498 results about "Lithium cobalt oxide" patented technology

The invention belongs to the field of batteries, and particularly discloses a lithium cobalt oxide positive electrode material and a preparation method and application thereof, the positive electrode material comprises a doped lithium cobalt oxide matrix, an inner coating layer and an outer coating layer; an inner coating layer is arranged on the surface of the doped lithium cobalt oxide substrate, and an outer coating layer is arranged on the surface of the inner coating layer; the doped lithium cobalt oxide matrix is LiCo < x > M < y > O < 2 >, and the inner coating layer contains LiF and AlF < 3 >; and Li3PO4 is contained in the outer coating layer. According to the invention, the lithium cobalt oxide matrix is doped by adopting the doping element, and meanwhile, the specific inner coating layer and the specific outer coating layer are arranged on the surface of the doped lithium cobalt oxide matrix, so that structural collapse and capacity attenuation of the positive electrode material in the charge-discharge process under high voltage can be avoided; and thus, the positive electrode material can have relatively high specific capacity and excellent cycling stability under high voltage.

In order to solve the problems that an existing positive electrode material is unstable in structure and low in energy density, the invention provides a positive electrode material and a preparation method thereof, a positive electrode plate and a battery, the positive electrode material comprises lithium cobalt oxide of a layered structure, the chemical formula of the lithium cobalt oxide is Li < 1-alpha-beta > Na < alpha > (Mg < gamma > Ti < delta > Co < 1-gamma-delta >) O2, alpha is smaller than or equal to 0.005, and beta is 0.02-0.05; gamma is equal to 0.002 to 0.004, delta is equal to 0.001 to 0.003, and gamma + delta is equal to 0.003 to 0.006.

A lithium-ion secondary battery having excellent discharge characteristics even in a low-temperature environment is provided. The lithium-ion secondary battery includes a positive electrode, a negative electrode, and an electrolyte solution. The positive electrode includes lithium cobalt oxide with a median diameter (D50) of greater than or equal to 1 μm and less than or equal to 12 μm. The lithium cobalt oxide contains magnesium in its surface portion. The negative electrode includes a graphite particle, a silicon particle, and a polymer including a carboxy group. The electrolyte solution contains a mixed solvent of a fluorinated cyclic carbonate and a fluorinated chain carbonate.

This invention relates to a method for preparing a p-aminobenzenesulfonic acid blended nanofiltration membrane and its application. The invention aims to address the technical problem that existing polymer thin films struggle to simultaneously increase permeate flux while improving retention rate. This invention provides a nanofiltration membrane with high efficiency in separating cobalt and lithium ions and significantly enhanced permeate flux. It achieves this by doping p-aminobenzenesulfonic acid during the preparation of traditional TFC nanofiltration membranes, efficiently introducing sulfonic acid groups to promote the formation of an ordered nanochannel structure in the polyamide network, thereby increasing water flux. Simultaneously, the negative charge carried by the sulfonic acid groups enhances the overall electronegativity of the membrane, making it more effective against Co ions. 2+ The electrostatic adsorption capacity is significantly higher than that of Li + This enables efficient separation of cobalt and lithium ions. The nanofiltration membrane material provided by this invention can be widely used in the resource-based treatment of acid leaching wastewater from lithium cobalt oxide batteries, achieving efficient separation and recovery of cobalt and lithium, and improving economic benefits and resource utilization.

The invention relates to the technical field of batteries, in particular to a composite positive electrode material, a preparation method thereof and a battery. The composite positive electrode material comprises a positive electrode substrate, a fast ion conductor layer and a halide layer, the positive electrode substrate comprises a doped lithium cobalt oxide material; the fast ion conductor layer is positioned on the surface of the positive electrode substrate and comprises an oxide of a metal element Q with a spinel phase; the halide layer is located on the surface of the fast ion conductor layer and comprises element lithium, metal element M and halogen X. Through coordination and cooperation of the matrix material, the fast ion conductor layer and the halide layer, the structural stability and the surface morphology of the material can be effectively improved, the defects of the material are overcome, and the composite positive electrode material has excellent conductivity and has excellent cycling stability and rate capability at high temperature and / or high voltage, so that the battery has high safety performance.

The invention belongs to the field of preparation of a lithium ion battery positive electrode material, and particularly relates to an organic metal framework coated lithium cobalt oxide positive electrode material as well as a preparation method and application thereof. According to the scheme, a lithium cobalt oxide material, methanol, dimethyl imidazole cobalt, titanium carbide and sodium dihydrogen phosphate monohydrate are mixed according to the mass ratio of 1: (0.070-0.080): (0.001-0.002): (0.001-0.003): (0.001-0.002) and sintered, and the lithium cobalt oxide positive electrode material coated with the organic metal frame is obtained. According to the scheme, by utilizing the synergistic effect of a metal organic framework coating layer formed by pyrolysis of dimethyl imidazole cobalt, a three-dimensional conductive network constructed by titanium carbide and a phosphate interface layer, the mechanical strength of the coating layer is synergistically improved, lithium ion diffusion is accelerated, the internal resistance of the battery is reduced, the side reaction of an electrode / electrolyte is reduced, and the volume expansion of lithium cobalt oxide and cobalt dissolution are inhibited; and the high-temperature cycling stability and the rate capability of the lithium cobalt oxide battery are obviously improved. Meanwhile, the invention also provides an application of the organic metal framework coated lithium cobalt oxide positive electrode material in a battery.

The invention belongs to the technical field of waste lithium battery recovery, and particularly relates to a method for selectively extracting lithium from a waste lithium battery positive electrode material based on activation and oxidation, which comprises the following steps: mixing the waste lithium battery positive electrode material, an oxidizing agent, an activating agent and a solvent, stirring and leaching, and carrying out solid-liquid separation to obtain a lithium-rich leaching solution and valuable metal leaching residues; wherein the activating agent is one or more than two of divalent ferrite, divalent cobalt salt, divalent manganese salt, divalent copper salt and monovalent silver salt, and the waste lithium battery positive electrode material is selected from one or more than two of waste nickel cobalt lithium manganate batteries, waste nickel cobalt lithium aluminate batteries, waste lithium cobalt oxide batteries and waste lithium manganate batteries. Through the synergistic effect of the oxidizing agent and the activating agent, preferential extraction of lithium in the raw material is achieved in one step, the problem that the lithium loss amount is large in the later lithium extraction process is solved, and the method has the advantages of being easy and convenient to operate, short in technological process, good in lithium selectivity, high in lithium leaching rate, wide in temperature application range and low in recovery cost.

The invention relates to the technical field of lithium ion batteries, in particular to a high-voltage lithium cobalt oxide positive electrode material and a preparation method thereof. According to the technical scheme, the chemical composition of the positive electrode material is at least two elements selected from Al, Mg, Ti and Zr. Through triple strategies of multi-element synergistic doping, core-shell structure design and surface defect regulation and control, breakthrough improvement of the performance of the high-voltage lithium cobalt oxide positive electrode material is achieved, and especially through the synergistic effect of a specific element combination Al + Mg + Ti and the coupling effect of the gradient-distributed F element and the nanometer defect structure, the performance of the high-voltage lithium cobalt oxide positive electrode material is improved. The structure phase change and the interface side reaction in the high-pressure circulation process are effectively inhibited, and the cycle life and the thermal stability of the material are remarkably improved.

The invention discloses a method for regenerating and preparing high-voltage lithium cobalt oxide by using an invalid lithium cobalt oxide material, and belongs to the technical field of battery recovery. The method comprises the following steps: S1, carrying out ball milling and mixing on failed lithium cobalt oxide powder and a sodium source, and then carrying out solid-phase sintering to obtain a P2 type sodium cobalt oxide and lithium cobalt oxide material; s2, the P2 type sodium cobaltate and lithium cobaltate material is placed in a lithium-containing solution for a hydrothermal reaction, a regenerated O2-O3 cotype lithium cobaltate material is obtained, the regenerated O2-O3 cotype lithium cobaltate material has the advantages of being good in cycling stability, high in rate capability, high in low-temperature performance and the like under the high voltage of 4.6 V, and the performance of the regenerated O2-O3 cotype lithium cobaltate material is superior to that of a commercial lithium cobaltate material.

The invention provides a method for strengthening recovery of a waste lithium iron phosphate material by using waste lithium cobalt oxide as an oxidizing agent. The method comprises the following steps: discharging and disassembling waste lithium iron phosphate and lithium cobalt oxide batteries to obtain positive plates; dissolving aluminum foil in the positive plate in a sodium hydroxide alkaline leaching solution to obtain lithium iron phosphate and lithium cobalt oxide positive electrode powder; the method comprises the following steps: leaching lithium iron phosphate positive electrode powder by adopting a deep-eutectic solvent, and meanwhile, realizing an enhanced leaching process by taking lithium cobalt oxide positive electrode powder as an oxidizing agent; and carrying out coordination separation and photo-reduction separation on the completely leached solution to realize selective recovery of cobalt, iron, phosphorus and lithium. According to the method, the oxidation-reduction capacity of the material is fully utilized to strengthen the leaching process, efficient recovery of valuable elements in the waste positive electrode material is achieved, and additional addition of an oxidizing agent and a reducing agent is avoided. The method can achieve the purposes of synergistic enhanced leaching and selective separation of the waste lithium cobalt oxide material and the waste lithium iron phosphate material, and is low in cost, high in recovery rate and wide in industrial application prospect.

The invention provides a coated modified lithium cobalt oxide material, a preparation method thereof, a positive electrode and a lithium ion battery. The preparation method comprises the following steps: providing a mixture, wherein the mixture sequentially comprises first lithium cobalt oxide particles, a coating agent and second lithium cobalt oxide particles from bottom to top; sequentially carrying out first mixing, second mixing and third mixing on the mixture; and sintering to obtain the coated modified lithium cobalt oxide material. The D50 particle size of the first lithium cobalt oxide particles is larger than that of the second lithium cobalt oxide particles; the mixing rotating speeds of the first mixing, the second mixing and the third mixing are sequentially increased. In the lithium cobalt oxide coating modification process, the positions of the first lithium cobalt oxide particles, the second lithium cobalt oxide particles and the coating agent in the mixture in the vertical direction are designed to form a sandwich structure, and a three-stage mixing process is combined, so that the mixing uniformity of the coating agent and the lithium cobalt oxide material is remarkably improved, and the coating performance of the lithium cobalt oxide material is improved. And uniform coating of the coating element on the surface of the lithium cobalt oxide material is realized.

The invention provides a positive plate, a battery, a battery pack and electric equipment. The positive plate comprises a positive current collector, a first positive active layer and a second positive active layer, wherein the first positive active layer and the second positive active layer are stacked on at least one side of the positive current collector; the first positive electrode active layer comprises a first positive electrode active material, and the second positive electrode active material comprises a first positive electrode active material and a second positive electrode active material; the first positive electrode active material comprises at least one of a manganese-based positive electrode active material, an iron-based positive electrode active material and a manganese-iron mixed-based positive electrode active material, and the second positive electrode active material comprises at least one of a ternary positive electrode active material, lithium cobalt oxide, lithium nickelate and lithium titanate; the second positive electrode active layer further comprises a second conductive agent, and the second conductive agent comprises at least two linear conductive agents and at least one of a sheet-shaped conductive agent and a point-shaped conductive agent. The positive plate has a special structure and composition, and can effectively improve the impedance increase of the battery and improve the cycle performance of the battery.

The invention relates to the technical field of batteries, in particular to a high-temperature-resistant lithium cobalt oxide positive electrode material and a preparation method and application thereof.The high-temperature-resistant lithium cobalt oxide positive electrode material comprises a lithium cobalt oxide matrix and a coating layer coating the surface of the lithium cobalt oxide matrix, the lithium cobalt oxide matrix is doped with Mg, Ti and La, and the coating layer is a fast ion coating layer of a Li-Gd-Ti-O4 spinel phase. Bulk phase doping is carried out through a high-temperature solid-phase method, Mg, Ti and La are doped in a lithium cobalt oxide matrix, and the lattice structure thermal stability of lithium cobalt oxide under high voltage (4.4 V) is improved; a fast ion coating layer of a Li-Gd-Ti-O4 spinel phase is formed on the surface of a lithium cobalt oxide matrix by adopting a solid phase method, and the comprehensive performance of the lithium cobalt oxide positive electrode material is improved through multiple mechanisms such as the lattice stabilization effect of rare earth ions, the interface barrier effect of composite oxide and lithium ion conductivity regulation and control; particularly, the capacity, the cycling stability, the thermal stability, the high-voltage tolerance and the like are realized.

The invention belongs to the technical field of lithium batteries, and particularly relates to a lithium cobalt oxide positive electrode material and a preparation method and application thereof. When the D50 particle size of the lithium cobalt oxide positive electrode material is 10-20 microns, the specific surface area of the lithium cobalt oxide positive electrode material is 0.4-0.8 m < 2 > / g; the real density of the lithium cobalt oxide positive electrode material is 4.85-5.03 g / cm < 3 >, and the tap density is 2.35-2.50 g / cm < 3 >; the lithium cobalt oxide positive electrode material has an R3-m space group structure, and the peak intensity ratio I (003) / I (104) of a 003 peak to a 104 peak in an XRD spectrogram of the lithium cobalt oxide positive electrode material is greater than or equal to 2.5. The method is characterized in that inert gas is introduced into a Li-Na hydrothermal replacement system to form aerosol, and Li-Na exchange is carried out under the protection of the aerosol, so that the D50 particle size, the specific surface area, the true density, the tap density and the I (003) / I (104) of XRD of the lithium cobalt oxide positive electrode material are in specific parameter ranges; the obtained lithium cobalt oxide positive electrode material has excellent lithium de-intercalation dynamic performance, so that a lithium ion battery is endowed with excellent capacity performance and rate capability.

The present application relates to the technical field of secondary batteries, and provides a secondary battery and an electronic device. A positive electrode in the secondary battery provided in the present application comprises lithium cobalt oxide having a lamellar rock salt type structure, the lithium cobalt oxide has a space group R-3m, and the lithium cobalt oxide comprises an Mg element, a Ni element and an Al element, and can synergize with a nitrile compound having a suitable content in an electrolyte, thereby improving the stability of the positive electrode material. The present application can improve the floating charge performance of the secondary battery and reduce the impedance, and thus the secondary battery has good safety and reliability.

The invention provides a method for treating discharge wastewater of a waste lithium battery, which comprises the following steps: S1, pulping a lithium cobalt oxide material by using discharge wastewater, and adding a first oxidant for reaction to obtain primary oxidized slurry; s2, mixing the primary oxidized slurry with high-grade matte nickel, and adding a second oxidizing agent for reaction to obtain secondary oxidized slurry; s3, the secondary oxidation slurry and an iron circulation activating agent are mixed for acid leaching, a liquid phase is taken after solid-liquid separation, and metal leaching liquid containing nickel and cobalt is obtained; wherein the first oxidizing agent comprises persulfate, the second oxidizing agent is selected from hydrogen peroxide, and the iron circulation activating agent is at least one of sodium hydrosulfite or sodium pyrosulfite. According to the method, short-range efficient selective recovery of valuable metals is realized through cooperation of lithium cobalt oxide and high nickel matte, the influence on the environment is greatly reduced, and the economic cost of the process is reduced.

The invention relates to a lithium cobalt oxide positive electrode material and a preparation method and application thereof. According to the method, a matrix and a coating layer located on the surface of the matrix are included, and the matrix and the coating layer form a sandwich composite structure lithium cobalt oxide positive electrode material with a (R-3m) (P63mc + P63 / mmc) (R-3m) space group. According to the scheme provided by the invention, the defects of O3-phase lithium cobalt oxide can be effectively improved, and the lithium cobalt oxide has four-high characteristics of high capacity, high rate, long service life and high safety, and particularly has excellent structural stability and conductivity under high voltage.

The invention relates to the technical field of batteries, in particular to a high-voltage lithium cobalt oxide / silicon carbon system lithium ion battery electrolyte, a lithium ion battery, a battery module, a battery pack and an electric device. The high-voltage lithium cobalt oxide / silicon carbon system lithium ion battery electrolyte comprises a non-aqueous organic solvent, a lithium salt and functional additives, the functional additives comprise a lithium salt additive, a first additive, a second additive and a third additive, the first additive is selected from unsaturated sulfonate additives, the second additive is selected from unsaturated sulfonate additives, and the third additive is selected from unsaturated sulfonate additives. The second additive is selected from unsaturated disiloxane additives, and the third additive is selected from fluoro-carbonic ester additives. The components of the electrolyte cooperate with each other, so that a stable and compact solid electrolyte interface can be formed on the surfaces of a positive electrode and a negative electrode, side reaction of the electrolyte on the surface of a pole piece is effectively inhibited, silicon-carbon negative electrode expansion and positive electrode transition metal dissolution are inhibited, the stability of the interface in the cycle process is improved, and the cycle performance of the lithium ion battery is effectively improved.

The invention belongs to the technical field of lithium ion batteries, and particularly discloses a composite coated high-voltage lithium cobalt oxide positive electrode material as well as a preparation method and application thereof. The positive electrode material comprises an inner core, and a first coating layer and a second coating layer which sequentially coat the inner core from inside to outside; the inner core is a doped lithium cobalt oxide matrix, the chemical formula is Li1 + xCo1-yM1yM2zO2, x is more than or equal to 0 and less than or equal to 0.1, y is more than or equal to 0.001 and less than or equal to 0.05, z is more than or equal to 0.001 and less than or equal to 0.05, M1 is selected from at least one of Al, Ni and Fe, and M2 is selected from at least one of Mg, Al, Zr, Zn, Ni, Fe, Sr, Mo, Ta and W; the chemical formula of the first coating layer is La1-mNmCoO3-n.Co3O4, m is greater than 0 and less than 1, n is greater than 0 and less than 3, and N is selected from one or two of Ca, Mg, Fe, Zn, Ba and Zr; and the second coating layer is cobalt oxide of YOF and Y. The core problems of bulk phase structure degradation, serious interface side reaction, interface impedance increase and the like under high voltage can be cooperatively solved.

The invention relates to a gel electrolyte precursor and a preparation method thereof, a gel electrolyte and a secondary battery, and belongs to the technical field of methods or devices for directly converting chemical energy into electric energy. The gel electrolyte precursor comprises a polymeric monomer, a catalyst, an initiator and a lithium salt, the polymeric monomers comprise a monomer A and a monomer B; the monomer B comprises at least one of a polyether compound, a polysiloxane compound, boric acid and a derivative thereof. The gel electrolyte formed by polymerizing the gel electrolyte precursor has relatively high oxidation potential, can be matched with a ternary positive electrode or a lithium cobalt oxide positive electrode, and remarkably improves the cycle performance of a battery.

The invention provides a positive electrode material and a preparation method thereof, a positive electrode plate and a secondary battery, and belongs to the field of battery materials, the positive electrode material comprises an inner core and a composite coating layer coating the surface of the inner core; the inner core comprises lithium iron phosphate, and the composite coating layer comprises a carbon material and a metal oxide; wherein the metal oxide comprises at least one of lithium titanate, lithium manganate and lithium cobalt oxide. The carbon material and the metal oxide containing titanium, cobalt and manganese are compounded to serve as the composite coating layer to coat the lithium iron phosphate core, on one hand, the microstructure characteristics of the metal oxide containing titanium, cobalt and manganese are utilized, richer channels are provided for lithium ion diffusion, on the other hand, the high electron conductivity of the carbon material is utilized, and the lithium ion diffusion efficiency is improved. The prepared positive electrode material can simultaneously have relatively high electronic conductivity and lithium ion diffusion rate, and when the positive electrode material is used as a lithium ion battery, the charge-discharge performance and the cycle life of the lithium ion battery are remarkably improved.

The invention relates to the technical field of batteries, in particular to a lithium ion secondary battery. Comprising a positive electrode plate, a negative electrode plate and an electrolyte, the positive electrode plate comprises lithium cobalt oxide, the negative electrode plate comprises a silicon-based material, the electrolyte comprises a fluorosulfonamide compound, a nitrile compound and a first solvent, the first solvent comprises at least one of fluoroether, fluorobenzene and acetic acid 2, 2-difluoroethyl ester, and by taking the total mass of the electrolyte as a standard, the total mass of the lithium cobalt oxide and the total mass of the nitrile compound are equal to or smaller than 1. The content c1 of the fluorosulfonamide compound and the content c2 of the nitrile compound meet the following condition: 0.1 < = c1 / c2 < = 30; and the charging cut-off voltage of the lithium ion battery is greater than or equal to 4.48 V. The lithium ion secondary battery disclosed by the invention has relatively high energy density, relatively good cycle performance, excellent high-temperature storage performance and relatively good low-temperature performance.

The utility model discloses an oxide and carbon nano tube coated lithium cobalt oxide positive electrode particle which comprises an LCO large particle which is an irregular cube, a plurality of LLZO large particles and a plurality of LLZO small particles are coated on the outer surface of the LCO large particle, and the whole body forms a composite LCO large particle; wherein the large LLZO particles and the small LLZO particles are distributed on the large LCO particles in a convex arc shape; an LLZO dielectric phase layer is formed between the bottoms of the LLZO large particles and the LCO large particles and between the bottoms of the LLZO small particles and the LCO large particles, and the LLZO dielectric phase layer is mainly used for guiding lithium ions and is secondarily used for protecting the LCO large particles; the lithium ion guiding capability of the large LLZO particles and the small LLZO particles is far higher than that of the large LCO particles, and the large LLZO particles and the small LLZO particles are not prone to side reaction with the lithium ions. The large LLZO particles, the small LLZO particles and the large LCO particles are all of a crystal structure. Wherein CNTs of different sizes are arranged on the peripheries of the composite LCO large particles, and the CNTs integrally wrap the composite LCO large particles. The CNT has a short-chain CNT and a long-chain CNT.

The invention provides a lithium cobalt oxide composite material and a preparation method thereof, a positive plate and a lithium ion battery. The lithium cobalt oxide composite material comprises first lithium cobalt oxide composite particles and second lithium cobalt oxide composite particles; the first lithium cobalt oxide composite particles comprise first lithium cobalt oxide and a lithium-rich positive electrode material coating the surface of the first lithium cobalt oxide; the second lithium cobalt oxide composite particles comprise second lithium cobalt oxide and a lithium-rich positive electrode material coated on the surface of the second lithium cobalt oxide; the D50 particle size of the first lithium cobalt oxide composite particles is larger than that of the second lithium cobalt oxide composite particles. The lithium-rich positive electrode material is arranged on the surface of the lithium cobalt oxide material, so that the first coulombic efficiency, the specific discharge capacity and the energy density of the battery are improved; and the first lithium cobalt oxide composite particles and the second lithium cobalt oxide composite particles with different particle sizes are selected for grading, so that the first charge-discharge capacity and the cycling stability of the material are improved, and the requirements of a high-performance lithium ion battery using a silicon-carbon negative electrode are met.

The invention relates to the technical field of batteries, in particular to a lithium ion secondary battery. Comprising an electrode assembly and electrolyte, and the electrode assembly comprises a positive plate, a diaphragm and a negative plate which are stacked and wound; the charging cut-off voltage of the lithium ion secondary battery is greater than or equal to 4.5 V; the positive plate comprises lithium cobalt oxide, the lithium cobalt oxide contains an element aluminum, and the mass content of the element aluminum in the lithium cobalt oxide accounts for 7000 ppm to 12000 ppm; the negative plate comprises a silicon-carbon material, and the silicon-carbon material comprises first silicon-carbon particles and second silicon-carbon particles; the sphericity degree of the first silicon-carbon particles is 0.8-1, the average particle size of the first silicon-carbon particles is 8-20 [mu] m, and the mass content of silicon is 30-60%; the sphericity degree of the second silicon-carbon particles is 0.8-1, the average particle size is D, and 1 [mu] m is smaller than or equal to Dlt; the mass content of the silicon element accounts for 20%-45%; the mass content ratio of the silicon element in the first silicon-carbon particles is greater than the mass content ratio of the silicon element in the second silicon-carbon particles. The lithium ion secondary battery can have both high energy density and high-temperature cycle stability.

A secondary battery with excellent cycle performance is provided. The secondary battery is an all-solid-state battery including a positive electrode current collector layer, a base film, a positive electrode active material layer, a buffer layer, and a solid electrolyte layer. The base film contains titanium nitride. The positive electrode active material layer contains lithium cobalt oxide. The buffer layer contains titanium oxide. The solid electrolyte layer contains a titanium compound. By using titanium oxide for the buffer layer, a side reaction between the positive electrode active material layer and the solid electrolyte layer can be suppressed, and cycle performance can be improved.

The invention relates to the technical field of batteries, in particular to a battery. The battery comprises a positive plate, a negative plate and a diaphragm, the diaphragm comprises a base material layer and a coating, the coating comprises first polymer particles, and two characteristic peaks exist in an XRD (X-Ray Diffraction) spectrogram of the coating and are respectively a first characteristic peak with a peak value of 20-22.8 degrees and a second characteristic peak with a peak value of 23-25 degrees; the positive plate comprises a positive current collector and a positive active layer, the positive active layer comprises a lithium cobalt oxide material, and two characteristic peaks exist in an XRD (X-Ray Diffraction) spectrogram of the lithium cobalt oxide material, namely a third characteristic peak with the peak value of 18-19 degrees and a fourth characteristic peak with the peak value of 44-46 degrees; the battery simultaneously meets the following relational expressions: Q1 / Q2 > = (Q3 / Q4) + 1, 2 < = Q1 / Q2 < = 8, 1 < = Q3 / Q4 < = 5, Q1 being the intensity of the first characteristic peak, Q2 being the intensity of the second characteristic peak, Q3 being the intensity of the third characteristic peak, and Q4 being the intensity of the fourth characteristic peak. The battery provided by the invention has relatively high thermal stability and relatively high safety performance.

The invention discloses a preparation method of a lithium cobalt oxide positive electrode material, the lithium cobalt oxide positive electrode material and a lithium battery, and relates to the technical field of lithium ion batteries. The method comprises the following steps: firstly, preparing a polycrystalline lithium cobalt oxide defective product and a single-crystal lithium cobalt oxide defective product, and respectively introducing doping elements in a first additive and a second additive into the polycrystalline lithium cobalt oxide defective product and the single-crystal lithium cobalt oxide defective product; a polycrystalline lithium cobalt oxide defective product, a third additive and a fourth additive are mixed and sintered, a sintering aid (the third additive contains a doping element M1) and a high-valence transition metal compound (the fourth additive contains a doping element M2) are matched, a high-melting-point Li-Co-M1-M2 phase is generated at the grain boundary, the grain boundary binding energy is improved, and therefore the compressive strength of the polycrystalline material is improved. After the grain boundary optimized lithium cobalt oxide defective product and the monocrystal lithium cobalt oxide defective product are graded, the lithium cobalt oxide positive electrode material with high compaction density can be obtained, and meanwhile, the positive electrode material can give consideration to rate performance and cycle performance.

The present application relates to the field of lithium battery positive electrode materials, and provides a lithium composite metal oxide and a preparation method therefor, and a lithium-ion battery. The lithium composite metal oxide comprises an inner core and a strontium-doped lithium cobalt oxide coating layer covering the surface of the inner core; the inner core is secondary particles formed by stacking single-crystal primary particles; strontium-doped lithium cobalt oxide in the strontium-doped lithium cobalt oxide coating layer is uniformly distributed on the surface of the inner core in an island shape. The strontium-doped lithium cobalt oxide coating layer reduces the formation of nickel oxide on the surface of a positive electrode material in the charging and discharging process of a battery, avoids the generation of micro-cracks, improves the structural stability, not only can protect the surface structure during subsequent water washing and avoid the generation of excessive rock salt phases, but also can avoid the dissolution of cobalt at high temperature. In addition, the present application also improves the initial efficiency and the cycle performance, and reduces the initial DCR and circulating DCR increase.

The invention relates to a lithium ion battery. The lithium ion battery comprises a positive pole piece and an electrolyte, the positive pole piece comprises a lithium cobalt oxide positive pole material, and the lithium cobalt oxide positive pole material comprises a substrate and a nitrogen-doped carbon coating layer coating the surface of the substrate; the electrolyte comprises a lithium salt, an additive and a solvent, the additive comprises lithium difluorophosphate, and the lithium difluorophosphate can react with the nitrogen-doped carbon coating layer of the lithium cobalt oxide positive electrode material to form a composite interface. According to the scheme provided by the invention, the dissolution of Co in the circulation process can be effectively inhibited, the interface stability is improved, and the generation of interface side reaction and side reaction products such as HF can be reduced, so that the battery has high energy density and long cycle life, and is suitable for being applied to energy storage devices in the fields of consumer electronics, new energy automobile power batteries, energy storage equipment and the like.