240 results about "Fast ion conductor" patented technology

The invention discloses a lithium ion battery composite diaphragm, a preparation method and a lithium ion battery, and relates to the technical field of lithium ion batteries. The lithium ion battery composite diaphragm comprises a base membrane and a functional coating arranged on the negative electrode side of the base membrane, the functional coating sequentially comprises an ion conducting layer, a thermal barrier layer and a self-repairing layer from the position close to the base film to the position far away from the base film; wherein the base membrane is a polyimide and aramid nanofiber blended electrostatic spinning membrane; the ion conducting layer comprises a compound of a modified fast ion conductor and polyvinylidene fluoride-hexafluoropropylene; the thermal barrier layer comprises a cross-linked network of boron nitride nanosheets and polybenzimidazole; the self-repairing layer comprises polyurethane microspheres loaded with dynamic disulfide bonds. The composite diaphragm provided by the invention can remarkably inhibit a purple area on the surface of a negative electrode, and enhance high-temperature self-protection and interface self-repairing of the lithium ion battery, so that the cycle and safety performance of the lithium ion battery are remarkably improved.

The invention discloses a LiAlO2 fast ion conductor coated silicon-carbon composite material as well as a preparation method and application thereof, and belongs to the technical field of lithium ion battery materials. The LiAlO2 fast ion conductor coated silicon carbon composite material has a core-shell structure; an inner core of the composite material is a silicon-carbon composite material, the silicon-carbon composite material is formed by coating a three-dimensional carbon material with an amorphous carbon layer and loading a nano silicon compound, a shell of the composite material is a LiAlO2 fast ion conductor layer, and the silicon-carbon composite material with a three-dimensional network structure is constructed, and the surface of the silicon-carbon composite material is coated with the LiAlO2 fast ion conductor layer, so that the composite material is obtained. According to the present invention, with the LiAlO2, the volume expansion of the nanometer silicon during the charge-discharge process can be effectively relieved, the stability of the silicon-carbon composite material structure can be improved so as to significantly improve the cycle performance of the battery, and the LiAlO2 can provide the rapid channel for the transmission of the lithium ion during the charge-discharge process so as to improve the rate performance of the battery;

The invention relates to the technical field of batteries, in particular to a composite negative electrode material as well as a preparation method and application thereof. The composite negative electrode material comprises a negative electrode base material and a fast ion conductor layer located on the surface of the negative electrode base material, the negative electrode base material comprises a silicon nanosheet and a carbon coating layer located on the surface of the silicon nanosheet, and the surface of the carbon coating layer is doped with element nitrogen; and the fast ion conductor layer comprises Li3PO4. According to the composite negative electrode material disclosed by the invention, through coordination and cooperation of all the layers, the problem of capacity fading of a pure silicon negative electrode in a circulation process can be relieved, stable long-cycle performance is realized, and a high capacity retention ratio is obtained.

The invention relates to the technical field of lithium ion batteries, in particular to a silicon-carbon negative electrode material and a preparation method thereof. The preparation method of the silicon-carbon negative electrode material comprises the following steps: carrying out liquid-phase coating treatment on a porous carbon material and a fast ion conductor precursor to form a porous carbon material coated with a fast ion conductor so as to prepare a modified porous carbon material; carrying out first chemical vapor deposition treatment by taking silane gas as a deposition precursor, and depositing nano silicon on the surface of the modified porous carbon material to prepare a silicon-carbon core; and carrying out secondary chemical vapor deposition treatment by taking a soft carbon gas source as a deposition precursor in an inert gas atmosphere, and depositing nano soft carbon on the surface of the silicon-carbon inner core to prepare the silicon-carbon negative electrode material. The preparation method of the silicon-carbon negative electrode material solves the technical problem that the electrochemical performance of the silicon-carbon material is poor due to the fact that the volume of the existing silicon material is expanded and the ionic conduction performance is reduced by a carbon coating technology.

The invention provides a positive electrode active material and a preparation method thereof, a positive electrode and a solid-state battery, and particularly relates to the technical field of solid-state batteries. The positive electrode active material has a core-shell structure, and the core-shell structure comprises a core layer and a coating layer coating the core layer; the core layer is made of a lithium-rich manganese-based material; and the coating layer is made of a fast ion conductor and a halide solid electrolyte. The fast ion conductor in the coating layer of the positive electrode active material can improve the ionic conductivity of the surface layer of the positive electrode active material, promote rapid migration of lithium ions and assist in improving the initial coulombic efficiency. Meanwhile, the coating layer improves the chemical stability of the positive electrode active material, effectively inhibits the interface side reaction between the positive electrode body and the sulfide electrolyte, and relieves the structural degradation in the cycle process. The coating layer can also be used as a buffer layer to inhibit stress generated by volume shrinkage and expansion in charge and discharge cycles, maintain good contact of an electrode interface, and realize improvement of the electrochemical performance of the material.

The invention relates to a lithium ion battery and a preparation method thereof. The lithium ion battery comprises a positive pole piece, a negative pole piece and a gel electrolyte, the gel electrolyte is formed by polymerizing an electrolyte prepolymerization solution, and the mass percentages of a cross-linking agent, a monomer and an initiator in the electrolyte prepolymerization solution are A%, B% and C% respectively; a positive electrode material layer in the positive electrode plate is formed by coating the surface of a positive electrode current collector with positive electrode slurry; the positive electrode slurry comprises a fast ion conductor, and the mass percentage content of the fast ion conductor in the positive electrode slurry is X%; the lithium ion battery satisfies the following relational expressions: the formula 1: 5 < B / A < 10; in the formula 2, C / (A + B) is more than 0.005 and less than 0.02; formula 3: 1.7 < = (A + B + C) / X < = 5.5. According to the scheme provided by the invention, a high-performance organic-inorganic hybrid network can be constructed, and the cycle performance of the battery is remarkably improved while the thermal shock performance of the battery is improved.

The invention provides a positive pole piece, a battery and a preparation method of the positive pole piece. The positive pole piece comprises a positive current collector and a composite layer arranged on the surface of at least one side of the positive current collector, the composite layer comprises a first composite layer, a second composite layer and a third composite layer which are sequentially arranged along the thickness direction of the positive pole piece, and the first composite layer is arranged on the surface of the positive current collector; the first composite layer comprises a first conductive agent and a first binder, the second composite layer comprises a positive electrode active material, a second conductive agent, a second binder and a first fast ion conductor, and the third composite layer comprises a third conductive agent, a third binder and a second fast ion conductor. According to the invention, the electrochemical performance of the battery prepared by a dry-method electrode preparation process can be effectively improved.

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 discloses a composite coated modified positive electrode material, a preparation method thereof and a secondary battery, the composite coated modified positive electrode material provided by the invention comprises a positive electrode material and a composite coating layer on the surface of the positive electrode material, and the composite coating layer is composed of a fast ion conductor and a conductive polymer. The used fast ion conductor is a self-synthesized fast ion conductor and has the characteristics of stable crystal lattice, low surface brittleness and high ionic conductivity, the fast ion conductor and the conductive polymer are simultaneously coated on the surface of the positive electrode material to form a composite coating layer, and an electron-ion double-conduction transmission network is formed on the surface of the positive electrode material; the interface stability of the positive electrode material is enhanced, the volume expansion effect is relieved, and the electrochemical performance of the positive electrode material is comprehensively and effectively improved.

The invention discloses a lithium-rich manganese-based positive electrode material with a fast ion conductor coating layer and bulk phase doping and a preparation method of the lithium-rich manganese-based positive electrode material, the surface of the lithium-rich manganese-based positive electrode material is coated with the coating layer composed of amorphous Li3PO4, the interior of the bulk phase is doped with other elements, the structural formula of the lithium-rich manganese-based positive electrode material is Li < 1 + a > Mn M < c > O < 2 >, m is one or more than one of Ni, Co, A1, Cr, Fe, Mg and Ce, 0 lt; a is less than or equal to 0.2, 0lt; b < = 1, 0lt; c < = 1, and a + b + c = 1. The method comprises the following steps: (1) fully mixing a lithium-rich manganese-based positive electrode material precursor, a certain proportion of lithium salt and a proper amount of phosphate; and (2) sintering the uniformly mixed sample in a certain atmosphere to obtain the lithium-rich manganese-based positive electrode material with the fast ion conductor coating layer and the bulk phase doping structure. The first coulombic efficiency of the lithium-rich positive electrode material is improved, the cycling stability and the rate capability of the lithium-rich positive electrode material are improved, and the requirements of a power battery can be met.

The application belongs to the technical field of lithium ion batteries, and relates to a solid-state electrolyte interface layer for a lithium metal negative electrode and an in-situ plasma construction method and application thereof. The core of the method is to use an organic-inorganic-alloy component precursor as a plasma reaction source, to control the mixing ratio and reaction conditions to perform plasma reaction on the surface of lithium metal, and to in-situ construct a unique gradient layered structure of an organic-inorganic-alloy composite artificial solid-state electrolyte interface layer. The outer layer of the solid-state electrolyte interface layer is a flexible organic phase, the middle layer is a rigid inorganic fast ion conductor, and the inner layer is a lithiumophilic alloy phase, which can synergistically inhibit lithium dendrite growth and significantly improve the interface stability of the lithium metal negative electrode. Meanwhile, the preparation method provided by the application is simple, rapid, efficient, environmentally friendly, mild in conditions and easy to control, significantly improves the cycle stability and coulombic efficiency of the lithium metal negative electrode, and is helpful to promote the development of high-energy-density lithium metal batteries.

The invention provides a lithium ion battery positive electrode material and a preparation method and application thereof. According to the lithium ion battery positive electrode material, the lithium ion battery positive electrode material has a core-shell structure, a lithium layered metal oxide, a composite double-phase coating layer and a carbon coating layer are distributed from the center to the surface of the lithium ion battery positive electrode material, and the composite double-phase coating layer is prepared from a fast ion conductor and an oxide. The lithium ion battery positive electrode material provided by the invention solves the problems of limited rate capability and poor cycling stability of a ternary material, improves the capacity retention ratio of a lithium ion battery under high-power charging and discharging conditions, inhibits interface side reaction between an electrode material and an electrolyte, and prolongs the service life of the battery. The invention also provides a preparation method and application of the lithium ion battery positive electrode material.

The invention provides a lithium nickel manganese oxide positive electrode material and a preparation method thereof, a lithium ion battery and electric equipment, and relates to the field of lithium ion batteries. Comprising an inner core and a coating layer, the chemical general formula of the inner core is Li Ni < x > Mn < y > M < z > M'wO < 4 >; m comprises one or more of Al, Mg, Co, Mn, Ni, Ti, Zr, W, Nb, P, Sb, F, Sr and Se; m'comprises one or more of Mg, Co, Mn, Ni, Ti, Zr, W, Nb, P, Sb, F, Sr and Se; the coating layer comprises a LiM ''O-type fast ion conductor, and M'' comprises one or more of Mg, Al, Co, Mn, Ni, Ti, Zr, W, Nb, Sb, La and Se. According to the lithium nickel manganese oxide positive electrode material, M and M'are cooperatively doped, and then fast ion conductor coating is performed, so that the ion conductivity of the positive electrode material and the structural stability of the material under high voltage are remarkably improved.

The invention belongs to the technical field of battery positive electrode materials, and particularly relates to a high-rate manganese-based positive electrode material and a preparation method and application thereof.The high-rate manganese-based positive electrode material sequentially comprises a manganese-based active core, a mesoporous fast ion conductor shell layer and a pretreatment layer formed by coating the surface of the manganese-based active core with a boron-containing compound in situ from inside to outside, and the functionalized carbon nanotube three-dimensional conductive network penetrates through the active core and the shell layer. The preparation method comprises the following steps: carrying out boron-containing compound liquid phase pretreatment on a manganese-based active core to form a surface pretreatment layer, carrying out oxidation functionalization and lithiation modification on carbon nanotubes in sequence to construct an embedded three-dimensional conductive network, carrying out ball milling-ultrasonic dispersion to prepare precursor sol, and carrying out coating to form a fast ion conductor shell layer. According to the high-rate manganese-based positive electrode material and the preparation method thereof, through the synergistic effect of multiple structures, dissolution of manganese ions and collapse of the material structure are effectively inhibited, the high-rate performance and cycling stability of the material are improved, and the high-rate manganese-based positive electrode material has a good industrialization prospect.

The application provides a modified lithium-rich manganese-based material, a modification method of the lithium-rich manganese-based material, a secondary battery and an electric device. The modified lithium-rich manganese-based material comprises a lithium-rich manganese-based material co-doped with anions and cations and a fast ion conductor material, and a chemical formula of the lithium-rich manganese-based material is xLi2MnO3·(1-x)LiNi y Co z Mn a O2, wherein 0

A composite negative electrode sheet, a preparation method therefor, and a lithium ion battery using same. The composite negative electrode sheet comprises a current collector (1), an active coating (2) and an insulating coating (3) which are sequentially arranged. The insulating coating (3) comprises a polymer, an inorganic filler and a fast ion conductor. The active coating (2) comprises a binder and an active material. The difference between the solubility parameters of the polymer and the binder is denoted as |△δ|, where |△δ|>0.5(J / cm3)1 / 2. The barrier property between the insulating coating (3) and the active coating (2) is effectively improved, thus improving the structural stability of the composite negative electrode sheet.

The invention relates to a fast ion conductor-stabilizer composite coated lithium manganese iron phosphate material as well as a preparation method and application thereof. The lithium manganese iron phosphate material comprises a lithium manganese iron phosphate inner core and a coating layer on the surface of the lithium manganese iron phosphate inner core, the coating layer is obtained by mixing sodium aluminosilicate, magnesium metaaluminate, a coating carbon source and a lithium supplement agent, coating the surface of the lithium manganese iron phosphate inner core with the mixture, and performing sintering treatment. According to the invention, sodium aluminosilicate and magnesium metaaluminate are combined with conductive carbon to carry out co-coating treatment on lithium manganese iron phosphate, and in a high-temperature sintering process, part of Na < + > / Al < 3 + > / Mg < 2 + > multi-ions are co-embedded into a near surface layer of a lithium manganese iron phosphate crystal, so that a unit cell structure which is more stable in structure and easier in Li < + > diffusion is formed. In the high-temperature sintering process, part of magnesium metaaluminate reacts with the lithium supplement agent to form an Al-based fast ion conductor, and sodium aluminosilicate has a wider Li < + > diffusion channel, so that the material has excellent rate capability.

The invention provides a lithium-rich manganese-based solid-state battery positive electrode material as well as a preparation method and application thereof, and relates to the technical field of solid-state battery positive electrode materials, the lithium-rich manganese-based solid-state battery positive electrode material comprises a lithium-rich manganese-based positive electrode material body and a composite coating layer of a fast ion conductor layer and an electronic conductor layer, and the composite coating layer coats the surface of the lithium-rich manganese-based positive electrode material body. Aiming at the problems of poor interface contact between a lithium-rich manganese base and a sulfide solid electrolyte in an all-solid-state battery, difficulty in ion transmission and unstable structure in a circulation process, the invention provides a lithium-rich manganese-based positive electrode material which can simultaneously realize high interface ion / electron conduction, excellent interface stability and effective inhibition of bulk phase structure degradation. Therefore, the electrochemical performance of the material in a solid-state battery is obviously improved.

The invention belongs to the technical field of new energy materials, and relates to a PVDF-HFP-based LATP and ZrO2 double-filler composite solid electrolyte and a preparation method thereof. The composite material is prepared by compounding an NASICON type fast ion conductor LATP, a multifunctional additive ZrO2, a PVDF-HFP polymer matrix and LiTFSI. The core of the lithium ion battery is that micron-sized LATP particles are utilized to construct a penetrating lithium ion rapid transmission channel, and meanwhile, nano-sized ZrO2 particles are introduced to assist dispersibility and induce amorphization of a polymer chain. The preparation method comprises the following specific implementation steps: dissolving PVDF-HFP and LiTFSI (in a mass ratio of X: Y) in N-methyl pyrrolidone (NMP), and stirring at a constant temperature; the preparation method comprises the following steps: dispersing LATP and ZrO2 in NMP according to a ratio, and carrying out ultrasonic treatment to obtain filler slurry; and mixing the two solutions, pouring into a mold, scraping the membrane, and carrying out vacuum drying to obtain the solid electrolyte membrane (PHLZ). The obtained PHZL composite solid electrolyte shows excellent electrochemical performance, and can still keep the specific capacity as high as 962.18 mAh / g after 300 cycles under the high current density of 1A / g. The invention provides an effective strategy for designing the solid electrolyte with high safety, high ionic conductivity and excellent cycle stability, and has important application value in the field of high-energy-density solid lithium batteries.

The invention relates to the technical field of preparation of a lithium ion battery positive electrode material, in particular to a lithium-rich manganese-based positive electrode material with a gradient buffer layer, a preparation method of the lithium-rich manganese-based positive electrode material and an all-solid-state battery. The lithium-rich manganese-based composite material sequentially comprises a lithium-rich manganese-based core material, a gradient buffer layer wrapping the lithium-rich manganese-based core material and a surface modification layer wrapping the gradient buffer layer from inside to outside, and the gradient buffer layer sequentially comprises a spinel inner layer, a fast ion conductor middle layer and a self-repairing polymer outer layer from inside to outside. According to the invention, the gradient buffer layer is constructed outside the lithium-rich manganese-based core material, so that the problem of poor stability of the positive electrode material is solved, the surface modification layer is constructed outside the gradient buffer layer, and the problem of poor interface contact is cooperatively solved through precise spatial arrangement of all functional layers and optimization of ion and electron transmission paths. The method realizes bulk phase structure stability and interface dynamic repair, and is especially suitable for a high-energy-density all-solid-state lithium battery system.

The aluminum fluoride coated nano silicon material is prepared from nano silicon powder, aluminum nitrate nonahydrate, ammonium fluoride, absolute ethyl alcohol and deionized water, and an aluminum fluoride coating layer and a nano silicon negative electrode material are compounded to form an aluminum fluoride coated nano silicon material structure. The aluminum fluoride coating layer on the surface can be converted into a fast ion conductor in the battery circulation process, so that the lithium ion diffusion rate is increased, and migration of lithium ions between the nanometer silicon negative electrode and the electrolyte is promoted. Under the coating protection effect of the coating layer, the volume expansion of the nano-silicon material is improved, the voltage attenuation speed is slowed down, the cycling stability is greatly improved, the cycling performance of the nano-silicon negative electrode material is improved, and silicon particle breakage, material pulverization and falling off from a pole piece are avoided. The coating amount of the aluminum fluoride coating layer is compared, and the optimal coating amount is given. The method has the advantages of low cost and high controllability.

The preparation method comprises the following steps: S1, uniformly mixing a lithium source, an iron source, a phosphorus source, a fast ion conductor and a rare earth compound, adding ethanol and an MOF material, and sintering at the temperature of 100-200 DEG C for 1-3 hours to obtain a lithium iron phosphate precursor A; s2, transferring the lithium iron phosphate precursor A into a tubular furnace, raising the temperature to 300-500 DEG C, introducing heteroatom gas, raising the temperature to 700-900 DEG C, and introducing carbon source gas to obtain a lithium iron phosphate precursor B; and S3, dispersing the lithium iron phosphate precursor B, a carbon source and a functional additive into a solvent, performing spray drying, and performing high-temperature sintering for 2-12 hours to obtain the high-capacity and high-compaction lithium iron phosphate positive electrode material. The diffusion path of lithium ions is shortened, and the transmission performance of the lithium ions is remarkably improved; meanwhile, the specific capacity of the material is improved; and moreover, agglomeration of iron phosphate is avoided, the coating uniformity is improved, the power performance is improved, and the compaction density of the lithium iron phosphate material is further improved.

The invention relates to the technical field of lithium ion batteries, in particular to an ultrahigh-nickel ternary positive electrode material as well as a preparation method and application thereof. The preparation method of the ultrahigh-nickel ternary positive electrode material provided by the invention comprises the following steps: mixing a first vinyl polymer, a precursor, a metal oxide and a solvent to obtain a spinning solution A; mixing a second vinyl polymer, a lithium source and a solvent to obtain a spinning solution B; respectively depositing the spinning solution A and the spinning solution B by adopting an opposite electrostatic spinning technology to obtain a film-shaped material, and sintering to obtain a matrix material; and coating the surface of a base material by a wet method to prepare a fast ion conductor coating layer, and carrying out second sintering to obtain the ultrahigh-nickel ternary positive electrode material. According to the method provided by the invention, the agglomeration phenomenon of the ultra-high nickel positive electrode material in the sintering process is effectively reduced, so that the lithium ion battery containing the ultra-high nickel ternary positive electrode material has relatively high capacity and excellent cycle performance.

The application provides a high-flexibility dielectric positive electrode binder and a preparation method thereof and a solid-state battery positive electrode. The high-flexibility dielectric positive electrode binder comprises a fluoropolymer matrix and a fast ion conductor; the fluoropolymer matrix is a copolymer of vinylidene fluoride (VDF) and a fluorine-containing comonomer, the fast ion conductor is in a one-dimensional nanowire shape and is dispersed in the fluoropolymer matrix; and the mass fraction of the fast ion conductor is 1% to 20% based on the fluoropolymer matrix. The application can simultaneously solve three core problems of physical continuity of an ion conduction path in the positive electrode, inhibition of a space charge layer at an interface and mechanical coating of active particles, thereby significantly improving the rate performance, cycle stability and actual energy density of the solid-state battery.

The invention discloses a high-performance electrode, a preparation method thereof and a solid-state battery. The high-performance electrode comprises a positive electrode, a current collector and a negative electrode, and the current collector is located between the positive electrode and the negative electrode; the negative electrode comprises a metal lithium composite material layer, and the metal lithium composite material layer comprises a granular metal lithium composite material or a pressure-deformed granular metal lithium composite material. The metal lithium composite material comprises: a lithium-containing core; the middle layer is constructed on the surface of the inner core and comprises a first framework formed by interweaving a first framework material, a second framework formed by a second framework material inserted into the first framework, and a limiting polymer for fixing the relative positions of the first framework and the second framework; and a housing comprising a conductive polymer layer and a lithium fast ion conductor distributed in the conductive polymer layer. The high-performance electrode has excellent cycle performance and high safety characteristics.

The invention discloses a positive electrode active material and a lithium ion secondary battery. The positive electrode active material comprises a lithium-rich manganese-based material, a first coating layer and a second coating layer, the first coating layer comprises a first fast ion conductor and coats part of the surface of the lithium-rich manganese-based material; the second coating layer comprises a first region and a second region which are connected with each other, the first region coats the lithium-rich manganese-based material which is not coated by the first coating layer, and the first region comprises lithium halide or a compound formed by the lithium halide and a second fast ion conductor; and the second region is coated with the first coating layer and comprises a compound formed by lithium halide and the first fast ion conductor or a compound formed by lithium halide, the first fast ion conductor and the second fast ion conductor. The two coating layers are closely connected in space and function, rapid ion / electron continuous transmission, stable interface chemistry and lasting physical protection are jointly achieved, and the rate capability and the cycling stability of the battery are improved while high-capacity exertion of the lithium-rich manganese-based material is guaranteed.

The invention discloses a modification method of a ternary positive electrode material. The modification method comprises the following steps: S1, carrying out a co-precipitation reaction on a solution of transition metal sulfate in an inert gas atmosphere; a sulfate solution of rare earth elements is synchronously added in the coprecipitation process, and a ternary precursor with the surface coated with rare earth hydroxide is formed; and S2, mixing the ternary precursor obtained in the step S1 with a lithium source, calcining in an air atmosphere, and cooling to obtain the fast ion conductor coated ternary positive electrode material, the rare earth elements are selected from one or more of lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium; the transition metal sulfate is soluble salt of Ni, Co and Mn. The rare earth element sulfate is added in the coprecipitation process, the rare earth element hydroxide is precipitated on the surface of the precursor, the lithium source is removed after filtering and drying, uniform mixing is performed, and the ternary positive electrode material which contains the rare earth element and is uniformly coated with the fast ion conductor is obtained after calcination, so that side reactions on the surface of the material are reduced; and the cycling stability of the positive electrode material is improved.

The invention belongs to the technical field of lithium ion batteries, and particularly relates to a modified single-crystal ternary positive electrode material as well as a preparation method and application thereof. The modified single crystal ternary positive electrode material comprises an inner core, a coating layer 1 and a coating layer 2 which are laminated in sequence, the general formula of the inner core is LixNiaCobMncLpO2 + q, x is more than or equal to 1.00 and less than or equal to 1.20, a is more than or equal to 0.10 and less than or equal to 0.60, b is more than or equal to 0.10 and less than or equal to 0.30, c is more than or equal to 0.10 and less than or equal to 0.30, p is more than or equal to 0.0001 and less than or equal to 0.03, q is more than or equal to 0 and less than or equal to 0.03, and L comprises at least one of Mg, Al, Ti, Zr, Y and Sb; the coating layer 1 comprises a fast ion conductor; and the coating layer 2 comprises a conductive polymer. According to the modified single crystal ternary positive electrode material provided by the invention, the rate capability and the cycle life are both considered while the high capacity is maintained.

The invention provides a multi-modified high-nickel ternary positive electrode material, a preparation method thereof and a solid-state battery. The multi-modified high-nickel ternary positive electrode material comprises a high-nickel ternary core, a fast ion conductor coating layer and a polymer ceramic nanofiber composite coating layer, wherein the fast ion conductor coating layer and the polymer ceramic nanofiber composite coating layer are sequentially arranged on the surface of the high-nickel ternary core. According to the multi-modified high-nickel ternary positive electrode material disclosed by the invention, a dual cooperative defense system of the fast ion conductor layer and the polymer ceramic composite layer is constructed, so that the interface problems of surface side reaction, transition metal dissolution and the like are effectively solved, and a bulk phase structure is indirectly stabilized through external constraint and reduction of surface induction factors; therefore, the comprehensive improvement of the capacity, the rate capability and the cycle performance of the high-nickel material under the conditions of high voltage and long cycle is realized.

This invention belongs to the field of battery active materials technology, specifically disclosing a lithium manganese iron phosphate composite material, its preparation method, and a secondary battery. The lithium manganese iron phosphate composite material includes a core and a first coating layer (carbon layer) and a second coating layer (fast ion conductor layer) sequentially covering the core from the inside out; the core comprises lithium manganese iron phosphate material LiFe. x Mn 1‑x D y PO4, 0 < x < 1, 0 ≤ y ≤ 0.1, D is the doping element; the fast ion conductor layer includes the fast ion conductor Li. a M b A c O d X e M represents titanium and / or zirconium, A represents nitrogen and / or phosphorus, and X represents at least one of fluorine, chlorine, bromine, or iodine, where 1 ≤ a ≤ 4, 0 ≤ b ≤ 5, 0 ≤ c ≤ 3, 0 ≤ d ≤ 12, and 0 ≤ e ≤ 2. This invention improves the structural stability and conductivity of lithium manganese iron phosphate by coating it with a fast ion conductor and a carbon bilayer, thereby enhancing the cycle life and rate performance of secondary batteries.