AlF₃-Al₂O₃ ALD Thin-Film-Coated Li_1.2Mn_0.54Co_0.13Ni_0.13O₂ Particles for Lithium-Ion Batteries: Long-Term Protection

Improving the performance of existing cathode materials of lithium-ion batteries (LIBs) through surface modification has been proven to be an effective way to improve the performance of LIBs. However, it is a challenge to use a traditional method to prepare an effective coating film, which meets the requirements of uniformity, continuity, electrochemical stability, and strong mechanical properties. In this study, an ultrathin AlF₃-Al₂O₃ film was coated on the surface of Li_1.2Mn_0.54Co_0.13Ni_0.13O₂ (LRNMC) particles by atomic layer deposition (ALD) in a fluidized bed reactor. A cathode electrolyte interphase layer mainly composed of inorganic components was formed on the surface of AlF₃-Al₂O₃-coated LRNMC during the charge/discharge cycling process, which led to the enhancement of capacity and cycling stability. In addition, the coating layer significantly increased the shelf life of the cathode particles. For LRNMC particles with one cycle of Al₂O₃ ALD and one cycle of AlF₃ ALD coatings, there was no obvious degradation of electrochemical performance after being stored for more than 1 year, indicating long-term protection of ALD films for LIB cathode particles.