198results about How to "High rate characteristics" patented technology

An electrolyte for a lithium secondary battery, the electrolyte including: a lithium salt; a non-aqueous organic solvent; and a piperazine derivative represented by Formula 1 having an oxidation potential lower than an oxidation potential of the non-aqueous organic solvent by about 2 V to about 4 V:

wherein, in Formula 1, X, Y, and R₁ to R₄ are defined in the specification.

The invention relates to the field of negative electrode materials of lithium ion batteries, and specifically to a nanometer lithium titanate/graphene composite negative electrode material and a preparation process thereof. According to the invention, micron-sized lithium titanate prepared by the solid phase method is subjected to ultrafine ball milling to obtain nanometer powder, and the nanometer lithium titanate powder and graphene are uniformly compounded and subjected to heat treatment so as to obtain a high performance lithium ion battery negative electrode material; the invention is characterized in that uniform distribution of graphene in the nanometer lithium titanate powder is realized through in situ compounding; the weight of graphene in the composite negative electrode material accounts for 0.5 to 20%, and the weight of lithium titanate accounts for 80 to 99.5%. The lithium ion battery negative electrode material has good electrochemical performance, 1C capacity greater than 165 mAh/g, 30C capacity greater than 120 mAh/g and 50C capacity greater than 90 mAh/g. Nanometer lithium titanate in the lithium ion battery negative electrode material prepared in the invention has high phase purity; the preparation process of the material is simple and is easy for industrial production.

The invention relates to a space buffer lithium-doped silicon oxide composite material, a preparation method of the composite material and a lithium ion battery, and belongs to the technical field ofthe lithium ion battery. The material is of a core shell structure; the core is a lithium predoped silicon oxide composite material; the shell is a coated with carbon layer. For the doped lithium, silicon oxide in the silicon oxide composite material is converted into lithium silicate through solid phase reaction in the preparation process. The preparation method of the space buffer lithium-dopedsilicon oxide composite material comprises the steps that after a lithium source is covered on the silicon oxide particle surface, a coating carbon layer is formed at the obtained particle surface through chemical vapor carbon deposition; the obtained coated material is sintered in vacuum or inert atmosphere; a surface coated lithium source reacts with silicon oxide; on one hand, the lithium doping of the silicon oxide material is realized; on the other hand, the building of a cavity structure is realized. The space buffer lithium-doped silicon oxide composite material has the characteristicsof high specific capacity, high first-time charging and discharging efficiency and long service life.

The invention discloses a preparation method of porous graphene. The method comprises the steps of: (1) stripping graphite oxide in a water/ethanol mixed solution with pH of 9-10, adding a chemical foaming agent and mixing them uniformly, carrying out filtering and drying to obtain a solid mixture; (2) placing the mixture in a reducing atmosphere, and performing heating expansion reduction to obtain expanded graphene; (3) blending the expanded graphene with strong base, and conducting high temperature activation; and (4) washing the product with hydrochloric acid and deionized water, and performing drying so as to obtain porous grapheme. The porous graphene prepared by the method involved in the invention has a specific surface area up to 2075m<2>/g, a pore volume up to 1.8cm<3>/g, and an average pore size of 1-7nm. As a supercapacitor electrode material, the specific capacitance can reach 155F/g under a current density of 1Ag<-1>. As a porous graphene electrode, the specific capacitance can reach 84.4% along with the increase of current density from 0.2Ag<-1> to 20Ag<-1>. The porous graphene has high specific capacitance and cycle stability. The preparation method disclosed in the invention has the advantages of simple process, low cost, and easy scale production.

The invention relates to a preparation method of a lithium ion battery carbon microsphere negative electrode material. The method comprises: mixing carbon black, a binder and a solvent to prepare a slurry, conducting spray drying for molding, and then carrying out a high temperature treatment so as to obtain the lithium ion battery carbon microsphere negative electrode material. The lithium ion battery carbon microsphere negative electrode material provided in the invention has a high degree of sphericity and a controllable particle size, so that close packing of the negative electrode material is realized, the volume energy density of electrodes is enhanced. Meanwhile, lithium ions can be embedded from all directions, and the structural stability, the rate capability and the first coulombic efficiency of the material are improved. The carbon microspheres internally have size-controllable gaps, which make up a plurality of ion transport channels, thus being conducive to improving the charge-discharge capacity and cyclic capacity retention rate of the material. Also, the main preparation raw material is carbon black, which has wide sources, no need for breaking, and a low price. And the preparation method has the advantages of simple process, environmental friendliness, low energy consumption and cost, and is easy for large scale production.

The invention discloses a Co3O4 nano lamellar material and a preparation method and application thereof. The preparation method comprises the following steps of: mixing cobalt salt, a surfactant, a precipitator and deioned water in stoichiometric ratio; transferring the mixed solution into a reaction kettle and carrying out hydro-thermal reaction for 17.5-18.5 hours at 115-125 DEG C; and then washing and drying to obtain a powdery mixed precursor; and carrying out heat treatment on the powdery mixed precursor in air to finally obtain the Co3O4 nano lamellar material. The prepared Co3O4 material is of a regular nano lamellar structure, and can be applied to the negative electrode of a chargeable lithium ion battery so as to improve the storage capacity of lithium.

The invention provides a silicon-based composite material, a preparation method thereof and a lithium-ion battery. The preparation method comprises a step of mixing SiOx and a carbon source to obtaina SiOx@carbon source mixture, a step of curing and carbonizing the SiOx@carbon source mixture under an inert atmosphere to obtain SiOx@carbon, a step of dispersing the SiOx@carbon in a solution with oxidant, simultaneously adding a conductive polymer monomer and a conductive carbon material, uniformly dispersing, and polymerizing in situ to obtain the silicon-based composite material. The silicon-based composite material is a double-shell core-shell structure material, an outer shell layer is a conductive polymer layer, an inner shell layer is a carbon layer, and the conductive carbon materialis embedded into the conductive polymer monomer. The silicon-based composite material obtained by the method can effectively improve the electrochemical performance of the lithium-ion battery when the silicon-based composite material is used as a negative electrode material of the lithium-ion battery.

The invention relates to a porous metal oxide-carbon composite thin-film electrode and a preparation method of the porous metal oxide-carbon composite thin-film, which belong to the technical field of lithium ion battery. The porous metal oxide-carbon composite thin film electrode free of other additional conductive agents and adhesives consists of a copper foil collector, and a porous metal oxide-carbon composite thin film on the surface of the copper foil collector. The preparation method of the porous metal oxide-carbon composite thin-film electrode comprises the following steps: blending a metal salt emulsion with an alkaline emulsion for reaction; demulsifying and centrifuging to obtain a precipitate; applying the precipitate on the surface of the copper foil collector; and calcining the copper foil collector twice to obtain the final product. The porous metal oxide-carbon composite thin-film electrode has the advantages of high specific capacity and high rate capability when used as the negative electrode of a lithium ion battery.

The invention discloses a method for preparing a metallic compound/porous carbon nanorod of a hierarchy structure, and belongs to the technical field of new energy. The method comprises the following steps: firstly, mixing inorganic transition metal salt, 1,4-naphthalic acid and water so as to obtain a turbid solution of an organic acid complex of metal ions; secondly, under a high-temperature hydrothermal condition, performing reaction for a certain period of time so as to generate a precursor of a metal organic frame; and finally, in the protection of an inert gas, performing high-temperature thermal treatment control, thereby obtaining the metallic compound/porous carbon nanorod. As a sodium-ion battery negative material, the metallic compound/porous carbon nanorod shows excellent multiplying power characteristic and cycling stability. The method has the advantages of being simple in preparation process, low in equipment requirement, rich in raw material resource, low in production cost, short in synthesis cycle, gentle in reaction condition, high in yield, free of template removal, good in material property and the like, industrial production can be easily achieved, and a product can be used in the field of electrochemical energy storage.

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 relates to a sulfonated polymer applied to a lithium battery electrode as a binder as well as a method for preparing the lithium battery electrode. The sulfonated polymer is used as the binder in electrode slurry of the lithium battery electrode, the obtained lithium battery electrode is used for assembling a lithium battery, and the lithium battery is relatively long in charging-discharge cycle life and stable in work under a relatively high current density. The sulfonated polymer with a sulfonic acid group has excellent capacity of transferring lithium ions, so that the lithium ions can be rapidly transmitted back and forth between an electrode active material and an electrolyte, and the lithium battery which is stable to run under the rapid charging-discharging condition can be obtained. The sulfonated polymer which is used as the binder is sufficient in cohesion force and binding strength, and the electrode active material and a conductive medium are stuck onto a current collector by the sulfonated polymer and are unlikely to fracture and dust, so that the lithium battery has sufficient capacity and cycle performance as well as excellent rate capacity.

The invention discloses a chrysanthemum-shaped cobaltosic oxide (Co3O4) material and a preparation method and application thereof. The preparation method comprises the following steps of: mixing cobalt salt, a surface active agent, a precipitating agent and a solvent in a stoichiometric ratio; putting a mixed solution into a reaction kettle and performing hydro-thermal reaction at the temperature of 95 to 105 DEG C for 7.5 to 8.5 h; washing and drying, and thus obtaining a powdery mixed precursor; and performing heat treatment on the powdery mixed precursor in air, and thus obtaining the chrysanthemum-shaped Co3O4 material. The obtained chrysanthemum-shaped Co3O4 material has better electrochemical performance and is applicable to a cathode of a rechargeable lithium ion battery.

The invention discloses a lithium manganese nickel oxide cathode material having nickel manganese concentration gradient and a preparation method thereof. The average chemical composition of the lithium manganese nickel oxide cathode material can be shown as a molecular formula of LiNi<0.5-x>Mn<1.5+x>O<4>, wherein x is more than or equal to 0.1 and less than or equal to 0.35, the concentration of Ni is gradually reduced in a gradient distribution manner from the particle center to the particle surface of the lithium manganese nickel oxide cathode material, and the concentration of Mn is gradually reduced in a gradient distribution manner from the particle center to the particle surface of the lithium manganese nickel oxide cathode material. The preparation method comprises the following steps of firstly, synthesizing a spherical-like particle having a core-shell structure by a co-precipitation process; and finally, preparing the lithium manganese nickel oxide cathode material with change on the nickel and manganese concentration by element diffusion during the high-temperature roasting process. The cathode material disclosed by the invention has excellent high-temperature cycle stability and rate performance, high reversible capacity, high chemical stability, long cycle life, and excellent comprehensive electrochemical performance.

The invention relates to a laminated Na3V2(PO4)3@rGo nanocomposite and an preparation method and an application therefor. The nanocomposite can be used as a sodium ion battery positive electrode active material with high rate capability and long service life; and the nanocomposite is formed by a sheet structure and rGO nano-sheets in a layer-to-layer overlapping manner, wherein the sheet structure is formed by nanoscale sub-unit Na3V2(PO4)3 particles. When the laminated Na3V2(PO4)3@rGo nanocomposite is used as the sodium ion battery positive electrode active material, the material is excellent in cycling stability and high in rate capability, so that the laminated Na3V2(PO4)3@rGo nanocomposite is the potential application material for the sodium ion batteries with high rate capability and long service life; and in addition, the preparation method is simple in process, capable of meeting the green chemistry demand, low in equipment requirement and good for the marketization promotion.

The invention discloses a polymerization emulsion, a preparation method thereof, an aqueous adhesive, and a preparation method and an application of the aqueous adhesive. The preparation method of thepolymerization emulsion comprises the following steps: adding water, a chain transfer agent and a sulfonic acid type reactive emulsifier, performing mixing, dropwise adding an acrylic monomer, performing pre-emulsifying, introducing an inert gas to remove O2, adding a cross-linking agent and an initiator, and performing RAFT polymerization to obtain the polymerization emulsion. The aqueous adhesive is prepared through compounding a water-soluble polymer compound, the polymerization emulsion and water, or is prepared through the RAFT polymerization of the water-soluble polymer compound, raw materials for preparing the polymerization emulsion and water. The invention also discloses the preparation method of the aqueous adhesive. The aqueous adhesive is applied to the production of a lithium-sulfur battery positive plate. The polymerization emulsion has the advantages of wide range of suitable monomers, easiness in control and uniform particle size distribution; the aqueous adhesive hasthe advantages of low solid content and wide viscosity range, and a positive electrode made by using the aqueous adhesive has excellent electrochemical performances; and the preparation methods have the advantages of simplicity, low cost, greenness and environmental protection.

The invention discloses a synthetic method for a cathode material lithium cobaltous phosphate used for lithium ion batteries. The method comprises a step of dissolving cobaltous acetate in deionized water to prepare an aqueous solution of the cobaltous acetate; a step of dissolving lithium hydroxide and sucrose in deionized water to prepare a lithium hydroxide/sucrose mixed solution; a step of adding phosphoric acid in deionized water to prepare a phosphoric acid solution; a step of adding the phosphoric acid solution into the aqueous solution of the cobaltous acetate to obtain a burgundy emulsion, stirring uniformly, adding the lithium hydroxide/sucrose mixed solution into the burgundy emulsion, mixing uniformly, and adding nitric acid to obtain a precursor solution; a step of subjecting the precursor solution under stirring to spray drying to obtain a precursor of lithium cobaltous phosphate powder; and a step of subjecting the precursor of the lithium cobaltous phosphate powder to vacuum calcination at 600-750 DEG C for 16-26 h to obtain the cathode material lithium cobaltous phosphate with a spherical porous structure and a high specific capacity.