789results about How to "Improve the first Coulombic efficiency" patented technology

The invention provides a silicon-based composite material, which is prepared from silicon particles, silicate and optional carbon, wherein the mixture of the silicate and the optional carbon forms a massive body, and the silicon particles are dispersed in the massive body. A preparation method comprises the following steps of: dispersing the silicon particles into absolute ethyl alcohol and/or deionized water to form suspension liquid; dispersing the silicate and the optional carbon into the absolute ethyl alcohol and/or the deionized water to form suspension liquid; ultrasonically oscillating the two kinds of suspension liquid respectively, and then stirring; dropwise adding the suspension liquid of the silicon particles into the suspension liquid of the silicate and the optional carbon to form mixed liquid, heating and stirring the mixed liquid until evaporating the mixed liquid into paste; then, putting the paste in an oven to be dried to obtain masses, and grinding and sieving to obtain undersize particles; and conducting heat treatment in an inert atmosphere, and grinding and sieving to obtain the silicon-based composite material. According to the silicon-based composite material, a lattice structure of the silicon particles can be ensured, therefore the activity of the silicon particles is ensured, and the energy density, the first-time coulomb efficiency and the high-temperature storage performance of lithium ion batteries are increased.

The invention discloses a composite hard carbon cathode material of a lithium ion battery and a preparation method thereof, aiming at improving the first coulombic efficiency. In the composite hard carbon cathode material, a coating object is coated outside a hard carbon matrix, a precursor of the hard carbon matrix comprises a thermoplastic resin which forms the hard carbon matrix by pyrolysis, and a precursor of the coating object is an organic matter. The preparation method comprises the steps of curing, pyrolyzing, pulverizing and coating. Compared with the prior art, a curing agent and adopant are added to the resin for curing, the cured mixture is taken as a carbon source, and then the carbon source is pyrolyzed and coated to finally obtain the composite hard carbon cathode material; and the first reversible capacity of the obtained composite hard carbon cathode material is more than 455.2mAh/g and the first coulombic efficiency thereof is more than 79.4% in the case of 0.2C, thus the obtained composite hard carbon cathode material has high capacity and high first coulombic efficiency, meets the requirement of the lithium ion battery with high capacity, high multiplying power and excellent high and low temperature cycle performance on the charge-discharge performances of the cathode material, has low production cost and is suitable for industrial production.

The invention discloses a silicon monoxide/silicon/lithium metasilicate composite negative electrode material. The silicon monoxide/silicon/lithium metasilicate composite negative electrode material comprises a silicon monoxide/silicon/lithium metasilicate composite material and an inorganic matter coating layer. The invention also provides a preparation method of the silicon monoxide/silicon/lithium metasilicate composite negative electrode material. The preparation method comprises the following steps: taking silicon monoxide and an inorganic compound of lithium element, mixing and ball-milling the silicon monoxide and the inorganic compound of the lithium element, sintering the obtained mixture in a protection gas environment, and naturally cooling the sintered mixture to obtain the silicon monoxide/silicon/lithium metasilicate composite material; and mixing and ball-milling the silicon monoxide/silicon/lithium metasilicate composite material and sintering the obtained mixture undera protection gas condition. The preparation method of the silicon monoxide/silicon/lithium metasilicate composite negative electrode material has the advantages of simplicity, safety, low cost, and easiness in operation and industrial production, and the obtained composite negative electrode material has the advantages of high reversible capacity, excellent cycle performances and high initial Coulomb efficiency.

The invention discloses a torispherical cathode material for a lithium ion battery, which has a 'shell-core' graphite composite microstructure, wherein an inner core may be spherical natural graphite, spherical artificial graphite, a mesocarbon microbead or a mixture of the three; a shell is a graphitized product of asphalt; an interlayer distance between the inner core and the shell ranges from 0.3360 to 0.3390nm; and the torispherical cathode material has a mesoporous structure with an aperture of 10 to 50nm, and the ratio of granular length to granular width of the graphite composite ranges from 1.0 to 2.0. The torispherical cathode material for the lithium ion battery has the advantages that: 1, the high-rate performance of the electrode material is improved; and the discharge capacitance of the electrode material still reaches 320 to 340mAh/g after 300 times of circulation at a 5C rate; 2, preparation cost is low and atmosphere pollution is avoided; and 3, the shape of the graphite raw material used by the invention is torispherical and favorable for the cladding uniformity of the asphalt and can better strengthen the structural stability of the composite.

The invention provides a lithium ion battery cathode material and a preparation method of the lithium ion battery cathode material as well as a lithium ion battery. The lithium ion battery cathode material comprises an inner core, a middle layer outside the inner core and an outer shell wrapping the middle layer, the inner core is Si-C particles, the middle layer is a foam layer, the outer shell is an amorphous carbon layer and the Si-C particles are formed by Si particles and C materials. Compared with the prior art, a middle carbon foam layer existing between the Si-C particle inner core and the amorphous carbon outer shell can form an conductive network structure, thus improving conductivity of a material and buffering enormous volume change of Si particles in the charge-discharge processes; and the amorphous carbon outer shell layer can maintain the core-shell structure of the cathode material, and the cladding layer of the core-shell structure can buffer the volume change, improve cycling stability of electrodes, reduce contact between active substances and an electrolyte, improve first coulombic efficiency of an electrode, prevent nanoparticle aggregation and enhance electrode conductivity.

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 invention relates to a high-capacity graphite material and a preparation method as well as application thereof. The high-capacity graphite material comprises artificial graphite and natural graphite, wherein the mass ratio of artificial graphite to natural graphite is 20:1 to 1:1. According to the preparation method, the artificial graphite and the natural graphite are uniformly mixed according to a certain mass ratio, and then surface modification is carried out on the mixture. The prepared graphite material has the advantages of high discharge capacity, high first efficiency, long cycle life, low cost and the like; the discharge capacity of the high-capacity graphite material can reach up to more than 350mAh/g (even reach up to more than 368mAh/g); a half-cell of the high-capacity graphite material charges and discharges at the 1C multiple power; after the high-capacity graphite material cycles for 100 times, the capacity retention ratio of the high-capacity graphite material is still more than 90% (even reaches up to more than 96.3%); the first efficiency reaches up to more than 95.5%; and the manufacturing cost is reduced by about 1-10%. The high-capacity graphite material provided by the invention not only can meet the requirement of a lithium ion power battery for the high multiplying power charge-discharge of the material, but also reduces the manufacturing cost of the cathode material of the lithium ion battery.

The invention discloses a pre-lithiation method of a lithium ion battery negative electrode material. The method is characterized in that by adopting a method of coating or covering the surface of metal lithium with a lithium ion barrier layer and/or controlling a resistance value of a connection conductor, the pre-lithiated current magnitude is limited, and the reaction speed of a primary battery between metal lithium and negative electrode materials is regulated so as to regulate the lithium-intercalation speed of the negative electrode material and formation speed of surface SEI films, and the circulation performance of the negative electrode material is improved based on the improvement on coulombic efficiency for the first time of the negative electrode material; moreover, the method is simple in process and easy to operate, and suitable for pre-lithiation of the commercial lithium ion battery negative electrode material; lithium consumed by irreversible reaction is supplemented, so that the coulombic efficiency for the first time and the capacity of the battery are increased, and the circulation performance of the battery is improved.

The invention relates to the technical field of lithium ion batteries, in particular to core-shell structured carbon for a cathode material of a lithium ion battery and a preparation method thereof, and the lithium ion battery taking the core-shell structured carbon as the cathode material and a preparation method thereof. The core-shell structured carbon comprises a hard carbon material serving as a 'core' and soft carbon 'shell' which is coated on the surface of the 'core'. On the one hand, the hard carbon material serving as the 'core' provides a large number of spaces for storing lithium and channels for lithium ions to move, and the energy density and power density of the material are improved, and on the other hand, the soft carbon 'shell' with a graphite structure ensures that the material has high coulombic efficiency and cycle performance, so that the lithium ion battery made of the core-shell structured carbon serving as the cathode material has high capacity, high power characteristic, high cycle performance and high first charge and discharge coulombic efficiency, the preparation method is simple, and the cost is low.

The invention discloses a modified high nickel ternary positive electrode material. The surface of a high nickel ternary positive electrode material is coated with a coating layer containing a fast ion conductor. The fast ion conductor has the chemical general formula of Li3x1La2/3-x1Ma1TiNz1O3, Li2+2x2Zn1-x2GeO4 or LiM'2(PO4)3, wherein M represents Ba<2+> and/or Sr<2+>, N represents Al<3+> and/orZr<4+>, x1 is greater than or equal to 0.04 and less than or equal to 0.167, a1 is greater than or equal to 0 and less than or equal to 1, z1 is greater than or equal to 0 and less than or equal to 1, x2 is greater than -0.3 and less than 0.8, and M' represents one or more of Zr, Ti, Ge and Hf. Compared with the existing positive electrode material, the modified high nickel ternary positive electrode material is provided with the coating layer containing the fast ion conductor and the coating layer can react with residual lithium on the surface of the material to reduce residual lithium on the surface of the material and inhibit side reactions of the residual lithium and the electrolyte so that material surface stability and cycle performances are improved. The modified high nickel ternary positive electrode material has good lithium ion deintercalation ability, improves the first discharge capacity of the material and first coulombic efficiency and has a good application prospect. The invention also discloses a preparation method of the modified high nickel ternary positive electrode material and a lithium ion battery.

The invention belongs to the technical field of lithium ion batteries and particularly relates to a method for supplementing lithium to a lithium ion battery pole piece. The method includes the following steps that 1, lithium colloidal particles of core-shell structures are prepared, shell layers are made of rubber and/or resin, core layers are made of metal lithium, and metal lithium is coated with the shell layer materials to form the lithium colloidal particles; 2, the lithium colloidal particles obtained in the step 1 and an electrode active material are mixed to prepared into electrode active slurry, then the surface of a current collector is evenly coated with the mixed electrode active slurry, and drying is carried out. The lithium colloidal particles of the core-shell structures are used for the battery pole piece to prepare a lithium-rich battery pole piece. The method for supplementing lithium to the lithium ion battery pole piece is easy to operate, safe and efficient, the risk that metal lithium is oxidized is avoided, the requirements for the environment and equipment are low, the production cost can be reduced, meanwhile, the first-time coulombic efficiency and cycle performance of a lithium ion battery adopting the battery pole piece are both obviously improved, and battery capacity losses caused by irreversible cycle are greatly reduced.

The invention provides a lithium ion battery and a lithium-rich anode sheet. The lithium-rich anode sheet comprises: a current collector; and a diaphragm, which contains an active substance and is formed on the current collector, wherein the diaphragm and the current collector form an initial anode sheet. The current collector in the initial anode sheet is a porous current collector. The initial anode sheet is rich in lithium on one side, and the lithium rich amount matches the lithium supplement capacity needed by the initial anode sheet. The lithium ion battery includes: a cathode sheet; an anode sheet; an isolation membrane disposed between the cathode sheet and the anode sheet; and an electrolyte solution. The anode sheet is a lithium-rich anode sheet. The lithium-rich anode sheet of the lithium ion battery provided by the invention not only overcomes the excess lithium supplement problem in traditional lithium-rich anode sheets, and also can effectively control the lithium supplement amount of the anode so as to realize uniform lithium supplement and enhance the first coulombic efficiency of the lithium ion battery adopting the lithium-rich anode sheet. Thus, the energy density of the lithium ion battery is greatly improved, and the lithium ion battery can be ensured with better electrochemical properties.

The invention discloses a silicon-base negative material with a silane coupling agent and conductive polymer two-layer cladding structure as well as a preparation method and application of the material. The silicon-base negative material is characterized in that monomer silicon is adopted as a substrate, the substrate is coated with a silane coupling agent decorative layer, and the silane coupling agent decorative layer is coated with protonic acid doping-state conductive polyaniline. The preparation method comprises the following steps: (1) ultrasonically blending a silane coupling agent and silicon powder, and refluxing the mixture of the silane coupling agent and the silicon powder at a given temperature so as to decorate the silicon powder; (2) ultrasonically blending aniline monomer and decorated silicon powder in an acid solution system, and performing in-situ polymerizing on the aniline monomer and the decorated silicon powder to obtain a silicon-base composite material which is coated with the conductive polymer; (3) washing, suction-filtering and vacuum-drying the mixed solution to obtain the silicon-base negative material with the silane coupling agent and conductive polymer two-layer cladding structure. When being doped in graphite, the silicon-base negative material can be used for preparing a negative material of a lithium ion battery. The preparation method is simple and easy, low in manufacturing cost, good in repeatability and convenient for industrialized mass production.

The invention provides a modified lithium manganese oxide electrode material for a lithium ion secondary battery, which is characterized in that the general formula is Li(4-x)A(x+y)Mn(5-y)O12.epsilonBOz. The synthesizing method comprises the following steps: weighing and mixing raw materials evenly in accordance with the stoichiometric ratio in the general formula and then adding the mixture of the raw materials to a container; adding an oxidizing solution, evening mixing and reacting for over 10 minutes, and then taking the materials out, washing and drying; and then carrying out high-temperature calcination and reaction for 1-30 hours at a temperature of 400-1200 DEG C under an oxygen-contained atmosphere, and cooling to obtain the modified lithium manganese oxide electrode material. Compared with an existing electrode material and a synthesizing technology, the modified lithium manganese oxide electrode material produced in the production process can improve the crystalline characteristic and the purity of products as well as the specific capacity, the initial coulomb efficiency, the cyclical stability and other characteristics in electrochemical property; and the modified lithium manganese oxide electrode material improves performances of the lithium ion battery, promotes the wider applications of the lithium ion battery and has significant economic meanings and practical value.

The invention discloses a lithium ion battery pre-lithiated silicon-carbon multilayer composite negative electrode material and a preparation method thereof. The composite negative electrode materialcomprises an amorphous carbon matrix, pre-lithiated silicon monoxide particles and a graphene material, wherein the graphene material is uniformly coated on an outer surface of the pre-lithiated silicon monoxide to form composite particles, and the composite particles are uniformly dispersed in the amorphous carbon matrix. After the silicon monoxide is pre-lithiated, the first effect of the silicon-based negative electrode material is greatly improved, the graphene material is light in weight, high in strength and excellent in conductivity, so mechanical property and conductivity of the composite material are greatly improved, the amorphous carbon matrix plays a role in isolating electrolyte and preventing silicon from being in contact with the electrolyte to generate a large number of unstable SEI films, and experiments show that the composite negative electrode material prepared has characteristics of good mechanical property, high conductivity, high initial coulombic efficiency andstable cycle performance.