46results about How to "Alleviate volume changes" patented technology

The invention discloses a preparation method of a lithium metal negative electrode with an ultrathin lithium-loving high-entropy alloy interface layer, and belongs to the technical field of lithium metal batteries. The preparation method comprises the following steps: dispersing a carbon nanotube coated high-entropy alloy composite material, lithium tin alloy powder and a hydrophobic polymer in a non-organic solvent, coating a copper foil with the mixture, and drying the copper foil to obtain an ultrathin, pre-lithiated and lithium-loving negative electrode of a high-entropy alloy interface layer. According to the preparation method of the lithium metal negative electrode with the ultrathin lithium-loving high-entropy alloy interface layer, catalytic elements in the high-entropy alloy composite material coated with the carbon nanotubes are used for inducing the carbon nanotubes to form a 3D conductive network framework, so that the current density of the electrode can be effectively reduced, lithium metal deposition can be accommodated, and the lithium metal negative electrode has a good application prospect. And meanwhile, release of lithium ions in the lithium tin alloy can be activated for lithium pre-supplement, so that generation of lithium dendrites and dead lithium is inhibited, the volume change of a lithium metal negative electrode in the charge-discharge cycle process is slowed down, and the cycle stability of the battery is improved.

The invention relates to the technical field of energy storage nano materials, and provides a ZIF-67-derived CoSe2-atNC hollow nano cubic box material and a preparation method thereof.The preparation method comprises the steps that a solution A is prepared from cobalt nitrate hexahydrate, cetyltrimethylammonium bromide and deionized water, a solution B is prepared from 2-methylimidazole and deionized water, and the ZIF-67-derived CoSe2-atNC hollow nano cubic box material is obtained; adding the solution A into the solution B, stirring to prepare a ZIF-67 precursor solution, and carrying out aging reaction to prepare a ZIF-67 nanocube material; preparing a solution C by adopting a ZIF-67 nanocube material and absolute ethyl alcohol, preparing a solution D by adopting tannic acid, deionized water and absolute ethyl alcohol, and adding the solution C into the solution D for etching reaction to prepare a TA-Co hollow nano cubic box material; carrying out first heat treatment on the TA-Co hollow nano cubic box material, mixing and grinding a product of the first heat treatment and selenium powder, and then carrying out second heat treatment to prepare the ZIF-67 derived CoSe2 (at) NC hollow nano cubic box material. The preparation method can be used for preparing the sodium battery negative electrode material with high specific capacity and high cycling stability.

The invention relates to a negative active material and a preparation method thereof, a negative pole piece and a lithium ion battery, and belongs to the technical field of electrochemistry. The negative electrode active material comprises a composite core material and a coating material, the composite core material comprises a substrate material and a first material, the substrate material is provided with a plurality of pores, and the first material is arranged on the pore walls of the pores of the substrate material; the coating material coats at least part of the outer surface of the composite core material; wherein the nucleation overpotential of lithium on the first material is smaller than the nucleation overpotential of lithium on the coating material, so that lithium ions are more prone to nucleation and deposition on the first material, and formation of lithium dendrites is reduced; the coating material further protects the inner core material and prevents the inner core material from being in direct contact with the electrolyte, so that the probability of side reaction between the metal lithium and the electrolyte / electrolyte is reduced, and the cycle performance is improved.

The present invention relates to the field of sodium ion batteries, and discloses a caged cobalt iron sulfide carbon nanofiber composite material and a preparation method and application thereof, the method comprising: obtaining a caged cobalt iron Prussian blue analog by a coprecipitation method, and preparing a spinning solution with a high molecular polymer as the main raw material; obtaining a beaded fiber precursor by electrostatic spinning, and after pre-oxidation in air and pyrolysis in an inert protective atmosphere, heat-treating it together with a sulfur source or a selenium source to obtain a caged cobalt iron sulfide (CoS2 / FeS2 or CoSe2 / FeSe2) carbon nanofiber composite material. The cage structure in the present invention can increase the contact area between the electrode active material and the electrolyte, and the carbon fiber skeleton can effectively improve the conductivity and alleviate the volume change of the electrode material during the charge and discharge process. When the prepared composite material is used as the negative electrode material of the sodium ion battery, it exhibits excellent long cycle performance and rate performance.

The invention belongs to the field of battery materials, and particularly relates to a dual-dimensional carbon-coated silicon-carbon negative electrode material as well as a preparation method and application thereof. The silicon-carbon negative electrode material comprises silicon-carbon composite particles, the silicon-carbon composite particles comprise carbon material matrix particles and elemental nano silicon attached to the carbon material matrix particles; the carbon material matrix particles contain metal nanoparticles; the surfaces of the carbon material matrix particles are coated with one-dimensional carbon fibers, and the surface of the elemental nano silicon is coated with a two-dimensional graphene-like carbon layer. The preparation method is characterized in that the metal nanoparticles are pre-embedded in the carbon material matrix particles to induce and regulate the generation of a specific carbon structure, and meanwhile, the ionic conductivity and the electronic conductivity of the silicon-carbon negative electrode material are improved, so that the cycle performance and the capacity retention ratio of the silicon-carbon negative electrode material are improved.

The invention discloses an iron-based MOFs composite electrode and application thereof. The preparation method comprises the following steps: firstly preparing Cu-coated Fe-ZIF powder in a coprecipitation manner, then preparing Fe2O3-coated Cu-coated Fe-ZIF powder by a hydrothermal reaction, step-by-step ultrasonic and vacuum arc method, and then fusing with S at high temperature by a hot melting method; and preparing the active material Fe2O3 (at) Cu (at) Fe-ZIF (at) S for the iron-based MOFs composite electrode. The Fe-ZIF material is selected as a metal frame to coat the surface of Cu, the Fe-ZIF material and Fe oxide are mixed, calcined and subjected to a direct-current vacuum arc method to synthesize the wooden-stick-shaped nanosphere particles, the defect concentration in a Fe2O3 structure can be effectively increased under the synergistic effect of the advantages of Cu-coated Fe-ZIF components, more loading space is provided for subsequent components such as sulfur, and the Fe-coated Fe-ZIF composite material has a good application prospect. The sulfur loading effect is improved, the sulfur utilization rate is improved, the volume change is relieved, and the battery performance is further improved.

The present invention relates to a positive electrode active material and a lithium secondary battery using the same, and more particularly, to a positive electrode active material that includes a lithium composite oxide comprising at least nickel and cobalt, and is capable of improving particle stability not only on the surface portion but also at the central portion of the lithium composite oxide due to the formation of a concentration gradient in which a cobalt concentration decreases from the surface portion to the central portion of the lithium composite oxide relative to the average radius of the lithium composite oxide to a predetermined thickness, a positive electrode comprising the positive electrode active material, and the lithium secondary battery using the positive electrode.

The application provides a high-nickel ternary material modification method and a high-nickel positive electrode material with a nitrogen-oxygen coating layer, and relates to the field of lithium ion batteries. In the high-nickel ternary material, surface lattice oxygen is gradually replaced by nitrogen atoms in a high-temperature long-time calcination process in a nitrogen-oxygen mixed atmosphere, so that a nitrogen-oxygen layer is formed on the surface, which is beneficial to the delocalization of electrons, thereby endowing the material with excellent electronic conductivity; meanwhile, the presence of the nitrogen-oxygen layer inhibits the transformation of the surface layer structure into a rock salt phase structure, which is beneficial to realizing efficient ion transport. The formation of the nitrogen-oxygen layer on the surface of the high-nickel ternary material can simultaneously improve the electronic and ionic conduction of the surface of the high-nickel positive electrode material, inhibit the interface side reaction, relieve the volume change, and thereby improve the cycle stability of the battery.

The invention relates to a preparation method of a seaweed derived alloy carbon sodium ion battery negative electrode material, and belongs to the technical field of sodium ion batteries, and the specific scheme comprises the following steps: step 1, drying cleaned seaweed leaves; 2, chopping the dried seaweed leaves, and calcining and carbonizing the chopped seaweed leaves and an activating agent; 3, washing the carbonized material with deionized water until the carbonized material is neutral, and drying to obtain a seaweed precursor; and 4, uniformly grinding the seaweed precursor and two metal salts, and reacting under microwave radiation to obtain the seaweed-derived alloy carbon sodium ion battery negative electrode material. The seaweed-derived alloy carbon prepared by the method can generate more active sites to store sodium ions, and the diffusion rate of the sodium ions is improved, so that the electrochemical performance is improved. In addition, in the synthesis process, the speed is very high, no solvent exists, and the yield is high.

The present application relates to the technical field of sodium battery materials, in particular to a sodium supplement coating based on a spiral iron-carbon composite material and a preparation method thereof, a spiral polypyrrole template is synthesized by a chiral template method, Fe3C@CNS spiral carbon composite material rich in Fe3C nanocrystals and iron single-atom sites is prepared through iron loading, sulfidation and high-temperature pyrolysis, Na2C2O4@Fe3C@CNS composite material is prepared by highly dispersing sodium oxalate on the surface and in the pores of the spiral carbon composite material through a recrystallization method, finally, a slurry is prepared by mixing the Na2C2O4@Fe3C@CNS composite material with a conductive agent and a binder, and the slurry is coated on the surface of an electrode to form a functional sodium supplement coating. The sodium supplement coating based on the spiral iron-carbon composite material and the preparation method thereof solve the problems of poor interface stability and first-cycle irreversible sodium loss of existing sodium ion batteries, realize efficient sodium pre-activation and interface synergistic regulation, and improve the comprehensive performance of the battery.

According to the Si-coated C / C nano composite material, the preparation method thereof and the high-performance lithium ion battery provided by the invention, nano silicon particles and dopamine hydrochloride are used as raw materials, and an amorphous carbon layer is formed on the surface of the raw materials through preparation, so that the conductivity of a silicon negative electrode is improved; and meanwhile, surface passivation or structure collapse of the silicon negative electrode caused by excessive lithium ion embedding is prevented. And carrying out one-step carbonization through a sol-gel method to obtain the silicon-coated carbon / carbon. Compared with the prior art, the silicon-electrolyte contact area is increased, so that the electron / ion transmission kinetics is improved. In addition, the silicon and carbon nanoparticles are mostly anchored on the porous three-dimensional frame, so that the agglomeration phenomenon of the silicon particles of the nanostructure can be prevented, meanwhile, a large amount of space is provided, the violent volume change of the silicon negative electrode in the charging and discharging process is relieved, and the silicon negative electrode is prevented from falling off from the current collector. The prepared lithium ion battery has the advantages of good cycle performance, high energy density, no toxicity, no pollution and the like.

The invention relates to the technical field of lithium ion batteries, and discloses a nickel-rich ternary positive electrode material as well as a preparation method and application thereof. The preparation method of the nickel-rich ternary positive electrode material provided by the invention comprises the following steps: S1, mixing a ternary positive electrode material precursor with a lithium salt, and sintering for the first time to obtain an intermediate product; s2, mixing the intermediate product, aluminum salt, pyrophosphoric acid and ethanol to obtain a mixed solution; and S3, drying the mixed solution, sintering for the second time, and cooling to obtain the nickel-rich ternary positive electrode material. According to the preparation method provided by the invention, the ion transport layer with high ionic conductivity is constructed on the surface of the positive electrode in situ, so that the migration kinetics of Li < + > is improved, adverse side reactions at an electrode / electrolyte interface are inhibited, and the capacity and cycle performance of the nickel-rich ternary positive electrode material under high magnification are improved.

The invention belongs to the technical field of lithium ion battery electrode materials, and discloses a SnS < 2 > (at) Sn-SA electrode material as well as a preparation method and application thereof. The preparation method comprises the following steps: mixing tetravalent tin salt, a sulfur source, sodium alginate and a solvent by adopting a one-step solvothermal method, so that H2S generated by decomposing the sulfur source in a solvothermal reaction process reacts with Sn < 4 + > in the tetravalent tin salt to generate SnS2 nanosheet particles; and performing chemical crosslinking on Sn < 4 + > in the tetravalent tin salt and carboxyl in the sodium alginate to form Sn-SA hydrogel, thereby obtaining the SnS < 2 >-Sn-SA electrode material which takes the SnS < 2 > nanosheet particles as an inner core and the Sn-SA hydrogel as a shell. The Sn-SA hydrogel of the shell in the SnS < 2 > (at) Sn-SA electrode material prepared by the invention effectively relieves the problems of large volume change, agglomeration and dissolution of SnS < 2 > in the charge-discharge cycle process, and realizes the unification of high-density energy storage and excellent performance.

The invention discloses a silicon negative electrode active material which sequentially comprises a silicon-based material inner core, a flexible solid electrolyte or gel electrolyte middle layer and a carbon-coated outer layer from inside to outside, the flexible solid electrolyte or gel electrolyte middle layer comprises a conductive agent, and the conductive agent comprises a carbon nanotube. According to the silicon negative electrode active material, the surface of the silicon-based material is coated with the flexible solid-state or gel-state electrolyte, so that the volume change of the negative electrode active material in the charging and discharging process is effectively relieved, the electrolyte is isolated, the stability of the negative electrode active material is improved, and the negative electrode active material has relatively high reversible specific capacity and relatively high specific surface area; and excellent long cycle performance is shown.

This invention provides a bipolar electrode and a bipolar all-solid-state battery. The bipolar electrode comprises a positive electrode film, a current collector, a bulk material layer, and a carbon material layer. Through the design of the carbonaceous framework and nucleating agent in the bulk material layer, efficient and dense lithium metal deposition is achieved under high voltage conditions. The carbon material layer significantly improves the interfacial contact between the bulk material layer and the all-solid-state electrolyte, reduces interfacial resistance, and improves the deposition and extraction efficiency of lithium metal in the bulk material layer. Furthermore, the carbon material layer provides storage space for lithium metal deposited from the positive electrode, mitigating volume changes during lithium metal deposition in the bulk material layer and improving the stability of the bipolar electrode. The bipolar all-solid-state battery fabricated using the bipolar electrode exhibits high rate capability and long lifespan.

This application provides a dynamic ion transport binder and its preparation method, a silicon-based anode, and an all-solid-state lithium-ion battery, relating to the field of solid-state batteries. The raw materials of the dynamic ion transport binder, by mass (100%), include: 60-80% nitrile compounds, 10-30% ether-based ion compounds, and 5-10% borate compounds. The dynamic ion transport binder employs a low-polarity elastic main structure, avoiding the introduction of a large number of highly active groups such as carboxyl and hydroxyl groups, thus effectively inhibiting the decomposition of sulfide electrolytes. The borate ester dynamic bonds formed by the borate compounds undergo reversible breakage and reconstruction under stress, thereby mitigating volume changes during silicon anode cycling. This dynamic ion transport binder can effectively improve the structural integrity of the silicon-based anode after cycling, reducing interfacial delamination and crack formation.

This invention discloses a method for preparing one-dimensional network nanotube MOF-derived selenide@porous carbon materials and their applications. The method includes the following steps: dispersing ZnCo-BTC nanowires in an ethanol-water solution to form a uniform suspension A; dissolving 2-methylimidazole in an ethanol-water solution to form a solution B; preheating solution B to the reaction temperature in a water bath, pouring in suspension A, stirring at a constant temperature, centrifuging the product, washing it multiple times with ethanol and water, and finally drying it to obtain a one-dimensional tubular MOF material. Annealing this one-dimensional tubular MOF material with melamine in an argon atmosphere yields a porous carbon nanotube material with a network structure. Mixing the one-dimensional network porous carbon nanotube material with selenium powder and annealing it under argon protection yields the one-dimensional network nanotube MOF-derived selenide@porous carbon material. This invention is simple to operate, the process is controllable, and the prepared product can be widely used in electrochemical energy storage, separation, catalysis, and drug sustained release.

The invention belongs to the technical field of sodium-ion batteries, and relates to a sodium-ion battery positive electrode material and a preparation method and application thereof. By accurately controlling the chemical proportion of the positive electrode material, the stability of the internal structure of the material and the maximization of the electrochemical activity are ensured. The strict definition of the chemical general formula is beneficial to ensuring that the material keeps good structural integrity in different voltage intervals, and the phenomena of transition metal ion migration, oxygen evolution and the like are avoided, so that the irreversible structural change of the positive electrode material caused by high voltage is reduced; a coating layer formed by zirconium zinc phosphate is formed on the surface of the positive electrode material, so that the stability of the material is further enhanced. The coating layer not only can effectively prevent direct contact between an electrolyte and an active substance and reduce side reaction, but also can relieve volume change of the material in a circulation process to a certain extent, so that the circulation stability of the battery is improved, and the overall service life of the battery is prolonged.

The present disclosure provides a composite negative electrode material, a preparation method, a negative electrode plate, a battery and an electrical device, wherein the composite negative electrode material comprises a porous silicon active material, a carbon-tin composite nanowire and a carbon nanotube; the carbon-tin composite nanowire comprises a tin nanowire and a carbon coating layer, and the carbon coating layer is coated on the surface of the tin nanowire; the carbon nanotube and the carbon-tin composite nanowire are attached to the porous silicon active material, wherein a part of the carbon-tin composite nanowire is attached to the pores of the porous silicon active material, and another part of the carbon-tin composite nanowire is extended and arranged in the outer area of ​​the porous silicon active material. The charge-discharge cycle performance of the silicon active material in the composite negative electrode material having the above structure is significantly improved.

The invention belongs to the technical field of nano materials, and particularly relates to a non-uniform tungsten oxide nanosheet with a hierarchical structure and a preparation method thereof, and the prepared tungsten oxide nanosheet is large in specific surface area and high in surface activity; the tungsten oxide nanosheets are non-uniformly distributed microcosmically, and the non-uniform tungsten oxide nanosheets with hierarchical structures are mutually coupled, so that agglomeration can be reduced to a certain extent; tungsten oxide nanosheets are combined on the micron level to construct a hierarchical structure, so that the material has rich holes, meanwhile, the volume change caused by structural stress generated in the material in the reaction process can be relieved, and the application of the material in the photoelectric field, especially in the field of electrode materials, is facilitated.

The invention relates to the technical field of electrode materials, in particular to a hollow iron phosphide / carbon nanofiber and a preparation method and application thereof. The preparation method comprises the following steps: S1, dissolving ferric acetylacetonate, phenylphosphonic acid and polymethyl methacrylate in an organic solvent to obtain a core layer solution; dissolving polyacrylonitrile in an organic solvent to obtain a skin layer solution; s2, respectively filling an injector with the core layer solution and the skin layer solution prepared in the step S1, and preparing a coaxial nanofiber membrane by adopting a coaxial electrostatic spinning method and adopting a carbon-coated copper foil or aluminum foil as a current collector; s3, the coaxial nanofiber membrane is pre-oxidized and then carbonized, and the hollow iron phosphide / carbon nanofiber is obtained. The iron phosphide-based composite material is formed by loading iron phosphide onto the carbon nanofibers, so that the structural stability and the conductivity of the iron phosphide-based composite material are improved, the hollow carbon nanofibers are prepared, the specific surface area of the material is increased, the active sites of the material are increased, and the electrochemical performance of the material is further improved.

This invention relates to the field of batteries and discloses a method for preparing nickel disulfide / copper sulfide / carbon composite hollow spheres and their applications. The invention uses hollow spherical Ni-MOF as a precursor, combined with subsequent ion exchange, PDA coating, glucose coating, carbonization, and sulfidation to prepare nickel disulfide / copper sulfide / carbon composite hollow spheres. This material inherits the porous hollow structure of Ni-MOF, providing a high-speed and efficient transport channel for ion diffusion in electrode materials, while mitigating volume change effects and improving the cycle life of sodium-ion batteries. Furthermore, the controllable introduction of appropriate amounts of copper ions through ion exchange to form a nickel-copper bimetallic sulfide heterostructure can accelerate ion diffusion kinetics, reduce the ion diffusion barrier, and enhance structural stability. Finally, the nitrogen-doped carbon derived from polydopamine carbonization in the middle layer improves the conductivity of the composite material and increases sodium storage active sites, while the outermost carbon layer derived from glucose carbonization further enhances the structural stability of the composite material.

The invention belongs to the technical field of solid-state batteries, and relates to a double-layer solid-state electrolyte membrane, a preparation method thereof and application of the double-layer solid-state electrolyte membrane in a solid-state battery. The double-layer solid electrolyte membrane comprises a positive electrode membrane and a negative electrode membrane which are arranged in sequence; the positive electrode film is prepared from a positive electrode film solution, and the positive electrode film solution comprises 1-3 parts by weight of nano zinc oxide quantum dots; the negative electrode film is prepared from a negative electrode film solution, and the negative electrode film solution comprises 1-4 parts by weight of nano zinc oxide quantum dots. The nano zinc oxide quantum dots are added into the positive electrode film and the negative electrode film, so that the mechanical strength and the ionic conductivity of the positive electrode film can be effectively improved; meanwhile, the nano-zinc oxide quantum dots have relatively strong adsorbability on the DMF solvent, and a large amount of residual DMF solvent is adsorbed in the nano-zinc oxide quantum dots, so that the large amount of residual DMF solvent is prevented from directly generating side reaction with the positive electrode material, and the ionic conductivity of the solid electrolyte and the charge-discharge performance of the battery are improved.

The application discloses a kind of supercapacitor negative high-efficiency composite electrode and preparation method thereof, including the block body iron of substrate and the outer layer PrNi x Fe 1‑x O3 conductive active layer, and Fe2O3 active layer between the two, by wet chemical etching and transient high temperature joule heat method in-situ synthesis active layer, and further utilize wet chemical brush coating and transient high temperature joule heat method in-situ synthesis conductive active layer, two are asymmetric sandwich structure, it is favorable to build charge transport path, improve charge transport efficiency, at the same time, can effectively relieve the volume change generated in the process of charge and discharge of iron oxide, unlike the characteristics of particle composite structure easy to collapse, inhibit the occurrence of electrode material pulverization, wherein, using transient high temperature joule heat preparation technology, layered in-situ build heterostructure, not only simple and fast, also make the structure compact and dense, maintain the stability of overall electrode structure, improve the long-period cycle charge and discharge capacity of electrode.

The application relates to the field of sodium ion batteries, and discloses a preparation method of hierarchical porous Fe7S8 / nitrogen-doped carbon composite nanowires and application thereof. The application takes NTA as a metal ion chelating agent, chelates zinc ions and iron ions through a solvothermal reaction, and prepares a ZnFe-NTA precursor; the precursor is pyrolyzed at high temperature under an inert atmosphere, metal ion reduction is induced through a carbon thermal reaction, low-boiling-point zinc particles are volatilized, nitrogen-doped carbon formed through in-situ conversion of an organic ligand is combined, and a hierarchical porous structure is generated; finally, a gas-phase sulfuration method is adopted to form Fe7S8, and the hierarchical porous Fe7S8 / nitrogen-doped carbon composite nanowires are obtained. When the composite nanowires are used as a negative electrode of a sodium ion battery, the hierarchical porous structure can effectively promote full infiltration of electrolyte and rapid migration of sodium ions, and can improve cycle stability and rate performance.

The invention provides a composite current collector and a preparation method and application thereof. The composite current collector comprises a polymer film layer which is provided with a through hole structure penetrating through the surfaces of the two sides; the lithium-loving compound nano arrays are distributed in non-porous areas on the surfaces of the two sides of the polymer film layer; and the metal layers are located in areas, where the lithium-loving compound nano array is not distributed, of the surfaces of the two sides of the polymer film layer. The composite current collector provided by the invention has the advantages of stable structure, tight combination of each structural layer, difficult falling and excellent mechanical flexibility, provides abundant deposition space for lithium ion deposition, enhances the conductivity of the current collector, improves the energy density and cycle life of the battery, and also reduces the occurrence probability of thermal runaway of the battery.

The invention discloses a high-nickel ternary positive electrode material and a preparation method and application thereof, and belongs to the technical field of batteries and battery materials, a coating layer is formed on the surface of the high-nickel ternary positive electrode material through silicon dioxide, direct contact between an electrode material and an electrolyte is effectively isolated, and then through a thiol-ene click reaction, the high-nickel ternary positive electrode material is obtained. The graphene / titanium dioxide core-shell whisker is used as a reinforcing phase to coat the surface of the silicon dioxide coating layer again, so that the interface bonding force between the two coating layers is increased, the volume change caused by lithium ion intercalation and deintercalation can be coped, the structural stability of the material is kept, and the specific discharge capacity, the capacity retention rate and the cycling stability are favorably improved; according to the graphene / titanium dioxide core-shell whisker, titanium dioxide containing whiskers is synthesized on the surface of graphene containing a lamellar structure through microwave heating and serves as a core layer, then a shell-structure lanthanum metal framework is synthesized in a hydro-thermal mode, and the interface bonding force can be further improved through the mechanical interlocking effect.

The invention relates to the field of sodium ion batteries, and discloses a preparation method and application of a ferrocobalt bimetallic sulfide nitrogen-doped porous carbon framework composite material. The preparation method comprises the following steps: by taking aminotriacetic acid as a ligand, chelating cobalt and iron ions through ball milling to prepare a CoFe-NTA precursor; the precursor is pyrolyzed, metal ions are subjected to carbon thermal reduction, and nitrogen-doped carbon formed by in-situ conversion of nitrilotriacetic acid can be tightly combined with ferrocobalt sulfide, so that the volume change generated during deintercalation of sodium ions can be effectively relieved, the cycling stability of the material can be enhanced, and the conductivity and the sodium ion diffusion rate of the composite material can be improved; and carrying out gas-phase vulcanization to finally obtain the ferrocobalt bimetallic sulfide nitrogen-doped porous carbon framework composite material. The nitrogen-doped porous carbon framework is beneficial to contact between electrolyte and an electrode material, active sites are fully utilized, the structural stability of the composite material can be enhanced, and when the nitrogen-doped porous carbon framework is used as a sodium-ion battery negative electrode, the nitrogen-doped porous carbon framework shows excellent sodium storage performance.

The invention relates to a preparation method of a porous crystalline-amorphous Ge coexisting composite anode material, and belongs to the technical field of lithium ion battery alloying anode materials. Germanium dioxide is used as a germanium source, a reaction product amorphous GeO2 / C is prepared through a hydrothermal method, crystalline and amorphous Ge powder is obtained after air atmosphere annealing and reducing atmosphere sintering, then porous Ge precursor powder is obtained through high-temperature and high-pressure reaction purification, the porous Ge precursor powder is sintered in a protective atmosphere, and the porous GeO2 / C / Ge composite material is obtained. And the porous crystalline-amorphous Ge coexisting composite anode material is obtained. When the porous crystalline-amorphous Ge coexisting composite anode material is used as an anode of a lithium ion battery, the volume change in the charge-discharge process can be buffered, the adsorption active sites of lithium ions can be increased, the transmission distance of the lithium ions can be reduced, and the dynamic process of ion diffusion can be accelerated, so that the specific capacity and the long-period cycle stability of the lithium ion battery can be improved.

This invention discloses a two-dimensional porous silicon, its preparation method, and its application in lithium batteries, belonging to the field of materials technology. The silicon-calcium alloy powder is immersed in hydrochloric acid solution, and after the reaction is complete, it is filtered and dried to obtain siloxane powder. The siloxane powder is then heat-treated in a vacuum environment, during which the siloxane is first oxidized to SiO. x SiO x Further high-temperature processing leads to a disproportionation reaction, generating uniformly distributed two-dimensional Si / SiO2. The two-dimensional Si / SiO2 is then immersed in a hydrofluoric acid solution, where the hydrofluoric acid reacts with the SiO2. After complete reaction, the mixture is repeatedly centrifuged and washed, then vacuum dried to obtain a two-dimensional silicon material with a porous structure. The preparation method of this invention is simple, controllable, and highly practical. The two-dimensional porous silicon prepared by this method possesses a crystalline structure and an ultrathin layered structure, which can effectively mitigate volume changes in the negative electrode material and accelerate lithium-ion diffusion when used in lithium-ion batteries.