Improvement of High Voltage Cycling Performances of Li[Ni_(1/3)Co_(1/3)Mn_(1/3)]O_2 at 55℃ by a (NH_4)_3A1F_6 Coating

摘要

The surface of Li[Ni_(1/3)Co_(1/3)Mn_(1/3)]O_2 particles was modified by a simple dry coating with (NH_4)_3AlF_6 as a coating agent. The (NH_4)_3A1F_6-coated Li[N_(1/3)Co_(1/3)Mn_(1/3)]O_2 showed enhanced lithium-ion intercalation stability and thermal stability at 55℃ and a high cutoff voltage of 4.5 V. Electrochemical impedance spectroscopy and transmission electron microscopy showed that the (NH_4)_3A1F_6 coating on the Li[Ni_(1/3)Co_(1/3)Mn_(1/3)]O_2 particles played a key role in stabilizing the interface between the cathode and the electrolyte.