Modification on improving the structural stabilities and cyclic properties of Li1.2Mn0.54Ni0.13Co0.13O2 cathode materials with CePO4

A simple CePO4 modification method on Li1.2Mn0.54Ni0.13Co0.13O2 is introduced. A series of CePO4-coated Li1.2Mn0.54Ni0.13Co0.13O2 materials accompanying with PO43- anion doping were successfully synthesized via a simple wet method. XRD, SEM, HR-TEM, FE-EPMA, XPS, and electrochemical measurements were used to characterize the pristine and modified materials. The results exhibit that CePO4@ Li1.2Mn0.54Ni0.13Co0.13O2 samples showed improved structural stabilities and cyclic properties. It is because that CePO4 coating film could effectively prevent Li-rich materials from the corrosion of HF during the cycle process and restrict the side reactions over electrolyte and electrode. Also, when doping with PO43- anions, the layered structure was enhanced due to the strong bonding of PO43- anions, compared with M-O bonds (M = Ni, Mn, Co). Particularly, 3 wt.% CePO4-modified material exhibits the excellent cyclic retention of 86.9% at 100 mA g(-1) with the 100th discharge capacity of 210.7 mAh g(-1), while pristine sample exhibits a poorer cyclic retention of 76.1%. To further investigate the modification information, the distributions of elements Mn, Ni, Co, Ce, P, and O in cross section for CePO4-modified material were obtained via FE-EPMA test.