Vacuum Drying of Flexible LiFePO₄ Electrode for Lithium Ion Battery: An Experimental Study

We reported the vacuum drying of flexible Li-ion battery electrode of LiFePO₄ coatings,deposited on Al-foil by spray painting.The influence of the drying pressure and temperature on moisture evaporation-rate of LiFePO₄ coating electrode was investigated.The results show that the pressure and temperature had a major impact.To be specific,the moisture evaporation-rate increased with an increase of temperature and/or a decrease of pressure,because of the significant increase of moisture diffusion-coefficient of LiFePO₄ electrode,estimated to be in 1.11×10⁽-9) to 1.86×10^-9 m²/s range.Depending on the pressure,the moisture activation energy was in 9.70~19.83 kJ/mol range.Henderson model was found to well describe the vacuum drying of LiFePO₄ coating.We suggest that the vacuum drying of LiFePO₄ electrode be of some technological interest in industrial production of Li-ion battery.