4548 results about "Cathode material" patented technology

The invention relates to a method for preparing a lithium iron phosphate / carbon composite material of a lithium ion battery, which belongs to the technical field of lithium ion batteries. The method for preparing the lithium iron phosphate / carbon composite material of the lithium ion battery comprises the following steps of: 1) preparing a suspending graphene-dispersed aqueous solution system, namely, crushing graphite to 1 to 5 microns, adding the crushed graphite into distilled water or purified water, adding 0.1 to 5 percent of surfactant, heating with stirring the mixed solution to 180 to 250 DEG C in a sealing way, performing stirring for 2 to 6 hours and reducing the temperature; 2) crushing lithium iron phosphate to the particle size of 1 to 5 microns, adding the crushed lithium iron phosphate into the distilled water or the purified water, adding with stirring 0.01 to 1 percent of coupling agent, performing uniform stirring, adding the graphene-dispersed aqueous solution, and performing stirring and filtration; and 3) vacuum-drying solid powder obtained by the filtration, and calcinating the dried solid powder for 2 to 12 hours to obtain the graphene-coated lithium iron phosphate cathode material. The method has the advantages of simple process, high material performance, high conductivity, high bulk density, high compacted density and the like.

The invention discloses a lithium manganese iron phosphate positive electrode material with a core-shell structure, which is prepared by the following steps: mixing a manganese source, an iron source, a phosphorus source, lithium carbonate and a carbon source, grinding and drying to prepare a pre-sintered material; then carrying out gas crushing on the pre-sintered material to obtain a pre-gas crushed material, and carrying out heat preservation at the temperature of 200-600 DEG C; putting the pre-gas crushed material subjected to heat preservation into an iron salt solution for quenching reaction to obtain iron compound coated lithium manganese iron phosphate; and finally, mixing the lithium iron manganese phosphate coated with the iron compound, a lithium source, a phosphorus source and a carbon source, grinding, drying, and carrying out secondary calcination to obtain the lithium iron manganese phosphate material with the core-shell structure. During preparation of the lithium manganese iron phosphate positive electrode material, a lithium manganese iron phosphate pre-sintered body and an iron salt solution are subjected to a quenching reaction to form an iron compound coated lithium manganese iron phosphate pre-sintered body, and then the iron compound coated lithium manganese iron phosphate pre-sintered body and other raw materials of lithium iron phosphate are subjected to a secondary calcination reaction to generate the composite positive electrode material with a core-shell structure. A coating structure is formed, the reaction between manganese and electrolyte is reduced, the dissolution of manganese is inhibited, the Gingtaler effect of manganese is relieved, and the stability of the material is improved; and the material has the advantages of high energy density, high power density, excellent cycle performance and strong core-shell interface bonding force.

The embodiments described herein involve electrochemical cells that have a heating element integrated into the electrochemical cell. In some aspects, an electrochemical cell comprises an anode current collector, an anode material disposed on the anode current collector, a cathode current collector, a cathode material disposed on a first side of the cathode current collector, a separator disposed between the anode material and the cathode material, and a heating element disposed on a second side of the cathode current collector, the second side opposite the first side. The heating element may include an electrically conductive material and a conductive material and disposed in an insulative material.

The invention discloses a zinc-iodine battery positive electrode material based on corn straw shell derived porous carbon and a preparation method of the zinc-iodine battery positive electrode material. According to the material, corn straw shells serve as the sole carbon source, an indigenous nitrogen-doped biomass charcoal carrier with a hierarchical pore structure is prepared through pre-carbonization and KOH activation processes, and the material is characterized in that the specific surface area is larger than or equal to 1500 m < 2 > / g, and the micropore proportion is larger than 90%. The iodine is loaded on the carrier (the iodine content is greater than or equal to 45wt%) through a vacuum sublimation method to form the indigenous nitrogen-doped biomass charcoal / iodine composite material. According to the positive electrode material, through the synergistic effect of physical confinement and pyridine nitrogen chemical adsorption, the multi-iodide shuttle effect is effectively inhibited, so that the capacity retention rate of the zinc-iodine battery is greater than or equal to 93% after 40000 cycles under the current density of 2A g <-1 >, and the capacity retention rate is greater than 45% under the rate of 10A / g. The method has double benefits of agricultural waste resource utilization and high-performance energy storage device development.

The invention discloses a modified carbon-coated sodium manganese ferric phosphate pyrophosphate / sodium ferric phosphate pyrophosphate positive electrode material as well as a preparation method and application thereof, and relates to the technical field of new energy materials. The preparation method comprises the following steps: preparing MnFe-MOF from a manganese source, a first iron source and a first organic ligand under a hydrothermal reaction; a second iron source, the MnFe-MOF and a second organic ligand are subjected to a hydrothermal reaction, and MnFe-MOF / Fe-MOF is obtained; uniformly mixing with a sodium source and a phosphorus source, and sintering to obtain a positive electrode material; and carrying out high-temperature gas-phase etching treatment to obtain the fluorine-doped carbon-coated modified sodium manganese ferric phosphate pyrophosphate / sodium ferric phosphate pyrophosphate positive electrode material. The material disclosed by the invention has a coating modified structure, so that an interface side reaction caused by direct contact between sodium ferromanganese phosphate and an electrolyte can be effectively avoided, a manganese dissolution phenomenon is reduced, and the structural stability of the material is improved; and meanwhile, the material has high conductivity, excellent structural stability, excellent long cycle life and excellent rate capability.

The invention relates to the technical field of lithium ion batteries, in particular to a gradient-doped lithium iron phosphate positive electrode material and a preparation method and application thereof. The invention provides a gradient doped lithium iron phosphate positive electrode material, on a particle cross section of the lithium iron phosphate positive electrode material, a particle center is taken as a circle center, a distance from the particle center to a nearest surface is taken as a radius R, a concentric circle region with a radius of 0.5 R is taken as a central region, and the rest part is a surface layer region, the metal doping amount of the central region is D1, the metal doping amount of the surface layer area is D2, D1 is larger than D2, delta D is equal to D1-D2, and delta D is larger than or equal to 2000 ppm and smaller than or equal to 4000 ppm. In the obtained lithium iron phosphate positive electrode material, sufficient compaction density can be ensured, the problem of poor dynamic performance of the positive electrode material can be well solved, and the discharge performance and rate capability of the lithium iron phosphate positive electrode material are effectively improved.

The invention discloses a method for regenerating waste lithium iron phosphate into a lithium manganese iron phosphate positive electrode material under assistance of element doping. According to the method, the waste lithium iron phosphate is successfully regenerated into the lithium manganese iron phosphate material with excellent performance through solid-phase sintering and element doping. Compared with a traditional repairing and regenerating method, the method has the advantages that upgrading and regenerating of the waste lithium iron phosphate are realized, and the market competitiveness of regenerated products is improved. Compared with other methods, the method does not need an acid leaching step, and the recovery process is simpler and more environment-friendly. And an element doping modification means is introduced, so that the performance of the regenerated lithium manganese iron phosphate material is further improved. The invention aims to provide a green, efficient and high-valued method for upgrading and regenerating the waste lithium iron phosphate positive electrode material into the lithium iron manganese phosphate positive electrode material with industrial application prospects.

The invention discloses a positive electrode material of an upward flow type electrochemical dephosphorization system, and the preparation method comprises the following steps: preparing a polyaniline-coated ZIF-8 derived carbon loaded magnesium-aluminum double-metal hydroxide electrode material, and the preparation process comprises ZIF-8 carbonization in a nitrogen atmosphere, aniline oxidation polymerization, and loading of magnesium-aluminum double-metal hydroxide by a coprecipitation method; the electro-adsorption positive electrode material belongs to a polyaniline magnesium aluminum double-metal hydroxide mesoporous synergistic platform in ZIF-8 derived carbon, and has a nano frame with strong pore accessibility and high electrochemical activity; the synergistic process comprises attraction of polyaniline to phosphate ions and trapping of the magnesium-aluminum double-metal hydroxide. The electrode prepared by the method has a unique mesoporous framework, a large number of phosphorus removal sites are obtained on the surface of the electrode, a rapid ion storage behavior mainly based on a capacitance control process is realized on a solid-liquid interface, phosphate in water can be effectively separated in an electro-adsorption system, and the method is a pollution control process with a clear mechanism.

The invention belongs to the field of battery materials, and discloses a high-entropy high-nickel positive electrode material which comprises a base material LiNixCoyMzO2, a base further comprises a lithium-site doping element and a nickel-site doping element, the surface of the base is coated with an island-shaped coating layer, and the island-shaped coating layer is a nano metal oxide layer. The preparation method comprises the following steps: uniformly mixing a high-nickel hydroxide precursor, a lithium source, a compound containing an element A and a compound containing an element B, carrying out two-stage sintering, mixing with a metal oxide containing an element C and a metal oxide containing an element D, and sintering to obtain the high-entropy high-nickel positive electrode material. Lithium doping in a bulk phase of the high-entropy high-nickel positive electrode material can improve the electronic conductivity of a single crystal material, increase the interlayer spacing of transition metal and inhibit lithium and nickel positive ions from being mixed, and nickel doping can improve the structural stability and thermal stability of the material, inhibit irreversible phase change of H2-H3 and stabilize lattice oxygen of the material; the doping modification of the two sites further improves the performance of the material.

The invention discloses an A-site high-entropy solid oxide fuel cell cathode material as well as a preparation method and application thereof, and provides an A-site high-entropy solid oxide fuel cell cathode material Pr < 0.2 > M < 0.2 > La < 0.2 > Ba < 0.2 > Sr < 0.2 > Co < 0.8 > Fe < 0.2 > O < 3-delta > with a perovskite phase. The preparation method comprises the following steps: S1, weighing multi-element metal nitrates, and mixing to obtain a first mixed solution; s2, dissolving ethylenediamine tetraacetic acid in ammonia water to obtain a second mixed solution; mixing the first mixed solution, the second mixed solution and citric acid to form a mixed precursor solution; s3, carrying out second heating treatment on the mixed precursor solution, and adjusting the pH value to form a gel precursor; and S4, carrying out pre-sintering treatment, third heat treatment and calcination treatment on the gel precursor to obtain a high-grade powder precursor, and carrying out ball milling and sieving treatment to obtain the A-site high-entropy solid oxide fuel cell cathode material. The cathode material is high in stability and good in chemical compatibility with a barrier layer GDC, provides high-quality mass transfer channels and active sites for O2 / O- / O2-, and has good electrochemical performance at medium and low temperatures.

The invention provides a ternary positive electrode material and a preparation method thereof, a positive electrode and a battery, and is applied to the field of batteries, the ternary positive electrode material comprises a self-supporting micro-cage structure, the material of the micro-cage structure is a high-nickel ternary material, the micro-cage structure is internally provided with a cavity, and part of the cavity in the micro-cage structure is filled with a conductive agent. A cavity is formed in the micro-cage structure and can allow lithium ions to enter and exit. Through the structural design, the volume expansion or shrinkage of the high-nickel ternary material in the charging and discharging process can be effectively inhibited, the structural change of the material is reduced, the stability of the high-nickel ternary material is improved, and the cycle performance of the battery is further improved.

Embodiments described herein relate to electrochemical cells with multiple separators, and methods of producing the same. A method of producing an electrochemical cell can include disposing an anode material onto an anode current collector, disposing a first separator on the anode material, disposing a cathode material onto a cathode current collector, disposing a second separator onto the cathode material, and disposing the first separator on the second separator to form the electrochemical cell. The anode material and / or the cathode material can be a semi-solid electrode material including an active material, a conductive material, and a volume of liquid electrolyte. In some embodiments, less than about 10% by volume of the liquid electrolyte evaporates during the forming of the electrochemical cell. In some embodiments, the method can further include wetting the first separator and / or the second separator with an electrolyte solution prior to coupling the first separator to the second separator.

Embodiments described herein relate to electrochemical cells with multiple separators, and methods of producing the same. A method of producing an electrochemical cell can include disposing an anode material onto an anode current collector, disposing a first separator on the anode material, disposing a cathode material onto a cathode current collector, disposing a second separator onto the cathode material, and disposing the first separator on the second separator to form the electrochemical cell. The anode material and / or the cathode material can be a semi-solid electrode material including an active material, a conductive material, and a volume of liquid electrolyte. In some embodiments, less than about 10% by volume of the liquid electrolyte evaporates during the forming of the electrochemical cell. In some embodiments, the method can further include wetting the first separator and / or the second separator with an electrolyte solution prior to coupling the first separator to the second separator.

A modified nickel-based positive electrode material comprises a nickel-based positive electrode material matrix and a doping element doped in the nickel-based positive electrode material matrix, the electronegativity of the doping element is higher than that of lithium and transition metal elements in the nickel-based positive electrode material matrix, and the porosity of the material is 10%-20%. The preparation method comprises the following steps: mixing and sintering a positive electrode material precursor, a lithium source and a doping agent to obtain a sintered product; washing and drying the sintered product to obtain a washed product; and mixing the washed product with a coating agent, and sintering to obtain the modified nickel-based positive electrode material. The invention also discloses a lithium ion battery. In the modified nickel-based positive electrode material, a part of doped elements enter a lattice body of a nickel-based positive electrode material matrix, the electronegativity of the doped elements is larger than that of lithium and transition metal elements, the doped elements have higher covalence, higher bond strength and higher oxidation potential, lattice oxygen in the structure is stabilized, precipitation of the lattice oxygen is reduced, and therefore the structural stability of the material is improved.

The invention discloses a method for selectively extracting lithium from a positive electrode material / black powder of a waste lithium ion battery. Performing chlorination transformation on the waste lithium ion battery positive electrode material / black powder to obtain chlorination transformation slag; and then, leaching the chlorination transformation slag with water to obtain a lithium chloride solution and lithium extraction slag. And a lithium chloride solution obtained through primary leaching can be used as a leaching solution to circularly leach the chlorination transformation slag, and after Li < + > in the circulating leaching solution is fully enriched, a lithium precipitation reagent is added into the circulating leaching solution, so that the Li < + > is opened in a lithium salt precipitation form. The method has the advantages of low reaction temperature, high reaction efficiency, high valuable metal yield, low production cost and the like, and has a good application prospect.

The present application discloses a method for recycling and preparing lithium iron phosphate from waste lithium iron phosphate batteries, which comprises the following steps: oxidizing and acid-leaching the recycled lithium iron phosphate battery powder to obtain acid-leached lithium solution and iron-phosphorus filter residue; adjusting the pH of the acid-leached lithium solution for purification and concentration, adding a phosphorus source and adjusting the pH to 9.5 - 10.5 to obtain solution A; subjecting the iron-phosphorus filter residue to secondary acid-leaching, iron dissolution, adding a phosphorus source and adjusting the pH to 6.5 - 7.5 to obtain solution B; mixing solution A and solution B for coprecipitation reaction, and filtering to obtain lithium iron phosphate precursor and reaction mother liquor; subjecting the lithium iron phosphate precursor to anaerobic drying, mixing with a carbon source and sintering to prepare a carbon-coated lithium iron phosphate cathode material. The method provided by the present application has the advantages of short recycling path, few reaction by-products and environmental friendliness, and can recycle all components of lithium, iron and phosphorus in the waste lithium iron phosphate battery powder. At the same time, the by-product is ammonium sulfate, a high-quality fertilizer raw material, which has great application prospects.

A method of synthesis of single crystal nickel-rich cathode materials can include preparing a precursor solution by dissolving lithium nitrate, nickel nitrate, manganese nitrate, and cobalt nitrate in water, aerosolizing the solution of a) in a stream of air using an ultrasonic sprayer, preheating the resulting droplets, premixing the droplets with methane, decomposing the droplets by passing through a co-flow burner, depositing solid particles on a filter, and calcinating the solid particles in a furnace in oxygen to produce a single crystal cathode material.

The invention relates to a process for recycling and regenerating a waste lithium iron phosphate positive electrode material by using a specific chelating agent. The method comprises the following steps: carrying out heat treatment on a waste lithium iron phosphate positive electrode material, putting separated waste lithium iron phosphate powder into a ball milling tank, adding organic acid and a chelating agent, and carrying out ball milling; after the ball milling is finished, adding hydrogen peroxide, uniformly stirring and mixing, adjusting the pH value to 2-3 by using nitric acid, and filtering to obtain a filter cake which is iron phosphate; adding saturated sodium carbonate into the filtrate, precipitating, and recovering lithium carbonate; putting the iron phosphate, the lithium carbonate, the iron source, the lithium source and the phosphorus source in the step S3 into a ball mill for ball milling, and performing high-temperature solid-phase sintering after ball milling to obtain a regenerated lithium iron phosphate material; the chelating agent disclosed by the invention is prepared from (9ci)-2-(2-propenyl)-1-cyclopentene-1-carboxylic acid, 2-mercaptobenzimidazole carboxylic acid, an ethylene boric anhydride pyridine complex and potassium persulfate. The regenerated lithium iron phosphate material prepared by the method has excellent electrochemical performance.

The invention discloses a high-conductivity carbon-coated lithium iron phosphate positive electrode material and a preparation method thereof, and relates to the technical field of lithium iron phosphate positive electrode materials, the high-conductivity carbon-coated lithium iron phosphate positive electrode material comprises a spherical lithium iron phosphate matrix, modified lithium niobium vanadate uniformly coating the exterior of the nanoscale spherical lithium iron phosphate matrix, and a composite carbon layer uniformly coating the exterior of the modified lithium niobium vanadate; wherein the spherical lithium iron phosphate matrix has a smaller specific surface area, so that the reduction of side reaction is facilitated, and the interface impedance can be reduced; the modified lithium niobium vanadate can improve the electronic conductivity of the positive electrode material and the diffusion rate of lithium ions; an organic carbon source in the outermost composite carbon layer is carbonized to form a continuous amorphous carbon layer which uniformly coats the surfaces of the particles, so that a basic electron channel is provided, and side reaction of an electrolyte is inhibited; the inorganic carbon source constructs a three-dimensional conductive skeleton, and a long-range conductive network is formed through the bridging effect of nanowires / sheets, so that the interface contact resistance is reduced, and the conductivity of the positive electrode material is improved.

The invention discloses a high-density lithium manganese iron phosphate positive electrode material and a preparation method thereof.The preparation method of the high-density lithium manganese iron phosphate positive electrode material comprises the following steps that 1, an iron source, a lithium source, a manganese source, a phosphorus source, an additive, a dispersing agent and a carbon source are added into deionized water, grinding, drying and sintering are conducted, and a primary material is obtained; and 2, coating the primary material with a polydopamine layer, and sintering to obtain the high-density lithium iron manganese phosphate positive electrode material, wherein the dispersing agent is polyethylene glycol tert-octyl phenyl ether; the carbon source is polyvinyl alcohol and at least one of glucose, carbon nanotubes and graphene; the additive is at least one of magnesium oxide and silicon oxide. The high-density lithium manganese iron phosphate positive electrode material disclosed by the invention has relatively good electrical performance and compaction density, and a battery prepared from the high-density lithium manganese iron phosphate positive electrode material has good electrochemical performance.

The invention provides a lithium supplement agent. The lithium supplement agent comprises lithium oxalate particles, conductive carbon particles and additive particles, the conductive carbon particles comprise at least one of carbon black, carbon nanotubes, graphene and ketjen black; the additive particles comprise at least one of MnO2, NiO, Co3O4, TiO2, Fe3O4, MnC, TiC, Mo2C and MoO3, and the additive particles comprise at least one of MnO2, NiO, Co3O4, TiO2, Fe3O4, MnC, TiC, Mo2C and MoO3. According to the lithium supplementing agent disclosed by the invention, by limiting the structure and components of the lithium oxalate lithium supplementing agent, the carbon material is respectively coated in the lithium oxalate and the additive to form a good conductive network, and finally a composite material of the lithium oxalate, the carbon material and the additive is formed, so that the decomposition voltage can be sufficiently reduced; the lithium supplement effect of the lithium oxalate can be exerted to the maximum extent.

The preparation method comprises the following steps: 1, dispersing an iron source, a phosphorus source, a lithium source, a carbon source, a dispersing agent, an element doping agent and a solvent in proportion, dividing the dispersed slurry into three parts of slurry A, B and C in proportion, respectively grinding the three parts of slurry, and respectively carrying out spray drying; 2, pre-sintering the three parts of spray materials at different temperatures, and crushing the pre-sintered materials; and step 3, mixing the crushed pre-sintered materials so as to realize multi-stage grain composition. Carrying out dry mixing on a carbon source and the pre-crushed material according to a certain mass ratio; and 4, carrying out secondary sintering, crushing and demagnetizing on the mixed material to obtain the multi-stage grading high-compaction lithium iron phosphate positive electrode material. According to the invention, primary sintering material grain grading and secondary carbon coating and sintering strengthening are realized through graded particle size design, and the compaction density and the specific capacity of the lithium iron phosphate positive electrode material are synergistically improved.

Embodiments described herein relate to electrochemical cells with multiple separators, and methods of producing the same. A method of producing an electrochemical cell can include disposing an anode material onto an anode current collector, disposing a first separator on the anode material, disposing a cathode material onto a cathode current collector, disposing a second separator onto the cathode material, and disposing the first separator on the second separator to form the electrochemical cell. The anode material and / or the cathode material can be a semi-solid electrode material including an active material, a conductive material, and a volume of liquid electrolyte. In some embodiments, less than about 10% by volume of the liquid electrolyte evaporates during the forming of the electrochemical cell. In some embodiments, the method can further include wetting the first separator and / or the second separator with an electrolyte solution prior to coupling the first separator to the second separator.

The invention discloses a preparation method and application of a zinc-bromine flow battery positive electrode material, and belongs to the field of zinc-bromine flow batteries. The preparation method comprises the following steps: dissolving aniline and a dithio compound in an acidic ice bath, dropwise adding a peroxy strong oxidant to generate a polyaniline-disulfide bond copolymer, dialyzing, and freeze-drying to obtain powder; then heating soluble silver salt, a reducing agent, a hydrophilic dispersing agent and an organic sulfydryl silane coupling agent to prepare functionalized nano-silver particles; the powder and nano-silver particles are dispersed in N-methyl pyrrolidone for ultrasonic treatment, and dynamic self-repairing coating slurry is prepared; and performing acid pretreatment on the carbon fiber paper, and performing electrochemical deposition on the slurry to prepare the zinc-bromine battery positive electrode material. According to the zinc-bromine battery positive electrode material, the coulombic efficiency and the voltage efficiency of a zinc-bromine flow battery are remarkably improved and the cycle life of the zinc-bromine flow battery is remarkably prolonged through methods of dynamic covalent bonds, nano-silver catalysis, a hierarchical pore structure, carbon fiber pretreatment and the like, and the zinc-bromine flow battery positive electrode material has chemical stability, efficient bromine adsorption capacity and excellent catalytic activity.

The present invention relates to the field of battery materials, and provides a lithium manganate cathode material coated with lithium triborate and a preparation method thereof. The cathode material is a porous lithium manganate / lithium triborate composite electrode material, which includes porous lithium manganate with a highly connected directional columnar pore structure and a lithium triborate coating covering the pore surface, with a mass ratio of (86.0~92.0):(8.0~14.0), a coating thickness of 600~800 nm, a pore diameter of 45~95 μm, and a porosity of 65~78%. The preparation method includes: preparing a precursor colloidal solution by the sol-gel method, obtaining porous lithium manganate through low-temperature freezing molding and freeze-drying, and forming a cathode substrate through pre-oxidation and high-temperature sintering; subsequently, using vacuum-assisted impregnation, ultrasound, and nitrogen pressure to promote the penetration of the lithium triborate precursor solution, and forming a uniform coating layer through gradient drying and annealing treatment. The present invention significantly improves the crystal structure stability of the cathode material, inhibits manganese dissolution, improves the cycle life and rate performance, and has wide application value.

The present invention discloses a method for producing manganese monohydrogen phosphate trihydrate, a method for recycling Mn-containing mother liquor, and a cathode material, relating to the technical field of lithium-ion batteries. In the present invention, a solid manganese carbonate slurry is used as a bottom liquid to synthesize manganese monohydrogen phosphate. Through precipitation solid-phase transformation, an octahedral morphology feature is constructed, which has a larger specific surface area. During the subsequent synthesis of lithium iron manganese phosphate, it helps to improve the reactivity of Mn and form a more uniform lithium iron manganese phosphate cathode material, thereby improving the compaction capacity and electrochemical performance of the cathode material.

The present invention discloses a graphene-coated lithium iron phosphate cathode material and a preparation method thereof, belonging to the technical field of lithium iron phosphate cathode materials. First, iron phosphate is loaded on graphene, and by controlling the pH adjustment time, small-particle-size FePO 4 / GO and large-particle-size FePO 4 / GO are accurately obtained. Iron phosphate is loaded on single-walled carbon nanotubes to prepare FePO 4 / SWCNT. Then, the loaded material and a lithium source are subjected to a pre-calcination reaction to grow and form graphene-coated lithium iron phosphate. Finally, dopamine is oxidized and self-polymerized to form polydopamine, which is coated on the outer layer of the graphene-coated lithium iron phosphate. After calcination and carbonization, a double coating of porous carbon material and graphene is formed. The particle size distribution of the prepared cathode material is optimized by using iron phosphate materials with different particle sizes and shapes to improve its tap density, and the conductivity is improved by graphene coating, endowing the cathode material with excellent electrochemical performance.

The invention relates to an electrochemical cleaning method for removing organic matters on the surface of a silicon carbide wafer, which comprises the following steps of: immersing the silicon carbide wafer with the polluted surface into electrolyte containing bivalent and / or trivalent ferric salt, applying voltage or current between a cathode material and an anode material, and carrying out electrochemical reaction to remove the organic matters on the surface of the silicon carbide wafer. The surface of the silicon carbide wafer is subjected to organic matter removal. According to the method, an electrochemical oxidation method technology is adopted, the strong oxidation effect of hydroxyl free radicals is utilized, organic residues on the surface of the silicon carbide wafer are oxidized and decomposed into short-chain organic matter, water, carbon dioxide and other products, and the purpose of removing the organic residues is achieved. The method provided by the invention is simple and efficient, can quickly remove organic pollutant residues on the surface of the silicon carbide wafer, does not use high-concentration chemicals and organic component cleaning agents which are difficult to degrade in the cleaning process, is safe and reliable to operate, reduces the consumption of the chemicals, avoids secondary pollution, and is more environment-friendly.

The invention discloses a preparation method of a high-capacity lithium iron manganese phosphate cathode material. In the method of the invention, by doping nickel and modifying polyethylene glycol, the intrinsic conductivity of the material is improved. At the same time, the lattice distortion caused by doping inhibits the growth of grains, improves the grading of particles, shortens the diffusion path of lithium ions. Meanwhile, nickel in nickel and fluorine modified polyethylene glycol can form nickel oxide on the surface of carbon sources such as carbon black or carbon fiber, which promotes the electron and ion transport between the cathode material and the electrolyte to a certain extent, improves the energy density and cycle performance of the battery. Fluorine can improve the interfacial composition between the carbon source and the cathode material, promote the transfer and diffusion of lithium ions, and improve the charge / discharge rate and capacity retention of the battery. Therefore, doping nickel and modifying polyethylene glycol in the invention have a synergistic effect. Especially when the molar amount of doped nickel is 0.02, the prepared battery has a high capacity and excellent rate performance.

Embodiments described herein relate to electrochemical cells with dendrite prevention mechanisms, and methods of producing and operating the same. In some aspects, an electrochemical cell can include an anode and a cathode material disposed on a cathode current collector, the cathode material and the cathode current collector forming a cathode. The electrochemical cell further includes a first separator disposed on the anode, a second separator disposed on the cathode, and an interlayer disposed between the first separator and the second separator, the interlayer including electroactive material, the interlayer including a source of lithium ions, the lithium ions configured to migrate toward the anode upon a voltage difference between the interlayer and the anode exceeding a threshold value. In some embodiments, the anode can include an anode material disposed on an anode current collector. In some embodiments, the anode material can include graphite, silicon, and / or hard carbon.