Lithium-ion battery and manufacturing method thereof

Abstract

The invention discloses a lithium-ion battery and a manufacturing method thereof. The lithium-ion battery comprises a battery casing, a pole core and electrolyte, wherein the pole core and the electrolyte are accommodated in the battery casing in a sealed manner; the pole core consists of a positive pole, a negative pole and a septum layer located between the positive pole and the negative pole; the negative pole comprises a current collector and a negative sizing material coated on the current collector and made from a carbon silicon composite negative material; the carbon source of the carbon silicon composite negative material is an amphiphilic carbon material, and the carbon source is crystalline silicon with a particle size of 3-10 nm; the carbon silicon composite negative material adopts a core-shell structure with a carbon shell and a silicon core, the particle size is 30-50 nm, and the sophericity is 50-80 percent; and the specific capacity of the carbon silicon composite negative material is 503-1,028 mAh / g, and a 100-cycles capacity conservation rate is more than or equal to 85 percent. The lithium-ion battery manufactured by adopting the manufacturing method is high in battery specific capacity and low in cost, has the characteristics of high energy density and excellent multiplying factor, and is good in low-temperature performance.

Description

technical field [0001] The invention relates to a lithium ion battery and a preparation method thereof, belonging to the technical field of lithium ion batteries. Background technique [0002] Lithium-ion secondary batteries have high energy density, high working voltage, long cycle life, no pollution, and good safety performance, making them widely used in portable electronic devices, electric vehicles, large-scale energy storage, space technology, and national defense industries. The application prospect has become a research hotspot during the "Twelfth Five-Year Plan" period. [0003] One of the key technologies of lithium-ion batteries lies in the research on negative electrode materials, so as to improve the performance of batteries. Graphite material has the characteristics of good conductivity, high crystallinity, low price, and high safety. It is currently the most important negative electrode material in the production of commercial lithium-ion batteries. However,...

AI Technical Summary

Problems solved by technology

[0010] The above material is a single carbon negative electrode material. Due to the capacity bottleneck of the carbon material, the further improvement of the specific capacity of the material is limited.