Stabilizing Lithium-Rich Li 1.2 Ni 0.13 Mn 0.54 Co 0.13 O 2 Cathode via Fast-Ionic Li 3 AlF 6 Surface Coating

Improving interfacial stability and cycling performance remains a critical challenge for lithium-rich layered oxide cathodes. Surface coatings that combine high lithium-ion conductivity alongside electrochemical and chemical stability offer a promising route to address these limitations. Here, we report the application of a fast-ionic β-Li 3 AlF 6 -coating, exhibiting a wide electrochemical stability window up to 6.48 V and excellent chemical compatibility, on Li 1.2 Ni 0.13 Mn 0.54 Co 0.13 O 2 cathode via a sol–gel calcination method. Structural and electrochemical analyses reveal that the Li 3 AlF 6 -coated material exhibits improved structural stability, reduced voltage decay, and superior cycling stability compared to the noncoated material. These findings establish Li 3 AlF 6 as a compelling surface coating and highlight the potential of fluorinated coatings in stabilizing high-energy-density cathode materials.