In recent years, LIFEP04 has become one of the most promising positive electrode materials in the power lithium-ion battery due to low cost, high-specific capacity, safe and environmentally friendly. However, the shortcomings of the material is poor conductivity, and the capacity attenuation is quickly attenuated when the high current charge is discharged, and does not meet the needs of practical applications.It is usually improved by coating or metal ion doping. For example, in 1999, Ravet was synthesized with carbon raw material, 2002 Scrosati with a metal coating, 2003 Chiang uses Nb, Ti doping to modify it. S.phung and Y.M.chiang, etc., the un-doped LIFEP04 activation can be close to 500meV, while the activation of Doped LIFEP04 can only be 60 ~ 80Mev. The results of the application of the first principle calculation show that LIFEP04 is a semiconductor, the energy level width between the conduction band and the price is about 0.3 eV.
Accordingly, Chiang et al. Proposes a two-phase model: During the charge and discharge of the battery, the proportion of Fe3 + / Fe2 + will change, so that the LIFEP04 crystal is also varied between the P-type and N-type. During charging, the presence of Li + defects increases the content of Fe3 +, that is, the P-type component is increased; the discharge is exactly the opposite, that is, the P-type transition into an n-type.
The individual FE2 + and Fe3 + has a poor conductivity, and the FE3 + / FE2 + mixing valence form formed after doping can effectively enhance the conductivity of LIFEP04. The LIFEP04 doped according to the above method has excellent charge and discharge properties, especially large current properties, even at a current of 21.5c (3225mA ¡¤ G-1, more than 150mAh ¡¤ g-1 meter), can still be obtained. The specific capacity of 60mAh ¡¤ g-1. According to this ratio, the lithium ion battery in doping LifeP04 is used as a positive electrode can completely meet the power requirements of the electric vehicle, and even the specific power is 4000 to 10,000W ¡¤ kg ratio of 5 to 10Wh ¡¤ kg-1 super. Capacitors far exceeds the range of general lithium-ion batte Recommend: LiFePO4 Battery Manufacturer Energy storage battery Manufacturer Integrated machine energy storage battery series Manufacturer Lead lithium battery Manufacturer Outdoor Backup Battery Manufacturer Portable outdoor power supply Manufacturer Power battery Manufacturer Powerwall LiFePO4 Battery Manufacturer Battery rack Manufacturers Telecom LiFePO4 Battery Manufacturer Wall mounted battery storage Manufacturer China Lifepo4 Battery
