Carbon nanotube lithium battery conductive agent

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Lithium batteries in the application field of carbon nanotubes: improving the conductivity of positive and negative electrodes

Conductive agents are key auxiliary materials for lithium batteries, and their main function is to improve the conductivity of positive and negative electrodes. The positive electrode active materials of lithium batteries generally have poor conductivity, which makes the electrode internal resistance high and the discharge depth insufficient, which in turn leads to low utilization of active materials and large residual capacity of the electrode.

The conductive agent plays the following roles:

1) Improve the transmission rate of electrons in the electrode and improve conductivity;

2) Improve the infiltration of the electrode into the electrolyte, increase the migration rate of lithium ions, and improve the charging and discharging efficiency and service life of the electrode;

3) When the volume of the positive electrode material changes during charging and discharging, a good conductive network is constructed to improve conductivity. At present, the mainstream conductive agents are carbon black, carbon nanotubes, conductive graphite, VGCF (vapor-grown carbon fiber) and graphene.

Compared with traditional conductive agents, carbon nanotube and graphene conductive agents have good conductivity and low dosage. Carbon black, conductive graphite and VGCF are traditional conductive agents, which form point, surface or line contact conductive networks between active materials; carbon nanotubes and graphene are new conductive electrode materials, which form line contact and surface contact conductive networks respectively. In terms of dosage, the amount of conductive agent added depends on the electrochemical system of different battery manufacturers, generally 1%-3% of the weight of the positive or negative electrode, and the amount of carbon nanotube conductive agent powder used is only 1/6-1/2 of the traditional conductive agent.

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