Improvement of Electrochemical Performance of Li[Ni0.8Co0.15Al0.05]O₂ Cathode Materials by AlF₃ coating at Various Temperatures

A thin AlF 3 layer of ∼10 nm was uniformly coated on the particle surface of Li[Ni 0.8 Co 0.15 Al 0.05 ]O 2 . The AlF 3 coating improved cycle performance at 55, 30, and –10 °C and improved storage characteristics at 60 °C. In studies of differential capacity (d Q/ d V ) versus voltage, the AlF 3 -coated Li[Ni 0.8 Co 0.15 Al 0.05 ]O 2 showed little variation in redox peaks with cycling. Electrochemical impedance spectroscopy suggested that the AlF 3 coating played an important role in stabilizing the interface between the cathode and the electrolyte.