US-12626908-B2 - Swelling-inhibited silicon-carbon composite anode material with increased capacitance, method for preparing the same, and battery having the same

US12626908B2US 12626908 B2US12626908 B2US 12626908B2US-12626908-B2

Abstract

A method for preparing a swelling-inhibited silicon-carbon composite anode material with increased capacitance includes nanocrystallization of a silicon material to obtain a primary nano-silicon material in a protective environment, self-assembling the primary nano-silicon material with a first carbon source and a macromolecular polymer, and then adding a second carbon source for the self-assembly to obtain a secondary nano-silicon material with a layered structure. The method further includes granulating the secondary nano-silicon material to obtain a precursor, and sintering the precursor to obtain the silicon-carbon composite anode material. The method is simple and easy to control, and is tailored to industrial production. A battery with the silicon-carbon composite anode material on an anode electrode is also disclosed.

Inventors

Mao-Sung Chen
HONG-ZHENG LAI
Tseng-Lung Chang

Assignees

SOLIDEDGE SOLUTION INC.
HON HAI PRECISION INDUSTRY CO., LTD.

Dates

Publication Date: 20260512
Application Date: 20220428
Priority Date: 20211210

Claims (8)

1 . A method of preparing a silicon-carbon composite anode material, comprising: nanocrystallizing a silicon material in a protective environment to obtain a primary nano-silicon material, wherein the protective environment is a vacuum environment, or the protective environment is obtained by introduction of an inert gas or a solvent; self-assembling the primary nano-silicon material with a first carbon source and N-allyl-(2-ethylxanthate) propionamide in the protective environment, and then adding a second carbon source for the self-assembly to obtain a secondary nano-silicon material having a layered structure, and the N-allyl-(2-ethylxanthate) propionamide has a hydrophobic group and a hydrophilic group; granulating the secondary nano-silicon material to obtain a spherical precursor; and sintering the spherical precursor in a reducing gas or a vacuum environment under a temperature of 800° C. to 1200° C. to obtain the silicon-carbon composite anode material.
2 . The method of claim 1 , wherein the first carbon source comprises at least one of asphalt, graphite, and graphene.
3 . The method of claim 1 , wherein the second carbon source comprises at least one of carbon black, carbon nanotube, and carbon nanofiber.
4 . The method of claim 1 , wherein the inert gas comprises at least one of argon, nitrogen, and helium.
5 . The method of claim 1 , wherein the solvent comprises at least one of diethylene glycol, polyethylene glycol, propylene glycol, and dimethyl sulfoxide.
6 . The method of claim 1 , wherein the reducing gas comprises a mixture of nitrogen and hydrogen.
7 . The method of claim 1 , wherein a particle size of the primary nano-silicon material is 10 nm to 50 nm.
8 . The method of claim 1 , wherein a particle size of the spherical precursor is 5 μm to 10 μm.

Description

FIELD The subject matter herein generally relates to batteries, and more particularly, to a silicon-carbon composite anode material, a method for preparing the silicon-carbon composite anode material, and a battery comprising the silicon-carbon composite anode material. BACKGROUND Silicon is used as an anode material, and due to its advantages over graphite of low cost, being environmentally friendly, with a high specific capacity (4200 mAh g−1), a high voltage platform, and no lithium deposition on its surfaces during charging. However, the silicon material may swell considerably (˜300%) during lithiation and shrink sharply during delithiation. These repeated and severe volume changes (also called volume effect) may cause cracking and powderization of the silicon material, resulting in structural collapse and loss of electrical contact between the anode material and a current collector, reducing the cycling ability and stability of a battery. Furthermore, because of the volume effect, it is difficult for the silicon material to form a stable solid electrolyte interface (SEI) in the electrolyte. With surface destruction of the structure, new silicon is exposed on the surface to continuously form an SEI film, which may aggravate corrosion of the silicon material and reduction in capacitance. Thus, the silicon material is usually oxidized to form a silicon oxide shell, which may inhibit swelling of the silicon material. However, the conductivity of silicon oxide is low, which may slow down the transfer of charge. In addition, the cycling performance is impacted by lithium-ion consumption. BRIEF DESCRIPTION OF THE DRAWINGS Implementations of the present disclosure will now be described, by way of embodiments only, with reference to the attached figures. FIG. 1 is a flowchart of a method for preparing a silicon-carbon composite anode material according to an embodiment of the present disclosure. FIG. 2 is a diagrammatic view showing a self-assembly process of a homogenous carbon substrate, a macromolecular polymer, and a primary nano-silicon material according to an embodiment of the present disclosure. FIG. 3 is a diagrammatic view of a silicon-carbon composite anode material according to an embodiment of the present disclosure. FIG. 4 is a diagrammatic view of a battery with the silicon-carbon composite anode material according to an embodiment of the present disclosure. FIG. 5 is an XRD (X-Ray diffraction) pattern of the silicon-carbon composite anode materials prepared in Example 1 and Comparative Example 1. FIG. 6 is an SEM (scanning electron microscope) image of the silicon-carbon composite anode material prepared in Example 1. DETAILED DESCRIPTION Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by persons skill in the art. The terms used herein are only for the purpose of describing specific embodiments, and not intended to limit the embodiments of the present application. In this application, descriptions such as “first”, “second” etc. are only used for description purposes and should not be understood as indicating or implying their relative importance or implying the number of indicated technical features. Thus, a feature defined as “first” and “second” may expressly or implicitly include at least one of that features. In the description of the present application, “plurality” means more than one unless expressly and specifically defined otherwise. Some embodiments of the present application will be described in detail below with reference to the drawings. The following embodiments and features of the embodiments may be combined with each other in the absence of conflict. Referring to FIG. 1, an embodiment of the present disclosure provides a method of preparing a silicon-carbon composite anode material, the method comprises the following steps: S1: in a protective environment, nanocrystallizing a silicon material to obtain a primary nano-silicon material. The protective environment is an environment under vacuum, or the protective environment is obtained by introducing an inert gas or solvent. In some embodiments, the silicon material may be the silicon material having a particle size greater than 10 μm (semiconductor grade). The nanocrystallization includes, but is not limited to, mechanical processing, mechanical ball milling, etc. The mechanical ball milling can be dry milling or wet milling. The primary nano-silicon material can also be prepared by chemical deposition method or physical vapor deposition method, in an alkane atmosphere such as CH4 during the deposition process to form a carbon coating on the primary nano-silicon material. The carbon coating is further sintered to form a carbonization layer on the primary nano-silicon material. However, these deposition methods have high cost and are not suitable for large-scale industrial production. In some embodiments, the inert gas includes at least one of argon (Ar), nitroge