High-rate spherical hard carbon composite material and preparation method thereof

Abstract

The invention discloses a high-magnification spherical hard carbon composite material and a preparation method thereof, the high-magnification spherical hard carbon composite material has a core-shell structure, the core is a high-magnification spherical secondary particle hard carbon material, the shell is an inorganic lithium salt coating material, and the shell and the core are connected through a coupling agent. The preparation method of the high-magnification spherical hard carbon composite material comprises the following steps: preparing the high-magnification spherical secondary particle hard carbon material, wherein the high-magnification spherical secondary particle hard carbon material is obtained by mixing a high-magnification spherical secondary particle hard carbon precursor and a coupling agent; the high-rate spherical secondary particle hard carbon material is subjected to cyclic deposition of an inorganic lithium salt under the conditions that the pressure is 0.1-0.5 Torr and the temperature is 150-250 DEG C; and forming an inorganic lithium salt deposition layer with uniform thickness on the surface of the high-magnification spherical secondary particle hard carbon material layer by layer, and cooling to room temperature after completing circulating deposition to obtain the high-magnification spherical hard carbon composite material.

Description

technical field [0001] The invention belongs to the field of lithium ion battery material preparation, in particular to a high-rate spherical hard carbon composite material and a preparation method thereof. Background technique [0002] With the improvement of the fast charging performance, low temperature performance and life expectancy of lithium ion batteries, the anode materials used in lithium ion batteries are required to have high specific capacity, low temperature performance and large interlayer spacing. Hard carbon is a kind of amorphous carbon that is difficult to graphitize, and the interlayer spacing is larger than that of graphite negative electrode, and it has good fast charge and discharge performance, especially excellent low temperature charge and discharge performance. [0003] However, due to the high specific surface area of ​​hard carbon and the porous structure of the material itself, the first efficiency of the material is low and the specific capacit...

AI Technical Summary

Problems solved by technology

[0003] However, due to the high specific surface area of ​​hard carbon and the porous structure of the material itself, the initial efficiency and specific capacity of the material are low.

One of the measures to improve the first-time efficiency of hard carbon materials is to do material doping, which improves the specific capacity and first-time efficiency of the material, but the voltage platform of the material will increase, which will affect the improvement of its energy density; on the other hand, material packaging Coating improves the initial efficiency of the material, but the dynamic performance of the material decreases after coating

[0004] For example, patent CN102820455A discloses a lithium-ion battery hard carbon negative electrode material and its preparation method. The hard carbon negative electrode material is doped with silicon and phosphorus, which improves the specific capacity of the material, but due to the small layer spacing of silicon and phosphorus materials , little improvement in the rate performance of Li-ion

For example, the patent CN201811546458.1 discloses a negative electrode material for a sodium ion battery and its preparation method. First, the soft carbon is activated and then coated with hard carbon; The defect and edge surface of the material reduce the irreversible capacity loss caused by the intercalation and deintercalation of sodium ions, and effectively improve the first-week Coulombic efficiency; although the first-time efficiency of the material is improved, the kinetic performance of the material is reduced

Images