part of lithium source and the second part of lithium source to the multi-element precursor containing nickel and manganese is larger than 1.25. And the primary particles are relatively large in size, so that the positive electrode material has excellent structural stability and has no cracks in crystals, and the lithium ion battery prepared from the positive electrode material has excellent volume specific capacity and cycling stability.

The invention provides a positive electrode material precursor and a preparation method thereof, a positive electrode material, a battery and electric equipment, and belongs to the technical field of lithium batteries. According to the positive electrode material precursor provided by the invention, the positive electrode material precursor is hydroxide containing transition metal, the positive electrode material precursor comprises secondary particles composed of primary particles, and the particle size D50 of the secondary particles is 6-25 [mu] m; the surface of the secondary particle is of a porous structure, and the average section porosity is 25-55%; each secondary particle comprises an inner core layer and a shell layer in the radius direction, and the porosity of the section of the inner core layer of each secondary particle is smaller than that of the section of the shell layer. According to the positive electrode material precursor provided by the invention, the capacity, the rate capability and the cycle performance of the battery can be remarkably improved through the optimal design of the morphology structure.

Active materials (e.g., alkali-metal metal phosphate (e.g., lithium iron phosphate), alkali-metal metal oxide and / or alkali-metal metal cyanide materials), preparation processes, and apparatuses useful in the manufacture thereof are described. Well-ordered active material particles (e.g., lithium iron phosphate particles) prepared by the processes and manufacturing apparatuses disclosed herein are also described.

The invention provides a positive active material and a preparation method thereof, a positive pole piece, a battery and electric equipment, the change rate d of the characteristic peak interplanar spacing of the positive active material (104) is greater than or equal to 0.05% and less than or equal to 0.5%, d = (d before-d after) / d before * 100%, d before is the interplanar spacing of the characteristic peak of the positive active material (104) measured by an X-ray diffractometer before circulation, and d after is greater than or equal to 0.05% and less than or equal to 100%. And d, measuring the interplanar spacing of the characteristic peak of the positive electrode active material (104) by an X-ray diffractometer at 45 DEG C after circulation for 80 weeks. Therefore, the interplanar spacing change rate of the positive electrode active material before and after circulation is small, which shows that the crystal structure stability of the positive electrode active material is good, the positive electrode active material is not easy to pulverize in the long-term circulation process of the battery, and the cycle performance of the battery can be improved.

The invention discloses a lithium ion battery positive electrode material and a preparation method thereof, the lithium ion battery positive electrode material comprises an active substance, a conductive additive, a binder and a thermal stability additive, the active substance is # imgabs0 # with a layered structure, x + y + z = 1, 0.5 < = x < = 0.8, 0.1 < = y < = 0.3, 0.1 < = z < = 0.3, the conductive additive is a compound of a carbon nanotube and graphene, and the thermal stability additive is a mixture of a carbon nanotube and graphene. The binder is a mixture of polyvinylidene fluoride and sodium carboxymethyl cellulose, the thermal stability additive is a mixture of lithium phosphate and aluminum oxide, the sum of the mass fraction of the lithium phosphate and the mass fraction of the aluminum oxide in the thermal stability additive is 0.5-10%, and the mass fraction of the lithium phosphate is 0.5-5%. According to the lithium ion battery positive electrode material and the preparation method thereof, the stability of the positive electrode material at high temperature can be improved, the thermal runaway risk is reduced, and the cycle life of the battery is prolonged.