Conductive agent is to ensure that the electrode has good charge and discharge performance. It is usually added in a certain amount when making the pole piece. A large amount of conductive material plays a role in collecting microcurrent between active materials and between active materials and current collectors to reduce the contact resistance of the electrode and accelerate the movement rate of electrons. It can also effectively increase the concentration of lithium ions in the electrode material. The migration rate in the electrode thus improves the charge and discharge efficiency of the electrode.
Conductive carbon black conductive agent
Conductive carbon black is characterized by particles It has a small diameter, a particularly large specific surface area, and particularly good electrical conductivity. It can absorb and retain liquid in batteries.
Carbon black conductive agents include: acetylene carbon black,350G, carbon fiber (VGCF), carbon nanotubes (CNTs) , Ketjen black (KetjenblackEC300J, KetjenblackEC600JD, Carbon ECP, Carbon ECP600JD).
Acetylene Black (Acetylene Black): When pyrolyzed by calcium carbide method or naphtha (naphtha) Acetylene with a purity of more than 99% is obtained by decomposing and refining the by-product gas, and is carbon black obtained after continuous pyrolysis; Acetylene carbon black is one type of conductive carbon black, with high purity and good thermal conductivity , low ash content, low sulfur content, and non-absorbent surface.
Ketjen Black: High-efficiency superconducting carbon black specially used for lithium batteries. It has a branched chain shape, high purity, and particularly good conductivity. Currently, the popular Japanese Ketjen Black manufacturer on the market is JapanLION Company. In China, it is promoted and developed by Shanghai Cuike Chemical Technology Co., Ltd. Serve.
Graphite conductive agents (KS, SO) Graphite conductive agents include: KS-6, KS-15, SFG-6, SFG-15, etc.
KS-6: Large particles of graphite powder, feather-shaped, with a certain The lithium storage function is used in the positive electrode in actual production.
SFG-6: It is more suitable to be used as a conductive agent for negative electrodes, scales Shaped graphite can improve the surface properties of the negative electrode.
Graphene: Surface contact with conductive agent, best conductivity, but The requirements for dispersion are too high.
Select method
Choose differentconductive agentsfor different process conditions strong>, the following are several aspects:
1. The total cost of the battery;
2. Battery rate performance requirements;
3. Particle size and morphology of battery positive and negative active materials ;
4. Battery high and low temperature performance requirements;
5. Requirements for ion conductivity;
6. The proportion and amount of conductive agent, etc.
The most important thing about the conductive agent is its dispersion. In addition to using mechanical operations, you must also pay attention to its dispersion. Procedure (such as: the order of adding special dispersants, conductive agents, etc. in batches or portions).
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