2825results about How to "Improve cycle performance" patented technology

The invention provides a sodium ferric pyrophosphate positive electrode material cooperatively doped with anions and cations, a preparation method of the sodium ferric pyrophosphate positive electrode material and a sodium ion battery, and relates to the field of sodium ion batteries. The anion and cation synergistically doped ferric sodium phosphate pyrophosphate positive electrode material comprises an inner core and a coating layer covering the outer surface of the inner core, the inner core comprises ferric sodium phosphate pyrophosphate, the coating layer comprises carbon, the chemical formula of the ferric sodium phosphate pyrophosphate is Na4-2yFe2.91-xQx (PO4) 2-yP2O7Fy, x is more than 0 and less than or equal to 0.3, and y is more than or equal to 0.03 and less than or equal to 0.08; q comprises at least one of Sn, Ni, Cu, Mg and Mn. The introduced Q positive ions and F negative ions can keep the crystal structure of the body material stable, and the positive ions and the negative ions have a synergistic effect, so that the band gap of the positive electrode material is reduced, the state density near the Fermi level of the positive electrode material is increased, the conductivity of the positive electrode material is enhanced, the specific capacity of the positive electrode material is improved, and the rate and the cycle performance are promoted.

The invention provides a positive plate, a preparation method thereof and a battery. The positive plate comprises a positive current collector, and a first positive active coating and a second positive active coating which are sequentially arranged on at least one side of the positive current collector, the first positive electrode active coating is close to one side of the positive electrode current collector, and the first positive electrode active coating comprises a first manganese iron lithium phosphate active material and a nickel-cobalt-manganese ternary active material; in the first positive electrode active coating, the mass ratio of the first lithium manganese iron phosphate active material to the nickel-cobalt-manganese ternary active material is (80-90): (8-15); the second positive electrode active coating is far away from one side of the positive electrode current collector, and the second positive electrode active coating comprises a second lithium manganese iron phosphate active material; the surface density rho1 of the first positive electrode active coating and the surface density rho2 of the second positive electrode active coating meet the following conditions: rho1 is greater than or equal to 240 g / m < 2 >, and rho2 is greater than or equal to 240 g / m < 2 >; and rho1-rho2 is less than or equal to 5g / m < 2 >. The positive plate has relatively high electron conduction and ion conduction performance, meanwhile, the polarization of the positive plate is effectively reduced, and the cycle performance and the thermal stability of the battery are greatly improved.

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 provides a high-rate and high-first-effect biomass hard carbon composite negative electrode material and a preparation method and application thereof, the hard carbon composite negative electrode material has a core-shell structure, the core-shell structure comprises a core, an inner shell and an outer shell, the core comprises biomass hard carbon containing P and graphite microcrystals, the inner shell comprises graphene, and the outer shell comprises a carbon nanotube. According to the invention, the surface of the biomass hard carbon is coated with the graphene layer, the carbon nanotubes grow on the surface of the graphene in situ, and transition metal synergistically induces the hard carbon to be arranged and grow along the graphene layer in a high-temperature carbonization process, so that the graphene coating layer is tightly coated, and the cycle performance of the material is improved; transition metal ions catalyze graphitization to generate a more regular and ordered graphite-like layer microcrystalline structure coating layer, so that the defects of graphene and carbon nanotubes are reduced, and the first coulombic efficiency is improved; in addition, the ion transmission capability is improved by phosphorus doping, the electron transmission capability is improved by graphite microcrystals generated by catalysis in hard carbon, and the rate capability is ensured by synergistic improvement of ion transmission and electron transmission.

The invention discloses an adhesive, lithium battery negative electrode slurry, a lithium battery negative electrode and a lithium battery. The adhesive comprises an acrylic copolymer; polymeric monomers of the acrylic copolymer comprise an acrylic monomer, an acrylonitrile monomer, an acrylamide monomer and a selective acrylate monomer; the preparation method of the acrylic acid copolymer comprises the following steps: mixing an acrylic acid monomer with water, adding alkali for neutralization until the neutralization degree is greater than or equal to 50% and less than 100%, then adding an acrylamide monomer and an acrylonitrile monomer, selectively adding an acrylic ester monomer, heating to a reaction temperature in a protective atmosphere, and carrying out a reaction for 2-4 hours to obtain the acrylic acid copolymer. Adding an initiator to initiate an aqueous solution polymerization reaction to generate an acrylic copolymer; practice shows that the binder has higher molecular weight and better electrical performance, when the binder is applied to the negative electrode of the lithium battery, excellent binding power and battery cycle performance can be obtained while the use amount of the binder is reduced, and the binder can be used for preparing the lithium battery, related electrodes and the like.

The invention relates to the technical field of lithium ion batteries, in particular to a lithium iron manganese phosphate-ternary material composite positive electrode lithium ion battery formation method and a lithium ion battery, the formation method comprises the following steps: S1, allowing a soft package cell to stand in a vacuum environment; s2, applying a first pressure and heating, and then carrying out constant current charging to 20%-40% SOC at a small current of 0.02-0.05 C; s3, second pressure is applied, heating is conducted, then constant current charging is conducted to 50%-70% SOC with the large current of 0.1-0.2 C, and the second pressure is larger than the first pressure; s4, applying a third pressure and heating, and then performing constant-current discharge at the current of 0.2-0.5 C until the SOC is 30-50%; and S5, performing high-temperature aging on the soft package battery cell. According to the formation method provided by the invention, the cycle performance of the lithium iron manganese phosphate-ternary material composite positive electrode lithium ion battery is improved.

The invention relates to the technical field of lithium ion batteries, and provides a lithium cobalt oxide composite material which comprises a core body and a coating layer coating the core body, the core body comprises O2-phase lithium cobalt oxide, and the O2-phase lithium cobalt oxide is doped with an element M; the coating layer comprises an oxide containing an N element; the M element comprises at least one of Al, Mg, W, Ti, La, Zr, Ni, Mn and Y; n comprises at least one of Al, Mg, Y, W, Nb, La, Zr, Ti and P. The lithium cobalt oxide composite material provided by the invention is used as a positive electrode material of a lithium ion battery, and the cycling stability of the lithium ion battery under high potential is improved.

The invention relates to the technical field of secondary batteries, in particular to a conductive composite current collector, a preparation method thereof and a battery. The conductive composite current collector comprises a supporting layer, a metal layer arranged on at least one surface of the supporting layer and a PTC (Positive Temperature Coefficient) bottom coating arranged on the surface, far away from the supporting layer, of the metal layer, the supporting layer comprises a polymer base membrane and conductive fibers dispersed in the polymer base membrane; the PTC undercoat layer includes a conductive polymer and a conductive agent dispersed in the conductive polymer. The conductive composite current collector provided by the invention is high in conductivity and excellent in safety, the probability of thermal runaway of the battery at a high temperature is effectively reduced, and the rate capability and the cycle performance of the battery are improved.

The invention provides a graphite negative electrode material and a preparation method thereof, a dry-method electrode, a battery and electric equipment, and belongs to the technical field of battery manufacturing. The graphite negative electrode material is of a core-shell structure, an inner core is graphite, a shell is a polymer coating layer, the polymer coating layer can conduct ions but cannot conduct electrons, and the graphite negative electrode material can effectively inhibit PTFE from generating side reaction with lithium ions on the surface of a negative electrode, so that the first discharge gram capacity, the first effect and the cycle performance of a corresponding battery are improved.

The invention provides a lithium ion battery and electric equipment, the lithium ion battery comprises a positive pole piece and an electrolyte, active substances in the positive pole piece comprise a phosphate lithium positive pole material and nickel cobalt manganese lithium oxide, and the electrolyte comprises a positive pole film-forming agent, a negative pole film-forming agent and a lithium salt, the lithium salt comprises lithium hexafluorophosphate and lithium bis (fluorosulfonyl) imide, the lithium ion battery meets the following formula: # imgabs0 #, NL is the mass ratio of the lithium nickel cobalt manganese oxide to the lithium phosphate positive electrode material, Salt is the sum of the molar concentrations of the lithium hexafluorophosphate and the lithium bis (fluorosulfonyl) imide in the electrolyte by taking mol / L as the unit, and the sum of the molar concentrations of the lithium hexafluorophosphate and the lithium bis (fluorosulfonyl) imide in the electrolyte is the sum of the molar concentrations of the lithium hexafluorophosphate and the lithium bis (fluorosulfonyl) imide. Add is the mass ratio of the positive electrode film-forming agent to the negative electrode film-forming agent. When the ternary material is doped in the lithium manganese iron phosphate or the lithium iron phosphate, the proportion of the positive and negative electrode film-forming agents and the proportion of the heat-resistant high-lithium salt can be adjusted according to the mixing proportion of the lithium manganese iron phosphate and the lithium iron phosphate, so that the cycle performance of the battery is improved.

The invention belongs to the technical field of sodium ion battery negative electrode materials, and particularly relates to an amylocellulose composite hard carbon material as well as a preparation method and application thereof. Pre-oxidation and pre-carbonization are carried out step by step, the starch cellulose composite hard carbon material is prepared through low-temperature pre-oxidation, a ball milling method, low-temperature pre-carbonization and a high-temperature pyrolysis method in sequence, the obtained starch cellulose composite hard carbon material is used for preparing the negative electrode of the sodium-ion battery, and then the sodium-ion battery is further constructed. An electrochemical performance test result shows that the obtained sodium ion battery has excellent first-circle coulombic efficiency, cycle performance and rate capability; moreover, the preparation method of the starch cellulose composite hard carbon material is simple to operate, can perform a pre-oxidation process in an air atmosphere, does not need additional oxidation treatment, is environment-friendly, can prevent the starch cellulose composite material from melting and foaming in high-temperature pyrolysis, improves the cycling stability of the material, and is suitable for industrial production.

The invention discloses a lithium manganese iron phosphate composite material, a preparation method thereof and a lithium ion battery containing the lithium manganese iron phosphate composite material. The preparation method comprises the following steps: grinding, sintering and crushing a mixture of the lithium iron manganese phosphate, the lithium iron phosphate precursor and water to form the lithium iron manganese phosphate composite material, the sintering temperature is 650 DEG C to 750 DEG C; wherein the lithium manganese iron phosphate forms an inner core of the lithium manganese iron phosphate composite material, and the average particle size of the inner core is 600 nm to 1200 nm; the lithium iron phosphate precursor forms a lithium iron phosphate coating layer and a carbon coating layer of the lithium manganese iron phosphate composite material. The lithium manganese iron phosphate composite material provided by the invention can effectively improve the ginger-Taylor effect of the lithium manganese iron phosphate and improve the electrochemical cycle performance of the material at the same time.

The invention relates to a polymer coated graphite negative electrode material and a preparation method and application thereof, the preparation method comprises the following steps: mixing polyacrylonitrile and graphite by adopting a ball milling method, then treating by adopting a liquid phase coating method to coat the surface of the graphite with a layer of polyacrylonitrile, and then carrying out low-temperature heat treatment to obtain the cyclized polyacrylonitrile coated graphite negative electrode material. The compact, flexible, high-electron and high-ion conductive coating is constructed on the surface of the graphite, so that the mechanical stability and the chemical stability of the graphite negative electrode material are effectively enhanced, the problem that a coating material is easy to break and fall off in a long-cycle process in the prior art is avoided, the interface performance of a graphite negative electrode and an electrolyte is improved, and the service life of the graphite negative electrode is prolonged. The volume expansion of the graphite negative electrode material is inhibited, the electrochemical activity of the graphite negative electrode material is enhanced, the electron transmission rate is accelerated, the rate capability and the cycle performance of the graphite negative electrode are further improved, and the preparation process is simple, green and environment-friendly, and is beneficial to industrial production and application.

The invention provides an anion-cation co-doped modified lithium manganese phosphate positive electrode material and a preparation method thereof, the lithium manganese phosphate positive electrode material comprises anion-cation doped lithium manganese phosphate and a carbon layer, the carbon layer is coated on the surface of the anion-cation doped lithium manganese phosphate, the chemical general formula is LiMn < 0.6 > Fe < 0.4-x > M < x > PO < 4-y > Fy, 0.001 < = x < = 0.03, 0.01 < = y < = 0.5, and 0 < = y < = 0.5. M is a cation, and Y is a fluorine ion. According to the preparation method, carbon layer coating and anion and cation co-doping modification of the lithium manganese iron phosphate positive electrode material are simultaneously realized through a one-step hydrothermal method, and the prepared lithium manganese iron phosphate positive electrode material is in an irregular spherical shape, relatively smooth in particle surface, and relatively high in large and small particle grading and compaction; after a performance test, compared with an electrode material which is not doped with anions and cations, the material disclosed by the invention has the advantages that the stability and the discharge capacity of the material are remarkably improved, and the electrochemical performance of the lithium manganese iron phosphate positive electrode material is effectively improved.

The invention specifically discloses a lithium ion battery. The lithium ion battery comprises a positive plate and a negative plate, the positive plate comprises a positive active material, and the positive active material is in four-stage grain composition and comprises first-stage grains, second-stage grains, third-stage grains and fourth-stage grains; the primary particle size R1 of the first-stage particles is smaller than 100 nm, and the first-stage particles account for 5%-30% of the positive electrode active material; the primary particle size R2 of the second-stage particles is more than or equal to 100nm and less than 400nm, and the proportion of the second-stage particles in the positive electrode active material is 10-50%; the primary particle size R3 of the third-stage particles is greater than or equal to 400 nm and less than 1000 nm, and the third-stage particles account for 5-30% of the positive electrode active material; the primary particle size R4 of the fourth-stage particles is larger than or equal to 1000 nm and smaller than or equal to 4000 nm, and the fourth-stage particles account for 5%-20% of the positive electrode active material; the negative plate comprises a graphite negative electrode material, the residual carbon content of the surface of the graphite negative electrode material is 0-5%, and the graphitization degree of the graphite negative electrode material is 90-97%. The method has the advantage of improving the energy density and high-temperature performance of the lithium battery.

The invention discloses a preparation method and application of a prussian blue material, and belongs to the field of battery materials.The preparation method of the prussian blue material comprises the following steps that S1, a solution containing ferrocyanide is prepared to serve as a raw material A, a solution containing transition metal salt is prepared to serve as a raw material B, a to-be-doped solution C containing alkali metal ions is prepared, the method comprises the following steps: S1, preparing a to-be-doped solution C containing transition metal ions, S2, adding a base solution into a container, continuously adding the raw material A and the raw material B into the base solution, and stirring and mixing to form a precipitate, and S3, in the precipitation process, continuously adding the to-be-doped solution C into the raw material A and continuously adding the to-be-doped solution D into the raw material B until the precipitation is finished to obtain the Prussian blue material. According to the invention, the moisture resistance, the rate capability and the cycle stability of the Prussian blue material are greatly improved.

The invention discloses a silicon carbon material, a preparation method thereof and a lithium ion battery. The preparation method of the silicon-carbon material comprises the following steps: S1, adding an alkaline reagent into a mixed solution containing a porous carbon-loaded silicon substrate, transition metal salt and a solvent, and drying to obtain a first precursor; s2, performing carbon deposition on the first precursor by adopting a chemical vapor deposition method, performing in-situ growth of a carbon nanotube, and then performing acid pickling and drying to obtain a second precursor; s3, performing silicon deposition on the second precursor by adopting a chemical vapor deposition method, and forming silicon nanoparticles and / or silicon nanowires in the carbon nanotubes in situ to obtain a third precursor; and S4, carrying out carbon coating on the third precursor to obtain the silicon carbon material. The silicon-carbon material is excellent in expansion inhibition performance and compressive strength and has excellent conductivity, and the lithium ion battery containing the silicon-carbon material can give consideration to excellent capacity performance, rate performance and cycle performance.

The invention provides a secondary battery and a preparation method and device thereof, and the secondary battery comprises a positive pole piece, a negative pole piece, a solid electrolyte, a first modification layer and a second modification layer. One of the first modification layer and the second modification layer is located between the positive pole piece and the solid electrolyte, and the other one of the first modification layer and the second modification layer is located between the negative pole piece and the solid electrolyte; the first modification layer and / or the second modification layer comprises 20 wt%-60 wt% of polymer, 10 wt%-65 wt% of lithium salt and 2 wt%-45 wt% of inorganic particles. The thickness of the first modification layer and / or the second modification layer is relatively thin, easy to control and relatively good in uniformity, so that the interface resistance between the positive pole piece and / or the negative pole piece in the secondary battery and the solid electrolyte is remarkably reduced, the side reaction between the solid electrolyte and the positive pole piece and / or the negative pole piece is avoided, and the service life of the secondary battery is prolonged. And the first modification layer and / or the second modification layer have / has good thermal stability, so that the cycle performance of the secondary battery can be improved.

The invention relates to the technical field of sodium ion batteries, in particular to a sodium ferric sulfate positive electrode material and a preparation method and application thereof. The preparation method of the sodium ferric sulfate positive electrode material comprises the following steps: obtaining a carbon foam substrate; weighing raw materials according to the stoichiometric ratio of the sodium ferric sulfate positive electrode material, and adding the raw materials into a solvent to obtain a mixed solution; depositing the mixed solution on a carbon foam substrate by adopting an electrostatic spray deposition method to obtain a precursor film; and sintering the precursor film to obtain the sodium ferric sulfate positive electrode material. According to the preparation method, the carbon foam is adopted as a substrate material, the sodium ferric sulfate precursor is prepared through electrostatic spray deposition, and then the sodium ferric sulfate material is obtained through sintering treatment, so that the specific discharge capacity, the rate capability and the cycle performance of the sodium ferric sulfate material are all remarkably improved.

The invention relates to the technical field of battery materials, in particular to a graphite negative electrode material and a preparation method and application thereof. The graphite negative electrode material comprises graphite particles, the average length La of the graphite particles in the alpha-axis direction of microcrystals is larger than or equal to 40 nm, the average thickness Lc of the graphite particles in the c-axis direction of the microcrystals is larger than or equal to 25 nm, and the interlayer spacing d002 ranges from 0.336 nm to 0.338 nm, and the number parameter of the microcrystals contained in each single graphite particle is defined as N = D503 / (La2 * Lc); d50 is the median particle size of the graphite particles, the unit is [mu] m, and the numerical value of N is more than 0 and less than or equal to 0.04. The graphite negative electrode material disclosed by the embodiment of the invention comprises the graphite particles with stable microcrystalline structure, large microcrystalline size and large interlayer spacing, so that the expansion and stress distribution uniformity of the negative electrode material in the circulation process is improved, the diffusion of ions in the graphite particles is facilitated, the consumption of active lithium is reduced, and the service life of the negative electrode material is prolonged. And the dynamic and super-long cycle stability of the graphite negative electrode material is improved.

The invention discloses a preparation method of a hard-soft carbon coated silicon-carbon negative electrode material, which comprises the following steps: S1, mixing nano silicon and graphite to obtain silicon-carbon mixed powder; s2, dissolving asphalt in absolute ethyl alcohol, then mixing with the silicon-carbon mixed powder, and carrying out carbonization treatment; s3, dissolving sucrose in water, then mixing with the composite material obtained in S2, and performing carbonization treatment to obtain a hard-soft carbon coated silicon carbon negative electrode material; wherein the carbonization temperature in the step 2 and the carbonization temperature in the step 3 are both 1200-1300 DEG C. According to the hard-soft carbon coated silicon-carbon negative electrode material and the preparation method thereof, the mixture of silicon and graphite is subjected to soft carbon coating and hard carbon coating through asphalt and cane sugar in sequence, so that the obtained hard-soft carbon coated silicon-carbon negative electrode material not only can inhibit volume expansion of silicon, but also shows excellent rate capability and cycle performance.

The invention relates to the technical field of battery materials, and discloses a lithium cobalt oxide composite positive electrode material with a coating layer, a preparation method thereof, a positive electrode and a battery. The lithium cobalt oxide composite positive electrode material with the coating layer comprises a main body and the coating layer coated outside the main body, the chemical formula of the main body is LixNayCo1-zMzO2, x is more than or equal to 0.7 and less than or equal to 0.74, y is more than 0 and less than or equal to 0.1, z is more than or equal to 0 and less than or equal to 0.1, and M is selected from at least one of Al, Mg, W, Ti, La, Zr, Y, Ni, Mn and Nb; the coating layer is a metal oxide; and a crystal phase in the main body is a T2 and O2 composite phase. The preparation method comprises the following steps: firstly preparing a P2-phase sodium cobalt oxide precursor, coating the precursor, and then carrying out ion exchange with a lithium source mixed molten salt to finally obtain the composite positive electrode material of T2 and O2 composite phase lithium cobalt oxide with a coating layer. The positive electrode material has good electrochemical performance.

The invention relates to the field of lithium ion batteries, in particular to a fluorine-containing soluble polyimide adhesive special for a lithium battery and a preparation method and application of the fluorine-containing soluble polyimide adhesive. The fluorine-containing polyimide is prepared by reacting dianhydride and diamine, the dianhydride comprises 4, 4 '-hexafluoroisopropyl phthalic anhydride (6FDA), the diamine comprises 4, 4'-diaminodiphenylamine (NDA), and the structural formula of the fluorine-containing polyimide (6FDA-NDA) is # imgabs0 #. The electrode material prepared from the adhesive material obtained by the invention has the characteristics of low impedance and high adhesion, the assembled lithium battery shows higher magnification, and the adhesive material shows excellent magnification performance and adhesion performance when being applied to the lithium ion battery, especially a silicon-containing negative electrode lithium ion battery, and has a good industrial prospect.

The invention belongs to the technical field of battery positive electrode preparation, and particularly relates to a mixed coating coated nickel-rich layered oxide positive electrode and application thereof. The mixed coating coated nickel-rich layered oxide positive electrode is an NCM system positive electrode material, and the proportion of a Ni material in an NCM ternary system is greater than or equal to 92 wt%; the ratio content of Ni of the nickel-rich layered oxide positive electrode coated with the mixed coating in three elements of Ni, Co and Mn is greater than or equal to 92 mol%; and the nickel-rich layered oxide positive electrode coated with the mixed coating is coated with Li3PO4 and / or Li3BO3 and / or LiNbO3. The positive electrode material provided by the invention can effectively reduce the space charge layer effect and interface side reaction between the positive electrode and the electrolyte, the lithium ion migration efficiency is high, and the cycle performance of the assembled battery is good.

The invention discloses a method for preparing a composite iron-based polyanion positive electrode material. The structural formula of the positive electrode material is represented as Na4Fe3 (PO4) 2 (P2O7) (at) Camp, mXenes are sodium ferric pyrophosphate compositely coated by an MXenes material and a carbonaceous precursor, and the preparation method comprises the following steps: weighing a sodium source, a ferrous source, a phosphorus source and a carbon source according to a stoichiometric ratio, uniformly mixing, grinding, spray-drying and sintering at high temperature to obtain the composite iron-based polyanion positive electrode material, and the carbon source comprises iron-nickel doped polyethylene glycol. The composite iron-based polyanion positive electrode material provided by the invention is remarkably improved in the aspects of energy density, rate capability and cycle life, and the preparation process is simple to operate, reliable in flow, quick in preparation process and easy for industrial production, so that an ideal scheme is provided for commercialized sodium ion battery positive electrode materials.

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 relates to a preparation method of a three-dimensional ferrocobalt metal oxide oxygen evolution catalyst. According to the method, foamed nickel is selected as a carrier, the foamed nickel is pretreated, a metal ion and ethanol mixed solution is evenly adsorbed to the surface of the foamed nickel, then open fire ignition is carried out, and a second-level self-limiting combustion process is carried out, so that metal ions form a ferrocobalt metal oxide material with a three-dimensional network structure in situ on the surface of the foamed nickel. The method is simple and easy to implement, a target product can be generated within second-level time, and the area of a foamed nickel matrix is adjusted according to needs, so that the three-dimensional ferrocobalt metal oxide catalyst is prepared on a large scale. The material obtained by the invention is used as an oxygen evolution anode catalyst, and the three-dimensional network-shaped ferrocobalt metal oxide oxygen evolution catalyst shows excellent electrochemical performance.

The invention relates to a lithium manganese iron phosphate positive electrode material and a preparation method thereof, and an electrochemical device, the preparation method of the lithium manganese iron phosphate positive electrode material comprises the following steps: mixing a manganese source, an iron source, a first phosphorus source, a lithium source, a first carbon source and a magnesium source, and carrying out primary grinding to obtain a first slurry; carrying out primary sintering on the first slurry to obtain a lithium manganese iron phosphate precursor; mixing the lithium manganese iron phosphate precursor, a second phosphorus source, a second carbon source and a niobium source, and performing secondary grinding to obtain second slurry; the second slurry is subjected to secondary sintering, the lithium manganese iron phosphate positive electrode material is obtained, the magnesium element exists in a bulk phase of the lithium manganese iron phosphate positive electrode material in a doping mode, and the niobium element exists in a coating layer of the lithium manganese iron phosphate positive electrode material in a coating mode. According to the preparation method, magnesium and niobium are co-doped and coated, and through the synergistic effect of magnesium and niobium, the electron and ion conductivity, the specific capacity and the cycle performance of the lithium manganese iron phosphate positive electrode material are jointly improved.

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 relates to the technical field of batteries, in particular to a silicon-carbon negative electrode material and a preparation method and application thereof. The silicon-carbon negative electrode material comprises a carbon substrate, nanometer silicon particles and doping elements, the nanometer silicon particles are uniformly embedded in the carbon substrate, the doping elements are doped in the carbon substrate, and the doping elements comprise fluorine elements and phosphorus elements. The silicon-carbon negative electrode material disclosed by the invention has good uniformity, the nano silicon particles are uniformly embedded in the spherical carbon matrix, and the carbon matrix can effectively relieve volume expansion of the silicon particles in a lithium intercalation / deintercalation process, so that the cycle performance of a battery is improved; and fluorine and phosphorus elements are doped in the carbon matrix, so that the electron / ion conductivity of the silicon-carbon negative electrode material can be improved, and the rate capability of the battery is improved.