1590results about How to "Improve Coulombic efficiency" patented technology

A method of producing a material capable of electrochemically storing and releasing a large amount of lithium ions is provided. The material is used as an electrode material for a negative electrode, and includes silicon or tin primary particles composed of crystal particles each having a specific diameter and an amorphous surface layer formed of at least a metal oxide, having a specific thickness. Gibbs free energy when the metal oxide is produced by oxidation of a metal is smaller than Gibbs free energy when silicon or tin is oxidized, and the metal oxide has higher thermodynamic stability than silicon oxide or tin oxide. The method of producing the electrode material includes reacting silicon or tin with a metal oxide, reacting a silicon oxide or a tin oxide with a metal, or reacting a silicon compound or a tin compound with a metal compound to react with each other.

The invention has a grain structure with an outer shell and several inner cores. The grain size is from 100 nanometers to 100 microns. The inner cores are compound grain that includes active substance and conducting additive. The outer shell is a carbon layer. The active substance takes 20-95wt% of total cathode active material, and is mixture of one or several transition metallic compound selected from silicon and lithium storage whose thermodynamic equilibrium potential is less than 1.5v. The cathode material can be made by using mechanical process or thermal method, and can be directly used as cathode material or used with other existing cathode material.

The invention discloses an artificial graphite negative electrode material for a lithium ion battery and a preparation method thereof. The preparation method for the artificial graphite negative electrode material comprises the following steps: preparing powder, adding a binder and/or a crystal nucleus-induced growth additive, kneading, carrying out compression molding, thermally roasting, carrying out nodulizing shaping and/or fusing, carrying out ultrahigh-temperature graphitization, screening, removing magnetism and screening. The preparation method disclosed by the invention is simple to operate, easy to control, lower in production cost and suitable for industrial production. The prepared artificial graphite negative electrode material has high graphitization degree, high compactness, high capacity, high coulombic efficiency, high conductivity and high multiplying power, and can be used for the lithium ion battery.

The invention discloses an anode material for a lithium metal battery. The anode material comprises a current collector and a carrier which is in tight fit with the current collector, wherein the carrier has a three-dimensional framework structure; a gap of the three-dimensional framework structure is filled with lithium metal; the carrier is selected from at least one of polymelamine, polyacrylonitrile, polyaniline, polyimide, polyvinylidene fluoride and polytetrafluoroethylene. The anode material disclosed by the invention has the advantages that a nonconductive polymer with the three-dimensional framework structure is used as the carrier, and stable deposition of lithium ions is realized by using interaction of functional groups contained in the carrier and the lithium ions; meanwhile,volumetric expansion is inhibited, internal stress of the battery is relieved, and thereby the aim of inhibiting growth of lithium dendrites is achieved. The coulombic efficiency, the safety of the lithium ion battery obtained by assembling the anode material prepared disclosed by the invention is remarkably improved and cycle life is obviously prolonged.

The invention relates to a silicon/carbon composite microsphere negative electrode material as well as a preparation method and an application for the same. The silicon/carbon composite microsphere negative electrode material is silicon/carbon composite microspheres internally provided with pore structures; and each microsphere comprises a matrix material of hard carbon, and an active material of silicon powder. The preparation method for the silicon/carbon composite microsphere negative electrode material comprises the following steps of: uniformly mixing silicon powder, soft carbon, carbon black, a soluble carbon-containing organic adhesive and a solvent with formula amounts to obtain a slurry; and performing spray-drying and carbonization on the slurry to obtain the silicon/carbon composite microsphere negative electrode material. The silicon/carbon composite microsphere negative electrode material provided by the invention has the advantages of being high in tap density, high in reversible capacity, good in cyclicity, good in rate capability, safe and reliable, and high in first-week coulombic efficiency; the preparation method provided by the invention is simple in process, environment-friendly, low in energy consumption and cost, and easy to realize large-scale production.

The present invention discloses an inorganic-organic nano composite solid electrolyte membrane and a preparation method and application thereof. The composite solid electrolyte is a novel inorganic-organic nanocomposite combining the respective advantages of inorganic ceramic solid electrolyte and organic polymer electrolyte and is composed of a negative electrode protective layer, a support layerand a positive electrode interface layer. The support layer plays a supporting role, and the main component of the negative electrode protective layer is the inorganic solid electrolyte with good mechanical properties, which can effectively inhibit the growth of lithium dendrite; and the positive electrode interface layer is mainly composed of organic polymer electrolyte with good flexibility, ensures good contact with active materials and provides a continuous ion transport channel. In the present invention, the composite solid electrolyte with good interface compatibility is prepared by coating on both sides of the support layer, and the process is simple and efficient. The composite solid electrolyte can effectively inhibit dendritic crystal and reduces interface resistance so that a solid lithium metal battery has higher energy density and longer cycle life.

The invention discloses a method for preparing a silicon/carbon composite material with a magnesiothermic reduction process, and belongs to the technical field of composite material preparation. The method comprises the following steps: (1) mixing a silicon dioxide source, an organic carbon source and a solvent, carrying out ball-milling to prepare a uniformly pulpous mixture, and obtaining a silicon dioxide-carbon precursor composite material through drying; (2) mixing the silicon dioxide-carbon precursor composite material with magnesium powder to carry out a magnesiothermic reduction reaction, collecting products and carrying out acid pickling and washing, and drying to obtain the silicon/carbon composite material. According to the method, silicon dioxide reduction and high temperature carbonization are completed by using a one-step process, and the method has the advantages of simple technical process, low cost and large-scale production; the prepared composite material effectively maintains the appearance of porous silicon, so that the composite material has preferable capability for bearing volumetric strain; the porous composite material is applied to a lithium battery, so that the lithium-ion de-intercalation depth is small, the ion diffusion path is short, the reversible capacity and coulombic efficiency of the lithium battery are effectively improved, and the cycle life is prolonged.

The invention discloses a lithium metal negative electrode for a secondary battery. The lithium metal negative electrode comprises a three-dimensional porous current collector, a lithium metal activesubstance dispersed into pores of the current collector, and a lithium deposition induction layer compounded on any plane of the current collector. Furthermore, the invention further discloses a preparation method and application of the negative electrode, and a lithium-ion secondary battery obtained through assembly of the negative electrode. The lithium metal negative electrode has the unique advantage that the lithium deposition induction layer is deposited on one plane of the current collector, so that unexpected improvement of the stability, especially the stability at high current density (for example, 3-5mA/cm<2>), of the negative electrode is facilitated. According to the method, the problems of pore plugging and lithium dendrite growth caused by preferential deposition of lithiumon the surface of the electrode in the three-dimensional porous lithium negative electrode are effectively solved, the charge-discharge coulomb efficiency of a lithium positive electrode is improved and the cycle life of the lithium positive electrode is prolonged.

The invention relates to a negative electrode material used for a lithium battery and a preparation method and application thereof, the negative electrode material includes a conductive substrate material layer and a silicon based thin film material layer, the silicon based thin film material layer contains one or more components selected from the group consisting of silicon element, SiOX and silicon alloy, wherein, 0 < X =< 2; in the silicon based thin film material layer, silicon accounts for 10-100% of the weight of the silicon based thin film material layer; the silicon based thin film material layer is a thin film formed by regular and/or irregular columnar and/or fibrous micro nano naps, wherein the micro nano naps are connected with each other by root parts, and the root parts of the micro nano naps are connected with the conductive substrate material layer; gaps are existed among the micro nano naps, and the porosity among the micro nano naps is 2%-98%; the diameter size of the micro nano naps is 1 nm to 10 mum, and the thickness of the silicon based thin film material layer is 50 nm-10 mum.

The invention relates to a high-performance silicon-carbon cathode material and a preparation method thereof. The preparation method comprises the following steps: (1) dispersing silicon into a solvent, carrying out liquid-phase ball-milling, so as to obtain nano-silicon dispersion liquid, adding graphite, and carrying out liquid-phase ball milling so as to uniformly mix nano-silicon with graphite; (2) carrying out granulation on slurry obtained the step (1), so as to obtain graphite/nano-silicon composite particles; (3) carrying out granulation on the product of the step (2) and asphalt by virtue of a mixed kneading-pressing-crushing method, so as to obtain graphite/nano-silicon/asphalt composite particles, and carrying out mechanical fusion so as to realize spheroidization and uniform coating of the graphite/nano-silicon/asphalt composite particles in one step; and (4) carrying out carbonization, scattering and sieving, so as to obtain the high-performance silicon-carbon cathode material. The preparation method is simple and low in cost and can be used for easily producing the high-performance silicon-carbon cathode material in large scale.

The invention discloses a lithium-sulfur battery with a conductive adsorption layer, and an application of a conductive polymer film. The lithium-sulfur battery comprises a sulfur-containing positive electrode sheet, a separation film, and a lithium negative-electrode sheet. A conductive absorption layer is arranged between the sulfur-containing positive electrode sheet and the separation film. The application comprises that the conductive polymer film prepared from a conductive polymer, a conductive agent, and an adhesive is arranged as a conductive absorption layer between the sulfur-containing positive electrode sheet and the separation film of the lithium-sulfur battery, such that the lithium-sulfur battery is prepared. The prepared lithium-sulfur battery has the characteristics of high specific capacity, high coulombic efficiency, and long service life. The conductive polymer film has the advantages of low raw material cost, simple preparation method, and suitability for industrialized productions.

The invention discloses a cathode material for a long-circulation lithium-sulfur battery and a preparation method thereof. The cathode material is compounded from the following materials: a three-dimensional metallic oxide or metallic sulfide/carbon composite material and a sulfur-containing material, wherein the three-dimensional metallic oxide or metallic sulfide/carbon composite material is compounded from the following materials: a metallic oxide or metallic sulfide, and a carbon composite material. The carbon composite material is a nanocarbon composite material, with a two-dimensional structure, compounded by a one-dimensional material and a two-dimensional material. The sulfur-containing material is elemental sulfur or a polysulfide containing a -Sm- structure in which m is greater than 2. The cathode material for the long-circulation lithium-sulfur battery prepared in the invention has high conductivity and a three-dimensional space structure, the coulombic efficiency and cycle performance of the lithium-sulfur battery can be improved effectively, and meanwhile the cathode material has excellent rate capability.

The invention provides a carbon material for a battery electrode, which comprises a carbon powder material as a composite of carbonaceous particles and an a carbon material derived from an organic compound prepared by allowing the organic compound serving as a polymer source material to deposit onto and/or permeate into the carbonaceous particles to thereby polymerize the polymer material and then heating at 1,800 to 3,300° C., and which has an intensity ratio of 0.1 or more for peak intensity attributed to a (110) plane to peak intensity attributed to a (004) plane determined through X-ray diffraction spectroscopic analysis on a mixture of the carbon material and a binder resin when pressed at 10³ kg/cm² or higher. The carbon material which undergoes less deformation/orientation due to application of pressure, has high discharge capacity and small irreversible capacity and exhibiting excellent coulombic efficiency, cycle characteristics and leakage-current load characteristics.

The invention discloses lithium molybdate serving as a secondary battery electrode material. In an execution mode, a chemical formula of the electrode material is Li (2-x)MoyMzO(3-u), wherein x is larger than or equal to minus 2 and smaller than or equal to 2, y is larger than 0 and smaller than or equal to 5, z is larger than or equal to 0 and smaller than or equal to 9, u is larger than or equal to minus 9 and smaller than or equal to 3, and M comprises one element selected from C, N, F, Na, Mg, Al, Si, P, S, Cl, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Br, Rb, Sr, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Cd, In, Sn, Sb, Te, I, Cs, Ba, Ta, W, Re, Os, Ir, Pt, Au, Hg, Pb, Bi, Po, At, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu or combination of the elements. The electrode material is characterized by having very high specific capacity, excellent cycle performance, rate capability and safety.