4results about How to "Reduce irreversible capacity" patented technology

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 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.

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.