A preparation method of a low-cost amorphous carbon-coated silicon monoxide composite material

Abstract

This invention relates to a low-cost method for preparing amorphous carbon-coated silicon suboxide composite material. By employing a high-energy ball milling process to reduce the size of the silicon suboxide material, graphene and trimesic acid are introduced in stages, followed by high-temperature carbonization to obtain the amorphous carbon-coated silicon suboxide material. This material is then used as an electrode for lithium-ion batteries, exhibiting excellent electrochemical performance. This invention establishes a method for preparing carbon-coated silicon suboxide anode materials using amorphous carbon, realizing the high-value-added utilization of silicon suboxide materials, and therefore has significant research value.

Description

Technical Field

[0001] This invention relates to a method for preparing an amorphous carbon-coated silicon suboxide anode material for lithium-ion batteries. Background Technology

[0002] Lithium-ion batteries are a type of green and clean energy storage device, characterized by high energy density, long cycle life, wide operating temperature range, light weight, no memory effect, low self-discharge, and no pollution. They are currently used in various electronic devices, large-scale grid energy storage, and new energy vehicles. Lithium-ion batteries mainly consist of electrodes, separators, and electrolytes, with electrode materials playing a crucial role in battery performance. Therefore, designing and developing electrode materials with high capacity, long cycle life, and excellent rate performance is key to promoting the rapid development of lithium-ion batteries.

[0003] Silicon suboxide-based anodes are a new type of battery anode material. They have advantages such as high specific capacity, low discharge plateau, and abundant energy storage, which can improve battery capacity and cycle life. They also have high energy density, enabling them to store more energy and have higher energy output in the same volume.

[0004] Carbon-based materials possess excellent electrical conductivity and structural stability, and are abundant and inexpensive. Carbon-coated composite materials can effectively improve the electrical conductivity of composite materials. When coated on the surface of silicon suboxide materials, carbon can not only hinder the continuous contact between the electrolyte and the electrode interface, reducing the generation of side reactions, but also alleviate the volume effect of the alloying reaction and maintain the integrity of the electrode structure. Summary of the Invention

[0005] The purpose of this invention is to provide a low-cost method for preparing amorphous carbon-coated silica-suboxide composite materials.

[0006] This invention relates to the preparation of a low-cost amorphous carbon-coated silicon suboxide composite material. The size of the silicon suboxide material is reduced by employing a high-energy ball milling process, followed by the phased introduction of graphene and trimesic acid, and high-temperature carbonization to obtain the amorphous carbon-coated silicon suboxide material. This material is then used as an electrode for lithium-ion battery anodes, exhibiting excellent electrochemical performance.

[0007] The synthesis steps include the following: First, 5 g of industrial-grade silicon suboxide produced by Xinjiang Jingshuo New Materials Co., Ltd. and 100 g of milling beads are added to a high-energy ball mill jar and milled at 400 rpm for min. -1 Submicron-sized silicon suboxide was obtained by ball milling at a certain speed for 20 hours. Next, 1 g of submicron-sized silicon suboxide, 0.02 g of graphene, and 100 g of milling beads were added to a high-energy ball mill jar and milled at 700 rpm for 20 minutes. -1The silica was ball-milled at a rotation speed of 3.5 h for 3.5 h to obtain graphene-coated silica. Finally, 0.5 g of graphene-coated silica and 0.5 g of trimesic acid were placed in an agate mortar and ground for 30 minutes to ensure uniform mixing. The mixture was then placed in a tube furnace purged with nitrogen and heated at 5 °C for 3 minutes. -1 The temperature was increased to 900℃ at a certain rate and held for 2 hours to obtain an amorphous carbon-coated silica-suboxide composite material. Attached Figure Description

[0008] Figure 1 These are SEM and TEM images of the amorphous carbon-coated silica-suboxide composite material prepared by high-energy ball milling and high-temperature carbonization using graphene and trimesic acid as carbon sources, according to the present invention. Figure 1 As can be seen from a, the size of the prepared carbon-coated silicon suboxide is between 100 nm and 500 nm; Figure 1 β-silicon suboxide is completely encapsulated within amorphous carbon, and the amorphous carbon layer is composed of amorphous carbon.

[0009] Figure 2 Thermogravimetric and Raman spectra of amorphous carbon-coated silica-substrate composite materials. (Example:) Figure 2 As shown in figure a, the carbon content in the amorphous carbon-coated silica-suboxide composite material is 14.62%. Calculations... Figure 2 The peak value of b, I of amorphous carbon-coated silica-suboxide composite material D / I G The value is 1.04, indicating that it has a high content of disordered carbon and a large number of defective structures.

[0010] Figure 3 The graph shows the electrochemical performance of the amorphous carbon-coated silicon suboxide composite material prepared in this invention as the negative electrode active material for lithium-ion batteries. Figure 3 a represents the charge-discharge curve of a coin cell assembled with lithium as the counter electrode, at 0.1 A g. -1 At the given current density, the first-cycle discharge capacity is 1509.3 mAh g. -1 The initial Coulomb efficiency was 74.2%. Figure 3 b represents amorphous carbon-coated silicon suboxide electrode material at 0.1, 0.3, 0.5, 1.0, and 1.2 A g. -1 Rate performance under current density for 10 cycles. Figure 3 c represents 0.5 A g of amorphous carbon-coated silicon suboxide electrode material. -1 The system exhibits excellent long-cycle performance at current densities, with a reversible capacity of 635.4 mAh g after 600 cycles. -1 The capacity retention rate was 77%. Detailed Implementation

[0011] Example 1 (1) Add 5 g of industrial-grade silicon suboxide produced by Xinjiang Jingshuo New Materials Co., Ltd. and 100 g of grinding balls into a high-energy ball mill jar, and mill at 400 rpm for min. -1 Ball milling at a rotation speed of 20 hours yielded submicron-sized silicon suboxide; (2) Add 1 g of submicron-sized silicon suboxide, 0.02 g of graphene and 100 g of grinding beads into a high-energy ball mill jar, and mill at 700 rpm for 1 minute. -1 Ball milling at a certain speed for 3.5 hours yielded graphene-coated silicon suboxide. (3) Place 0.5 g of graphene-coated silicon suboxide and 0.5 g of pyromellitic acid in an agate mortar and grind for 30 minutes to mix them evenly. Then place the mixture in a tube furnace purged with nitrogen and heat at 5°C for 10 minutes. -1 The temperature was increased to 900℃ at a certain rate and held for 2 hours to obtain an amorphous carbon-coated silica-suboxide composite material.

Claims

1. A method for preparing a low-cost amorphous carbon-coated silica-suboxide composite material, characterized in that, Follow these steps: (1) Add 5 g of industrial-grade silicon suboxide produced by Xinjiang Jingshuo New Materials Co., Ltd. and 100 g of grinding balls into a high-energy ball mill jar, and mill at 400 rpm for min. -1 (2) 1 g of submicron-sized silicon suboxide, 0.02 g of graphene and 100 g of milling beads were added to a high-energy ball mill jar and milled at 700 rpm for 20 hours to obtain submicron-sized silicon suboxide. -1 The graphene-coated silicon suboxide was ball-milled at a rotation speed of 3.5 h for 3.5 h to obtain graphene-coated silicon suboxide. (3) 0.5 g of graphene-coated silicon suboxide and 0.5 g of trimesic acid were placed in an agate mortar and ground for 30 h to mix them evenly. Then the mixture was placed in a tube furnace with nitrogen gas introduced into it and ground at 5 ° C for 30 min. -1 The temperature was increased to 900℃ at a certain rate and held for 2 hours to obtain an amorphous carbon-coated silica-suboxide composite material.

2. According to the preparation method described in the claim, the resulting amorphous carbon-coated silicon suboxide composite material can be used as a negative electrode material for lithium-ion batteries.

Images