175results about How to "Improve capacity play" patented technology

The invention discloses a modified composite material containing silicon-base material, a preparation method thereof, and an application thereof in a lithium ion battery. The composite material includes a silicon-base core and a modifying layer covering same. The modifying layer includes a polymer covering film and a nano-conductive material embedded therein. The modified composite material not only can isolate an electrolyte to inhibit side reactions of the electrolyte on the surface of the material, thus improving overall performance of the battery, but also can improve electric conductivityand improve structural stability due to the unique structure by embedding the nano-conductive material in the polymer. Tension is absorbed by means of deformation, so that problems of breaking and pulverization and stripping of the electrode during processing and use of the silicon-base negative material are solved. The problems of pulverization and stripping of the electrode due to large expansion during charge/discharge processes of the silicon-base material are solved, thus stabilizing the structure of the electrode and improving cycle performance of the cell.

The invention discloses a high-nickel ternary lithium ion power battery electrolyte and a high-nickel ternary lithium ion power battery. The electrolyte includes a non-aqueous organic solvent, a lithium salt, a conductive additive, a film forming additive and an infiltration additive, wherein the conductive additive is lithium difluorophosphate, the film forming additive is ethylene sulfate, and the infiltration additive is at least one of fluorophosphazene and fluoroethylene carbonate; and synergism and mutual promotion of the three additives makes an excellent SEI film be formed on the surface of an electrode and effectively promotes all dynamic processes in the lithium ion battery. The power battery electrolyte has the advantages of good lithium ion transmission characteristic, good oxidation resistance, guaranteeing of high power characteristic and good cycle performances of the power battery, and high safety.

The invention discloses a modified composite material containing a silicon base material, which comprises a silicon base core and a polymer cladding layer covering the surface of the core, and a preparation method and use thereof in a lithium ion battery. The method comprises the steps of : 1) adding a polymer into a liquid solvent and dispersing to obtain a slurry; 2) adding a silicon-based material or a mixture of that silicon-based material and the carbon material into the slurry and mixing the solid and liquid; 3) removing the solvent to obtain a modified composite material containing a silicon-based material. As the polymer coat layer is introduced on the surface of the silicon base core, so that the electrolyte can be isolated and the side reaction of the electrolyte on the surface of the silicon base core can be prevented; the method can also improve the crushing, electrode pulverization and peeling of the silicon-based negative electrode material in the process of processing and using, and reduce the electrode crushing and peeling caused by the huge volume expansion of the silicon-based material in the process of charging and discharging, so as to achieve the purpose of stabilizing the electrode structure and improving the cell cycle performance.

The present invention provides a battery positive electrode and a preparation method thereof, and a lithium ion secondary battery. The positive electrode comprises a conductive substrate and a material layer coated on the conductive substrate surface, wherein the material layer comprises a first conductive material layer attached on the conductive substrate, a first active material layer attached on the first conductive material layer, a second conductive material layer attached on the first active material layer, and a second active material layer attached on the second conductive material layer, and the compact density of the second active material layer is lower than the compact density of the first active material layer. According to the present invention, characteristics of excellent pore size distribution, good electrolyte infiltration and material shedding resistance are provided, and the prepared battery has characteristics of good cycle performance, low internal resistance, excellent rate capability, excellent high temperature storage performance and high energy density.

The invention discloses an organic-inorganic composite solid electrolyte. The solid electrolyte is characterized by being prepared from an acrylate material, lithium salt, a crosslinking agent, an initiator, a plasticizer, a fast ionic conductor and a porous rigid support material. The preparation method of the inorganic composite solid electrolyte is characterized by comprising steps as follows:mixing the acrylate material with the lithium salt to completely dissolve the lithium salt in acrylate; adding the crosslinking agent and the plasticizer to the mixed solution, and stirring the mixture evenly; adding the fast ionic conductor to the mixed solution, and performing ultrasonic treatment or stirring to disperse the conductor uniformly; adding the initiator to the mixed solution, and performing stirring uniformly; uniformly pouring the mixed solution on the porous rigid support material; performing heating initiation at 60-100 DEG C to enable the acrylate material to be copolymerized with the crosslinking agent to obtain the organic-inorganic composite solid electrolyte. The solid electrolyte has the advantages that the preparation method is simple, the production efficiency ishigh, and the assembled solid lithium battery has lower impedance and higher capacity.

The invention discloses a lithium ion battery formation method. A negative electrode active substance of a lithium ion battery comprises a lithium-rich manganese-based positive electrode material. Theformation method includes at least three times of charge-discharge cycles; in the two former charge-discharge cycles, charge cut-off voltage is lower than 4.4V, discharge current is higher than charge current, and the second-time charge current is higher than the first-time charge current; in the last charge-discharge cycle, the charge cut-off voltage is not lower than 4.4V, and the charge current is not lower than the second-time charge current. By the step voltage charge-discharge formation method, a stable SEI film can be formed on the surface of a negative electrode in repeated low-voltage charge-discharge processes while a stable CEI film is formed on the surface of a positive electrode, side reaction between electrolyte and an electrode piece can be inhibited, gas generation is reduced, and accordingly the problem of battery swelling is solved. In addition, by the method, structural stability and capacity exertion of the lithium-rich manganese-based positive electrode material under a high voltage can be improved, and the cycle performance and the energy density of the battery are improved as well.

A preparation method of a high-capacity monocrystalline type ternary cathode material comprises steps as follows: S1, a nickel cobalt manganese hydroxide precursor of a core-shell structure is prepared with a coprecipitation method, a loose and porous core is prepared by intermittently introducing a certain quantity of bicarbonate at the initial stage of core making, after core making ends, and loose flaky shells are prepared by substantially reducing the rotation speed and increasing pH; meanwhile, at the core-shell transition stage, a dispersant is added to effectively prevent agglomerationof the shells due to decrease of the rotation speed; S2, the prepared precursor and lithium salt are mixed and calcined once in the oxygen-rich atmosphere at the high temperature, and the monocrystalline type ternary cathode material is obtained. A battery is prepared from the ternary cathode material and has high capacity and good safety performance due to high lithium ion transport efficiency and reduced anisotropy in crystals. The problem of poor capacity of the material because of low lithium ion transport efficiency of monocrystalline type ternary materials is effectively solved. Besides,the monocrystalline type ternary cathode material is prepared through one-time sintering, the preparation procedure is simple, and the production cost is low.

The invention discloses a graphite material at the negative pole of a lithium ion battery, which comprises interphase graphite and artificial graphite in mass ratio of 90:10 to 20:80. The graphite material has the advantages of highly compacted density, small specific surface area, high discharge capacity, long circulating life, high charge-discharge efficiency and high product performance-price ratio. The invention also provides a method for preparing the graphite material, which has the advantages of simple, convenient and feasible technology, wide raw material sources and lower cost.

The invention discloses a carbon coated sodium manganese pyrophosphate@graphene oxide composite material with a sandwich structure, as well as a preparation method and application thereof. The composite material is formed by stacking graphene oxide sheets, wherein carbon coated sodium manganese pyrophosphate particles are uniformly distributed on the surfaces of the graphene oxide sheets. The preparation method comprises the following steps: adding the graphene oxide into an aqueous solution in which a phosphorus source, a sodium source, a manganese source and a complexing agent are dissolved, and performing ultrasonic treatment, liquid nitrogen freezing and freeze drying sequentially to obtain a precursor; putting the precursor under protective atmosphere and performing heat treatment to obtain the carbon coated sodium manganese pyrophosphate@graphene oxide composite material with the sandwich structure. The carbon coated sodium manganese pyrophosphate@graphene oxide composite material serving as a sodium ion battery positive electrode material has excellent electrochemical property; the 'Na-Mn-P-O' system resource is rich, and the cost is low; the preparation method is simple to operate, and the commercial application prospect is wide.

The invention provides a three-dimensional mixed conductive adhesive used for lithium battery, and a battery containing the adhesive. The adhesive contains a carbon nanotube, a graphene and a polymerhaving a chemical bonding effect with the carbon nanotube and the graphene. The carbon nanotube and the graphene in the adhesive are mixed according to a certain proportion to form a three-dimensionalconductive network; polymer groups and groups on the graphene carbon nanotube are effectively combined to improve the intensity of the compound; and the compound is perfectly dispersed when the electrode slurry is prepared. During the charging-discharging process, the three-dimensional compound conductive adhesive is capable of better controlling the expansion and the shrinkage of the active material of the electrode plate, and effectively improves the cycling stability and the rate capability of high-capacity high-volume-change type electrode material, such as the silicon-based cathode material, the tin-based cathode material, and the high-volume-change type electrode material that can be expanded into the new battery system in the future.

The invention relates to the field of batteries, and in particular relates to a long-life, high-energy density and low-cost mixed cathode material for lithium ion secondary batteries and a preparation method thereof. The mixed cathode material for the lithium ion batteries, provided by the invention, comprises the following raw components in percentage by weight: 20-60% of doped lithium-manganese spinel composite oxide and 40-80% of doped lithium-nickel-cobalt-manganese composite oxide. According to the mixed cathode material for the lithium ion batteries, provided by the invention, proper doping is carried out on lithium-manganese spinel to ensure that the lattice imperfection can be effectively reduced, the crystal structure is stabilized, the lattice distortion is restrained, the manganese dissolution is reduced, the cycle life is prolonged, the large current charge-discharge property and safety performance can be improved so as to satisfy the important requirements on the lithium ion batteries for EV (Electric Vehicles) and HEV (Hybrid Electric Vehicles); for the lithium-nickel-cobalt-manganese composite oxide of a layered structure, the doping has the same effect and the cycle performance, the rate performance and the safety performance can be better improved.

In order to solve the problem that electrolyte in the prior art difficultly takes into account the electrochemical properties of flame retardant properties, circulation and the like, the invention relates to electrolyte with flame retardant functions and capability of improving cyclic properties for a lithium ion battery. The electrolyte is prepared from a non-aqueous organic solvent, lithium saltand an additive; the additive is prepared from a phosphonitrile compound, perfluorinated hexanone and a perfluoroalkyl ether compound. By using the electrolyte for the lithium ion battery, disclosedby the invention, the lithium ion battery has the advantages of superior normal temperature and high temperature cycle performance, no inflation under high temperature storage conditions, small internal resistance change and capability of realizing the aims of improving the circulation and taking the flame retardant effect into account.

The invention relates to an aqueous binder. The aqueous binder is characterized in that the aqueous binder is emulsion contains emulsion particles of a core-shell structure, the core of each emulsion particle of the core-shell structure contains fluorine-containing polymer A and fluoride-free oleophylic polar polymer B, a shell of each emulsion particle of the core-shell structure contains hydrophilic polymer M, and the solid content of the emulsion particles of the core-shell structure in the emulsion is 5-50 wt%. An electrode slice prepared with the aqueous binder is applied to a lithium ion battery, the capacity of the lithium ion battery can be highly brought into play, the adhering performance of an interface between the electrode slice and an isolating membrane is good, and the cycle life of the cell is long; the isolating membrane treated with the aqueous binder is high in ionic conductivity and can be firmly adhere to the electrode slice.

The invention discloses a positive electrode active material precursor and a preparation method thereof, and a positive electrode active material. The positive electrode active material precursor comprises secondary particles formed by aggregation of a plurality of primary particles, each secondary particle comprises an internal area and an external area coating the external side of the internal area, the density of the internal area is smaller than that of the external area, and the density of the external area is gradually increased from inside to outside. According to the positive electrodeactive material precursor of the invention, the positive electrode active material adopting the positive electrode active material precursor has high initial charge specific capacity, initial discharge specific capacity, initial coulombic efficiency and cycle performance, so that the lithium ion secondary battery can have high initial charge specific capacity, initial discharge specific capacity,initial coulombic efficiency and cycle performance at the same time.

The invention discloses a formation method for a lithium ion battery. The method comprises the steps of carrying out formation on the lithium ion battery, after the lithium ion battery is filled with an electrolyte and is subjected to standing, at a temperature of 35-55 DEG C by 0.01-0.5C charging current under a vacuum-pumping condition. The method adopts high-temperature negative pressure for realizing formation; the exhaust gas generated from the internal of the battery in the formation process is exhausted in time; a uniform and stable SEI film is formed on the negative electrode of the lithium ion battery at a high-temperature environment; the battery processed by the formation method has the advantages of high capacity volatilization of active materials, low internal resistance, low expansion rate, long cycle life and long storage life, so that the product quality is improved, and the service life of the battery is prolonged; and meanwhile, the method has the advantages of short formation time, high equipment utilization ratio and low energy consumption, so that the method is an efficient formation method suitable for batch production of the lithium ion batteries.

The invention protects a formation process for a high-energy-density flexibly-packaged power lithium-ion battery. The process comprises the steps that liquid is injected into a cell, the cell stands,pre-edge-sealing is performed, and the cell is vertically placed into a pressure fixture; the surface of the cell is pressurized, a certain temperature is set, primary charging is performed on the cell, and pressure, temperature and charging currents are set in a stepped mode; after charging is completed, primary second-sealing is performed, and meanwhile air is pumped while a certain vacuum degree is maintained; and standing, secondary pressurization, normal-temperature charging and secondary second-sealing are performed. According to the formation process, the high-temperature pressurizationformation process is adopted, and compared with normal-temperature normal-pressure formation, sufficient wettability of an electrolyte and an anode/cathode active material is improved, and an electrochemical reaction is benefited; in the last step of primary formation, formation pressure is raised, formation temperature is lowered, the uniformity, compactness and stability of an SEI film generated on the surface of a cathode are improved, generation of a thick interface film is avoided, and internal resistance is lowered; and capacity performance of the cell is enhanced.

The invention discloses a method for preparing a polymer gel electrolyte cell. The method comprises the following steps of: (1) polymer powder pretreatment: performing high-speed ball-milling on a polymer powder body, and thus obtaining powder with the granularity less than 1 mu m; (2) polymer powder dispersion: mixing the polymer powder which is obtained by ball-milling in the step (1) with a non-aqueous solvent, lithium salt and an additive to prepare sub-micron-sized polymer suspended dispersion liquid; and (3) electrolyte gelatinization: injecting the polymer suspended dispersion liquid which is prepared in the step (2) into a lithium ion cell for full immersion, gelatinizing at high temperature for 1 to 12 hours, and cooling to obtain the polymer gel electrolyte cell. Compared with the prior art, the polymer gel electrolyte cell prepared by using the method is high in ionic conductivity, low in battery internal resistance, long in cycle life, high in high-temperature performance, high in safety performance and free from liquid leakage risk. The polymer gel electrolyte cell is obviously superior to an electrolyte cell prepared by using a conventional preparation method in terms of comprehensive performance.

The invention relates to a lithium metal negative electrode, a preparation thereof and application of the lithium metal negative electrode. According to the lithium metal negative electrode, lithium metal is taken as a substrate; the surface, facing a positive electrode, of the substrate is sequentially coated with a solid lithium salt layer and a polymer electrolyte layer. When the lithium metalnegative electrode is applied to a lithium metal battery, an electrolyte system in which lithium ion concentration from a positive electrode to the negative electrode is in low-to-high gradient distribution can be formed. With the electrolyte with lithium ions in gradient distribution adopted, the problems of low ionic conductivity and high interface contact impedance in a solid electrolyte can beeffectively solved, and the problem of poor stability of an SEI film in a liquid electrolyte can be also solved; lithium dendritic crystal growth can be inhibited; and the cycling stability of a lithium battery can be improved. The electrolyte has important practical application value.

The invention discloses a composite cathode material of a low-temperature lithium ion battery, a cathode plate of the low-temperature lithium ion battery, a preparation method thereof, and a lithium ion battery. The composite cathode material is composed of lithium iron phosphate, a carbon nano tube/polypropylene composite material, carbon nanofibres and a lithium containing compound, wherein the mass ratio of lithium iron phosphate, the carbon nano tube/polypropylene composite material, carbon nanofibres to the lithium containing compound is (90-94):(1-2):(1-2):(0.5-1). The composite cathode material of the low-temperature lithium ion battery provided by the invention is capable of effectively supplying lithium ions consumed for formation of an SEI film in a process of charging and discharging the lithium ion battery, and providing more lithium ions for the lithium ion battery in a low-temperature charging, discharging and cycling process; the low-temperature performance and the cycle performance of the lithium ion battery are improved; due to the composite cathode material of the low-temperature lithium ion battery provided by the invention, the first-time discharging efficiency of the lithium ion battery can be increased; capacity playing of active substances is promoted; and thus, the energy density of the lithium ion battery is increased.

The invention provides a formation method of a lithium-ion battery. The formation method comprises the following steps of (A) carrying out liquid injection of the lithium-ion battery, standing at roomtemperature for 12-24h and then standing at 40-45 DEG C for 8-20h; (B) charging the battery at the current of 0.01-0.03C until the voltage is 3.5-3.8V, and keeping the environment temperature at 5-15DEG C; (C) charging the battery at the current of 0.03-0.06C until the voltage is 3.8-4.35V and keeping the environment temperature at 20-30 DEG C; (D) charging the battery at the current of 0.06-0.15C until the voltage is 4.55-4.65V, charging the battery at constant voltage of 4.55-4.65V until the current is smaller than or equal to 0.02C and keeping the environment temperature at 20-30 DEG C; and (E) carrying out high-temperature ageing. According to the formation method of the lithium-ion battery, the internal resistance of the battery can be effectively reduced, the cycle performance of the battery is improved and the energy density of the battery is improved.

A lithium primary battery comprise TiNbxO2 (2 +2. 5x) core and graphene coating layer, lithium primary battery and preparation method thereof, wherein that mass fraction of the graphene coating layeris 0.01%-5% wt%, where x is 1.8-2.3. A manufacture method comprises mix a titanium source and a niobium source, and sintering to obtain a TiNbxO2 (2 +2.5 x) material; TiNbxO (2 + 2.5 x) was mixed withgraphene or graphene precursor and sintered to obtain graphene-coated titanium niobium oxide composite electrode material. The primary lithium battery uses the graphene-coated titanium niobium oxidecomposite electrode material as the positive electrode active material and the lithium as the negative electrode active material. The TiNbxO_(2 +2.5 x) composite electrode material utilizes the high lithium storage capacity of TiNbxO (2 +2.5 x) and the good conductivity of graphene, and adopts the graphene-coated TiNbxO (2 +2.5 x) material, which greatly improves the gram capacity exertion and magnification performance of the material. The preparation method is simple and the cost is low. The lithium primary battery has high energy density, high safety and reliability, and has the characteristics of large current pulse.