117 results about "Metal dissolution" patented technology

The invention discloses a monatomic catalyst with an oxygen-nitrogen co-doped hollow carbon nanocage as a support carrier and a preparation method and application thereof. The monatomic catalyst comprises an oxygen-nitrogen co-doped hollow carbon nanocage carrier and a transition metal monatomic loaded on the carrier, the transition metal single atom is coordinated in the form of M (N-C) 2 (N-O) 2. Transition metal hydrochloride, 1, 10-phenanthroline monohydrate and silicon dioxide and resorcinol formaldehyde copolymer nanospheres with a core-shell structure are mixed and then subjected to a reflux reaction, rotary evaporation and drying are carried out, and an obtained solid is subjected to grinding, pyrolysis and etching to remove SiO2 to prepare the composite material. The monatomic catalyst is high in environmental interference resistance, wide in pH application range, high in activity and good in repeatability, and efficient removal of various toxic substances is achieved; the metal dissolution rate is low, and secondary pollution cannot be caused; the preparation process is simple, conditions are mild, and the method has wide industrial application prospects.

The invention provides a preparation method of a nickel-based composite oxygen evolution anode for alkalescent electrolyte. According to the invention, nickel-based alloy is used as substrates, two same substrates are respectively used as a working electrode and an auxiliary electrode, two-electrode system electrochemical oxidation reduction treatment at room temperature is carried out in a mixed solution of phosphate, carbonate and chloride, and two reconstructed nickel-based composite oxygen evolution electrodes are obtained at the same time. In the electrochemical oxidation process, nickel ions and other metal (Fe, Co, Cr and Mn) ions are dissolved out from the nickel-based alloy under the etching assistance of chloride ions; in the electrochemical reduction process, water on the electrode is reduced to form hydroxyl. Under continuous oxidation reduction, substance reconstruction is carried out to generate a composite catalyst layer of phosphate, carbonate and hydroxide of nickel and other metals, so that not only can the oxygen evolution activity be improved, but also metal dissolution and corrosion passivation when the catalyst is used in a weakly alkaline solution can be inhibited, and the durability of the electrode is greatly improved.

The invention relates to the technical field of electro-catalysis and hydrogen energy, in particular to a modified LDH-based catalyst and a preparation method and application thereof. The preparation method comprises the following steps: mixing trimesic acid, water, an organic solvent, a nickel salt, a cobalt salt and an iron salt, carrying out electro-deposition, washing and drying to obtain a NiFeCo-LDH (TA) catalyst; the preparation method comprises the following steps: soaking a NiFeCo-LDH (TA) catalyst in a silver salt solution, washing and drying to obtain the modified LDH-based catalyst. The modified LDH-based catalyst provided by the invention can effectively resist chloride ion corrosion and inhibit dissolution of active metals in layered double hydroxides (LDH) under high current density in seawater, can reach industrial grade current density under relatively low overpotential, and can stably run for more than 1000 hours.

The invention discloses a method for preparing a g-C3N4 loaded Fe and Mn bimetallic catalyst with high efficiency and low cost, and belongs to the technical field of catalysts. Manganese ferrite is adopted as a bimetal source, a melamine one-step calcination method is combined, synthesis of g-C3N4 and loading of Fe and Mn are synchronously achieved, manganese ferrite is decomposed into FeOx and MnOx nanoparticles in the calcination process, the FeOx and MnOx nanoparticles and nitrogen sites of g-C3N4 form strong coordinate bonds, metal atomic-scale dispersion can be achieved, and metal ion migration is inhibited; through the bimetallic synergistic effect of Fe and Mn, the oxidation-reduction capacity of the catalyst can be remarkably improved; through the unique thermal decomposition characteristic, the bimetallic synergistic effect and the strong chemical bonding of the manganese ferrite and g-C3N4, the efficient exposure of active sites, the remarkable improvement of the oxidation reduction capacity and the effective inhibition of metal dissolution are realized, and the preparation method also has the advantages of high efficiency, low cost and small secondary pollution risk.

The invention relates to a water treatment and membrane separation technology, and provides an integrated catalytic separation membrane, a preparation method thereof, and a water treatment method and system. According to the membrane, polyvinylidene fluoride is used as a continuous phase to form a porous matrix, and cerium dioxide is embedded and fixed in a mode of uniform dispersion in a membrane body in a phase inversion membrane forming process; in the presence of illumination and peroxysulfate, active species are generated through in-situ activation on a membrane-water interface, and membrane separation is completed synchronously. The water treatment method comprises the following steps: adding peroxymonosulfate or peroxydisulfate into a water body to be treated, and filtering through the membrane under illumination; the photothermal effect generated by organic matter degradation intermediates in operation inhibits membrane pollution and maintains flux. According to the invention, short-range coupling of active sites and mass transfer channels is realized, the medicament and energy utilization rate is improved, the coating stripping and metal dissolution risk is reduced, and the method is suitable for drinking water pretreatment, reclaimed water deep treatment and treatment of water containing natural organic matters / humic acid.

The invention provides a nucleation granulation treatment method and treatment system for incineration fly ash and flue gas, and belongs to the technical field of incineration waste treatment. The treatment method comprises the following steps that solid particles in incineration flue gas are removed, CO2 in the incineration flue gas is enriched, and CO2-rich waste gas is obtained; metal ions in the incineration fly ash are leached out through an amphoteric electrolyte solution, solid-liquid separation is conducted, and leaching liquid containing the metal ions and purified fly ash are obtained; and in the presence of nucleation granulation seed crystals, the CO2-rich waste gas is introduced into the leachate for a reaction, and carbonate granulation bodies, a regenerated ampholyte solution and tail gas are obtained. The treatment method and system provided by the invention are based on a nucleation granulation technology, and can simultaneously realize mineralization fixation of CO2 in incineration flue gas, removal and granulation recovery of metal ions in incineration fly ash, and metal dissolution-mineralization circulation.

The invention discloses a tetrathiomolybdate intercalated ternary iron-magnesium-zinc layered double hydroxide catalyst, a preparation method thereof and an application of the tetrathiomolybdate intercalated ternary iron-magnesium-zinc layered double hydroxide catalyst in degrading azo dyes by activating peroxymonosulfate. According to the method, a carbonate intercalated ternary LDH precursor is synthesized through a hydrothermal reaction, interlayer anions are replaced with nitrate and tetrathiomolybdate through ion exchange, and the target catalyst is obtained. In the catalyst, a unique Fe-Mg-Zn ternary metal laminate and a MoS < 2-> intercalation structure cooperatively construct a multi-active center, and MoS < 2-> is used as an electron donor to promote cyclic regeneration of Fe < 3 + > / Fe < 2 + >. The catalyst keeps ultrahigh activity in a wide range of pH (potential of hydrogen) of 3-9, can completely degrade 10 mg / L of acid orange 7 within 5 minutes, and is stable in structure and low in metal dissolution risk. The problems of low activity, slow Fe < 3 + > reduction, metal ion dissolution and the like under neutral and alkaline conditions in an advanced oxidation technology based on peroxymonosulfate are solved, and the method has important application value in the field of printing and dyeing wastewater treatment.

The invention provides an electronic waste metal resource harmless extraction process based on a green chemical method, and aims to realize efficient recovery and harmless treatment of precious metals and common metals in electronic wastes. According to the process, low-toxicity organic acid (such as citric acid and oxalic acid) is adopted as a solvent, and metal dissolution and selective complexation are carried out under the condition of normal temperature or low temperature. By regulating and controlling the pH value of the solution and the concentration of the complexing agent, efficient separation and extraction of metal are achieved. The system integrates an automatic monitoring module, the dissolving, electrolyzing and precipitating processes are adjusted in real time, meanwhile, a cyclic waste liquid treatment system is adopted, and water resource consumption and waste liquid discharge are effectively reduced. Compared with a traditional high-temperature smelting and acid leaching process, the method has the advantages that energy consumption and environmental pollution are greatly reduced, and the metal recovery rate and economic benefits are improved. The process is suitable for treating various electronic wastes, conforms to the green and environment-friendly concept, and has a wide market application prospect.

The invention provides a NiMoO4-coated NiSe2-PA core-shell nanowire electrocatalyst as well as a preparation method and application thereof, and belongs to the technical field of electrocatalytic materials. The preparation method comprises the following steps: dissolving a Mo source, a Ni source and urea in water, and then mixing with a Ni matrix for hydrothermal reaction to obtain a NiMoO4 precursor; taking the NiMoO4 precursor and selenium powder as raw materials, and preparing NiSe2-coated NiMoO4 by adopting a chemical vapor deposition method; the NiSe2 (at) NiMoO4 is subjected to a self-assembly reaction in a phytic acid solution, and the NiMoO4 (at) NiSe2-PA core-shell nanowire electrocatalyst is obtained. According to the electrocatalyst, the industrial-grade current density and the high-stability alkaline seawater OER performance are achieved, the problem of metal dissolution in the selenide electrooxidation process is solved, and a simple and effective strategy is provided for reasonably designing the high-activity and corrosion-resistant industrial-grade seawater electrolysis catalyst.

The invention belongs to the technical field of inorganic nano materials and electro-catalysis, and particularly relates to a cobalt-based spinel oxide nano material as well as a preparation method and application thereof. The cobalt-based spinel oxide nano material comprises a conductive substrate and cobalt-based spinel oxide grown on the surface of the conductive substrate, the molecular formula of the cobalt-based spinel oxide is MxCo1-xO4, and M is transition metal or P-region metal and is selected from one or more of titanium, vanadium, chromium, manganese, iron, nickel, aluminum, cerium and neodymium. Multiple metal elements are doped into a cobaltosic oxide lattice, and the intrinsic structure of spinel is not changed by metal doping. Multiple metal elements are highly uniformly dispersed in the material, so that active sites are comprehensively regulated and controlled, the material shows excellent thermodynamic and chemical stability under harsh conditions of high temperature, large current, concentrated alkali and the like, is suitable for various electrolysis modes, has no metal dissolution risk in long-term operation, can effectively avoid the problems of membrane poisoning and membrane degradation, and has good application prospects. Wide application prospects are shown.

The invention belongs to the technical field of metallurgy, and particularly relates to an electrochemical dissolution method and device for promoting dissolution of high-temperature alloy, and the electrochemical dissolution device comprises an electrolytic bath, an anode plate, a cathode plate, a pore plate, a vibration basket, a vibrator, a stirrer, an oxygen generator and a heating and circulating pump; an electrochemical dissolving device is adopted, a titanium plate serves as an anode plate, a graphite plate or an iridium ruthenium plate serves as a cathode plate, an electrolyte is added into an electrolytic bath, the waste high-temperature alloy is placed into a vibration basket, an oxidizing agent is introduced into the electrolytic bath, electrolysis at 70 DEG C is conducted under the stirring and vibration conditions, filtering separation is conducted, and the waste high-temperature alloy is obtained. And electrolyte and anode mud are obtained. The method has the advantages of efficient metal dissolution, short recovery period and good recovery effect.

The invention discloses a fuel cell dry membrane electrode and a preparation method thereof, a catalyst and an ionomer are mixed in an aqueous solution, in the directly used catalyst, platinum black particles and a carbon carrier are anchored through a surface functional group, platinum nanoparticles are good in dispersity, and in the aqueous solution, the platinum black particles and the carbon carrier are uniformly dispersed. The negative-SO3H group from the ionomer particles can attract the positively-charged Pt particles, so that the ionomer can uniformly cover the surfaces of the Pt particles, an ionomer / Pt particle interface is spontaneously formed, the ionomer can be uniformly distributed on metal active sites, on one hand, the transfer of protons to the active sites can be accelerated, the reaction kinetics can be improved, and on the other hand, the reaction efficiency can be improved; on the other hand, metal dissolution or poisoning is reduced, and membrane electrode performance and service life are improved. The use of toxic and expensive organic solvents is avoided, a more environment-friendly and lower-cost dry preparation process is adopted, proton membrane swelling in the preparation process is avoided, and the proton conductivity is improved.

A method for electrochemically assisted green leaching of a decommissioned lithium ion battery belongs to the technical field of decommissioned lithium battery key metal recycling and decommissioned battery recovery, and specifically comprises the following steps: disassembling a decommissioned ternary lithium battery, taking out a positive electrode material, cleaning, drying and grinding the positive electrode material to obtain a positive electrode material; placing the mixture and a weak acid solution in a reaction container to form a leaching system; mounting an inert electrode in the reaction container, connecting an external direct-current power supply, and gradually adjusting the voltage according to the potential requirement of metal ion dissolution to respectively leach nickel ions, cobalt ions and manganese ions to obtain a multi-metal-containing pregnant solution; and adding a precipitant into the obtained solution for precipitation to generate lithium carbonate precipitate, filtering, washing, drying and recovering to obtain the high-purity lithium compound. According to the method, use of strong acid and complex chemical reagents is reduced, the complexity of waste liquid treatment is remarkably reduced, and efficient recovery of target metal is achieved by controlling the metal dissolution process step by step.

The invention relates to the technical field of wastewater treatment, in particular to an iron-based nano-enzyme coupled photocatalytic system and application thereof in organic wastewater degradation, and the iron-based nano-enzyme coupled photocatalytic system comprises the following components in percentage by weight: 10-20% of iron-based nano-enzyme, 15-25% of a modified photocatalyst, 25-35% of a porous carrier, 3-8% of an electron mediator, 1-3% of a pH regulator and 0.5-2% of a rare earth element dopant; the iron-based nano-enzyme is nitrogen-doped iron-copper-cobalt trimetal nano-enzyme, the molar ratio of Fe to Cu to Co is (6: 1: 1)-(8: 1: 1), the doping amount of N is 3-6at%, the particle size is 20-50nm, and the peroxidase activity is 120-150U / mg; the modified photocatalyst is graphene quantum dot-carbon dot co-modified titanium dioxide, the total loading capacity is 2-5 wt%, and the forbidden bandwidth is 2.8-3.0 eV; the porous carrier is a mesoporous silica-carbon nanotube-montmorillonite composite material. According to the invention, the synergistic degradation effect is excellent, refractory pollutants can be decomposed, and no toxic intermediates exist; the catalyst is suitable for high-salt and high-turbidity wastewater with different acidity and alkalinity, is good in stability, can be recycled, and is less in metal dissolution; the energy consumption is low, the operation is simple and convenient, the treated wastewater reaches the standard and can be recycled, and the environmental and economic benefits are remarkable.

To provide a metal melting method that can dissolve a molten raw material that has a smaller density than molten iron and is floating on the surface of molten iron more efficiently and in a short time.SOLUTION: A metal melting method according to the present invention is a metal melting method in an AC electric furnace comprising three upper electrodes and a raw material input tube provided on the side surface or upper surface of the furnace body, the method comprising: a step of inputting a raw material for melting having a density smaller than that of molten iron from the raw material input tube from the ceiling; a step of melting the raw material for melting using an arc as a heat source while continuously supplying the raw material for melting into the furnace; a step of forming a rotational flow field in a horizontal direction with respect to the molten iron surface; and a step of moving the raw material for melting to a high temperature region in the furnace by applying a centripetal force to the raw material for melting floating on the molten iron surface by means of the rotational flow field.SELECTED DRAWING: Figure 1

The invention discloses a carbon-coated manganese dioxide catalyst as well as a preparation method and application thereof, and relates to the technical field of preparation of catalytic materials. The method comprises the following steps: pretreating manganese dioxide, adding deionized water, uniformly stirring, then adding a dispersing agent and a carbon source, and emulsifying to obtain a mixture; carrying out sand milling, and then carrying out spray drying to prepare a carbon-coated manganese dioxide catalyst precursor; and placing in an activation gas for activation to prepare the carbon-coated manganese dioxide catalyst. Manganese dioxide is used as a main catalytic activity center, and the surface of manganese dioxide is coated with a layer of carbon material, so that manganese dissolution is reduced, the activity and stability of the catalyst are improved, and the problems of metal dissolution and secondary pollution of residual hydrogen peroxide in decomposition of N-methyl morpholine oxide by traditional manganese dioxide are solved; and application and popularization are facilitated.

The application discloses a method for recycling valuable metals in black powder in waste lithium batteries based on a Na2EDTA-malic acid mixed system, which comprises the following steps: 1) discharging, disassembling, crushing and screening the waste lithium batteries to obtain the black powder; 2) dispersing the black powder in a primary leaching liquid, adjusting the pH value of the primary leaching liquid to 3.0-4.5, and performing leaching in a water bath under stirring conditions, wherein the water bath temperature is controlled to be 50-90 DEG C, and the reaction is performed for 1-4 h, so that the metals in the black powder are dissolved into the liquid phase to form leaching slurry; and 3) performing liquid-solid separation on the leaching slurry obtained in the step 2) to obtain a leaching liquid containing Li, Ni, Co and Mn and leaching residue. The application has small corrosion, is green and environment-friendly, has high leaching efficiency, and is suitable for large-scale application.

The invention discloses an electrolyte of a ternary lithium ion battery, a preparation method of the electrolyte and the ternary lithium ion battery. The ternary lithium ion battery comprises an organic solvent system, a lithium salt system and an additive system, the organic solvent system is composed of at least one cyclic carbonate and at least one chain carbonate; the additive system comprises a cyclic compound, and the cyclic compound has the following structural formula; wherein X is any one of P, B and P = O; y is a C1-C6 carbon chain group containing an alkylene group, a carbonyl group, a sulfinyl group, a sulfonyl group or a fluoroalkylene group; the flame-retardant and anti-overcharge fabric has flame-retardant and anti-overcharge And moreover, by regulating and controlling the composition of the SEI film, the growth of lithium dendrites can be inhibited, the dissolution of transition metal can be reduced, the stability of the ternary lithium ion positive electrode material is improved, and the cycle life of the ternary lithium ion battery is prolonged.

Disclosed is a metal element recovery method which comprises: a step (1) for obtaining an acidic first solution by dissolving a metal in a crushed product of a lithium ion battery in an acidic aqueous solution; a step (2) for changing divalent iron ions in the first solution to trivalent iron ions; a step (3) for obtaining a second solution and a first precipitate that contains an iron compound or the like by adjusting the pH of the first solution to fall within the range of 3.0 to 5.0; a step (4) for obtaining a third solution and a second precipitate that contains copper sulfide by adding a sulfurizing agent to the second solution and adjusting the pH of the second solution to fall within the range of 4.0 to 5.0; a step (5) for obtaining a fourth solution and a third precipitate that contains nickel hydroxide or the like by adjusting the pH of the third solution to fall within the range of 7.0 to 8.5; and a step (6) for obtaining a fifth solution and a fourth precipitate that contains a lithium compound by concentrating the fourth solution while injecting a carbon dioxide gas thereinto.

The invention relates to the technical field of water treatment, and provides a composite material for water treatment, which comprises: a porous base material; the catalyst layer is formed on the surface of the porous base material; the biological affinity layer is formed on the surface of the catalyst layer; the enhancement layer is formed on the surface of the biological affinity layer, and the enhancement layer is graphene quantum dots. The invention further provides a preparation method of the composite material in the technical scheme and water treatment equipment. According to the composite material provided by the invention, through'metal oxide-biological affinity layer-graphene quantum dot 'ternary synergy, deep coupling of ozone oxidation and biodegradation is realized, the ozone removal rate is increased, the microbial biofilm formation rate is increased, the biofilm formation period is shortened to 3-5 days, and the biofilm density is increased by 30%; and the COD (Chemical Oxygen Demand) removal rate is relatively high. Moreover, the composite material provided by the invention is relatively stable, the metal dissolution rate in a high-humidity environment is less than or equal to 1%, and the service life is prolonged to more than 3 years.

The application relates to the technical field of electrolytic polishing, and discloses a stainless steel cavity surface treatment device with an electrolytic polishing function, which comprises an electrolytic machine and an electrolytic tank arranged on the electrolytic machine, and linear driving mechanisms are arranged on the two sides of the electrolytic machine and extend along the height direction of the electrolytic machine. The stainless steel cavity surface treatment device with the electrolytic polishing function is provided with a pumping pipe at the top end of a limiting pipe and is equipped with a pump body, so that the electrolyte in the stainless steel container can be pumped and circulated, the flowability and the updating speed of the electrolyte on the inner wall of the container are effectively improved, the bubble adhesion is reduced, the problem of uneven metal dissolution caused by slow electrolyte updating is avoided, the generation of surface defects such as pitting, mottling and scratches is reduced, the uniformity of the surface color of the workpiece is ensured, the quality of the electrolytic polishing is improved, and meanwhile, the electrolyte is filtered after being pumped through a return pipe and is then delivered back to the electrolytic tank, so that the electrolyte can be recycled.

The structure is simplified, and the molten metal flows more smoothly, allowing for efficient dissolution and heating. [Solution] The furnace body 10 has heating chambers 12 and 13 that communicate with an input port 11 for non-ferrous metal materials, and a tapping chamber 14 that can receive a portion of the molten metal heated to a predetermined temperature in the heating chambers 12 and 13 and from which the molten metal can be removed, and a rotating blade 20 for circulation that is provided in the center of the heating chambers 12 and 13 to circulate the molten metal, and a plurality of electric heaters 30 and 40 provided in the heating chambers 12 and 13 to raise the molten metal to a predetermined temperature.

A process for treating anodizing wastewater and waste metal according to an embodiment of the present invention may comprise the steps of: storing anodizing wastewater for each type of acidic wastewater; dissolving the waste metal in the acidic wastewater; generating hydrogen and a metal salt solution by performing an oxidation-reduction reaction of the acidic wastewater and the waste metal; and adding a hydrophilic colloid solution to the metal salt solution.

The invention relates to a diamond electrolytic purification method, and relates to the technical field of diamond purification, the diamond electrolytic purification method comprises a raw material screening step, a pretreatment step, an electrolytic purification step and a separation and purification step, the temperature of the electrolyte is 40-50 DEG C, the flow velocity of the electrolyte is 0.5-1.5 m / s, the diamond particles are washed, energized electrolysis is carried out for 8-12 h, the current density is 20-30 mA / cm, ultrasonic treatment is carried out while electrolysis is carried out, the ultrasonic frequency is 10-20 kHz, and mixed slurry is obtained. According to the diamond obtained through the electrolytic purification method, efficient metal dissolution can be achieved, the metal dissolution efficiency is improved, the diamond structure is protected, and the diamond purity is improved.

The application discloses a lithium ion battery and a preparation method thereof. The positive electrode material contains boron elements, and the distribution amount of the element B meets the following characteristics: the content of boron in the positive electrode material is less than or equal to 20% of the total mass of boron elements, the content of boron elements in the negative electrode is less than or equal to 20% of the total mass of boron elements, and the content of B elements in the electrolyte is greater than or equal to 60% of the total mass of boron elements. The method improves the accumulation orientation of the transition metal layer, improves the charge density distribution of oxygen elements, cooperatively improves the stability of the negative electrode SEI film, reduces the electrolyte consumption and metal dissolution, and improves the mechanical compression resistance.

The invention discloses a Co-Cu / rGO-Ti electrode and a preparation method and application thereof, and belongs to the technical field of sewage electrochemical treatment.The preparation method comprises the following steps that a Ti net is pretreated, and the pretreated Ti net is obtained; gO is dispersed in deionized water, and a GO dispersion liquid is obtained; co salt and Cu salt are mixed in deionized water, and a Co-Cu mixed salt solution is obtained; immersing the pretreated Ti net into the GO dispersion liquid, taking out the Ti net, and drying the Ti net to obtain dried GO-Ti; dipping in a Co-Cu mixed salt solution at a constant temperature, taking out and drying to obtain a dipped and dried electrode; and putting the GO into a muffle furnace for calcination, reducing the GO into rGO by adopting a high-temperature calcination method, and decomposing the Co-Cu salt into metal oxide nanoparticles, thereby finally obtaining the Co-Cu / rGO-Ti electrode. According to the invention, agglomeration of Co-Cu particles can be avoided, uniform distribution and long-term stability of active sites are ensured, cyclic utilization of the electrode is ensured, dissolution of Co-Cu metal can be reduced, and secondary pollution is avoided.

A copper electrolyte comprising (a) a water-soluble copper salt; (b) a complexing agent; (c) a leveling agent; (d) optionally, a polar solvent; (e) optionally, a pH adjusting agent; and (f) the balance of water. The copper electrolyte has a pH in the range of from about 8 to about 11, preferably from about 8.2 to about 9.5. The copper electrolyte can be used to deposit ultra-thin copper layers on conductive substrates that are free of pinholes and other defects and inhibit metal dissolution.

The invention provides a positive electrode material, a preparation method and a battery. The positive electrode material comprises an active substance, a first shell layer coating the surface of the active substance and a second shell layer coating the surface of the first shell layer, the active substance comprises transition metal; the first shell layer comprises a first polymer, and the first polymer has a fluorine-substituted aryl group; the second shell layer includes a second polymer having at least one group selected from an amino group, an acyl group, or an amide. The first polymer not only has good conductivity, but also can inhibit the dissolution of transition metal; functional groups in the second polymer can capture transition metal ions, so that the dissolution of transition metal is further inhibited. The first shell layer and the second shell layer are combined to form a dual-coating structure, so that the overall conductivity of the positive electrode material can be improved, and the problems of voltage attenuation and cycle deterioration caused by metal dissolution are reduced.

A composite lithium replenisher, its preparation method, and a secondary battery are disclosed. The composite lithium replenisher includes an active lithium unit and a functional unit. The active lithium unit contains a complexing group; the functional unit contains a self-healing group, which is connected to the active lithium unit. The composite lithium replenisher can self-repair through the self-healing group. This composite lithium replenisher can form a dense SEI film on the positive electrode surface, thereby inhibiting the problem of metal dissolution catalysis and reducing the electrolyte oxidation decomposition rate. The self-healing group can undergo reversible breakage-recombination during charge-discharge cycling, regulating and repairing the damaged SEI film after cycling, making the SEI film more stable, and inhibiting lithium dendrite growth and uncontrolled lithium deposition caused by local polarization. The synergistic effect of both improves the problem of metal dissolution catalysis during the delithiation process of the lithium replenisher, which further exacerbates the SEI film rupture.

This invention discloses a highly efficient and low-cost method for preparing g-C3N4-supported Fe and Mn bimetallic catalysts, belonging to the field of catalyst technology. This invention uses manganese ferrite as the bimetallic source, combined with a one-step calcination method using melamine, to simultaneously achieve the synthesis of g-C3N4 and the loading of Fe and Mn. During calcination, manganese ferrite decomposes into FeO. x and MnO x Nanoparticles form strong coordination bonds with the nitrogen sites of g-C3N4, enabling atomic-level dispersion of metals and inhibiting metal ion migration. Through the bimetallic synergistic effect of Fe and Mn, the redox capacity of the catalyst can be significantly improved. Manganese ferrite, through its unique thermal decomposition characteristics, bimetallic synergistic effect, and strong chemical bond with g-C3N4, achieves efficient exposure of active sites, significant improvement of redox capacity, and effective inhibition of metal dissolution. It also has the advantages of high efficiency, low cost, and low risk of secondary pollution.