CNT has good electrical conductivity and the one-dimensional structure could form a continuous conductive network among the active materials of the electrodes. The electrode has greater toughness with the CNT added, and prevents the peeling phenomena incurred due to the change of material volume in charge-discharge process and prolongs the life cycles. CNT also improves the infiltration capacity of the electrolyte solution in electrode materials greatly.
Application of CNT- silicon composite materials in the anode of lithium battery
Using silicon as the anode materials of a lithium battery has very high theoretical specific capacity (4200 mAh/g). In the meantime, silicon has lower discharge voltage, which can help to have higher voltage output from the lithium-ion battery. Silicon is also very rich in reserve. However, silicon changes greatly in volume in the charge-discharge process (about 400%) so that silicon fail by pulverization quickly after several cycles and the cycling stability becomes poor. Silicon is also low in the electrical conductivity. CNT not only restrains the volume change of silicon materials in the charge-discharge process, but also is conducive to improving the transport diffusion rate of lithium ions in materials by virtue of the excellent electrical conductivity. This improves the lithium storage performance of the anode.
Application of CNT- metallic oxide composites in the anode of lithium battery
Similar to Silicon, the metallic oxide is also low in electrical conductivity and has great volume change in the charge-discharge process. CNT combines with the metallic oxide in the nanoscale to overcome the poor electrical conductivity of metallic oxide and reduce the polarization phenomenon in the charge-discharge cycles. Additionally, CNT can also provide the mechanical framework for the metallic oxide particles to avoid pulverization and capacity decline.
