266results about How to "Reduce Shuttle Effect" patented technology

The invention discloses a preparation method of a sulfur-active carbon/graphene composite material. The preparation method comprises the following steps of (1) pre-processing a biomass raw material; (2) mixing the pre-processed biomass raw material, graphene and an activating agent to form a solid mixed material; (3) performing activation, washing, solid-liquid separation and drying on the solid mixed material to obtain an active carbon/graphene composite material; and (4) combining the active carbon/graphene composite material with sulfur to obtain the sulfur-active carbon/graphene composite material. The composite material provided by the invention has the advantages of simple preparation process step, high efficiency and low energy consumption, and production on a large scale can be achieved.

The invention discloses a preparation method of an oxidized Mxene/S compound applied to a lithium-sulphur battery cathode, relates to a preparation method of an S compound applied to the lithium-sulphur battery cathode, and aims to solve the technical problem of complex process of an existing Mxene/S compound preparation method. The preparation method disclosed by the invention comprises the following steps: 1, preparing Mxene powder; 2, oxidizing; 3, performing a water bath method. According to the preparation method, oxidized Mxene with high conductivity is taken as an S carrier, the preparation process is simple and safe, the production cost is low, large scale production is hopefully realized, and the oxidized Mxene/S compound as a lithium-sulphur battery cathode material has very highspecific capacity and cycling stability. The preparation method is applied to preparation of the lithium-sulphur battery cathode material.

The invention provides a preparation method for a three-dimensional carbon nanotube/nitrogen-doped graphene/sulfur electrode slice. The preparation method comprises the following steps of (1) adding the carbon nanotube, graphite oxide and polyacrylonitrile to N-methyl pyrrolidone, performing an ultrasonic reaction, coating an aluminium foil with mixed paste, and performing vacuum drying to obtain the electrode slice; (2) putting the obtained electrode slice into a muffle furnace under ammonia gas protection, heating to 400-500 DEG C, and naturally cooling; and (3) enabling the electrode slice obtained in the step (2) to be fully inserted into a Na2S2O3 solution, and slowly adding hydrochloric acid to the solution in a dropwise manner until the PH value of the solution reaches 6.5-7.5, taking out the electrode slice, and drying the electrode slice to obtain a positive plate. The electrode slice prepared by the invention can be directly used for the positive electrode of a lithium-sulfur battery without requiring a conductive agent and a binder, so that the cost of the electrode is greatly lowered.

The invention provides a lithium-sulfur battery self-supporting cathode material and an electro-spinning preparation method thereof. Polyacrylonitrile and polymethyl methacrylate serve as precursors of electrostatic spinning yarns, composite nano-fiber membranes are prepared by an electro-spinning method, pre-oxidation and carbonization heat treatment of the electrostatic spinning fiber membranesare implemented to form a self-supporting in-situ nitrogen doped porous carbon nano-fiber structure, self-supporting in-situ nitrogen doped porous carbon nano-fiber membranes are soaked in carbon disulfide solution of sulfur, drying and heat treatment in the argon atmosphere are implemented to obtain the self-supporting lithium-sulfur cathode material. According to the material, the polymethyl methacrylate serves as a template agent, self-supporting in-situ nitrogen doped carbon nano-fibers with porous structures are formed in a heat treatment and pyrolysis manner, the loading capacity of thesulfur is improved, dissolution of polysulfide is restrained, and the nano-fibers can directly serve as electrode materials.

The invention discloses a positive electrode of a lithium-sulfur battery using a nitride/carbon nano tube as an interlayer, the battery and a preparation method. The preparation method comprises the following steps: preparing a nitride/carbon nano tube interlayer on the sulfur-containing positive electrode to form the positive electrode of the lithium-sulfur battery using the nitride/carbon nano tube as the interlayer; and carrying out assembling in an inert atmosphere to obtain the lithium-sulfur battery using the nitride/carbon nano tube as the interlayer, wherein the lithium-sulfur batteryusing the nitride/carbon nano tube as the interlayer comprises a positive electrode shell, the positive electrode of the lithium-sulfur battery using the nitride/carbon nano tube as the interlayer, adiaphragm, an electrolyte, a metallic lithium negative electrode and a negative electrode shell from bottom to top in sequence. The electrical conductivity of the positive electrode is improved, the transmission rate of lithium ions is promoted and the overall impedance of the battery is reduced by introducing the carbon nano tube with extremely high electron transport capacity and certain physical absorption capacity, and the diffusion of polysulfide is effectively limited inside the interlayer by adding nitrides with extremely high chemical adsorption capacity of polysulfide, so that the purposes of effectively relieving aero effect and improving the cycle performance of the battery are reached.

The invention relates to a preparation method of an S-C positive pole microwave composite material of a high cycle performance lithium sulfur battery. Firstly, sulfur, carbon materials are put into a ball mill for ball-milling mixing, and then put into a microwave oven for microwave heating and compositing to prepare the S-C positive pole microwave composite material with high dispersion uniformity. The S-C positive pole microwave composite material and a conductive agent are ground and mixed uniformly, the S-C positive pole microwave composite material and a binder are dispersed in an organic solvent in a certain proportion, and stirred to prepare paste, and then the paste is evenly coated onto a current collector sheet, and dried to prepare a positive pole. The preparation method adopts an advanced microwave heating method, has the advantages of fast heating speed, mild conditions and high efficiency, the prepared positive pole composite material is stable in structure, the battery has good cycle stability, at the same time, the commercial carbon material with low price is used, the material cost is greatly reduced, and the preparation method is suitable for popularization.

The invention discloses an S@NPC/CNT composite material and a preparation method and application thereof. The S@NPC/CNT composite material is obtained from an NPC/CNT composite material by sulfur loading. The NPC/CNT composite material is composed of nitrogen doped porous carbon and carbon nanotubes in the interweaving mode. The nitrogen doped porous carbon is a carbon material derived from a Zn/Co-bimetallic organic framework. The nitrogen doped carbon material is obtained by stirring, drying, calcining and acid treatment of a methyl alcohol and water mixed solution containing zinc and/or cobalt transition metal salt, organic ligand and a carbon material, and finally the high sulfur loaded S@NPC/CNT composite material is prepared by a melt diffusion method. The material exhibits extremelyhigh sulfur content. In addition, the invention also discloses the application of the high sulfur loaded nitrogen doped carbon material prepared by the method in a lithium sulfur battery. The composite material is used for an anode material of the lithium sulfur battery. The obtained battery has high area capacity and good electrochemical performance. The efficient method for preparing the nitrogen doped carbon material with high performance and high sulfur content is provided.

The invention discloses a lithium-sulfur battery using nitride/graphene as separation layers and a positive electrode and a preparation method thereof. The lithium-sulfur battery consists of a positive electrode, a diaphragm, an electrolyte and a negative electrode, wherein the positive electrode contains sulfur which is coated onto an aluminum foil; then, a layer of separation layer based on nitride/graphene is coated; due to the existence of the nitride and graphene in the separation layer; the conducting performance of the battery is improved; the diffusion of polysulfide can also be effectively inhibited, so that the shuttle effect can be effectively relieved; the electric chemical performance of the battery can be improved.

The invention discloses a lithium-sulfur battery. The lithium-sulfur battery is composed of a positive electrode material coating a current collector, a diaphragm, an interlayer, an electrolyte and a negative electrode material, wherein the positive electrode material is composed of a carbon/sulfur active material, a conductive agent and a binder; the diaphragm is a polypropylene diaphragm; the interlayer is a carbon nano tube paper or a carbon nano tube paper acidized by nitric acid; and the negative electrode material is a metallic lithium piece. When a current density is 0.5C(1C=1675mA.g<-1>), a first specific discharge capacity is 1039.9 mAh.g<-1>; after circulating 50 circles, the specific discharge capacity is 674.1 mAh.g<-1>, and an attenuation rate is only 0.1%.

The invention provides a preparation method for a boron-nitrogen-co-doped three-dimensional structured positive electrode material of a lithium-sulfur battery. The preparation method comprises the following steps of (1), adding graphite oxide into water for performing ultrasonic processing to form a graphene oxide suspension liquid; (2), adding ammonium hydroxide to the graphene oxide suspension liquid, and then adding sodium borohydride to the graphene oxide suspension liquid to obtain three-dimensional boron-nitrogen-co-doped graphene; (3), adding the three-dimensional boron-nitrogen-co-doped graphene obtained in the step (2) and ketjen black into N-methyl pyrrolidone for performing an ultrasonic reaction to form a suspension liquid; (4), adding sulfur to the N-methyl pyrrolidone for performing an ultrasonic reaction until the elemental sulfur is fully dissolved to form a suspension liquid; and (5), mixing the two kinds of suspension liquid obtained in the step (4) and the step (3), and then adding distilled water to obtain the three-dimensional structured positive electrode material of the lithium-sulfur battery. Due to sulfur adsorption by the synergistic effects of boron atoms and nitrogen atoms in the boron-nitrogen-co-doped graphene, the shuttle effect is lowered, so that the cycling life of the lithium-sulfur battery is prolonged.

Belonging to the technical field of energy materials, the invention in particular relates to preparation and application of a graphdiyne material modified diaphragm. Directed at the problems of low electron conductivity, poor cyclic stability, the shuttle effect of lithium polysulfide and the like in existing lithium-sulfur battery diaphragms, solution in-situ polymerization is applied for deposition of a graphdiyne carbon nanomaterial on a commercial diaphragm. Preparation of the diaphragm mainly includes the steps of: preparation of a graphdiyne monomer serving as a carbon protective layer and deposition of a graphdiyne material in a solution on the surface of a commercial diaphragm. The graphdiyne material modified diaphragm prepared by the method has the characteristics of simple and controllable preparation process, easy large-scale preparation, stable material structure, etc. The prepared diaphragm can reduce the shuttle effect of polysulfides in the electrochemical reaction process, and improves the capacity and cycle performance of energy storage devices.

The invention provides a hollow carbon-sulfur positive electrode composite material coated with flaky manganese dioxide and preparation and application thereof. The carbon and sulfur composite material coated with the manganese dioxide has a carbon content of 10% to 30% and a manganese dioxide content of 10% to 30%, a sulfur content of 40% to 80%, wherein the manganese dioxide is a sheet-like structure and is tightly wrapped on the outer surface of the hollow carbon-sulfur composite material, and the sulfur is mainly distributed in hollow carbon ball cavities and carbon layer mesopores. Hollowcarbon balls with mesoporous structures are prepared with a one-step method with tetraethyl orthosilicate as a silicon source and resorcinol and formaldehyde as carbon sources, the method is simple,the process is controllable, and the carbon balls are uniform in particle size. The manganese dioxide of the sheet-like structure is subjected to thermal processing and is coated, the hollow carbon balls provide sufficient space for carrying the sulfur, the rich point-to-point contact between the carbon balls can ensure rapid electron transfer, sheet-like manganese dioxide coating layers at the surfaces of the carbon balls have strong chemical adsorption on polysulfides, the 'shuttle effect' is effectively alleviated, and the cycle stability and rate performance of the battery are improved.

The invention discloses an electrode of a lithium sulfur battery and a preparation method thereof. The electrode of the lithium sulfur battery includes an active substance layer containing sulfur, and conductive hydroxyl or carboxyl layers are formed on the upper surface and the lower surface of the active substance layer respectively; the active substance layer and the conductive hydroxyl are combined, or the active substance layer and the conductive carboxyl layers are combined, through external pressure, a surface substance of the active substance layer generates cross-linking interaction and hydrogen bond interaction with a fiber component of the conductive hydroxyl or carboxyl layers. The hydroxyl or carboxyl layers have high specific surface area, can adsorb polysulfide and inhibit a back-and-forth shuttling effect. The three-layer electrode structure has higher porosity, can store more electrolyte liquids, is conducive to slow down dissolution of sulfur and polysulfide, thereby ensuring occurrence of positive electrode reactions and improving the discharge capacity of the battery. Increase of the electrolyte liquid viscosity due to dissolution of the sulfur and polysulfide is also effectively alleviated. The preparation method is simple, and is easy to popularize and apply.

The invention belongs to the technical field of lithium sulfur batteries and particularly relates to an additive-free sulfonated graphene/sulfur electrode slice and a preparation method and application thereof. The preparation method comprises the following steps: firstly, modifying graphene oxide to obtain sulfonated graphene with good water solubility and electrical conductivity; dispersing the sulfonated graphene in a sodium thiosulfate solution, adding a sulfuric acid solution and forming a sulfonated graphene/sulfur compound through a disproportionation reaction; carrying out size mixing on the compound through taking absolute ethyl alcohol as a solvent and coating a carbon-coated aluminum foil with the size to obtain the electrode slice which is applied to positive electrodes of the lithium sulfur batteries. The preparation method disclosed by the invention is simple in process and good in reproducibility; the raw material has excellent electrical conductivity and a certain viscosity, so that conductive carbon black and binder are not needed in the manufacturing of the electrode slice and the volume energy density of the positive electrode materials of the lithium sulfur batteries can be greatly increased; in addition, generated intermediate products can be prevented from being diffused into electrolyte, so that the shuttle effect is reduced, and the cycle performance and the rate performance of the lithium sulfur batteries are increased.

The invention relates to a preparation for a lithium sulfur battery modified anode material. The preparation includes mixing sublimed sulfur and a conductive agent according to a mass ratio of 6:3, adding absolute ethyl alcohol, performing ball milling for 6 hours, drying in a vacuum drying box for 12 hours at the temperature of 50 DEG C to 80 DEG C to obtain a mixture, mixing the mixture and hollow nickel fiber tubes according to a mass ratio of (5-9):1, adding an adhesive, dispersing in a dispersing agent, stirring to obtain slurry, coating the slurry on a metal aluminum foil which is subjected to acetone ultrasonic cleaning, and drying in the vacuum drying box for 12 hours at the temperature of 60 DEG C to obtain the lithium sulfur battery anode material. The preparation for the lithium sulfur battery modified anode material has the advantages that electrochemistry performances of battery cyclicity and the like are improved, and the performances and cyclic service life of the battery can be improved.

The invention relates to a functional interlayer for a lithium sulfur battery and a preparation method of the functional interlayer. MAX phase ceramic powder is adopted as a raw material, nitrogen-doped MXene is prepared firstly and then hydrothermal reaction is carried out to prepare a nitrogen-doped MXene composite copper sulfide self-supporting film. According to the preparation method, a preparation process of the functional interlayer is simplified, and meanwhile, a problem that effective components are crushed and fall off from a diaphragm during a battery circulation process after coating in a traditional method is also avoided. The nitrogen-doped MXene composite copper sulfide self-supporting film is used as the functional interlayer of the lithium sulfur battery and has the characteristics of good electrical conductivity, large specific surface area, multiple storage sites and high rate performance, the lithium polysulfide can be adsorbed, and the loss of active substances canbe effectively reduced.

The invention provides a preparation method of a lithium-sulfur battery composite separator. The lithium-sulfur battery composite separator comprises a commercial Celgard separator and a polyacrylonitrile/graphene oxide layer, wherein the polyacrylonitrile/graphene oxide layer is arranged on a surface of the commercial Celgard separator, the thickness of the polyacrylonitrile/graphene oxide layer is 1-10 micrometers, and the mass ratio of polyacrylonitrile and graphene oxide in the polyacrylonitrile/graphene oxide layer is (0.2-1):1. A Nitrile group on the polyacrylonitrile in the polyacrylonitrile/graphene oxide layer and oxygen on a surface of the graphene oxide are both strong polar groups, high chemical absorption can be formed on a polysulfide which is formed during the charge-discharge process, the polysulfide can be effectively prevented from penetrating through the separator to reach a negative electrode, a shuttle flying effect is reduced, and the lifetime of a lithium-sulfur battery is prolonged.

The invention discloses a lithium-sulfur battery composite positive electrode material. Graphene oxide is used as a matrix of the battery positive electrode material, a graphene/ferroelectric composite material is obtained after the graphene oxide and a ferroelectric material are compounded, and then the graphene/ferroelectric composite material is mixed with nano sulfur according to a mass ratio of 3:7 to prepare the lithium-sulfur battery composite positive electrode material; and the ferroelectric material is one of barium titanate, lead titanate, potassium niobate, strontium titanate, lithium niobate or lead zirconate titanate. According to the lithium-sulfur battery composite positive electrode material disclosed by the invention, excellent electrical conductivity and structural stability of the graphene oxide are utilized, and the graphene oxide is used as an excellent conductive network and the positive electrode matrix, so that electrical conductivity of the positive electrode material is improved; and by utilizing strong adsorption of ferroelectricity of the ferroelectric material on polar polysulfide, dissolution and shuttling of the polysulfide in electrolyte are inhibited, so that loss of active substances is reduced, coulombic efficiency of a lithium-sulfur battery is improved and a cycle life of the lithium-sulfur battery is prolonged.

The invention relates to a method for fabricating a regenerative polysulfide-scavenging layer (RSL). The method includes embedding nanowires or nanocrystals of metal oxides with a membrane of carbon nanotubes (CNTs); and forming the RSL with the embedded nanowires or nanocrystals of the metal oxides and the membrane, so as to enable lithium-sulfur batteries with high energy density and prolonged cycling life. The invention also relates to a lithium-sulfur battery that contains the RSL.

The invention provides a carbon aerogel-loaded selenium composite material, which comprises carbon aerogel and active substances loaded in micropores of the carbon aerogel, wherein the active substances are selected from one or more of sulfur, selenium particles and selenium sulfide particles. According to the carbon aerogel-loaded selenium composite material, the adsorption property of the porousstructure of the carbon aerogel to limit the active substance particles in the porous structure of the carbon aerogel, thereby significantly reducing the shuttle effect of a polyselenide. Meanwhile,the method is easy and convenient to implement, easy to implement and has the feasibility of industrial production; and no impurities are generated in the composite material synthesis process, thus ensuring the comprehensive performance of the composite material.

The invention discloses a preparation method of a nitrogen-doped graphene/copper sulfide/hollow sulfur composite material. The preparation method comprises the following steps: step (1), adding powdered sulfur into carbon dioxide, stirring and dissolving to form a uniform solution; step (2), ball-milling high-purity nickel powder through a high-energy ball grinding mill, adding the high-purity nickel powder after ball-milling into the solution, stirring to form uniform suspension liquid, mechanically stirring, and carrying out spray drying to form sulfur clad spherical particles; step (3), adding the spherical particles into a ferric chloride solution, stirring for reaction, washing and filtering; and step (4), adding a filtered precipitate into a solution containing copper chloride, thioacetamide and a surface active agent, stirring to form uniform suspension liquid, heating and stirring for reaction, centrifuging and washing to obtain copper sulfide clad sulfur particles. In the composite material, a space is reserved for the volume expansion, in the charging and discharging process, of sulfur material through the design of a hollow structure, so that the electrochemical performance can be effectively improved.

The invention belongs to the technical field of new energy materials, and particularly relates to a zinc sulfide/rGO (reduced graphene oxide) composite material as well as a preparation method and application thereof. The preparation method of the zinc sulfide/rGO composite material containing the sulphur vacancy comprises the following steps: ZnS/GO is prepared as follows: carbon disulfide is added into a ethylenediamine water solution drop by drop, and the mixture is named as a solution A; graphene oxide GO is added into an ethylene glycol solution to be subjected to ultrasonic treatment, and the mixture is named as a solution B; the solution B is added into the solution A and continuously stirred, and then a mixed solution is obtained; a zinc nitrate solution is added dropwise into themixture while stirring; the mixed product is heated and cooled to room temperature, and then subjected to centrifuging and washing, and the dried product is ZnS/GO; then the ZnS/GO prepared in the step (1) is reduced at high temperature under the condition of argon-hydrogen combination gas, and ZnS<1-x>/rGO containing the sulphur vacancy is obtained. The invention adopts a simple and safe one-potwet chemical sulphur loading method and abandons a traditional fusing diffusing method, the loss is reduced, and the loading capacity of active sulphur is as high as 90%.