CeF3-modified LiNi1/3Co1/3Mn1/3O2 cathode material for high-voltage Li-ion batteries

A facile chemical deposition method has been adopted to prepare cerium fluoride (CeF3) surface modified LiNi1/3Co1/3Mn1/3O2 as cathode material for lithium-ion batteries. Structure analyses reveal that the surface of LiNi1/3Co1/3Mn1/3O2 particles is uniformly coated by CeF3. Electrochemical tests indicate that the optimal CeF3 content is 1 wt%. The 1 wt% CeF3-coated LiNi1/3Co1/3Mn1/3O2 can deliver a discharge capacity of 107.1 mA h g−1 even at 5 C rate, while the pristine does only 57.3 mA h g−1. Compared to the pristine, the 1 wt% CeF3-coated LiNi1/3Co1/3Mn1/3O2 exhibits the greatly enhanced capacity and cycling stability in the voltage range of 3.0-4.5 V, which suggests that the CeF3 coating has the positive effect on the high-voltage application of LiNi1/3Co1/3Mn1/3O2. According to the analyses from electrochemical impedance spectra, enhanced electrochemical performance is mainly because the stable CeF3 coating layer can prevent the HF-containing electrolyte from continuously attacking the LiNi1/3Co1/3Mn1/3O2 cathode and retard the passivating layer growth on the cathode.