36results about How to "Improve long-term cycle stability" patented technology

The invention provides a method for preparing a silicon negative electrode material containing a surface modification film and belongs to the technical field of lithium ion batteries. The method comprises a step of dissolving a polymer into water, adding a silicon material, stirring while heating, and removing moisture in a solution to obtaining a silicon material coated with a polymer film A, anda step of dissolving PAN in an NMP solvent, stirring to completely dissolving the PAN, adding the silicon material coated with the polymer film A and a conductive agent into a PAN solution, stirringwhile heating, and removing the NMP solvent in the solution to obtain a silicon negative electrode material containing the surface modification film. A silicon negative electrode artificial modified film of the invention can satisfy the use of a common SBR type binder in a silicon carbon negative electrode, so that graphite and the silicon negative electrode respectively form suitable SEI films without mutual influence, and the cycle stability of a battery is further improved. The method for preparing the silicon negative electrode artificial modified film in the invention is simple and convenient, and the silicon carbon negative electrode can be compounded by using a conventional water-based compounding method.

The invention relates to a lithium-based negative electrode material for a solid-state battery, and a preparation method and an application thereof. The lithium-based negative electrode material comprises the following components in parts by weight: 20-98 parts of lithium, and 2-80 parts of a blending agent. After the lithium is mixed with the blending agent, the mixture is heated to 180-400 DEG C, and the lithium-based negative electrode material is obtained after evenly stirring the heated mixture. The lithium-based negative electrode material is used in an all-solid-state battery and is compounded with a solid-state electrolyte. Compared with the prior art, the lithium negative electrode viscosity, lithium metal surface energy and the like are regulated and controlled through adopting the method of hot-melt compounding the lithium metal and the blending agent, carbon and oxygen elements are introduced in a controllable manner to realize tight combination between a negative electrodepole piece and the solid-state electrolyte, meanwhile, the interface composition between a negative electrode and the electrolyte is regulated and controlled, the interface resistance of the negativeelectrode and the electrolyte is reduced, the limit current density for lithium dendrite growth in the negative electrode and electrolyte circulation is improved, the reversible charge and dischargecapacity of the negative electrode is increased, and the stability during the interface cycle process of the negative electrode and the solid-state electrolyte is improved.

The invention discloses a high-entropy Prussian blue material, and the molecular formula of the high-entropy Prussian blue material is NaxMIN[Fe(CN)6]zwH2O, wherein M is n different transition metal elements, n is greater than or equal to 5, yn is greater than or equal to 0.01 and less than or equal to 0.90, y1 + y2 + y3 + y4 + y5+... + yn = 1, w is less than or equal to 4.0, x is greater than or equal to 1.40 and less than or equal to 1.95, and z is greater than or equal to 0.90 and less than or equal to 0.98. The high-entropy Prussian blue material is of a monoclinic phase structure, the microstructure of the high-entropy Prussian blue material is large-size crystal particles, and the crystal particles are uniform in size, single in shape and regular in polyhedral morphology. The invention also provides application of the high-entropy Prussian blue material as a positive electrode material in a sodium-ion battery and a preparation method of the high-entropy Prussian blue material. A coprecipitation method is adopted, and the high-entropy Prussian blue material with high specific capacity, good rate capability and excellent cycle performance is obtained through selection of source materials, technological process design and selection and control of technological parameters in preparation.

The invention discloses a preparation method of a silicon carbon composite material and application thereof used as a lithium ion battery negative electrode material. Porous elemental silicon is prepared by taking a molecular sieve and silicon dioxide aerogel as a silicon source, metal elemental powder as a reducing agent and a low-temperature molten salt as a medium and achieving reduction of metal power on silicon dioxide during thermal processing in a certain temperature, and then the silicon carbon composite material is obtained by mixing the elemental silicon and asphalt and performing high-temperature carbon coating. Due to the porous characteristic of a raw material, the prepared silicon carbon composite material has a good three-dimensional porous structure, a good buffer effect onvolume expansion of a silicon negative electrode during the circulation process is achieved, moreover, the electron conductivity of the material after carbon coating is greatly improved, and long-term circulation stability of a silicon-based negative electrode material is facilitated. The method is low in cost of the raw material and simple in process and is suitable for industrial production ona large scale.

Electrochemical cells that cycle lithium ions are provided. The electrochemical cells have an electrode that includes a silicon-containing electroactive material that undergoes volumetric expansion and contraction during the cycling of the electrochemical cell; and an electrolyte system that promotes passive formation of a flexible protective layer comprising a lithium fluoride-polymer composite on one or more exposed surface regions of the silicon-containing electroactive material. The electrolyte system includes a lithium salt, at least one cyclic carbonate, and two or more linear carbonates. At least one of the two or more linear carbonate-containing co-solvents is a fluorinated carbonate-containing co-solvent. The electrolyte system accommodates the volumetric expansion and contraction of the silicon-containing electroactive material to promote long term cycling stability.

The invention provides a positive electrode material for lithium ion batteries, comprising a lithium transition metal-based oxide powder having a general formula Li_1+a((Ni_z(Ni_0.5Mn_0.5)_y Co_x)_1−kA_k)_1−aO₂, wherein A is a dopant, with −0.025≤a≤0.025, 0.18≤x≤0.22, 0.42≤z≤0.52, 1.075<z/y<1.625, x+y+z=1 and k≤0.01. Different embodiments provide the following features:

• the lithium transition metal-based oxide powder has a carbon content ≤1000 ppm or even ≤400 ppm;
• the lithium transition metal-based oxide powder has a sulfur content between 0.05 and 1.0 wt %;
• the powder further comprises between 0.15 and 5 wt % of a LiNaSO₄ secondary phase.

The invention provides a modified sodium ion battery cobalt-free positive electrode material, a preparation method thereof, and a sodium ion battery. The preparation method comprises the following steps: carrying outfirst sintering treatment on a sodium source, a nickel source, a manganese source and a doping agent to obtain a first sintering product, wherein the doping agent can be represented by the following chemical formula: McDd, the element M is selected from one of elements of the IA group, the IIA group, the IIIA group, the IIIB group, the IVB group, the VB group or the VIB group, and the element D is selected from one of elements of the IIIA group, the VA group or the VIIA group; and carrying out second sintering treatment on the first sintered product and a coating agent in an oxygen or air atmosphere to obtain the modified sodium ion battery cobalt-free positive electrode material. The modified sodium ion battery cobalt-free positive electrode material prepared by the method has the advantages of low cost and stable structure, and the long-acting cycle stability, the electrochemical specific capacity and the rate capability of the positive electrode material can be greatly improved.

The invention discloses a water-based zinc-manganese battery fiber with a dual-function protective layer and a preparation method of the water-based zinc-manganese battery fiber. The fiber battery is obtained by taking a carbon nanotube fiber loaded with a manganese dioxide/carbon nanotube film/3, 4-polyethylene dioxythiophene composite material as a positive electrode and a carbon nanotube fiber deposited with zinc as a negative electrode, winding the two electrodes to form a winding structure, injecting a liquid electrolyte and packaging. The preparation method comprises the following steps: preparing the PEDOT/CNT/manganese dioxide/current collector positive electrode, preparing the flexible zinc negative electrode, and assembling the fiber zinc-manganese dioxide total battery. The carbon nanotube film provides a continuous conductive channel for electron transport in the charge-discharge process and enhances the mechanical stability of battery fibers, and the PEDOT can enhance the contact between the carbon nanotube film and manganese dioxide and reduce the poor dissolution of active substances so as to improve the conductivity. A flexible wearable electronic device with excellent performance can be prepared by weaving the fiber battery into a fabric.

The invention belongs to the technical field of lithium metal batteries, and particularly discloses a preparation method of a metal oxide composite self-supporting heat-conducting carbon film. The method comprises the following steps of (1) cracking a polymer to obtain a polymer carbon material, mixing the polymer carbon material with graphene, and pressing to form a film, namely obtaining the self-supporting heat-conducting carbon film; and (2) carrying out coordination reaction on a solution containing the self-supporting heat-conducting carbon film, an M metal source and an organic ligand to obtain a metal organic framework-self-supporting heat-conducting carbon film material, and then carrying out carbonization treatment to obtain the self-supporting metal oxide composite heat-conducting carbon film. The invention also provides a negative electrode obtained by filling the metal oxide composite self-supporting heat-conducting carbon film with lithium and an application method of thenegative electrode in a lithium metal battery. The material obtained by the technical scheme provided by the invention has excellent performance, and can significantly improve the long cycle performance of the lithium metal battery.

The invention discloses a SnO2 modified MoS2 hollow microsphere loaded sulfur positive electrode composite material and an application thereof. The preparation method comprises the following steps: firstly, preparing a MnCO3 microsphere template, carrying out hydrothermal reaction on the microsphere template, a molybdenum source and a sulfur source to obtain MnS@ MoS2 core-shell microspheres, etching the MnS@ MoS2 core-shell microspheres in diluted hydrochloric acid, and annealing obtained precipitates to obtain MoS2 microspheres; preparing the microspheres into a MoS2 microsphere solution byusing deionized water, dispersing the solution, adding SnCl4. 5H2O and NaOH, uniformly stirring, transferring the obtained mixed solution into a stainless steel autoclave with a PTFE lining, reacting,and treating to obtain a MoS2@SnO2 composite material; and compounding the obtained material with a sulfur powder by using a melt infiltration method to obtain a MoS2@SnO2/S positive electrode material. The product disclosed by the invention is used as a positive electrode material for manufacturing a lithium-sulfur battery, and has the advantages of a relatively high reversible specific capacity, an excellent rate capability, excellent long-term cycling stability and the like.

The invention relates to an all-solid-state battery and a preparation method thereof. The all-solid-state battery comprises a positive electrode, an organic-inorganic composite electrolyte, a multifunctional intermediate layer and a negative electrode which are sequentially stacked, the preparation raw materials of the multifunctional middle layer comprise a high-molecular polymer, an ionic liquid monomer, an initiator and a solvent; the ionic liquid monomer comprises at least one unsaturated carbon-carbon double bond; and the cation of the ionic liquid monomer is selected from one or a combination of more of piperidine cation, quaternary ammonium salt cation and pyrrole cation. The all-solid-state battery is of an integrated structure, the problem that lithium intercalation and deintercalation reactions are difficult to complete due to the use of ionic liquid is solved, and the long-acting cycle stability of the all-solid-state battery is ensured.

The invention discloses a preparation method of a lithium di-ionic total battery using a mixed carbon material as positive and negative electrodes. The method comprises the following steps: firstly preparing the mixed carbon material; then using the mixed carbon material to prepare the mixed carbon positive and negative electrodes, and then preparing a lithium salt electrolyte; and finally assembling the mixed carbon positive and negative electrodes and the lithium salt electrolyte to form the total battery. The carbon material used for the positive and negative electrodes is easy to get and is cheap and environmentally friendly, the mixed carbon material is mixed from various carbon materials, the structure is stable, the mixed carbon material is not consumed or lost in the charge-discharge process, the long-term cycling stability is high, and the rate capability is excellent.

The invention discloses a positive electrode material of a lithium-sulfur battery. The positive electrode material comprises a sulfur-containing positive electrode material and a transition metal compound. The transition metal compound can generate a transition metal sulfide when the lithium-sulfur battery performs discharging, and the transition metal sulfide is poorly soluble in an electrolyte.According to the positive electrode material, the transition metal compound and the polysulfide ions in a discharge product can form the transition metal sulfide in the lithium-sulfur battery system.The transition metal sulfide is insoluble in an electrolyte so that the transition metal sulfide plays a role in fixing the polysulfide ions of the positive electrode, and shuttling of the polysulfideis blocked fundamentally.

The invention provides an oxygen-deficient tungsten oxide/polypyrrole core-shell nanowire array electrochromic film and application, an all-solid-state lithium metal battery and a preparation method of the electrochromic film, and belongs to the field of battery materials. A lithium-conducting channel of the oxygen-deficient tungsten oxide/polypyrrole core-shell nanowire array electrochromic filmprovided in the invention shifts from a single LAGP ceramic lithium-conducting channel to a two-way lithium-conducting channel by polymer and LAGP simultaneously, thereby improving the diffusion rateof lithium ions, reducing side reactions between an electrolyte and a lithium metal, stabilizing an interface reaction between the lithium metal and the electrolyte, preventing a dendritic crystal from growing and being connected with positive and negative electrodes to cause a short circuit, preventing a lithium dendrite crystal from piercing a separator and further causing a short circuit, improving the capacity retention efficiency of a battery, and prolonging the cycle life of the battery; the battery can maintain stable performance at different temperatures; and at the same time, the thickness of the oxygen-deficient tungsten oxide/polypyrrole core-shell nanowire array electrochromic film can be adjusted as needed.

The invention discloses a NiFe2O4 nano composite material, which comprises at least two graphene layers and at least one NiFe2O4 layer arranged between the graphene layers. The invention further discloses a preparation method and an application of the composite material. The nano composite material has excellent electrical properties.

The invention discloses a preparation method of a cyclic polymer and application of a structured gel electrolyte based on the polymer in a solid-state sodium battery, and belongs to the technical field of solid-state sodium batteries. The invention discloses a preparation method of a structured gel electrolyte based on a cyclic polymer, which comprises the following steps: preparing the cyclic polymer by using polyethylene glycol diacrylate, a chain transfer agent and an initiator through a reversible addition fragmentation chain transfer free radical polymerization strategy, then adding the cyclic polymer into a liquid electrolyte to obtain a polymerization precursor solution, and finally preparing the structured gel electrolyte based on the cyclic polymer. And then the structured gel electrolyte is obtained by adopting a photo-initiated active free radical polymerization mode. The preparation method is simple in synthesis route and low in production cost. Meanwhile, the structured gel electrolyte disclosed by the invention has relatively high ionic conductivity and an electrochemical stability window, and the assembled solid sodium battery has excellent long-term cycling stability.