Effects of lithium tungsten oxide coating on LiNi0.90Co0.05Mn0.05O2 cathode material for lithium-ion batteries

A lithium tungsten oxide (LWO) coating layer is introduced on the surface of the Ni-rich layered LiNi0.90Co0.05Mn0.05O2 (NCM) cathode material to improve the electrochemical performance such as cycle stability and rate capability. The tungsten oxide is converted to a lithium tungsten oxide by reacting with lithium residues such as LiOH and Li2CO3 on the surface of the Ni-rich layered LiNi0.90Co0.05Mn0.05O2 cathode material. The LWO layer is successfully coated on LiNi0.90Co0.05Mn0.05O2. The 0.5 wt% LWO-coated NCM exhibits excellent rate capability and cycling retention of 84.6% after 80 cycles compared to the pristine NCM (76.6% after 80 cycles). The role of the LWO layer is summarized as improving the surface stability and rate capability of the Ni-rich layered cathode material by acting as a protective layer between the electrolyte and the active material and a lithium-ion conductor.