The negative electrode material in a lithium-ion battery is the carrier of lithium ions and electrons during charging, playing a role in energy storage and release. It accounts for approximately 5%-15% of the battery cost, making it one of the most important raw materials for lithium-ion batteries.
Currently, natural/artificial graphite remains the dominant anode material for lithium batteries globally, while new anode materials such as mesophase carbon microspheres (MCMB), lithium titanate, silicon-based anodes, HC/SC, and lithium metal are also experiencing rapid growth.
As a carrier for lithium-ion intercalation, the negative electrode material of a lithium-ion battery must meet the following requirements:
1. The insertion redox potential of lithium ions in the negative electrode substrate should be as low as possible, close to the potential of metallic lithium, thereby resulting in a high input voltage for the battery;
2. A large amount of lithium in the matrix can undergo reversible insertion and extraction to obtain high capacity;
3. During the insertion/de-embedding process, the main structure of the negative electrode undergoes little or no change;
4. The change in redox potential with the insertion and extraction of Li should be as small as possible, so that the battery voltage will not change significantly and can maintain a relatively stable charging and discharging process;
5. The intercalation compound should have good electronic and ionic conductivity to reduce polarization and enable high-current charging and discharging;
6. The main material has a good surface structure, enabling it to form a good SEI with the liquid electrolyte;
7. The inserted compound exhibits good chemical stability across the entire voltage range and does not react with electrolytes after forming the SEI;
8. Lithium ions have a large diffusion coefficient in the host material, which facilitates rapid charging and discharging;
9. From a practical point of view, the materials should be economical and environmentally friendly.
The anode material for lithium-ion batteries significantly affects the initial efficiency and cycle performance of lithium-ion batteries. Future development of lithium-ion battery anode materials will focus on higher capacity, higher energy density, higher rate performance, and better cycle performance.
