119results about How to "Reduce irreversible capacity loss" patented technology

Irreversible first cycle capacity loss in lithium secondary cells having a cell electrode based on a powdered material and a binder may be significantly decreased or eliminated by using an aliphatic or cycloaliphatic polyimide binder. Compared to conventional polyimide binders prepared by reacting an aromatic dianhydride and a diamine, the disclosed polyimide binders have decreased aromatic carbonyl content, may be less likely to undergo electrochemical reduction, and may be less likely to consume electrons that might otherwise help lithiate the electrode.

The present invention includes compositions, surface and bulk modifications, and methods of making of (1−x)Li[Li_1/3Mn_2/3]O₂.xLi[Mn_0.5-yNi_0.5-yCo_2y]O₂ cathode materials having an O3 crystal structure with a x value between 0 and 1 and y value between 0 and 0.5, reducing the irreversible capacity loss in the first cycle by surface modification with oxides and bulk modification with cationic and anionic substitutions, and increasing the reversible capacity to close to the theoretical value of insertion/extraction of one lithium per transition metal ion (250-300 mAh/g).

A method for preparing a ternary anode material of a long-service-life and high-capacity lithium ion battery and belongs to the technical field of material synthesis. The method comprises the following steps: weighing a lithium source and NixCoyMnz(OH)2, uniformly mixing, pre-burning at a temperature of 400-600 DEG C for 2-6 h, and forging at a temperature of 700-1000 DEG C for 6-16 h; uniformly mixing the ternary anode material, the lithium source and nanometer TiO2; forging at a temperature of 700-950 DEG C for 3-8 h to obtain the ternary anode material which is prepared by twice lithium adding and twice forging. The ternary anode material is prepared through twice lithium adding and twice forging, and the extra lithium source which is introduced through twice lithium adding and twice forging is electrochemically pre-embedded in an anode. Meanwhile, the Li+ diffusion rate can be effectively increased through the doping of Ti4+, and the irreversible capacity loss is reduced. In an interval of 2.3-4.6 V, a discharging platform is prolonged, and the first discharging capacity, the cyclic performance and the rate performance of the material are obviously improved. The method is simple, effective, economical and practical and has a remarkable industrial application effect.

The invention relates to a method for effectively screening self-discharging batteries. The method comprises the following steps: (1) determining low-voltage-state voltage knee points of batteries by using a trickle charge method; (2) carrying out charging and discharging on the batteries, allowing the voltage of the batteries to be finally located at the low-voltage-state voltage knee points, and after the voltage of the batteries tends to be stable, measuring and recording the voltage OCV1 of each battery; (3) storing the batteries at a set temperature for a period of time and measuring and recording the voltage OCV2 of each battery; and (4) calculating the voltage drop value delta V of each battery, wherein delta V satisfies the equation that delta V = OCV1 - OCV2, and if the voltage drop value delta V of a battery exceeds a set value, the battery is a self-discharging battery need to be screened out. The method provided by the invention is more scientific, accords with principles, can more accurately screen out self-discharging lithium ion batteries and reduces irreversible capacity loss of batteries in the phase of screening of self-discharge; thus, excellent electrochemical performance and safety performance of batteries in subsequent usage are guaranteed.

The invention provides lithium supplement paste for a lithium secondary battery. The lithium supplement paste comprises a lithium-containing compound, a conductive agent, a bonding agent and an organic solvent, wherein the bonding agent is a bonding agent which can be dissolved in a non-aqueous electrolyte solution. In the obtained lithium secondary battery, the cycle property of the battery is enabled not to be changed, and the energy density of the lithium secondary battery is remarkably improved.

The invention discloses a lithium sulfur battery anode material and preparation method thereof, melamine formaldehyde resin rich in nitrogen is taken as a carbon source and nitrogen source, a nitrogen-rich hollow eggshell with the diameter of 100-300 nm is prepared with a nanometer SiO2 casting method, the interfacial adsorption of polysulfide is enhanced by the aid of the combined effect of physical adsorption and chemical adsorption, migration and shuttle effects of the polysulfide are effectively restrained, and charge and discharge stability of a lithium sulfur battery is enhanced. At the same time, an eggshell structure is formed after the hollow eggshell is filled with sulfur, and an interior gap exists between a sulfur inner core and a polymer shell so as to accommodate volume expansion in a sulfur atom lithiation process. The lithium sulfur battery anode material is applied to preparation of a lithium sulfur battery anode and the lithium sulfur battery. The lithium sulfur battery has excellent cycle performance and capacity retention ratio.

The invention discloses a lithium ion battery negative electrode for reducing irreversible capacity loss. The lithium ion battery negative electrode comprises a negative electrode current collector and a negative electrode paste, wherein the negative electrode paste is coated on the surface of the negative electrode current collector and comprises the following constituents based on mass: 25-45% of negative electrode active substance, 0.3-5% of conductive agent, 0.3-5% of binding agent, 0-2% of surfactant, 0.0001-0.01% of lithium salt and 50-70% of water, and the percentage sum of all constituents is 100%. With the lithium ion battery negative electrode disclosed by the invention, the irreversible capacity loss of the battery can be effectively reduced, and the energy density of the battery is improved. The invention also provides a preparation method of the lithium ion battery negative electrode for reducing the irreversible capacity loss. The process step is simple, and the method is high in operability, is easy to implement, and can be completely applied to industrial production of a lithium ion battery at a large scale.

The invention belongs to the field of electrochemistry and particularly relates to a high-capacity lithium-enriched positive electrode material and a reparation method thereof. The molecular formula of the high-capacity lithium-enriched positive electrode material is Li[Li<x-beta>Na<beta>Mn<1-y-z-alpha>Co<y>Ni<z>Y<alpha>]O2, wherein x is more than or equal to 0 and less than or equal to 0.6, y is more than 0 and less than or equal to 0.4, z is more than 0 and less than or equal to 0.4, alpha is more than or equal to 0 and less than or equal to 0.1 and beta is more than or equal to 0 and less than or equal to 0.2; the result of (1-y-z-alpha) is more than 0 and the result of (x-beta) is more than 0. The lithium-enriched positive electrode material containing Na and Y has the characteristics of low first-time irreversible capacity, large electrochemical capacity, high cycling stability, excellent rate performance and the like. The preparation method has the advantages that a preparation process is simple, raw materials are cheap and easily available, the cost is low, the high-temperature calcination time is very short, the repeatability is good and the industrialization is easy to realize.

The invention relates to a method for preparing a high-capacity long-life lithium ion battery lithium manganate cathode material and belongs to the technical field of material synthesis. The method comprises the following steps: 1, weighing out one or more lithium sources, a manganese salt and one or more doped trace metal elements for uniformly mixing, preburning for 2-6 hours at 400-600 DEG C, calcining for 6-16 hours at 700-1000 DEG C, removing tiny particles in a grading mode, and magnetically adsorbing metal ions to obtain lithium manganate or primary doped lithium manganate; 2, secondarily doping the lithium sources into the lithium manganate or primary doped lithium manganate obtained by the step 1 for uniformly mixing; 3, calcining the mixture for 3-8 hours at 600-850 DEG C to obtain a primary or secondary doped calcined lithium manganate material. According to the method, as active materials are introduced for two times, the diffusion rate of Li+ is effectively increased, the irreversible capacity loss is reduced, the reversible specific capacity of the cathode material is increased, and the cycling stability of the cathode material is improved. The process is simple, the high-temperature performance is improved obviously and reliably, and the prepared lithium manganate material has high capacity and good high-temperature cycle performance.

The invention belongs to the technical field of lithium ion battery material manufacturing process and discloses a Ce1-xZrxO2 nano solid solution homogenate modified lithium ion battery anode material and a preparation method thereof. A LiNixCoyM(1-x-y)O2 material preparation process includes: forming a coating of a nanoscale metal oxide according to a homogeneous precipitation method, wherein the nanoscale metal oxide refers to Ce1-xZrxO2 nano solid solution; after coating is finished, drying the coating, heating to 200-1000 DEG C at a heating temperature of 1-5DEG C/min, keeping the temperature for 2-20h, and naturally cooling to obtain the Ce1-xZrxO2 nano solid solution homogenate modified LiNixCoyM(1-x-y)O2 material. The prepared LiNixCoyM(1-x-y)O2 material has excellent high-temperature cycle performance and electrochemical interface stability. Compared with a traditional solid-phase method, the modification method is high in uniformity and reliability.

The invention discloses a doping method of a lithium-rich layered oxide positive electrode material, the material and a preparation method. The method comprises the steps of partially substituting lithium ions Li<+> of a lithium layer in a lithium-rich layered oxide by divalent positive ions Mn<+> and above to obtain the lithium-rich layered oxide positive electrode material containing a doping element.

The invention relates to the technical field of anode material for a lithium ion battery, and in particular relates to a method for modifying the surface of anode material Li1.2Ni0.13Co0.13Mn0.54O2 for the lithium ion battery. The method comprises the following steps: A. preparing lithium-rich anode material Li1.2Ni0.13Co0.13Mn0.54O2 powder; B. dispersing the Li1.2Ni0.13Co0.13Mn0.54O2 powder prepared in the step A into a solution of samarium nitrate and cerium nitrate; carrying out ultrasonic treatment, magnetic stirring, evaporation, drying and calcination treatment to obtain coated anode surface modification material Li1.2Ni0.13Co0.13Mn0.54O2 @ samarium-doped cerium oxide (SDC) with different SDC mass fractions. After the surface modification method is used, all the electrical properties of the lithium anode material can be comprehensively improved, namely, the first-time irreversible capacity of the material is reduced, the specific discharge capacity is increased, and the rate capability is improved; furthermore, the method is simple in technology, easy to operate, low in cost and environment-friendly, thus being suitable for large-scale industrial production.

The invention discloses an electrolyte, a preparation method thereof, a high-energy-density lithium ion battery containing the electrolyte and a preparation method thereof. The electrolyte comprises alithium salt, a non-aqueous organic solvent, a negative electrode film-forming organic additive and a modified additive. The negative electrode film-forming organic additive is any one or at least two of fluoroethylene carbonate, 1, 2-difluoroethylene carbonate, chloroethylene carbonate and vinylene carbonate, and the modified additive is any one or at least two of potassium carbonate, sodium carbonate and lithium carbonate. The electrolyte provided by the invention can quickly form a layer of compact, stable and thin SEI film with good mechanical properties on the surfaces of negative electrode material particles. The high-energy-density lithium ion battery containing the electrolyte can relieve the problems of lithium battery capacity attenuation, particle pulverization and the like caused by volume expansion of a silicon-based negative electrode in the recycling process, and has good cycling stability and rate capability.

The invention provides a preparation method of a carbon/carbon nanotube coated lithium iron phosphate composite material by in situ synthesis, and relates to the technical field of battery materials. The preparation method provided by the invention comprises the steps of weighing raw materials of a lithium source, iron powder, a phosphate and a carbon source; first performing ball-milling on the iron powder and the phosphate and adding hydrogen peroxide; and then adding the lithium source and the carbon source to obtain a slurry, drying and sintering under the protection of reducing/inert gas to obtain the composite material. According to the preparation method provided by the invention, the carbon/carbon nanotube coated lithium iron phosphate composite material is prepared by employing an in-situ synthesis method, so the heat treatment time is short; the composite material has relatively high carbon coating rate, stable electrochemical property and relatively good consistency, the cycle performance and the rate performance are greatly improved, the whole preparation process is simple, and the preparation method has the advantages of safety, high efficiency, low cost and environmental protection, etc.

The invention belongs to the technical field of lithium ion battery anode materials, and discloses a surface-modified lithium-rich layered transition metal oxide as well as a preparation method and application thereof. The surface-modified lithium-rich layered transition metal oxide is prepared by the following steps that: a transition metal compound precursor, a lithium source and molten salt aremixed, and an obtained mixture is heated to 780-980 DEG C, is cooled to room temperature, cleaning, filtering and drying are performed, so that a lithium-rich layered transition metal oxide can be obtained; and the lithium-rich layered transition metal oxide is uniformly mixed with a carbon-nitrogen source, the mixture is placed in a protective atmosphere so as to be subjected to a hydrothermal reaction at 130-230 DEG C, an obtained product naturally cools, water washing, suction filtration, and drying are performed, so that the surface-modified lithium-rich layered transition metal oxide canbe obtained. The structure of the surface-modified lithium-rich layered transition metal oxide sequentially comprises the lithium-rich layered transition metal oxide, an oxygen vacancy-rich lithium-rich layered transition metal oxide-spinel structure oxide symbiotic layer and a nitrogen-doped carbon nano layer. The surface-modified lithium-rich layered transition metal oxide shows relatively highspecific discharge capacity and cycling stability as an anode material.

The invention discloses a graphite-based composite material and a preparation method thereof and a lithium ion battery comprising the composite material. The method disclosed by the invention comprises the following steps: 1) uniformly mixing activated natural graphite and asphalt according to a proportion, adding to a fusion machine, charging inert gas and carrying out fusion and granulation under a certain temperature; and 2) carrying out carbonization treatment or graphitization treatment on a fusion and granulation product to obtain the graphite-based composite material. The battery which is assembled and whose negative electrode is prepared by adopting the graphite-based composite material has high capacity, and good rate capability and cycle performance; the initial lithium removal specific capacity is 360.1mAh/g or more, and the initial efficiency is 91.5% or more; and the room temperature charge-discharge cycles of the finished product battery is 300 weeks and the capacity retention rate is greater than 90%.

The invention belongs to the technical field of lithium-ion batteries, and in particular relates to a preparation method for a negative electrode material of the lithium-ion battery. The preparation method comprises the steps of ball-milling fine powder of artificial graphite wastes, SiO particles and organic carbon sources, thus acquiring mixed powder; then mixing the mixed powder with nitrogen-containing compounds; and nitriding in the atmosphere of protective gases at high temperatures of 300-1200 DEG C, thus acquiring the negative electrode material of the lithium-ion battery. According to the preparation method provided by the invention, the artificial graphite wastes can be better utilized for recycling, oxygen-containing functional groups on the surfaces of the artificial graphite wastes can be removed by nitrogen treatment, and primary coulombic efficiency, cycling stability and reversible capacity of the artificial graphite wastes can be improved. In addition, due to the mixture of silicon monoxide and the artificial graphite, both advantages can be integrated and both disadvantages can be weakened, and then the negative electrode material of the lithium-ion battery with high coulombic efficiency, good cycling performance, high capacity, high power and relatively small expansion can be acquired for the first time via effective coverage.

The invention discloses a preparation method of a lithium ion battery negative electrode for reducing irreversible capacity loss. The preparation method mainly comprises the following steps of (1) weighing a negative electrode active substance, a conductive agent, a binding agent, a surfactant, a lithium salt and water, and then dissolving the lithium salt in the water accounting for 10-20% of total water to obtain a lithium salt solution for use; (2) uniformly mixing the surfactant and the remaining water, and then adding and uniformly dispersing the conductive agent to form a conductive adhesive; (3) adding and dispersing the negative electrode active substance in the conductive adhesive, adding the binding agent, uniformly stirring, and then carrying out vacuum defoaming to obtain a negative electrode paste; and (4) uniformly applying the negative electrode paste onto the surface of the negative electrode current collector, uniformly spraying the lithium salt solution, and drying the lithium salt solution to obtain the lithium ion battery negative electrode. The process step is simple, the device requirement is low, the operability is high, the irreversible capacity loss of a battery can be effectively reduced, the energy density of the battery is enhanced, and the preparation method can be completely applied to industrial production of the lithium ion battery at a large scale.

The invention discloses a surface in-situ coated lithium-enriched material. Raw materials comprise a coating layer and a lithium-enriched material precursor, the raw material of the coating layer is a compound of a metal Me, the lithium-enriched material precursor is a mixture of at least one of oxide of MnMA, hydroxide, carbonate and oxalate and a lithium source, wherein Me and M are metal elements; and A is at least one of S, P, B and F. The invention further discloses a preparation method. A metal compound coats lithium-enriched material precursor particles, and then the lithium-enriched material precursor particles are sintered at high temperature to form a lithium-enriched material of which the surface is coated with spinel-containing oxide. The surface in-situ coated lithium-enriched material has the advantages that the surface stability and the conductivity of the surface in-situ coated lithium-enriched material are greatly improved, and therefore, the charging-discharging specific capacity, the efficiency, the multiplying power and the circling performance of the material are obvious improved. The surface in-situ coated lithium-enriched material is simple in preparation process, low in cost, good in result reproducibility and suitable for large-scale popularization.

The invention discloses a modification method of a cerium-tin compound oxide coated lithium-rich manganese-based positive material. The body of the material is a lithium-rich manganese-based positivematerial, and the surface coated substance of the material is a cerium-tin compound oxide material containing rich oxygen defects. The modification method comprises the following preparation steps: (1) dispersing the lithium-rich manganese-based positive material into a secondary water solvent, and forming a uniform mixed solution through ultrasonic oscillation to be marked as an A solution; (2) dispersing a metal salt containing Sn and Ce elements into the secondary water solvent, adding an alkaline source to adjust the pH of the solution to be 12, and marking the solution to be a B solution;(3) after uniformly mixing the A solution and the B solution, putting the mixture into water at the temperature of 140 to 220 DEG C inside a reaction still for heat treatment for 12 to 36 h, and washing, filtering and drying to obtain a precursor material; and (4) after sufficiently grinding the precursor material, carrying out calcinations at the temperature of 450 to 650 DEG C for 3 to 10 h, and cooling to room temperature so as to obtain the cerium-tin compound oxide coated lithium-rich manganese-based positive material. According to the method, the surface coating for the lithium-rich manganese-based positive material is realized through hydro-thermal treatment, the preparation technology is simple, and the obtained material is high in degree of crystallinity, high in capacity and good in rate capability.

The invention relates to a sodium-ion battery carbon negative electrode material prepared based on waste wood chips and a preparation method thereof. Waste wood chips are used as a biomass carbon source and subjected to pre-carbonization and low-heating-rate high-temperature carbonization treatment, metal heteroatoms are removed by washing with an acid pickling solution, and drying is performed to obtain a hard carbon sodium-ion battery negative electrode material. The waste wood chips are used as a biomass raw material, a large amount of chips generated in the production process of wood products can be fully utilized, and the material has the advantages of being environmentally friendly, low in cost and the like. A low-carbonization heating rate pyrolysis method is adopted, so that the effects of reducing defect concentration, increasing interlayer spacing and improving graphitization degree are achieved, and the electrochemical performance of the material is effectively improved. The hard carbon negative electrode material prepared by the method has relatively high first coulombic efficiency and reversible specific capacity, shows excellent cycling stability and rate capability, and is an ideal sodium-ion battery negative electrode material.