Hard carbon material for power and energy-storage battery and preparation method thereof

Abstract

The invention discloses a hard carbon material for a power and energy-storage battery and a preparation method thereof, and aims to solve the technical problem of improving high-rate charge-discharge performance of lithium-ion batteries. The material is provided with a hard carbon matrix, and a coating is coated outside the hard carbon matrix; and the surface of the hard carbon matrix has a honeycomb opening structure. The preparation method comprises the following steps of: dipping, washing, dewatering and drying, presintering at low temperature, crushing, pyrolyzing, crushing and coating. Compared with the prior art, the hard carbon material has the reversible specific capacity of more than 450mAh / g, the first cycle columbic efficiency of over 81 percent, 0.2C 300-cycles capacity-retaining rate of over 97 percent at the temperature of 60 DEG C, and the 0.2C 300-cycles capacity-retaining rate of over 88 percent at the temperature of -30 DEG C, has the advantages of excellent lithium intercalation and deintercalation capability and cycling stability, and simple preparation process, and is applicable to the lithium ion battery cathode materials for lithium ion power batteries, various portable devices and electric tools.

Description

technical field [0001] The invention relates to a battery negative electrode material and a preparation method thereof, in particular to a lithium ion power battery negative electrode material and a preparation method thereof. Background technique [0002] Since Japan's Sony Corporation commercialized lithium-ion batteries in 1991, lithium-ion batteries have rapidly become popular in mobile phones, miniature cameras, and handheld devices due to their advantages such as high energy density, high operating voltage, good load characteristics, fast charging speed, and safety and pollution-free. Computers, notebook computers and other fields have been widely used. In lithium-ion batteries, the capacity of the negative electrode material is one of the important factors affecting the capacity of the battery. In the prior art, graphite or modified graphite is used as the negative electrode material of the lithium ion battery. However, the theoretical maximum lithium intercalation ...

AI Technical Summary

Problems solved by technology

However, the theoretical maximum lithium intercalation capacity of graphite is only 372mAh / g. Due to the high degree of graphitization and highly oriented graphite layered structure, the graphite material has poor compatibility with organic solvents, and lithium will occur during the first charge and discharge. Co-intercalation with organic solvents, graphite interlayer exfoliation, and graphite particle cracking and pulverization lead to electrode structure damage and reduced charge-discharge cycles

In addition, because the flake structure of graphite only allows lithium ions to be intercalated and extracted along the boundaries of graphite crystals, the reaction area is small and the diffusion path is long, so it is not suitable for high-rate charge and discharge.

The theoretical lithium intercalation capacity of graphite is low, so it is not suitable as an anode material for ultra-high energy storage

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