11results about How to "Reduce irreversible capacity" patented technology

The invention relates to a negative electrode material and a preparation method thereof, a negative electrode plate, a battery and an electronic device. The preparation method of the negative electrode material comprises the following steps: dissolving a hard carbon precursor in a first solvent, and carrying out a hydrothermal reaction to obtain an intermediate A; performing heat treatment and acid pickling on the obtained intermediate A in a first protective gas atmosphere to obtain a hard carbon material; and adding 2, 2-dimethyl vinyl boric acid into a second solvent, stirring for the first time, adding the obtained hard carbon material, stirring for the second time, and baking to obtain the negative electrode material. The negative electrode material prepared by the preparation method disclosed by the invention has a stable and compact artificial solid electrolyte interface (SEI) membrane, the irreversible capacity of the material can be remarkably reduced, and the first coulombic efficiency and the capacity retention ratio of the battery are improved.

The invention relates to the technical field of batteries, in particular to a graphite composite material and a preparation method and application thereof. The graphite composite material comprises a base material layer and a coating layer, and the coating layer comprises a first material layer and a second material layer; the base material layer comprises graphite; the first material layer comprises an amorphous carbon material, and the amorphous carbon material is doped with a first nitrogen element; the second material layer comprises a graphite material, and the graphite material has a porous structure and is doped with a second nitrogen element; the concentration of the first nitrogen element is greater than that of the second nitrogen element. According to the graphite composite material, the first material layer can ensure the reversible capacity and the rate capability of the material; the graphitization degree of the carbon material in the second material layer is high, the irreversible capacity can be reduced, the low nitrogen concentration is beneficial to improving the conductivity, and the porous structure can shorten an ion diffusion channel, so that the energy storage capacity and the rate capability are improved.

A chemical pre-lithiation method for improving the initial coulombic efficiency of carbon-based current collectors and its application in lithium metal batteries is disclosed. The method uses a carbonized cellulose film as the current collector, which is obtained by dropwise addition of an active lithium solution under an argon atmosphere until the solution reacts fully. This invention uses 4,4'-dimethylbiphenyllithium as the active lithium species and diphenyl ether and 2-methyltetrahydrofuran as a mixed solvent. By using a high-temperature carbonized cellulose film as the current collector, it is possible to achieve a better promoting effect on the active lithium species while increasing the initial coulombic efficiency to over 100%, greatly compensating for the irreversible capacity loss in the early cycling stages of carbon-based current collectors.

The invention discloses a multilayer electrode preparation method, and relates to the technical field of battery electrode production. The preparation method comprises the following steps: mixing an active material, a conductive agent and a binder to obtain first slurry; adding a pore-forming agent into the first slurry, and mixing to obtain second slurry; coating a current collector with the first slurry to form a first electrode layer; coating the first electrode layer with second slurry to form a second electrode layer; alternately coating and drying the first slurry and the second slurry to form a multi-layer electrode; wherein the multi-layer electrode at least comprises a first electrode layer and a second electrode layer, the active material is a positive electrode active material or a negative electrode active material, the positive electrode active material is a carbon nanotube-copper sulfide composite material, and the second electrode layer is of a porous structure. According to the preparation method of the multi-layer electrode provided by the invention, the lithium ion battery with good cycle performance, slow capacity fading and high charge-discharge efficiency can be obtained.

The present invention provides a silicon-based composite negative electrode material and a preparation method and application thereof, wherein the silicon-based composite negative electrode material comprises pre-lithiated silicon oxide particles and an ion conductor coating layer located on the surface of the pre-lithiated silicon oxide particles. In the present invention, there is a strong binding force between the pre-lithiated silicon oxide particles and the ion conductor coating layer, which effectively stabilizes the structure of the material and achieves high-quality coating of the inner core while achieving pre-lithiation. Pre-lithiation of silicon oxide particles not only reduces the irreversible capacity of the silicon oxide negative electrode in the first cycle, but also improves its first coulombic efficiency; the high-quality ion conductor coating layer not only promotes Li + The transmission of silicon iodine improves the rate performance of silicon iodine negative electrode materials, and also effectively inhibits the side reactions between active materials and electrolytes, thereby improving the cycle stability of silicon iodine negative electrode materials.

The present invention discloses a high first-efficiency silicon oxide-based negative electrode material, comprising a partially lithiated silicon oxide core and composite particles composed of nanosilver coated on the surface of the core, a lithium titanate layer coated on the surface of the composite particles, and a carbon layer coated on the surface of the lithium titanate layer. The present invention also discloses a method for preparing the material. The present invention improves the problems of low conductivity and low first efficiency of silicon oxide materials, designs and constructs a silicon oxide-based negative electrode material with high first efficiency, small volume effect, and high conductivity, and has superior performance.

The application belongs to the technical field of lithium ion battery materials, and particularly relates to a kind of heteroatom doped pitch-based hard carbon composite material and a preparation method thereof, the preparation raw materials of the heteroatom doped pitch-based hard carbon composite material include the following components by weight fraction: 90-100 parts of pitch, 1-10 parts of crosslinking agent, 1-5 parts of heteroatomic compound, 1000-2000 parts of organic solvent, 1-10 parts of coupling agent, 5-20 parts of organic metal compound. The application uses lithium-containing heteroatomic compound to reduce the irreversible capacity loss inside the material, and at the same time, by matching pitch, crosslinking agent, coupling agent and the like, the electronic conductivity, tap density, first efficiency and other properties of the pitch-based hard carbon can be improved.

This invention relates to a graphite anode material with an in-situ grown onion carbon layer structure and its preparation method. The core of the graphite anode material is graphite, and the outer shell is an in-situ grown onion carbon layer with a thickness of 1 nm to 1000 nm; the particle size of the graphite anode material ranges from 500 nm to 100 μm. By growing a complete onion carbon layer on the surface of graphite particles, the embedding of polar molecules in the electrolyte is reduced. Compared to the currently commonly used method of coating amorphous carbon, the onion carbon layer grown on the surface of graphite particles has a smaller specific surface area, resulting in a thinner and more uniform SEI film, which can further reduce irreversible capacity.

The invention discloses a secondary spherical lithium-rich manganese-based positive electrode material as well as a preparation method and application thereof. According to the method disclosed by the invention, the secondary spherical lithium-rich manganese-based positive electrode material with thick-plate-shaped primary particles is prepared by adopting an ion exchange method, and the problems of structure and performance degradation of the lithium-rich manganese-based positive electrode material are relieved by synergistically utilizing a scheme of secondary particle design and lattice design. A test experiment result of a product shows that the secondary spherical lithium-rich manganese-based positive electrode material with thick plate-shaped primary particles prepared by the preparation method has a small specific surface area and high mechanical stability, the energy density and the cycling stability of the material are favorably improved, and the problem of voltage attenuation is solved.

This invention relates to the field of lithium-ion batteries, and more particularly to a negative electrode material for lithium-ion batteries and its preparation method. The invention provides a powdered carbon material with a core-shell structure. The core of this microporous carbon material is coated with a carbon material shell. The core has a particle size of 3-8 μm and contains a large number of micropores with a pore size of 0.001-0.5 nm, accounting for 60-90% of the total pore volume of the core. The remainder consists of micropores with a pore size greater than 0.5 nm-50 nm. The interlayer spacing of the 002 crystal planes constituting the core is 0.39-0.41 nm. The shell has a thickness of 10-1000 nm, preferably 10-200 nm, with a pore size of 0.001-10 nm. The interlayer spacing of the 002 crystal planes constituting the shell is 0.34-0.36 nm. The negative electrode material provided by this invention has a hard carbon structure with a large interlayer spacing, which facilitates the diffusion of lithium ions within it, enabling rapid charging and discharging within the electrode and achieving high-rate performance of the negative electrode material.

The invention discloses a negative electrode additive and a preparation method and application thereof, and the preparation method of the negative electrode additive comprises the following steps: (1) adding a conductive polymer monomer and an organic sodium salt into a solvent, and uniformly mixing to obtain a mixture; and (2) adding an initiator solution into the mixture prepared in the step (1), stirring, filtering, washing and drying to obtain the negative electrode additive. The negative electrode additive prepared by the preparation method is rich in sodium ions and has good conductivity, and a composite material formed by mixing the negative electrode additive with hard carbon can be used as a negative electrode material for constructing a sodium ion battery, so that the capacity and the first coulombic efficiency of the sodium ion battery are effectively improved; and the problem of fast capacity fading of the hard carbon negative electrode in the cycle process can be effectively relieved, so that the cycle stability of the battery is improved.