32results about How to "Reduce the "shuttle effect"" patented technology

The invention discloses a preparation method of a positive electrode material of a lithium sulfur battery. The preparation method comprises the following steps of putting graphene oxide, nanometer sulfur powder, boric acid and urea into a ball milling tank, performing ball milling and then adding into deionized water to obtain a mixture solution, performing ultrasonic wave dispersion at a normal temperature for 1-3h to obtain a mixed suspension liquid, and carrying out a spray drying process to prepare a boron nitrogen oxygen co-doped graphene / sulfur composite three-dimensional structured positive electrode material of the lithium sulfur battery. The boron nitrogen oxygen co-doped graphene / sulfur compound obtained in the invention has a simple and convenient preparation process; and through the simple spray drying process, the loosening and porous structure is manufactured, a relatively large specific surface area is obtained, and performance for bearing a large amount of elementary nanometer sulfur powder is further achieved, thereby improving the sulfur content of the positive electrode material.

The invention discloses a preparation method of a graphene coated carbon / sulfur composite material. The method includes: mixing carbon nanofiber with starch evenly, then adding deionized water, and conducting ultrasonic dispersion to obtain an evenly mixed solution; then subjecting the dispersed mixed solution to atomization by an ultrasonic atomizer to form uniformly dispersed fog beads, then bringing the fog beads into a tube furnace by inert gas for drying spheroidizing treatment and carbonizing treatment in order, thus obtaining carbon microspheres; then mixing the obtained carbon microspheres with elemental sulfur for heat treatment to obtain carbon / sulfur composite microspheres; and finally mixing the obtained carbon / sulfur composite microspheres with a graphene oxide aqueous solution, then adding a reducing agent for reduction so as to obtain the graphene coated carbon / sulfur composite material. The graphene coated carbon / sulfur composite material provided by the invention has high first discharge specific capacity and good capacity retention rate when used as a lithium-sulfur battery cathode material, also has the advantages of simple and feasible preparation method, low cost, and green and environmental protection, thus having good application prospects.

The invention discloses a preparation method for a composite conductive polymer coated with elemental sulfur and applications, and belongs to the electrochemical energy storage field. Concretely, a suspension containing pyrrole, aniline and thiophene monomers and elemental sulfur is employed as a supporting electrolyte, a platinum electrode is employed as an auxiliary electrode, aluminum foil is employed as a working electrode, a saturated calomel electrode is employed as a reference electrode, electrochemical parameters are adjusted, and polymerization of conductive polymer monomers is controlled while aggregation of elemental sulfur can be controlled synchronously. A polypyrrole / polyaniline / polythiophene composite conductive polymer film coated with elemental sulfur can be formed on the surface of the aluminum foil, and elemental sulfur can be bonded with polythiophene through S-S bonds. The composite conductive polymer film coated with elemental sulfur can be used as a positive pole piece of a lithium-sulfur battery directly, and the aluminum foil is employed as a positive pole current collector. The technology omits a combination process of elemental sulfur and a conductive polymer, and omits a later preparation process of introducing bonding agents during the pole piece preparation process. Operation is simple, and the swelling problem of a positive pole of a lithium-sulfur battery can be solved effectively.

The invention discloses a preparation method of a graphene coated carbon composite material. The method adopts sucrose, carbon fiber and graphene as the raw materials, and carries out ultrasonic dispersion, ultrasonic sprayer atomization and carbonization to effectively control the structural morphology of the composite material. The preparation method enables graphene to coat the carbon compositematerial so as to form a core-shell structure conductive network. On the one hand, the conductive network can better provide a channel for migration of ions and electrons, and improves the conductivity of positive electrode materials; and on the other hand, coating of the composite material surface with graphene can further inhibit the dissolution of a reduction product and improve the cycle performance of positive electrode materials. The graphene coated carbon composite material prepared by the method can load more elemental sulfur and hinder the dissolution of a polysulfide in an electrolyte solution when used for preparation of lithium-sulfur batteries, and then can reduce the "shuttle flying effect" of lithium-sulfur batteries, thereby improving the electrochemical performance of positive electrode materials.

The invention discloses a lithium-sulfur battery using a graphene coated carbon / sulfur composite material as a positive electrode material. The preparation method comprises the following steps: uniformly mixing a carbon / sulfur composite microsphere material, acetylene black and PVDF (Polyvinylidene Fluoride) in NMP (N-Methyl Pyrrolidone) according to a mass ratio of 80:10:10, coating the mixture onto an aluminum foil to prepare a positive pole piece; taking a metal lithium wafer as a negative electrode, and assembling into a button battery in a glove box, wherein the electrolyte is 1 MLiTFSI / DOL-DME, the volume ratio is 1:1, and the diaphragm is a celgard 2400 microporous membrane. The lithium-sulfur battery disclosed by the invention has high first discharging specific capacity, and the capacity retention ratio is excellent. Moreover, the preparation method is simple, feasible, low in cost, green and environmental-friendly, and has excellent application prospects.

The invention provides an ammonia-modified carbon quantum dot and its preparation method and its application in the electrolyte of lithium-sulfur batteries. The aldehyde compound is placed in an alkaline solution to react to obtain carbon quantum dots, and the obtained carbon quantum dots and ammonia water Reflux reaction to obtain ammonia-modified carbon quantum dots. Applying ammonia-modified carbon quantum dots as an additive to the electrolyte of lithium-sulfur batteries can effectively inhibit the dissolution of polysulfide compounds, reduce the "shuttle effect", and greatly improve the cycle performance of lithium-sulfur batteries.

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 discloses a titanium dioxide-coated lithium sulphur battery anode material and a preparation method thereof, used for solving the technical problem that an existing lithium sulphur battery anode material is low in specific discharge capacity. The technical scheme is that the anode material is prepared from sulphur, a carbon fiber sheet and a titanium dioxide casing. The preparation method comprises the steps of adsorbing a gas sulfur elementary substance by adopting the carbon fiber sheet, then using titanium dioxide to coat a mixture of the carbon fiber sheet and the sulfur elementary substance by adopting a titanium tetrachloride hydrolysis method, drying, cleaning, and drying again to obtain the titanium dioxide-coated lithium sulphur battery anode material. As elementary substance sulfur particles evenly cover the surface of the carbon fiber sheet and are externally coated by TiO2 evenly, the strong adsorption fixing capacity of the microcosmic structure of the carbon fiber sheet and the TiO2 to a polysulfide buffers volume change before and after sulfur lithiation and can limit the polysulfide generated in the charging and discharging processes of a lithium sulphur battery in a TiO2 nanotube, so that the specific discharge capacity and the cycling stability of the lithium sulphur battery are remarkably improved.

The invention discloses a method for preparing carbon / sulfur composite micro-sphere materials in the shapes of woolen yarn balls and a lithium-sulfur battery. Carbon micro-spheres in the shapes of woolen yarn balls can be prepared by the aid of electrostatic spinning processes, and sulfur can be loaded in the carbon micro-spheres to prepare carbon / sulfur composite micro-spheres for positive electrode materials for lithium / sulfur ion batteries. The method for preparing the carbon / sulfur composite micro-spheres includes stirring selected fibrous carbon materials or fibrous carbon precursors andbinders in solvents in a shear-type manner and uniformly dispersing the fibrous carbon materials or the fibrous carbon precursors and the binders in the solvents; carrying out electrostatic spinning treatment to obtain carbon precursor micro-spheres in the shapes of woolen yarn balls; carrying out carbonization treatment to obtain the carbon micro-spheres in the shapes of the woolen yarn balls. The obtained carbon micro-spheres in the shapes of the woolen yarn balls and the elemental sulfur are heated in a tube furnace to obtain the carbon / sulfur composite micro-sphere materials, and the carbon / sulfur composite micro-sphere materials can be used as the positive electrode materials for the lithium-sulfur battery. The method and the lithium-sulfur battery have the advantages that the positive electrode materials prepared from the carbon and composite materials for the lithium / sulfur ion batteries are excellent in morphology and performance as compared with conventional carbon materials and are high in first specific discharge capacity and excellent in capacity retention ratio when used as the positive electrode materials for the lithium-sulfur battery; the method is simple, feasibleand environmentally friendly, is low in cost and has an excellent application prospect.

The invention discloses a preparation method of a graphene coated carbon / sulfur composite material. The method includes: mixing carbon nanofiber with starch evenly, then adding deionized water, and conducting ultrasonic dispersion to obtain an evenly mixed solution; then subjecting the dispersed mixed solution to atomization by an ultrasonic atomizer to form uniformly dispersed fog beads, then bringing the fog beads into a tube furnace by inert gas for drying spheroidizing treatment and carbonizing treatment in order, thus obtaining carbon microspheres; then mixing the obtained carbon microspheres with elemental sulfur for heat treatment to obtain carbon / sulfur composite microspheres; and finally mixing the obtained carbon / sulfur composite microspheres with a graphene oxide aqueous solution, then adding a reducing agent for reduction so as to obtain the graphene coated carbon / sulfur composite material. The graphene coated carbon / sulfur composite material provided by the invention has high first discharge specific capacity and good capacity retention rate when used as a lithium-sulfur battery cathode material, also has the advantages of simple and feasible preparation method, low cost, and green and environmental protection, thus having good application prospects.

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 provides a sulfur-loaded modified graphene aerogel and a preparation method and application thereof, and relates to the technical field of battery materials. The sulfur-loaded modified graphene aerogel comprises nitrogenous macromolecular monomers, thiophene monomers, boric acid, graphene oxide, a dispersing agent and dithiothreitol. The advantages of large specific surface area and high conductivity of a graphene aerogel are utilized, a sulfur source is controlled to attach to the surface of the graphene oxide in a form of polythiophene, and the formed elemental sulfur can be uniformly dispersed in a conductive network established by the graphene aerogel, so that loading is stable, dissolving-out of the elemental sulfur during cycling is reduced, the swelling problem of an anode of a lithium sulfur battery is solved, and cycling performance of the lithium sulfur battery can be improved further.

The invention discloses a preparation method of a positive electrode material of a lithium sulfur battery. The preparation method comprises the following steps of putting graphene oxide, nanometer sulfur powder, boric acid and urea into a ball milling tank, performing ball milling and then adding into deionized water to obtain a mixture solution, performing ultrasonic wave dispersion at a normal temperature for 1-3h to obtain a mixed suspension liquid, and carrying out a spray drying process to prepare a boron nitrogen oxygen co-doped graphene / sulfur composite three-dimensional structured positive electrode material of the lithium sulfur battery. The boron nitrogen oxygen co-doped graphene / sulfur compound obtained in the invention has a simple and convenient preparation process; and through the simple spray drying process, the loosening and porous structure is manufactured, a relatively large specific surface area is obtained, and performance for bearing a large amount of elementary nanometer sulfur powder is further achieved, thereby improving the sulfur content of the positive electrode material.

The invention discloses a preparation method of a graphene-coated carbon nanofiber / sulfur composite material. The preparation method comprises the steps of performing uniform mixing on carbon nanofibers and starch, and then adding deionized water and performing ultrasonic dispersion to obtain a uniform mixed solution; next, adopting an electrospinning technique to prepare the obtained mixed solution into carbon microspheres, and next, performing carbonizing treatment in an inert gas atmosphere to obtain spherical carbon microspheres; performing heat treatment on the obtained carbon microspheres and elementary sulfur to obtain carbon / sulfur composite microspheres; and finally, performing mixing on the obtained carbon / sulfur composite microspheres and a graphene oxide water solution and thenadding a reducing agent for reduction, performing stirring to realize complete reaction, and carrying out filtering and drying to obtain the graphene-coated carbon nanofiber / sulfur composite material. When the graphene-coated carbon nanofiber / sulfur composite material is used as the positive electrode material of a lithium-sulfur battery, high initial charging-discharging specific capacity and excellent capacity retention ratio are achieved; and in addition, the preparation method is simple and easy to implement, low in cost, green and environment friendly, and high in application prospect.

The invention relates to a method for preparing a cathode material of a lithium-sulfur battery, and relates to an electrode formed by an active material. The method is characterized in that the graphene oxide reduction, boron doping and solvent thermal reaction are completed by one step, and the cathode material of the lithium-sulfur battery with a boron-doped graphene / sulfur composite three-dimensional structure is prepared by a one-step method. The defects that the cathode material of the lithium-sulfur battery has small and uneven sulfur load content, and low active material load and utilization rate, resulting in poor electrochemical performance of the lithium-sulfur battery in the prior art are overcome.

The invention belongs to the technical field of electrode materials, and discloses a method for preparing an ordered nano-array nitrogen-sulfur double-doped carbon / sulfur composite carbon rod material, comprising the following steps: S1. preparing an ordered nano-array precursor carbon rod; S2. Preparation of ordered nano-carbon rod array; S3. Preparation of ordered nano-array nitrogen-sulfur double-doped carbon / sulfur composite carbon rod material; this ordered nano-array nitrogen-sulfur double-doped carbon / sulfur composite carbon rod material is used for lithium / Cathode materials for sulfur-ion batteries. The lithium / sulfur ion battery positive electrode material made of the carbon / sulfur composite carbon rod material of the present invention has better appearance and performance than conventional carbon materials, and when used as a lithium sulfur battery positive electrode material, it has a high initial discharge specific capacity, The capacity retention rate is good, and the preparation method is simple and easy, low in cost, green and environmentally friendly, and has good application prospects.