1. Why must the industry upgrade silicon-carbon anodes?
The theoretical capacity of traditional graphite anodes is only 372 mAh/g, with performance already reaching its limit, making it unable to meet the high endurance demands of power batteries and high-end 3C batteries. In contrast, silicon-based materials boast a theoretical capacity of 4200 mAh/g, over 10 times that of graphite, making them the core direction for next-generation high-energy-density lithium batteries. However, pure silicon anodes suffer from two fatal shortcomings that prevent direct mass production: 1. Severe volume expansion: During lithiation/delithiation, the volume expansion can reach nearly 300%, easily causing material pulverization, electrode cracking, and a significant decline in battery cycle life; 2. Poor electrochemical performance: With extremely low intrinsic conductivity and weak fast-charging capability, the repeated breakdown and reconstruction of the SEI film continuously consumes electrolyte, reducing battery first-cycle efficiency and stability.
2. Porous Carbon: The Core Stabilizing Skeleton of Silicon-Carbon Anodes
The silicon-carbon composite route is currently the most mature high-capacity anode solution in industrialization. Lithium battery-specific porous carbon is not ordinary carbon-coated material but a three-dimensional multi-level pore skeleton that ensures the stable operation of silicon anodes, with three core functions:
01 Buffer Expansion Failure-Prevention Multi-Level Pore Channels Reserve Deformation Space, Accommodate Silicon Particle Charge-Discharge Expansion, and从根本上 Avoid Material Powdering and Electrode Cracking;
02 Construct a high-speed conductive network connecting the carbon skeleton and through-pores to establish dual channels for electrons and lithium ions, thereby reducing internal resistance and enhancing battery fast-charging performance;
03 Stabilized interface with lifespan-limited encapsulation of silicon particles reduces direct contact with the electrolyte, stabilizes the SEI film, and effectively enhances battery initial efficiency and long-cycle retention rate.
3、 Key understanding: Battery grade porous carbon ≠ ordinary activated carbon
Porous carbon for lithium batteries has extremely strict parameter requirements, requiring precise matching of pore size, pore volume, specific surface area, mechanical strength, purity, and pore connectivity. The more pores, the better. Ordinary activated carbon has a disordered pore structure, low strength, and high impurities, making it completely unsuitable for the production of silicon carbon negative electrodes. The preparation core of high-quality porous carbon relies on a dedicated lithium battery rotary furnace. Through precise carbonization and controllable activation processes, the multi-level pore structure of the silicon carbon composite system is customized to meet the performance requirements of high-end batteries.
4、 Mass production core: Empowering silicon carbon production through the entire process of rotary furnace
The entire production chain of high-performance silicon carbon negative electrode (precursor carbonization, activated pore formation, purification and grading, CVD vapor phase silicon deposition, secondary carbon coating) can rely on the integrated implementation of porous carbon carbonization/activation rotary furnace and silicon carbon dedicated CVD vapor phase deposition rotary furnace by China National Building Materials (Shaanxi) New Materials Equipment, solving the pain point of "excellent small-scale performance and poor mass production stability" in the industry.
The four core mass production advantages of the equipment
Advantage 1: Global precise temperature control: Balanced temperature field, eliminating uneven silicon deposition, pore blockage, and particle agglomeration caused by local temperature differences
Advantage 2: Dynamic and uniform rolling: The powder continuously and uniformly flips, with consistent heating and atmosphere contact, ensuring highly uniform performance of each batch of materials
Advantage 3: Safe closed-loop process: equipped with exclusive exhaust gas treatment, explosion-proof, and dust removal systems, suitable for high-risk CVD processes of silane, ensuring mass production safety
Advantage 4: Full stage adaptation: covering the entire process of small-scale, pilot, and mass production, supporting process iteration and rapid capacity scaling up
5、 Based on the perspective of industrialization, explore the development opportunities of silicon carbon anode together
Silicon materials broaden the upper limit of battery capacity, porous carbon maintains the bottom line of cycle stability, and high-precision rotary furnaces build a high line for large-scale production of silicon carbon negative electrodes
Material performance depends on design, and stable mass production depends on equipment. China National Building Materials (Shaanxi) New Materials Equipment focuses on the research and development of new energy thermal equipment, providing complete equipment solutions from the preparation of silicon carbon negative electrode porous carbon to CVD vapor deposition, helping high-performance silicon carbon materials to be scaled up, improve quality, and reduce costs.
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