Graphite Container for Negative Electrode Material

Silicon-carbon anode graphite containers (Graphite Containers for Silicon-Carbon Anodes) are the core high-temperature containers specifically designed for the research and production of the next-generation negative electrode material for high-energy-density lithium-ion batteries - silicon-carbon (Si-C) composites. As the key carrier throughout the entire process of silicon-carbon materials from mixing, granulation to final high-temperature sintering (Graphitization/Sintering), their performance directly determines the purity, microstructure and electrochemical properties of the silicon-carbon negative electrode. The products provided in this manual include various forms such as graphite sagger, graphite boat, and graphite box, all manufactured from ultra-high-purity isostatic pressing graphite above 99.99%. They fully meet the strict process requirements of lithium battery giants in the United States, South Korea, Japan, etc. for the next-generation negative electrode materials.

Key Preparation Process Points
Raw Material Selection: High-purity graphite with an ultra-high purity of over 99.99% is used as the raw material. For some high-end products, 99.995% (5N) grade nuclear pure graphite is adopted to ensure extremely low impurity content (Fe, Ni, Cu, S, P < 10ppb), avoiding contamination of the high-value silicon-carbon anode material.
Precision Processing: High-precision processing is carried out using a five-axis联动 CNC machining center to ensure that the key dimensions are controlled within ±0.05mm, and the surface roughness Ra ≤ 1.6μm, meeting the strict requirements of the silicon-carbon anode material for the uniformity and cleanliness of the container interior.
High-Temperature Purification and Degassing： After processing, all products need to undergo high-temperature vacuum purification treatment at 2800-3200°C to further reduce impurity content and gas emission rate (≤ 1.0 x 10⁻⁷ Pa・m³/s・kg), ensuring that no gas is released during the subsequent high-temperature sintering process and does not pollute the furnace environment and materials.
Surface Treatment (Optional)： SiC (silicon carbide) coating or PyC (pyrolytic carbon) coating can be provided according to customer requirements. The SiC coating can significantly improve the oxidation resistance and wear resistance of the container, extending its service life by 3-5 times; the PyC coating can provide better chemical inertness and avoid reactions with certain special silicon-carbon formulations.

Working Principle and Design Features
The core function of the silicon-carbon graphite container is to provide a clean, uniform, and stable reaction environment for the silicon-carbon composite material at temperatures ranging from 1000 to 2000°C, in an inert atmosphere (such as argon) or a vacuum environment.
Design Features:
Structural Optimization: Considering the volume expansion characteristics of silicon-carbon materials at high temperatures, the container is designed with appropriate wall thickness and internal space, which can not only ensure structural strength but also accommodate the expansion of the material and prevent cracking.
Temperature Uniformity: By optimizing the geometric shape, perforation, and wall thickness distribution of the container, the temperature distribution inside and on the surface of the container is ensured to be uniform (±2°C), which is the key to obtaining consistent silicon-carbon negative electrode materials with performance.
Material Selection: Isostatic pressed graphite, due to its excellent isotropic properties, becomes the preferred material for the silicon-carbon container, ensuring the dimensional stability and structural integrity of the container at high temperatures.

Precise dimension control and customized services
High-precision processing: Utilizing a five-axis CNC machining center for high-precision processing, the key dimension accuracy is controlled within ±0.05mm, and the surface roughness Ra is ≤1.6μm, ensuring that the containers can precisely match the customers' sintering furnaces.
Customization capabilities: Based on customers' DXF/STEP drawings or specific process requirements, we can provide customized design and processing services, including special shapes, sizes, internal structures, and surface treatments, to meet the individualized needs of different customers.
Rapid prototyping： With a professional R&D and processing team, we can quickly respond to customers' customization requirements. The prototype production cycle is only 7-10 days, helping customers accelerate the progress of new product development.

Mass Production of Si-C Anode Materials
Application scenarios: Large-scale production lines for high-energy-density lithium-ion batteries with silicon-carbon anode materials, used in fields such as electric vehicles (EV) and energy storage systems (ESS).
Customer challenges: Improving the batch consistency, energy density and cycle life of silicon-carbon anode materials, while reducing production costs and equipment downtime.
Our solution: Provide the SCS-9999 type silicon-carbon anode graphite crucible, manufactured with 99.99% high-purity isostatic pressure graphite, featuring excellent high-temperature stability and dimensional accuracy, which can be precisely matched with the customer's continuous or intermittent high-temperature sintering furnaces.