Preparation and Characterization of Fluorine and Magnesium co-doping LiNi0.8Fe0.1Al0.1O2 Cathode Materials for Lithium-Ion Batteries

Abstract With the vigorous development of new energy vehicles, cobalt in the traditional lithium-ion(Li-ion) battery industry chain is obviously in short supply. To manage this challenge, a new cobalt free cathode material Li[Ni0.8Fe0.1Al0.1]1-xMgxO2-yFy (x=0.01, y=0.01, 0.02, 0.03) with different f-doping contents (labeled Mg-1, Mg-F-1, Mg-F-2, Mg-F-3) was prepared by sol-gel method. XRD results show that the co-doping of Mg²⁺ and F⁻ reduces the mixing degree of cations and increases the lattice parameters. A small amount of Mg²⁺ and F⁻co-doping does not affect the layered structure of NFA materials. The results of SEM, EDS and elemental spectrum showed that Mg and F elements were evenly dispersed on the surface of the material and successfully doped into the crystal structure of the material. The co-doping of Mg²⁺ and F⁻ did not damage the surface of NFA primary particles. XPS results further confirmed that Mg²⁺ and F⁻were introuduced successfully into NFA materials. Compared with the original NFA material, the co-doping of Mg²⁺ and F⁻significantly improved the electrochemical performance of the pirstine material. Electrochemical results show that co-doping has the best first discharge specific capacity, first coulomb efficiency and cycle life. The first discharge specific capacity and coulomb efficiency at 0.1C were 171.8 mAh g⁻¹ and 88.1%, respectively. After 150 cycles at 0.1C, the capacity retention rate was 88.1%. This study emphasizes the broad prospects of this new material in the future cobalt free market.