Improvement of electrochemical properties of LiNi0.5Mn1.5O4 spinel material by fluorine substitution

LiNi0.5Mn1.5O4−xFx (0 ≤ x ≤0.1) cathodes, synthesized by ultrasonic spray pyrolysis at 900 °C, exhibit superior structural and electrochemical properties. The samples are characterized by X-ray diffraction, scanning electron microscopy, differential scanning calorimetry, and electrochemical measurements. During Li+ extraction, LiNi0.5Mn1.5O4−xFx has a smaller lattice variation and area-specific impedance than LiNi0.5Mn1.5O4. This enhances the rate capability, especially at high C-rates. LiNi0.5Mn1.5O4−xFx also exhibits better resistance than LiNi0.5Mn1.5O4 to attack by HF.